When do I need to worry about a course deviation indicator reverse sensing?

On this approach plate, which was talked about here, why is the back course on two different sides (one is shaded on the left, one is shaded on the right)?

The 108.5 IPKN localizer is there only to mark safe path out for missed approach procedure and is intended to be flown outbound, so it has the signal swapped so it indicates normally when flown outbound.

  How does a front course and a back course affect your CDI settings?

It does not affect settings of CDI at all, because ILS does not take the OBS course into account. It indicates left when it senses more of the left signal and right if it senses more of the right signal, independent of anything else.

What it affects is:

The left signal is on the left when flying the normal direction and this applies both before and after the transmitter. So when you fly in opposite direction, the left signal is on the right from your point of view, causing the reverse sensing.
With HSI you can compensate for it by selecting the normal course in the OBS. The instrument then still senses the same, but the instrument is now upside down, negating the reverse sensing.

  Are there any difference between these two CDIs?

No, since these are both CDIs.

There is a difference if you have HSI:

The difference between CDI and HSI is that on CDI the needle always moves left-right, indicating whether your position is left or right of the selected radial (via OBS for VOR, but fixed for ILS) independent on direction you are flying. So if you are actually flying the opposite direction, you must steer the other way.

In contrast the inner part of HSI rotates with compass, always pointing the arrow in the selected direction. This has two advantages:

you see how your direction of flight relates to the selected heading and
when you are flying in the opposite direction (backcourse), the needle is upside-down, negating the reverse sensing.

  And also, why is it labeled a VOR receiver?

Because it is (also) used to display VOR signal. Both CDI (where the needle always moves left-right) and HSI (where the inner part with the needle rotates with compass) are VOR indicators.

Note that almost always the same tuner is used to receive VOR and ILS signals and the same instrument is used to display them though the processing logic is different (VOR detects phase while ILS detects differences in the depth of modulation from the two signals).


Which are the advantages of low pressure levels during flight? (i.e during cruise flight in a commercial aircraft)

You want the lowest pressure that can be tolerated by most of the population for the purpose of maintaining adequate blood oxygen levels, which is generally considered to be 8000 ft above sea level. At 8000 ft, someone with degraded lung function, like a smoker, is effectively at 10000 ft plus and is already at the threshold of having marginal blood oxygen for peak brain function.

At 40000 ft this requires a pressure differential of a little over 8 psi between the interior and exterior and you build the pressure hull to that and no more (it's a certification requirement).  As per min's comment this is partly to keep from having to make the pressure hull any stronger than it needs to be (every pound over the minimum is non-revenue ballast) and also to minimize engine bleed demand, which can be thought of as lost energy being used to keep the balloon of the pressure hull inflated instead of making thrust.  So, bottom line is it would be better for the airplane, both structurally and from an energy use standpoint, to operate with lower pressure differential and higher cabin altitude, but now the crew would have to start using supplemental oxygen and more people in the back would be getting sick.

The 787, because of its carbon fuselage, is able to go with a higher differential structurally, and its electric-pump pressurization system is a bit more efficient than taking bleed air directly, so Boeing had the option to certify to a higher differential pressure, 9 psi, which gives a 6000 ft cabin at service ceiling.  They could have used 8 psi and just shaved off more weight and used slightly lighter air pumps, but instead they increased the differential.  This was done mostly as a cabin comfort sales feature and was thought of as a bigger sales benefit than going with the weight saving route.


How does a runway inspection radar work?

Looking at their patent it appears it uses a multi spectrum system (radar & electro optical) to track all object: birds, aircraft, and FOD.

It uses a radar to detect objects

  The potential foreign object source identifier subsystem preferably includes potential foreign object source detectors such as a tower-mounted millimeter wave sensor (MWS) detector

And a specialized light sensor to determine the makeup of the object

  FOD identification functionality may be added to the FOD detectors, such as functionality which identifies the material which constitutes the FOD. Remote spectrometry functionality, such as that used in mineral prospecting satellites, may be employed for this purpose.

A neat function too is the ability to determine the where the FOD came from and send pictures of the FOD and the offending source to airport officials

  The ascription output may be presented to an airport official in an airport control center on a display console which may show on a first portion  of a screen, an image of the detected FOD and its location, both preferably in a zoomable format, along with a time stamp, and on a second portion of the screen, an image or other representation of a most probable source of the detected FOD, preferably in a zoomable format, along with its time stamp.

It appears it also fuses sensor data with aviation data to augment it's determination

  flight database data indicating recent aircraft movements and optical identification data indicating vehicle movements is supplied to data fusion functionality which also receives ASMGCS data and weather data and interfaces

If it works as advertised it not only replaces visual inspection but also provides realtime feedback for bird control and communicating with aircraft falling apart.


Why do oblique-wing aircraft suffer from significant aerodynamic cross-coupling?

With the wing swept forward, a positive lift force on that wing will bend the wing upward and locally increase the angle of attack, especially to the outboard of a wing. The same thing happens on the wing swept backwards, only an upward deflection from lift force will reduce the local angle of attack, likewise to the greatest extent toward the wing tip where it is deflected upward the most. One wing will end up generating more lift than the other, which will require a rolling input from the aileron to cancel out. One could attempt to balance this out with different twist profiles of each wing, but that would only solve the issue in one g flight.

When, for example, the elevator is deflected to induce a positive pitching moment, the angle of attack on the wing increases and lift force increases. The increased lift generates an increased deflection of the wing. However, as outlined above, the impact on the local angle of attack due to that increased deflection is opposite between the left and right wings. This produces a coupled roll effect.

Finally, the asymmetric lift and therefore induced drag, in addition to the use the ailerons to counter this rolling tendency, will produce adverse yaw. To eliminate the sideslip you would need to use substantial rudder input, or a bank in the opposite direction of the adverse yaw induced sideslip.

Edit:

For a really simple visualization of the wing deflection inducing a local angle of attack change, take a piece of paper and hold it flat in the air in front of you, with the long edge facing you but turned away by 45 degrees (imagine you are looking at the leading edge of a 45 degree swept wing).  Bend the short end of the paper sheet that is farthest from you (the wing 'tip') upward. Your perspective is aligned with the freestream aerodynamic flow, and by bending the tip upwards you can now see the top of the outboard wing. For a normal rear swept wing this produces washout and unloads the outboard wing. Now imagine the short end of the paper sheet that is closest to you is the wing tip. Hold the wing 'root' fixed and bend the new wing tip up. The upward deflection increases the local angle of attack at the wing tip, rather than decreasing it as before for the rear swept wing.

As an aside, this is also the reason why forward swept wings are often aeroelastically unstable. An increase in the lift force produces more lift force due to the deflection, a positive feedback that can much more rapidly lead to divergent flutter!


What makes airplanes pitch up during landing?

The change in pitch during the landing is called the flare and it is controlled by the pilot (or autopilot for an autoland) using the elevators (i.e. pulling on the yoke). From the Boeing 737 NG FCTM (6.10 Landing):

  When the threshold passes under the airplane nose and out of sight, shift the visual
  sighting point to the far end of the runway. Shifting the visual sighting point assists
  in controlling the pitch attitude during the flare. Maintaining a constant airspeed
  and descent rate assists in determining the flare point. Initiate the flare when the
  main gear is approximately 20 feet above the runway by increasing pitch attitude
  approximately 2° - 3°. This slows the rate of descent.

  After the flare is initiated, smoothly retard the thrust levers to idle, and make small
  pitch attitude adjustments to maintain the desired descent rate to the runway.
  Ideally, main gear touchdown should occur simultaneously with thrust levers
  reaching idle. A smooth thrust reduction to idle also assists in controlling the
  natural nose-down pitch change associated with thrust reduction. Hold sufficient
  back pressure on the control column to keep the pitch attitude constant. A
  touchdown attitude as depicted in the figure below is normal with an airspeed of
  approximately VREF plus any gust correction.

The flaps are set much earlier during the approach phase. They are not changed any more during the landing phase.


What is the current status of the deployment of RNP 1 and RNP 2 airspaces and approaches in Europe?

A few years ago, each country in Europe had its own authority and plan for air traffic management. But this little continent is today the most busy in regard to air traffic, and without action, growth is nearly impossible. Thus countries have agreed to build a "single sky" system, the initiative is known as SESAR (here is the master plan). Those actions are part of the "Pilot Common Project" (PCP), sub-projects include "ATM functionalities 1" (AF 1). From the master plan:

  Enhanced terminal airspace using RNP-based operations consists of the
  implementation of environmentally friendly procedures for
  arrival/departure and approach using PBN in high-density TMAs, e.g.
  RNP 1 standard instrument departures and arrivals (RNP 1 SIDs and
  STARs).

and:

  Enhanced terminal airspace using RNP-based operations with RNP 1 SIDs,
  STARs and transitions (using radius to a fix-RF) and RNP APCH (lateral
  navigation/vertical navigation (LNAV/VNAV)) is planned for
  synchronised deployment at the 24 busiest airports in Europe by 1
  January 2024

The schedule:

The current implementation status for the 24 airports selected (from SESAR monitoring view):

While initially planned for 2018, RNP operational use is now planned for January 2024. Out of the 24 high density TMA (equivalent of FAA TCA), two are already ready (and RNP 1 is already operational for helicopter low routes in Oslo -- this early use is likely for environmental reasons).

I made this question a community question, it is open to improvement by anyone.


Flying coworkers with a commercial pilot's license (USA/FAA)

Since you have a CPL, you can receive compensation for flying.

Your question and concern is over the means of reimbursement which may have implications beyond that of the FAA. That said, I'm not a lawyer and I would suggest your company consult with one and establish a policy. Most companies I've worked for prohibit personal flying incidental to the business specifically due to liability concerns.

To avoid confusion, I would stick with option 1) as that makes it clear it's your choice to fly and not that of the business. If the company rents the plane, it may expose the company to additional FAA regulation as well as liability and tax implications.

As a point of explanation; before I retired from the USAF it was not uncommon to use private aircraft to travel on TDY (Temporary Duty - the military version of a business trip). The rules under AF regs and the Joint Travel Regulations (DoD) allowed you to travel using a privately owned aircraft or a rented aircraft. IIRC the AF required a CPL/IR and a total of 200 hrs. The rules also specified what expenses were allowed and how they were to be reimbursed.

If you used your own aircraft, it was classified as POV (Personally Owned Vehicle) travel. That was no different than driving your own car on the trip. In that case you were reimbursed at the POV mileage rate. That rate when I was in was actually less than the IRS allowed mileage rate and wouldn't come close to covering the cost. It also didn't matter if anyone was travelling with you, be it a coworker or family member.

If you rented an aircraft, it was treated the same as if the company allowed you to rent a car to make the trip. You were reimbursed your actual rental cost (wet) up to the cost airfare for the trip for all persons travelling together. What that meant was that if you traveled alone, the reimbursement was typically less than the rental cost (say \$400 for airfare vs \$600 rental). If you had two or more travelers, the airfare typically exceeded the rental cost and the entire rental was covered. The limitation was that only coworkers on travel orders counted towards the reimbursement.


What is the function of the scissors link in helicopter flight controls?

the scissor link ensures the upper swashplate rotates with the rotor blades (and the lower with the body) while ensuring enough movement for the plate to control the craft (tilting and up and down).

(http://en.wikipedia.org/wiki/File:Robinson-Rotorhead.jpg)

  To keep the stationary swashplate from rotating with the rotor, a scissor mechanism is added. The scissor connects the swashplate to the fuselage. The scissor consists of 2 parts which are connected by a hinge. One end is connected to the helicopter using a hinge, while the other is connected using a ball joint. This means that the swashplate can move freely up and down, and can freely tilt in any direction, but can't rotate around the mast.[source]

this is needed because the control linkage is typically attached with balljoints which would otherwise allow for too much relative movement.


What is the angle of Incidence of wing of Airbus A320?

The A320 wing is a complex design with no clear mention of chord or angle of incidence, as it is not topical to the operation of the aircraft. The wing is swept back, has variable symmetry from root to tip , as some say twisted. This info is not shared by Airbus.


How are north and east compents of the wind calculated, given a wind speed and direction?

Simply use trigonometric functions:

$V_{north} = -V \cos \theta $

$V_{east} = -V \sin \theta $

$V$ is wind speed

$\theta$ is wind direction clockwise relative to the true north (e.g. east is 90°). Note that wind direction is typically given as the direction from which the wind is blowing. If you have a wind direction that in given into the direction of air flow, then you should remove the minus signs from the formula's above.


Which organizations and individuals are invited for a review before the first flight of a new aircraft?

The level of contribution is your potential contribution to the particular flight test.

There are several levels:

Who gets a place in the aircraft? This should be test pilot(s) and maybe an engineer or two if the aircraft has enough space to carry them.
Who gets a place in the control room? This is the flight test engineer and systems engineers (experts for the engine, the control system, the landing gear and so on), also engineers familiar with the aerodynamics and flight mechanics of the plane. Generally, the number of people in the room should be kept small.
Who gets a place at the ceremony and press conference afterwards? Now only the test pilot is invited, and maybe the flight test engineer and the development project leader, but otherwise you will find mostly board members and PR people at the press conference. The engineers will be busy clearing the buffet at this time, anyway.

The responsibility to select who will get into the control room rests primarily with the flight test engineer and the test pilot. However, the whole aircraft development will already be observed by the FAA. From the FAA and Industry Guide to Aircraft Certification about the implementation of the planned flight test:

  During this Phase the Applicant and FAA work closely in managing, refining, and achieving their agreed PSCP to ensure that all agreed upon product specific certification requirements are met.

PSCP = Project Specific Certification Plan

Normally, FAA engineers are reviewing the planning, but do not get into the details such as who exactly will participate in the first flight. The company developing the aircraft prepares a plan and FAA will approve it without much hassle if the company has a record of conducting flight tests. If the company is a startup, however, closer scrutiny must be expected.


Why would a turboprop be better than an internal combustion engine for a UAV?

Mostly reliability, and weight.  A TP is far more reliable than a piston engine, and much lighter.  The TP's lighter installed weight makes up some for its higher specific fuel consumption.
You would use a piston engine to get operating costs as low as possible, and you're willing to live with lower reliability (you're forced to use turbocharging or supercharging, which reduces reliability further), and one of the new turbo-diesels would be the best option in that case (close to half the fuel burn of a TP and able to run on kerosene, or diesel perhaps).


Can multiple airfields be in the same airspace?

When there are several airports close to each other, a single ATC, formally known as Terminal Control Center may service all airports. The airspace boundaries and altitudes assigned to a Terminal Control Center, which vary widely from airport to airport, are based on factors such as traffic flows, neighboring airports and terrain.

London Terminal Control Centre is an example of a large and complex Terminal Control Center. Its service area is up to 20,000 feet and out to 100 nautical miles. It controls:

six London airports
one Royal Air Force station
provides en-route services to other aircraft that entered its airspace

Another example can be found with Berlin-Tegel and Berlin-Schönefeld, which have adjacent control zones that share a common boundary west to east and have an overlaying class C TMA airspace up to FL100. Both airports share the same TMA controller/approach sector:BREMEN RADAR Approach:    119.62

Image Source: www.skyvector.com

FAA is implementing a new airspace system which will increase efficiencies at metropolitan areas with complex air traffic flows. This system, known as Next Generation Air Transportation System is introducing the concept of a metroplex:

  In FAA parlance, metroplex refers to a system of airports in close
  proximity and their shared airspace that serve one or more major
  cities. A metroplex has at least one, but often two or more major
  commercial airports.


Can jet engines be used for VTOL civilian aircraft?

Can?

Of course they can.

Does it make sense?

No, it does not.

A VTOL needs thrust at least equal to its weight. That is much more than a fixed-wing aircraft (HTOL) needs. Airliners have lift-to-drag ratio around 18–20. That is in clean configuration; in landing configuration it might be about half (~10) and we need twice as much thrust in case an engine fails, so around ¼ weight. So a VTOL would need 4 times as much thrust as a HTOL.

Likely more, because the craft would still have to be capable of reasonably controlled landing in case of engine failure. And while rotorcraft can do that by autorotation and pilot of Harrier or F-35B can simply eject, jet-powered civilian VTOL would only have the remaining engines for it.

Now fortunately thrust and power are only indirectly related. To create thrust, force must be applied to the air. This force accelerates air, giving it some momentum and some kinetic energy. Thrust is (change of) momentum per time and momentum is mass time velocity while power is (change of) energy per time and energy is ½ mass times speed squared.

So we can produce a lot of thrust with little power by accelerating a lot of air by a little. Which means large propeller: a rotor. That's how helicopters get enough lift/thrust with reasonably small engine.

Unfortunately rotors are not very practical for flying fast. One would also be rather difficult to tilt. That's why V-22 Osprey and Augusta-Westland AW603 use a compromise that is somewhere between; large enough to still have good efficiency in hover and small enough to be possible to tilt.

What would definitely not be efficient for hover is a jet though. Jets are small and can't affect that much air; what they can is accelerate it a lot. That is necessary for flying fast, but it is terribly inefficient when flying slowly.

Military jets don't care. They want so powerful engine to fly very fast anyway and they don't care for efficiency much as decisive edge in combat is worth a lot of money. But for civilian transport the small advantage of being able to land closer to destination would not outweigh the disadvantage of being several times more expensive to operate. Flying the long distance with HTOL to a nearby airport and, if the destination is not reachable by car, hiring a helicopter just for the final part of the trip ends up being a lot cheaper.


During a turn, will slip necessarily lead to altitude lost?

Think of a slip or skid that the aircraft is flying sideways (referred to as uncoordinated).  This does increase drag, and therefore it requires either more power, or given sufficient speed, increased pitch to maintain altitude compared to flying straight through the air in coordinated flight.

A "skid" is when the aircraft nose is pointed inside a turn where the pilot feels centrifugal force outside the turn, like in a skidding car.  In a slip, the nose is pointed outside the turn whereby the pilot feels a force of falling down into the turn.  In straight flight, whether the nose is pointed left or right, uncoordinated flight is called a slip either way: a forward slip for losing altitude, and a side slip for landing.


Well you’ll have to comply with the terms of §61.73 in order to convert your military pilot ratings over to civilian pilot certificates and ratings. You would also need to obtain a logbook endorsement to operate a complex and high-performance airplane legally under the FAA’s rules.  This really should not be challenging for you.  If you really want to rent a twin i.e. a Cessna 310, a Diamond DA 42, etc.,  I would approach your FBO and ask to do a check out in the aircraft that you wish to rent.  The FBO instructor can include both the complex, and if necessary, a high-performance logbook endorsement along with the training.  I don’t know how many hours total that you have - I assume it’s somewhere in the order of 200 or so hours, which s typical of UPT grads - but FBOs may have additional minimum hour requirements to rent said aircraft.  They may also have to consult with their insurance policies to see if such a thing as feasible given how little time you have on light twin airplanes.

Keep in mind here that while you have time in real 'high performance' airplanes, GA aircraft are going to handle differently than what you’d have expected. This is particularly true of light twins which are going to be a lot more treacherous in the event of an engine failure than a centerline thrust jet like a T-38 would be.  I’ve worked as a CFI in a couple of FBOs now and have had the opportunity to check out a number of military personnel on light GA aircraft.  Out of all the people that come through those places, the highest number of accidents on smaller GA aircraft for rent were caused by airline pilots and military pilots simply because they are not used to the feel and control characteristics of smaller, lighter aircraft.  A guy can have 1000 hours in F-22s and still struggle to land a Cessna 172 because the handling characteristics are so different.   Said check out may take several hours both to get familiarized with the handling characteristics of the airplane as well as become familiar with the avionics and operation within the NAS as a civilian pilot.


Why does flight training usually start with (unsafe?) propeller planes and not with (safer?) jets?

Light Propeller Aircraft, if flown within their design limits, are just as safe as jets. If you do a proper and thorough daily inspection, you are far less likely to suffer any form of mechanical failure in the air. In saying this, the majority of all crashes, be it in a Jet Powered Airliner or a Propeller Driven Light Aircraft are caused due to pilot error.

You start out learning in a light single as:

They are lighter, and slower and can usually take the beating handed out by inexperienced pilots, this being:

Hard landings
Slipping onto the runway
Just hammering the day lights out of the engine.

Jet Aircraft are extremely expensive, and generally fairly heavy. Inexperienced pilots generally pay AU$80,000 for a Commercial Pilot License (In Australia) which qualifies you to fly single engine aircraft not over 5,700kg under the VFR by day. This is an absolute, level entry qualification looking for a job (most people will find that they at least also need a night VFR rating or a MECIR), so to add the cost of doing training in a jet on top of that, even if it is just for PPL, will be massive.
Jet Aircraft will be insured to be flown by pilots who have an amount of total experience and experience on aircraft/engine type. So, again, unless you're willing to pay the massive excess and premiums to be put on the insurance, you're going to have to fly a prop.

Now, you have identified that a lot of crashes are light singles (i.e. Cessna). This is because generally, these aircraft are not flown with the same discipline as a Jet Aircraft. Also, the pilots flying them are generally lower hour pilots who do not have as much experience (again, this is a generalisation, not an exact figure of the total community).

As for starting in a Jet, I honestly doubt that there is any flight school on the planet that will allow you to start training in a Jet (Even Fighter Jet pilots start out flying tiny little single engine aircraft).


Why have different departure hall and arrival hall locations?

I'm not sure if 'most' airports have this design. I've seen both cases (i.e. departures below arrivals and the other way around). Atleast for small airports, a few reasons come to mind for having departures above arrivals:

If arrivals is on ground floor, the baggage can come easily from the aircraft. This reduces complexity, especially in small airports.
Most of the aircraft are boarded using jet bridge- makes sense if they are boarded from first floor (or above); of course, jet bridges can also be used for disembarking, so this is questionable.
The upper floor offers a good view to enjoy while shopping or eating. This maybe the reason as more time is spent in departure. Also, if the arrival is in ground floor, one can simply 'walk out' as no checks are there (international flights are a different case).

None of these arguments are convincing, I guess.


Will it be more efficient if airplanes flap like birds?

In short, the answer is No. For many centuries, many proto-aeronautical engineers believed that the secret to manned flight would be found in complex flying machines that mimicked the flapping techniques of birds. These ornithopter designs were doomed from the start.

Aside from the obvious issues involving strong, rigid, durable, and light materials, there are tremendously complex psycho-muscular factors involved in biological flight mechanics that are impossible to duplicate with machinery. A bird has the benefit of nerve endings all over its body which provide immediate and intimate feedback of every minute shift and change. Additionally, the bird has fine motor control over its flight surfaces to a much greater degree than any aircraft can realistically replicate, and all at the speed of thought.
The good news is, efficiency can be relative. While the deft flight of a bird can be graceful, beautiful, and evolutionarily effective for its avian lifestyle, it will certainly never accomplish a trans-Pacific trip at 500 knots. Mankind has learned a lot from watching our feathered neighbors, but ultimately, our journey among the clouds lies along a different path from theirs.
That said, some small drone applications show promising possibilities for mimicking insect wings, so mother nature may still have a few more tricks to teach us.


What is the response time of Pulse Doppler Radar?

As Simon alluded, the aircraft's speed (example given Mach 1, approx. 340 m/s) is basically one-millionth the speed of the radar energy (traveling at near-light speed, or 300,000,000 m/s).  It's a non-factor.

Ideally, if you want to radar detect something (water droplets, for instance), the detected object needs to be bigger than one quarter-wavelength of the signal you are bouncing against it.  This alone dictates that the weather radar should operate in the microwave range, typically 8-12 GHz (quarter-wavelength approx. 6-10mm) for most systems.

Radar signals are sent out in pulses a few μs wide.  The pulse frequency is determined by how far out you are scanning.  More distant weather requires a longer "wait" time before a second pulse is sent out.  For instance, a pulse detecting weather 5km out will return about 35μs later (10000m round trip divided by the speed of light), but typically systems scan much further.  100Hz (pulses per second) pulse repetition frequency is not uncommon (i.e. every 10ms).  This is good enough to provide location only.  Pulse-Doppler radars provide an understanding of object movement (i.e. wind speed and direction) as well as location.

We also need to take into account the antenna scan time.  Because the radar signal only returns objects directly in front of the where the antenna is pointing, the antenna needs to be moved around so as to pick up a greater area, and so the scan time is largely affected by the scan pattern.  (Aircraft pitch/roll is also accounted for by most weather radar systems, though depending on the gyros, it is not uncommon for the radar to paint the ground momentarily during a maneuver.)  The Honeywell RDR 2100 takes 3-4 whole seconds to perform a full left-to-right scan (typically 90 degrees or more).

Scan time is also affected by the beam width.  Smaller antennas cannot focus as well as larger antennas, and so will produce a larger beam width, requiring fewer scans to produce a complete picture, at the expense of resolution.

Transferring all this weather data around takes additional time.  Commercial aircraft systems do this over an ARINC 708 data bus at 1mbit/s.  Range data, intensity, antenna azimuth/elevation, transmitter gain, information is all sent to be processed and displayed.  Higher resolutions will take longer to "paint" the screen than lower resolutions.  The actual data transfer time and display processing time is negligible, because your cockpit indicator might only have a refresh rate of around 60Hz, or a full screen update every 17ms, with a pixel response time less than 5ms.  For reference, this is the same refresh rate as a typical flat screen TV.

All told, from the time a radar pulse is sent out, detects weather, returns, is processed, and displayed on the screen, the time elapsed is typically no better than a half second, and typically longer.


How do pilots of small planes know where to move people?

Depending on the airline, and the size of the aircraft, the Weight and Balance calculations for each flight are either done by the pilots, or by the Flight Operations, Load Department.

If it is done by the pilots, they will receive the loading information which contains the weight and location of all passengers, cargo, and fuel. They then calculate manually, or by using software, the exact center of gravity.

If done by the Load Department, the center of gravity information will be communicated by radio or ACARS datalink.

It is not unusual to require a last minute seating or cargo change in order to ensure the aircraft is within the proper center of gravity limits for takeoff.


Why do different sites list different lengths of the lower deck bulk cargo compartment for the A330-300?

Some airlines have different specs. I can't comment on the examples you've given but one example I have encountered is on the A340-300.

The airline I worked for had conventional LD3 loading where the cans were loaded in pairs but for a while we had an A340 leased in from Swiss or Sabena (cant really remember which as it was more than 10 years ago) which had an additional LD3 position on the centreline of the aircraft in the space that would usually be available for bulk loading.

On thing which could affect the size of the bulk compartment is the location and number of toilets on the passenger deck. The plumbing usually lives under the floor.

Note the airbus site mentions that dimensions are approximate.


What are these light like panels on the overhead bins of Boeing 737?

They are indeed emergency cabin lighting. See, for instance, this photo of a similarly configured 737 interior.

(Łukasz Stawiarz - JetPhotos.net)


How often do jet-liners have touch and go landings?

Quite rare.

An approach abort that results in touchdown is called a "balked landing" and generally happens when you've started the landing transition, reducing power and starting the flare, where you are in a "low energy state" (speed decelerating below Vref and engines going to idle) at the time you make the go-around decision.  It's considered a high(er) risk maneuver like high speed rejects on takeoff, because at that point you are likely going to touch down, however briefly, whether you want to or not.

Normal missed approach go-arounds happen mostly because of weather where the runway environment wasn't visible at minimums, and maybe occasionally from a runway incursion that is noticed early, or something like a report of a flock of birds in the way, which would be most of those 1-3 per 1000 landings.  They happen at at least a hundred or couple hundred feet and usually don't involve actually touching down.

A balked landing will generally only be for something like a runway incursion at the last second, leaving you with a situation where landing and rolling out is obviously more dangerous than going around because you are probably going to hit something on the runway, and they are pretty rare events.  Balked landings are usually special maneuver covered in the initial type course and may be included in recurrent training.


Is this contrail from an airplane or a rocket?

I am pretty sure it is an aircraft.

When aircraft fly straight towards you they can appear like rockets. The contrail is distorted by winds in the upper airspace. Yesterday there were a lot of cirrus fibratus and cirrus uncinus in the upper atmosphere (at least above Frankfurt, and we are in the same weather system at the moment), and when aircraft fly through them the contrails typically wobble like in your picture.

Now, which aircraft was it?

The aircraft visible on the picture is not flying in sunlight anymore, but most of its contrail still is. It also just made a turn.

On the eleventh of April, sunset in Leiden was at 20:33 local time (18:33 UTC), setting in a bearing of 285 degrees.

Flightradar24 show this DHL Airbus A330 descending from FL 390. I would estimate that this picture was taken at 20:36 local time, perhaps a bit later. The turn is clearly visible on the picture and on FR24. The contrail matches that of a large twin engine. (my first guess was a 777, an A330 has a similar contrail. It is definitely not a 747).

A comparison picture created by ymb1 shows the shadow/lighted parts of the contrail highlighted, contrasted with the terminator on the map.


What does "Raven" [phonetic] means when used by ATC?

RAVNN (Pronounced Raven) is the name  of a waypoint in Maryland. From the FAA Fixes / Waypoints directory

  RAVNN MARYLAND BAL*C*174.00/22.98 OTT*C*070.89/12.17
  ENO*C*250.66/53.40 DCA*D*106.56 38-48-15.9900N 076-31-04.9100W

38°48'15.9900N 76°31'04.9100W(Google Maps link) is east of Washington.


How can an aircraft’s maximum design operating speed be greater than its never-exceed speed?

Maximum design operating speed means "we calculated the aircraft will break apart at that speed". It's obviously higher than the never-exceed speed, which means "you can safely operate the aircraft up to that speed".

Key here is the word "design". It always means something along the lines of "we calculated it to break at that load, please never try". The quotient of design load and maximum expected/allowed load is called safety factor. In this case, the safety factor is 1.1.


After a crash, does the information stored on flight recorders have expiration dates?

Everything will expire one day, including our Sun. Flight recorders are no exception.

Older flight recorders used magnetic tapes. They used to work like any other tape recorder. At present, solid-state memory boards are used. These are considered much more reliable than magnetic tapes, because no moving parts are involved like magnetic tapes.

Data from both recorders is stored on stacked memory boards inside the crash-survivable memory unit (CSMU). A CSMU is:

  ... is collectively the solid-state memory chips and a hardened metal
  container filled with specially designed heat insulating material. It
  is this container that provides the survivability, for it is able to
  withstand massive crushing loads, intense heat, and exceptionally high
  G forces, all of which is proven by crash survivability testing.

Image Source

You can see that the memory boards are inside stainless steel shell, which is designed to withstand the crash. Although there is a limit of writes on solid state memory, after a crash there are no more writes.

When the FDRs/CVRs are recovered from a crash scene, there are various methods to retrieve data, depending on the condition of flight recorders. This process can take weeks or months to complete.

Further reading: How Black Boxes Work


Why keep the doors open for aircraft in boneyards?

Scrapped aircraft are often cannibalized for parts, it's possible that the parts that were needed from this specific aircraft were the doors.

The photo provided in the question points to Victorville  boneyard, and some detective work using the partially visible registration indicates the 747 in the picture to be G-BNLU. Some digging on the reg shows us it was withdrawn in 2014

  Withdrawn British Airways Boeing 747-436 G-BNLU positioned Cardiff-Wales – Victorville this morning as BA9156.

It seems that at various times there have been 7 BA 747's stored at victorville

  747-400s; G-BNLA, B, C, D, G, H, U

And at least one has visited Victorville for a refit

  I was on airliners.net reading some posts/threads and I read one: G-BNLV is back from the desert!!

(Both above quotes from this thread)

Which lends weight to my original assertion of cannibalization, however nothing concrete as to whether U provided new doors to V.


What's the aisle width of long range business jet?

Based on this cabin layout of a Gulfstream G500 found on flexjet.com, I measured the aisle width at various places:

The total width is given as 7' 11'' = 241.3cm. The aisle width at the marked positions is then:

63cm (2' 1'')
68cm (2' 3'')
44cm (1' 5'')
51cm (1' 8'')
46cm (1' 6'')
57cm (1' 10'')
50cm (1' 8'')

This would give an average of 54cm (1' 9'') over the measured positions.

Interestingly, the narrowest part (44cm) is less than the FAA minimum for transport category aircraft with more than 10 seats (Is there any limit on how narrow aisles can be?), which would be 20in = 50.8cm.


Is data approval by DER/DAR still required under new FAR part 23?

It's not entirely clear how the process will work. The FAA hasn't updated AC 23-17C in response to the rule changes. I also haven't seen any discussion of changes to Production Certificates.

That said, Part 23 is still "AIRWORTHINESS STANDARDS: NORMAL CATEGORY AIRPLANES"
and there hasn't been any change to Part 21, so it appears that there still will be Type Certificates, and per 21.20 you stll need to show compliance to the relevant standards, which for normal Category is Part 23.

The big change to Part 23 is that it is more performance based instead of design based (what it must do, instead of how to do it).  So the actual means of showing compliance will need to change. I don't see DERs and DARs going away with respect to Part 23. I do expect that what they review and how they do it will likely change.

To your point, LSA receive a Special Airworthiness Certificate (based on ASTM Concensus Standards), as opposed to a Type Certificate defined in Part 21.21.


What are the FAA regulations concerning controlled descent of a light payload?

The FAA FAR says the following on the matter,

Sec. 91.15
Dropping objects.
No pilot in command of a civil aircraft may allow any object to be dropped from that aircraft in flight that creates a hazard to persons or property. However, this section does not prohibit the dropping of any object if reasonable precautions are taken to avoid injury or damage to persons or property.

As long as you take precautions not to hit anything you are ok. All things considered you are somewhat at the mercy of the FAA here, if something were to go wrong it would most likely be considered your fault.
After some looking around there are some other things to consider. Since you are using Magnus Force Cylinders to control the decent depending on how you look at it these can be considered a "Parachute" by the FAA definition

Parachute: means a device used or intended to be used to retard the fall of a body or object through the air.

Likewise what you are doing may also be considered a "Parachute Drop"

Parachute Drop: means the descent of an object to the surface from an aircraft in flight when a parachute is used or intended to be used during all or part of that descent.

Another interesting point is that from 100,000 ft you will be busting through the Class A airspace here in the US (and likely class E). For that you may want to read up on parachuting in controlled airspace.
Again similar to the dropping, parachuting must be done with caution

§105.5   General
No person may conduct a parachute operation, and no pilot in command of an aircraft may allow a parachute operation to be conducted from an aircraft, if that operation creates a hazard to air traffic or to persons or property on the surface.

Again a lot of this is open to interpretation, since you have no (presumed) way of controlling the vehicle on the decent I would say it does not fall under what the FAA considers a UAS/UAV. You may want to reach out to the FAA directly about doing something like this from the kinds of altitudes you intend to.


Is there a good source for estimating the per unit cost breakdown for a classic GA plane like the Cessna 172?

You can find an estimate in the Roskam book "Airplane Design Part VIII"

Which is partial on google books:
https://books.google.nl/books?id=GIHHFkd829cC&printsec=frontcover&dq=roskam+part+VIII&hl=en&sa=X&redir_esc=y#v=onepage&q=roskam%20part%20VIII&f=false

However, most Engineering Universities may have a copy of this series in their library. Most of the data you want to know, companies try their best to keep them private as it is information the competition would like to know.
In general most aircraft programs are based on an fixed set of sold units. If you know the cost of the individual units (aircraft) and the amount of units needed to sell to reach the break even point then you have a fairly good estimate over the program cost.


When conducting a circling approach, how close do you have to stay to the airport (especially with the new FAA requirements)?

The protected area for circling approaches is based on distance from the runway(s), and the size of that area (and your approach MDA) depends upon your aircraft's VREF or 1.3×VSO — or, if higher, your actual IAS approach speed. Here's the graphic the FAA uses to demonstrate this, along with the old protected area radii:

New circling minumums

For approaches that use the new criteria, both Aeronav and Jeppesen charts show an inverted "C" in the circling minimums section of the approach plate. This signifies that the approach uses the new, altitude-dependent protected areas. Those areas are defined in the same way as before, but with different radii.

Aeronav (NACO) format:

Jeppesen format:

As far as figuring out how large your protected area is in flight, you'll have to use the inverted "C" as a cue to look up the table that will be included in the appendices of the approach plates:

The NBAA has a more detailed description of the changes, but this basically sums it up.

The update leaves us with what is honestly a less-than-desirable system. Looking up a table to brief your circling radius in flight (or even prior to your flight) is certainly a lot less useful than simply printing the protected area radius on the minimums section. It's worth noting that feature was proposed in 2009 (p. 4) when the change was being discussed.


Can an aerodrome in class G airspace be controlled?

An airport in class G airspace can have an operating control tower. This is a case of a towered airport in uncontrolled airspace. The airspace is uncontrolled but tower communication must be established within a certain distance and for use of the airports runways.

There are applicable regulations that address this situation. 14 CFR §91.126 (d) requires pilots to establish and maintain communication with a Class G towered airport before entering a 4 NM radius below 2500 AGL.

As of today, Lake City, Florida (KLCQ) is an example of such an airport, although that will change at some point in the future.


Why do wings of passenger jet go dark during a flight?

As DeltaLima said, the change in brightness is probably due to the difference in lighting. The first picture is above the clouds, so the air is clear and the light is primarily from the sun. The second picture is in the clouds, so the air is moist and the light is much more diffuse, coming from all directions. This diffuse lighting and the moisture on the wing surface help to reflect more light. You can see this in the already reflective leading edge as well. In the first picture, mostly the darker sky is reflected, but in the second picture, the brighter clouds are reflected. The reflected light will be more evident in the darker areas than lighter ones.

Regarding the materials, they represent different parts of the wing. The darker section represents the main structure of the wing, so the surface is made of metal for strength. The sections around it do not carry as much load so they are made of composites to save weight. The metal conducts heat better, so it will tend to condense more moisture than the composite section, as the aircraft is descending from cold, dry air into warmer, moist air.

The surfaces do seem to have different finishes. This is probably related to the different types of material there.

Those pictures illustrate your question very well. I don't specifically remember noticing this sort of thing myself, but I will see if I have any myself showing the same thing.

Also... anyone know what plane this is? The pointed ends of the shock bodies, the VG's, and the static wicks outboard of the aileron make me think a 737 classic with winglet retrofit.


At what point is a turbine powered ducted propeller considered a turbofan?

tl;dr

They're pretty much all considered turbofans with a few exceptions from the '70s such as this experimental Britten-Norman Islander. They key difference is a prop can be considered a separate entity (add-on) to the turbine for a turboprop, but a fan is an integrated component for a turbofan.

Slightly longer answer

After a fair bit of thought and research I hope I've managed to come up with a satisfactory answer, though to start with a disclaimer. The aviation industry is far too fond of merging and creating new words to describe new engine architecture. Take Open Rotor vs. PropFan for example.

To get technical about it, you could look at the similar/reverse argument about the difference between an open rotor turbofan and a turboprop, as addressed by the EASA.

If you look at Appendix 1: Open Rotor Definition (Page 86) of that document they outlined the following key differences

  Open rotor module that cannot be distinguished as a separate entity

However the following was the agreed definition, which is still rather ambiguous.

  A Turbine Engine featuring contra-rotating fan stages not enclosed within
  a casing

I think the first one is more key, the prop can be considered as a separate entity, attached to the front of a turbine and powered by a gearbox. A fan is an integral part of the engine and cannot really be considered a separate entity, as it actually forms part of the low pressure shaft and is considered the first stage of the low pressure compressor.


Why won't you allow someone into the cockpit while on ground?

I don't agree with the strict enforcement of this rule by the DGCA (but I'm not an airline pilot so I think my opinion doesn't really count on this matter). But there is logic behind the ban - many safety-critical actions are completed before the plane has left the gate. Such actions include calculating takeoff speeds, briefing the departure procedures, and completing various checklists.

Having people in the cockpit could prove to be a big distraction when trying to complete these tasks, particularly when the time is limited anyway such as on a short turnaround.

Making a mistake before leaving the gate can definitely end in disaster. Take Emirates flight 407 in 2009. The crew entered an incorrect takeoff weight into the system. As a result there wasn't enough thrust to rotate and the A340 barely cleared the airport fence.


What is oil thermal expansion in the CFM LEAP 1A engine for the A320NEO?

When oil heats up, its volume expands (and its density goes down). This means that if you measure the level of oil in a gearbox when it is hot, the level will read high, and if you come back later and measure it after it has cooled back down to ambient, it will read low.

So if you were to fill a sealed gearbox with cold oil without taking its thermal expansion into account, when it then gets hot it might expand enough to overpressurize the gearbox and blow out its seals.

I had a tractor engine in which overfilling it with cold oil would then cause it to pump the box containing its ignition points full of engine oil once the engine had gotten hot. This would then foul the points and stop the engine.


What are typical insurance premium reductions for renters and owners as they earn instrument and commercial tickets?

(This is a US-based answer.)

There's no statistical information that I could find out there about this, but aircraft type, total hours, hours in type, age, previous claims etc. are all factored into the premium as well, so it's hard to make a simple comparison based on one variable. And as AOPA says:

  Not all carriers have the same guidelines for when they will offer a
  premium reduction.

But having said all that, it looks like an instrument rating is the key qualification to get. AOPA's insurance FAQ recommends it:

  Typical actions you can take to reduce your rates include:

  [...] Obtain an instrument rating.

I guess you could go through AOPA's quote process multiple times with different data to see what premiums come out, but just calling them is probably easier.

Avemco is a well-known aviation insurer and they're more specific. The wording is bit awkward but it looks like an instrument rating reduces your premium with them by 10%:

  Q: Is there any type of additional training that would lower my premiums?
  A: [...] obtain an upgraded certificate or Instrument
  Rating and you become eligible for the full 10% savings.

They don't say what an "upgraded certificate" means, but if you're one of the few people who have a commercial certificate but no instrument rating then perhaps that would count. Other insurance companies also say that advanced ratings can reduce your rates (here, here).

Finally, I can add a couple of comments from personal experience. I have AOPA renter's insurance and it's flat rate: your certification and experience don't matter at all. Second, when I was looking for life insurance, having an instrument rating cut my premiums a lot but it was a while ago and I can't remember the exact numbers. I do remember that they were reluctant to even consider me without it.


What would be the process to approve a minimal, standardized flight recorder for commercial balloons?

As Ron mentioned, if you want to produce a "standardized" voice recorder for balloons you'd be complying with FAA Technical Standard Order (TSO) C123 (currently revision C).

Along the same lines if you wanted to make a "standardized" flight data recorder it would need to comply with TSO C124 (and you would have to figure out what data would be useful to record, and how to get that data to the recorder).

If we're not sticking with an established actual standard then the next best thing are the personal portable electronic devices used in the flight - particularly if the balloon operators are using something like Foreflight, Garmin Pilot, WingX, etc. on a tablet. The NTSB lab has a good amount of experience in recovering useful data from these devices, and they can be almost as useful as an actual flight data recorder. Combined with an onboard camera (say a GoPro) capturing audio/video of the flight you can make an excellent reconstruction of events (and since many balloon operators offer their customers a flight video there's a good chance the cameras are already installed...)

It's worth noting however that none of these devices improves the safety of a given flight: CVRs, FDRs and even cockpit video are forensic tools used after a crash or incident to help us understand what happened, but their value is after an incident, and thus usually after loss of life.

The other NTSB recommendations (including carrying transponders) are aimed at actively improving the safety of individual flights, and may prevent incidents.


Do aircraft use the same or similar warning alarms for different alarm conditions?

Has boeing changed their alarm systems post that incident?

The story of Helios Airways flight 522 is complicated. It is not clear that a misidentified alarm was the cause of the crash.

Update:

If you are talking about the cabin altitude warning horn, that was allegedly misidentified as a take-off configuration, then nothing has been changed, at least up to May 2015 (see: The Boeing 737 Technical Guide, Version 70, May 2015, bottom of the page 50).

  "As the aircraft climbed, the pressure inside the cabin gradually decreased. As it passed through an altitude of 12,040 feet (3,670 m), the cabin altitude warning horn sounded. The warning should have prompted the crew to stop climbing, but it was misidentified by the crew as a take-off configuration warning, which signals that the aircraft is not ready for take-off, and can only sound on the ground.
  In the next few minutes, several warning lights on the overhead panel in the cockpit illuminated. One or both of the equipment cooling warning lights came on to indicate low airflow through the cooling fans (a result of the decreased air density), accompanied by the master caution light. The passenger oxygen light illuminated when, at an altitude of approximately 18,000 feet (5,500 m), the oxygen masks in the passenger cabin automatically deployed."m, Source: Helios Airways Flight 522.


What are the effects of crosswind on takeoff?

The upwind aileron is held down in order to keep the crosswind from pushing the airplane downwind. This is called crosswind drift. Usually the aileron begins fully deflected and reduced as it becomes more effective with increased airspeed. Upwind elevator is coupled with downwind rudder, which keeps the airplane in the centerline.

When I have taken off in a glider with a very strong crosswind, I have started the roll all the way on the downwind side of the runway and taken off diagonally upwind in order to  to reduce the crosswind component.


Is there a way to **decelerate** significantly without an "eyeballs-out" sensation?

If you need to have an average speed of Mach 3, then cruise at a speed higher than Mach 3 and land at Mach 0.2. And decelerate at a comfortable rate.

Or fly in a cryogenic wind tunnel to get the speed of sound down so much that Mach 3 is actual a very low speed.


How can pilots sleep or rest merely 1 hour after takeoff?

The military has been teaching people how to fall asleep fast for a long time and its quite doable. Keep in mind this pilot did not start working one hour ago, if he is relived after 1 hour he is likely at the end of his duty shift and may have been flying for the previous 7 hours and awake for some more time than that. Pilots hop time zones frequently so just because its daytime outside the aircraft does not mean that pilot started off his duty time in that time zone or even on that continent that day.

The relief pilots may have woken up just before the flight and had a nice hour to relax before "going to work".

The crew rest area is pretty nicely isolated and free of light and distractions making it an ideal place to sleep.


A North American T-6 Texan Trainer, probably the NJ/SNJ Texan variant.

"SNJ-1 at NAS Pensacola c1940" by U.S. Navy - U.S. Navy National Museum of Naval Aviation photo No. 1996.488.166.090. Licensed under Public Domain via Commons.

The North American Aviation T-6 Texan is a single-engined advanced trainer aircraft used to train pilots of various air forces including (but not limited to) USAAF, USN, RAF from (before) WWII well into the 1970s.


Would An-72-like (or any anhedral wing multi-engine aircraft) cruising at high speed, roll counter intuitively right, if left engine suddenly dies?

Simple answer: no, it wouldn't, otherwise it wouldn't be certified if it behaved like that :)

The real answer is the same as to why nearly all high-wing aircraft have anhedral. Yes, anhedral angle creates the 'adverse' roll effect, but it is made to counteract the excessive positive effect from all other factors, namely the wing sweep and the high-wing configuration itself. (The latter effect is more complicated than the usually assumed 'pendulum' effect: it has more to do with the added drag and cross-flow effects of the sideslipping fuselage (see, for example, here)).

As always, too much of a good effect is not good at all: excessive static stability causes oscillations, in this yaw/roll case known as Dutch roll, so anhedral is used to reduce the overall effect to a reasonable but still positive level.


When will the Canadian ADS-B satellite system be implemented?

This Advisory Circular, although from 2011, is still current and indicates that there will no Transport Canada ADSB mandate (being regulatory, it's not up to Nav Canada).  It appears the policy is to foster voluntary adoption of ADSB over time, and Nav Canada will create an environment where aircraft operators will get operational benefits by adopting it.

So the commercial world will likely switch over fairly quickly, while GA operators and private owners will do it gradually as the costs of the systems come down, and anyone who doesn't want to doesn't have to, and can continue using Mode C. I imagine that later on, when the system is mature, say in 5+ years from now, and GA ADSB systems are dirt cheap, TC/Nav Can will likely decide it's time to phase out surveillance radar completely, and then it'll be mandated for anyone that wants to operate in transponder airspace.


How do I plan for my PPL checkride which will involve a diversion?

This thread should be a great source of tips and tricks :)

The way to think about this is to think about the purpose of being asked to divert during your checkride.

What the examiner will be looking for is not that you have all of the information for every possible airport you might be asked to fly to.  The examiner is wanting to see that if you had to divert unexpectedly for whatever reason, that you are able to do this safely.  That's the bottom line.

In order to do this, you should start working on the problem during your ground planning, and for the purposes of your checkride, this will be no different to planning any other flight.

Plan for your alternate.  You should have charts, frequencies etc and of course, enough fuel.  Your examiner is not going to ask you to divert to somewhere when you reach your destination, it's going to be somewhere en-route.

As part of any good plan, you are going to familiarise yourself with possible diversions along the route.  If you had an urgent situation (not a dire emergency where nearest available is the only choice) requiring you to divert when you were flying solo after you gained your license, where would you go?

This doesn't mean that you need every possible piece of information for every possible airport but it does mean:

Do I have enough fuel to make possible diversions?
Do I have charts on board covering the areas to the left and right of my plan?   - Have I folded my charts so that it's easy to see what possible diversions there are easily?
Do I have Jeppesen (or whatever) on board and is it up to date?
Have I checked the METARs and NOTAMs for anything significant for those likely diversions.
Do I have my E6B or other planning tool and do I know how to use it fully?
Do I know what ATC agencies I would talk to along the route if I need assistance, even if flying in uncontrolled airspace?

In your notebook for the planned flight, write down the likely diversion airfields with their key details.

The list above should be part of any plan, not just for your checkride.

One of the key things you're going to need to figure out is "how long will it take me to get to the diversion"?  In order to know this, you're going to need to know the wind at the altitude you are going to be flying at. The way I handled this was to draw a circle on my chart, marked with the wind at altitude, then the corresponding ground speed already worked out on my E6B and written into the circle for each cardinal and mid-cardinal point on the compass rose.  You can glance at this little chart to instantly see that if, for example, the requested diversion needs me to fly a heading of 320, I will be doing 86 kts for an airspeed of 100 kts.  This saves you having to actually use your E6B in the cockpit to do this.  Mark off 0, 45, 90, 135 etc.

If you think about it, doing this in planning will prepare you for any *sensible" diversion you might be asked to make.

When it comes to the time of the diversion, the primary thing your examiner is looking for is do you get "aviate, navigate, communicate"?

The second thing the examiner is looking for is "can you safely divert from en-route"?

If you have planned thoroughly, and you follow aviate, navigate, communicate, then almost by definition, you will safely divert.

So your examiner suddenly says, OK, see that completely unexpected giant sandstorm ahead, you need to get down soon.  Please divert to "Mark Watney- Space Pirate" airport.

Avoid the single, most important thing in this whole exercise at this point.  Do no go into heads down mode.  It's easy to do if you are unprepared.  Your head should be down for at most 15 seconds.  Do each thing one step at a time, then scan and lookout.  If you are well prepared and planned, then not going heads down will be easy.

You now need 3 things immediately - everything else can come later.

What heading do I need to fly?
How long will it take me to get
there?
Can I make it?

For the heading, grab your chart, find the airport, then take a rough heading you need.  You don't, at this stage, need to be super accurate.  Within 10 or 15 degrees will be good.  The important thing is to begin flying to towards the diversion.  You can get the ruler out and refine your heading once you've got the initial diversion sorted out.  Don't forget to aviate.  Keep your head moving, keep your scan and lookout going.  When you set up for the new heading and turn on to it, remember the gross error check as you roll out.

How long will it take?  Again, you don't need to be super accurate.  Grab a quick measure of the distance from the chart and your ruler.  Then look at that wind chart you prepared earlier.  Get your estimated ground speed.

Can I get there?  You should know the aircrafts' fuels consumption numbers so do the quick calculation in your head.

During all of this, remember to aviate at all times.  Also, remember to conduct your normal en-route and turn check lists.

Now it's time to communicate.  If you are in controlled airspace, let them know you've diverted then start looking for who you might need to talk to along your diversion and get the next frequencies into the box.

When you are safely flying towards your destination, you can start to do some more detailed in-the-air planning to refine your estimated heading and fuel use if needed.  You can also now deal with "do I have the NOTAMs and METARs" I need?  It's OK not to have them all for every possible airport (you should have them for the most likely ones) because you can always call up ATC.  That's one of the reasons they are there - to help pilots dealing with unplanned contingencies.

Remember, the examiner is looking for prior planning and aviate, navigate, communicate.  If you do this, I hope that you will see that the unexpected diversion is not actually that scary.

This is primarily a planning exercise, not a flying exercise.  Arrive in plenty of time.  Recognise that every minute you spend planning will reduce your stress and workload in the air and aim to be ready to go, twiddling your thumbs and itching to get airborne, 15 minutes before your planned time to walk to the aircraft.

You might notice that I've repeated myself a lot.  That's deliberate.  Prior planning and aviate, navigate, communicate it what this is all about.

Good luck!


What is the difference between "Land 2" and "Land 3" annunciations for Boeing autopilot systems?

From "Smart Cockpit"

B777 Automatic Flight (PDF!)

  AFDS Status Annunciation
  The following AFDS status annunciations are displayed just above the PFD attitude display:
   • FLT DIR (the flight director is ON and the autopilots are not engaged)
   •   A/P (the autopilots are engaged)
  •   LAND 3 (three autopilots are engaged and operating normally for an
  automatic landing)
  •   LAND 2 (AFDS redundancy is reduced; in some cases, only two autopilots are available)
  •   NO AUTOLAND (the AFDS is unable to make an automatic landing).
  With a LAND 3 indication, the autopilot system level of redundancy is such that a single fault cannot prevent the autopilot system from making an automatic landing (fail operational).
  With a LAND 2 indication, the level of redundancy is such that a single fault cannot cause a significant deviation from the flight path (fail passive).
  An EICAS message is displayed for any fault which limits the capability of the automatic landing system. Aural alerts for EICAS messages not affecting safety of flight are inhibited until after touchdown. Changes in autoland status below 200 feet, other than a transition to
  NO AUTOLAND status, are inhibited.
  From Chapter 9, pages 22-23


What makes spiral instability less harmful than Dutch roll?

Because spiral instability is easier to address by the pilot than Dutch Roll tendencies.

Spiral instability is instability about the longitudinal axis. For example, spiral instability means that if the right wing tip moves down, it continues to move down rolling the plane to the right. Its simple to detect and address with left aileron.

Additional information on spiral instability available here: http://www.faatest.com/books/FLT/Chapter17/SpiralInstability.htm

Dutch Roll causes cross-control-type movements across two axes, the vertical and longitudinal axis, such that when the airplane rolls right, it yaws to the left, then it swings back the other way and rolls left, while yawing to the right. This movement is difficult for the pilot to counteract and the inputs from the pilot can actually amplify these movements.

Additional information on Dutch Roll tendancies available here: http://www.faatest.com/books/FLT/Chapter17/FreeDirectionalOscillations.htm


Do planes turn while climbing? Is this because of air characteristics variation?

Welcome to Aviation SE.

There is no need or reason to turn when going through clouds.  Aircraft frequently climb (or descend) and change direction at the same time.  If it happens in cloud, it's just a co-incidence.

As an example, on an approach, ATC often issue instructions such as:

  Turn left heading 300 degrees, descend and maintain 4000 feet.

The pilot will start turning towards heading 300 and start descending at the same time.

  Resume own navigation, climb flight level 370.

Following a previous instruction to deviate from the heading on the flight plan, the pilot is now cleared to turn back onto the planned track and climb to the planned flight level.

There is a high probability that you will see aircraft turning in clouds since arrival and departure routes, which is when most of the turning, climbing and descending is done, are when you are most likely to see aircraft in and out of clouds and manoeuvring.

In cruise, when an aircraft turns, it is also common to descend or climb since the altitude flown according to the heading is determined by the quadrantal and hemispheric rules.


How do I get a copy of a Pilot Operating Handbook?

Generally you won't find published POH documents for plans built homebuilts, as each aircraft is unique, the individual builder being the "manufacturer".  Possibly, a builder has made his own POH. Best bet is to write to the guy currently marketing the plans and selling parts, Creighton King.


How does an aircraft's weight affect the V-n diagram?

Well, answering your first question, the airplane weight does not really affect the V-n diagram because this diagram is developed knowing the structural forces that the airplane can take without being damaged.

Answering your question about the relation between the maneuverability and the airplane weight, the relation is just a "simple" physics problem. You just need to know the airplane characteristics like the center of gravity, the different aerodynamic factors and the effect of deflecting the control surfaces. When you solve the six equations with six variables of the differential system you can find how any characteristic of the airplane affects its maneuverability.

Finally, as you say, when the weight is low, the needed lift is less but this does not affect the V-n diagram because n stays more or less constant because:
 $n=\frac{L}{W}$. This diagram just shows us which are the relation between the aerodynamic forces and the weight. We all know that the weight is one of the problems for an airplane but it also helps to alleviate the bending moment on the wing root, that is why the last fuel tanks that are emptied on an aircraft are the ones that are further away from the fuselage.


How to compare two SFCs, one in thrust, the other in power (both turbofans)?

For comparing turboprops vs turbofans, you would normally divide the turboprop's SFC by the prop's thrust coefficient at comparison airspeed.

For two turbofans, always compare TSFC. It's a function of airspeed and altitude too, but the curves can be found in the paperwork, and for common engines online.

Jet engine SFC is rarely mentioned and has few practical applications outside of engine design and engineering. All the customer (pilot, etc) will see is thrust.

The FJ-44's TSFC is right there on the wiki page you've linked. The entry for 44-4 is n/a, but you can generally assume it about the same among the variants. The actual vatiance is within a couple percent.


How can pilots differentiate runways and taxiways during landing?

During daytime and good visibility, it should be pretty obvious that runway markings are white and taxiway markings are yellow. Runways have the runway designator in big white numbers at the end and a dashed centerline, while taxiways have a narrow continuous yellow centerline.

During nighttime, you will notice that runway lights are white or yellowish while taxiway lights are green (center) end blue (edge). Additionally, many runways have approach lighting, which taxiways obviously do not.

During low visibility, you won't be trying to identify the runway visually, since you will be performing an instrument approach, which will usually take you all the way to the threshold. For non-precision approaches, where some visual maneuvering is required, the information above regarding markings and lights apply equally.
In addition, taxiways are generally narrower than runways. While many runways do have parallel taxiways that run for the full length of the runway, in many cases the taxiways will have a few bends or be at a slight angle, whereas the runway will be completely straight and wider.
You should always study aerodrome charts and familiarize yourself with the airport layout before attempting to land at an airport. When doing so, pay attention to the airport layout, and try to notice any areas where confusion is likely (such as long straight taxiways that run parallel to a runway). If you come prepared, and pay attention to the details mentioned above, you should be home safe.


What are these sensors on the Night Stalkers' Chinook MH-47G?

Those sensors are part of the AN/AVR-2A Laser Warning System. Here is a closeup of the system components.

The AN/AVR-2A is a passive laser warning system which receives, processes and displays threat information resulting from aircraft illumination by laser designators, range finders and beam riding missiles. ... The AN/AVR-2A LDS consists of one interface unit comparator and four identical sensor units.; image from thaimilitaryandasianregion.wordpress.com
These sensors are installed on the MH-47G Chinook, as given in americanspecialops.com

Defensive systems
Common Missile Warning System (CMWS)
Suite Of Integrated Radio Frequency Countermeasures (SIRFC)
AN/AVR-2b Laser Warning System
XM216 Dark Flares (invisible to naked eye)


What does Top 1% mentioned by ATC refer to?

I'm guessing you're referring to a clip such as this one. JFK ground is just being a bit informal and fun (as you can tell from the rest of the clip) with their instructions. Although it isn't mentioned, the controller is probably referring to a business jet flight, such as ExecJet.

The "top 1%" refers to a ranking based on income, specifically those not in the lower 99%. The controller is basically telling them to follow the rich people in their fancy private jet. JustSid found another video where the controller explains it as "someone richer than both you and me."


How much oxygen is put in say a 180-seater A319 or A320 aircraft?

An A320 carries oxygen generators for passengers and cabin crew, pressurized oxygen for flight crew (including observers) and some portable oxygen bottles [1].
I can't find the exact volume of the pressurized container, but it is pressurized to around 1800 psi (124 bar) when full; [2] (page 148) gives minimum pressure for flight and how long for it should suffice.
Average amount of air inhaled by an adult human is usually given around 2 000 l/h, which contains around 400 l of oxygen (at standard pressure). The passenger masks are required to last quarter an hour, so they need to provide oxygen that would have 100 l at standard pressure (but at 0.15–0.2 bar only) per passenger. Plus there are some (around quarter) extra masks for people who are walking in the aisle at the moment decompression occurs.
Only flight crew masks must be able to provide pure oxygen at sea level pressure to be able to keep smoke or fumes out in case those enter the cockpit. These are always supplied from a pressurized bottle, because it must be possible to turn them on and off as they may be used in other cases too (fumes, pilot feeling unwell, preemptively if the pilot is alone for some time etc.) and the chemical generator will release all their oxygen once triggered.


"Report a 3 mile right base" - where is it measured from?

It's neither of the above, it's a base leg which will converge onto the final approach leg 3 miles out from the runway threshold. In other words when you turn from base onto final you'll be on a 3 mile final.


What is the relation between an airplane's altitude and the drag it is experiencing?

Yes, it does - skin friction increases with an increasing altitude.

The mechanism is linked more to temperature than to density, but the reasoning in your question is correct. There might be a few cases where viscous drag increases with Reynolds number (like laminar airfoils which lose their laminar bucket when the Reynolds number goes up), but in general the observation is true.

First a plot from Sighard Hoerners book Fluid Dynamic Drag:

Flow properties over altitude, from page 1-11 in Fluid Dynamic Drag, 1965 edition. The ratio of the actual Reynolds number to the Reynolds number at sea level $\frac{R}{R_0}$ shows a clear downward trend over altitude (which is plotted on the x axis). At 60,000 ft the Reynolds number at the same flow speed is only 12% of that on the ground. If you look at the same dynamic pressure, you have to correct that by the square root of the density ratio $\frac{\rho}{\rho_0}$, which is 0.3 at 60,000 ft. In total, the aircraft will fly in 60.000 ft at 40% of the Reynolds number at sea level when the dynamic pressure stays constant. Lift is proportional to dynamic pressure, therefore it is best to keep the dynamic pressure constant for the comparison.

Now for the viscous drag over Reynolds number: From the same book I copied a plot of lots of experimental data which shows the trend nicely:

Skin friction over Reynolds number, from page 2-6 in Fluid Dynamic Drag. Note that both axes are logarithmic to produce a nearly linear trend line. k denotes a correction for a flow which starts laminar but then turns turbulent when the critical Reynolds number is reached (critical = kritisch in German, hence the k).

For even more details I recommend this page from Stanford.

EDIT:

Your comments helped me to understand the source of your doubts. Drag and lift are proportional to dynamic pressure $q$, and this in turn is the product of speed $v$ squared and density $\rho$: $$q = \frac{v^2}{2}\cdot\rho$$
Reduce density, and you reduce drag. But this will also reduce lift. In the end, you want to support the same aircraft mass at lower density, so you need to do something to get lift back to its old level despite the drop in density. You do this by increasing speed. You restore the same dynamic pressure, in other words. Now the drag is also back to its old level, plus some more. Isentropic expansion means that temperature drops when density drops, and the thermodynamic law of isentropic expansion describes what happens to air in the atmosphere (isentropic = no change in entropy). Lower temperature means higher viscosity. Moving at the same dynamic pressure in lower temperature will generally cause more viscous drag.


Do concurrent operations on a single runway occur anywhere else besides AirVenture?

ICAO defined procedures for Reduced runway separation which to some extend permits concurrent operations on a single runway. ICAO does not mention anything about coloured dots, but the ICAO procedures do open up for doing something similar to what you are describing.

The following is from Doc 4444/PANS-ATM:

  7.11.4    For the purpose of reduced runway separation, aircraft shall be classified as follows:

  Category 1 aircraft: single-engine propeller aircraft with a maximum certificated take-off mass of 2 000 kg or less;
  Category 2 aircraft: single-engine propeller aircraft with a maximum certificated take-off mass of more than 2 000 kg but less than 7 000 kg; and twin-engine propeller aircraft with a maximum certificated take-off mass of less than 7 000 kg;
  Category 3 aircraft: all other aircraft.

[...]

  7.11.7    Reduced runway separation minima which may be applied at an aerodrome shall be determined for each separate runway. The separation to be applied shall in no case be less than the following minima:

  landing aircraft:

  a succeeding landing Category 1 aircraft may cross the runway threshold when the preceding aircraft is a Category 1 or 2 aircraft which either:

  has landed and has passed a point at least 600 m from the threshold of the runway, is in motion and will vacate the runway without backtracking; or
  is airborne and has passed a point at least 600 m from the threshold of the runway;
  a succeeding landing Category 2 aircraft may cross the runway threshold when the preceding aircraft is a Category 1 or 2 aircraft which either:
  has landed and has passed a point at least 1 500 m from the threshold of the runway, is in motion and will vacate the runway without backtracking; or
  is airborne and has passed a point at least 1 500 m from the threshold of the runway;
  a succeeding landing aircraft may cross the runway threshold when a preceding Category 3 aircraft:
  has landed and has passed a point at least 2 400 m from the threshold of the runway, is in motion and will vacate the runway without backtracking; or
  is airborne and has passed a point at least 2 400 m from the threshold of the runway;

  departing aircraft:

  a Category 1 aircraft may be cleared for take-off when the preceding departing aircraft is a Category 1 or 2 aircraft which is airborne and has passed a point at least 600 m from the position of the succeeding aircraft;

  a Category 2 aircraft may be cleared for take-off when the preceding departing aircraft is a Category 1 or 2 aircraft which is airborne and has passed a point at least 1 500 m from the position of the succeeding aircraft; and
  an aircraft may be cleared for take-off when a preceding departing Category 3 aircraft is airborne and has passed a point at least 2 400 m from the position of the succeeding aircraft.

(note: I have changed formatting slightly to better fit this format)

These general rules are interpreted different by different countries, but some different forms of reduced runway separation are used in different places of the world.


Why does a missile have small wings but better agility than a plane?

First of all, a missile is operating at a much higher dynamic pressure than the airplane. After all, it has to catch up with it to do its job. Since dynamic pressure scales with the square of airspeed, the wings of a missile twice as fast as the target would need only a quarter of the wing area to produce the same forces.

Secondly, the missile uses its thrust just as much as the lift from its vanes to change direction in the initial flight phase when the rocket motor runs and the biggest course changes are needed. With an airplane, this is normally not possible, since most planes need to fly in a small range of angles of attack and sideslips to operate properly. Exceeding those will produce substantially more drag and might lead to loss of control.

Lastly, the missile has to carry only the mass for a few seconds of flight. The burning time of a rocket motor is just a few seconds for short-range missiles, and their typical flight time is about 30 seconds. Since they do not need to carry the fuel to return to base, their mass can be held down, which improves agility.


Should the helicopter be washed after any sea mission?

The helicopter shown is an Anti-Submarine Warfare Helicopter. ASW helicopters generally have the ability to detect submarines either Passively or Actively. Passively, sonar-buoys are dropped into the sea and act as ‘microphones’. The returns from these can be triangulated to track submarines.
To achieve this, the helicopters altitude will generally be 1500ft amsl in this role. Unless the winds are very strong salt accretion is minimal. In the active role, the helicopter hovers above the sea and lowers an active sonorhead into the water. The height for this is normally between 40-80ft. The aircraft will stay in this position as long as it takes to establish a 360deg sweep, which is typically less than 5 minutes, or if in contact could remain in the hover for 30 minutes or longer. This process is repeated for the duration of the sortie, which may be up to 2-3 hours.
During this time, the helicopter is experiencing recirculating sea spray. Depending upon the wind / sea state, will determine how much salt accrets (windscreen wipers are required on occasion). The engines experience salt ingestion, which accrets on inlet guidevanes and compressors. As the sortie progresses it is possible to see a reduction in engine performance (the advice for this used to be to find a rain cloud to fly through).
On completion of a days flying over water the engines receive a compressor wash or after a single flight if particularly bad. The airframe will also be washed on a regular basis, perhaps every couple of days. Many bases operating ASW helicopters have dedicated ‘drive thru’ washes. The helicopter will ground taxi over an area with water jets set into the ground and water will spray the airframe and underside of the rotor blades to remove the salt, sometimes known as a ‘bird bath’.


Is the well known textbook-formula for net-thrust oversimplified or do I have a misinterpretation?

You forgot to take pressure into account. This formula works assuming your nozzle is well adapted and the exit flow is at atmospheric pressure. In your case the velocity is increased but the pressure drops as stated in Bernoulli's equation.
$$P_0+ 0.5\rho V_0^2 = P_1+ 0.5\rho V_1^2$$
This means that the pressure force on your nozzle will counteract the thrust provided by the fluid acceleration.
See this explanation  your general thrust equation if the pressure are different is
$$\text{Thrust} = (Q * V)_e - (Q * V)_0 + (P_e - P_0) * A_e $$
Given $A_e$ is the exit aera of the nozzle.


Intercepts and aerial combat in IMC (or my no-fly zone is full of clouds?!)

In the first scenario, where it sounds like you're assuming that the intruder aircraft is known to be hostile even without seeing it, a shot with a radar missile would be unaffected by the IMC, and that scenario is a pretty straight-forward kill.

The hard part of IMC for a modern fighter aircraft isn't killing the target, it's getting the positive ID on it that's necessary before shooting in order to assure the chain of command that you aren't, in fact, about to kill a neutral or friendly aircraft who's wandered into the wrong place at the wrong time with the wrong squawk.  THAT is where VMC becomes necessary, in most cases, to get the required visual ID on the target.

Using radar alone, an interceptor could close to some reasonably short distance (say, inside a mile, with some altitude separation as well), and if the unknown aircraft enters VMC even briefly, then the intercept could be completed to the point where one interceptor makes the visual ID.  With the aircraft being known to be hostile, that interceptor could break away, and a wingman, maintaining position further back, could then take the shot with a radar missile.

Presumably, the "bad guy" has some mission to complete, and most of those (though not all) tend to need VMC to accomplish -- dropping bombs or taking photos or whatever.  So chances are probably pretty good that the intruder is going to get to VMC eventually.  (Or, if he drops bombs off of radar/GPS, then that act itself might be sufficient confirmation of hostile intent that the interceptors would be cleared to engage, ensuring that the bandit doesn't live to ever repeat that mission.)


How does airfoil thickness affect the Mach number at which it experiences transonic flow?

The displacement effect causes the flow around a thick body to speed up more than around an equivalent but thinner body. The thicker body pushes the air aside and around itself more, causing the flow to accelerate relative to the vehicle and to become supersonic at a lower flight Mach number.

Wing sweep has a similar effect, as only the orthogonal speed component will be affected by the wing and the effective Mach number of all thickness-, camber- and angle-of-attack-related effects is reduced by the cosine of the sweep angle. Again, the displacement effect will be reduced by sweep.


Are turboprops more efficient than piston engines (thrust per fuel consumption)?

No, piston engines are more efficient.

Their output is given in kilowatts or HP because this does not change much with speed, unlike the thrust of a propeller. By running a piston engine a few times on a dynamometer stand you can get reasonable numbers which are valid over the full operating range. If you want to characterize them by their thrust, you would need to look at an engine-propeller combination at one particular speed, which is not very helpful.

Now you ask for specs of contemporary engines. The funny thing is that the efficiency of aviation piston engines has not changed much over the last decades. If you assume 250 g of fuel per kWh at full power for gasoline engines, this figure holds already for good WW II-era engines like the Jumo 213 A which was run on 87 octane gasoline. The low octane number restricted compression to 6.93:1, while the higher octane number of contemporary AVGAS allows for an 8.5:1 compression ratio in engines like the Lycoming O-360, which consumes 280 g of fuel per kWh. Adding fuel injection enabled Lycoming to reduce fuel burn to 240 g per kWh in the IO-390, which was first run in 2002.

Diesel engines are even more efficient; they typically consume 220 g per kWh. This low value was already possible with the venerable Jumo 205 of the 1930s which consumed only 213 g per kWh at its most efficient speed. Modern aerodiesels run at similar efficiency: The Thielert range of engines which have been taken over by Continental consume 220 g per kWh.

Even the best turboprops rarely achieve less than 300 g per kWh. The most modern version of the venerable Pratt&Whitney PT6 consumes 308 g per kWh, and only very recent developments can close the gap to piston engines. The Progress D27 claims a specific fuel consumption of 231 g per kWh while the Europrop TP400 one of 237 g per kWh. Note that here the remaining thrust from the exhaust has been converted into an equivalent power rating to achieve such good values.


When can airliners fly from Israel over Tunisia's and Algeria's airspace?

While Israel may be restricted from Middle Eastern Arab countries, North Africa is a bit different. The EASA has a list of countries they have a working agreement with, which includes both Israel and Tunisia

  As part of the process of creating a wider Common Aviation Area with its eastern and southern neighbours, the EU negotiated a comprehensive Euro-Mediterranean agreement with Tunisia which has been initialled on 11 December 2017.  This comprehensive agreement will result in an increase in the number of direct flights and boost trade and tourist flows between the EU and Tunisia.  Beyond market opening, the agreement also provides a modern framework and high standards for a wide range of aviation issues, such as safety, security, passenger rights, air traffic management, economic regulation, competition issues or social aspects.

As to Algeria (not in the EASA), the answer is probably more mundane: airspace fees

  Many countries use airspace fees as a form of revenue and, sometimes, as a form of leverage during political negotiations. This causes prices and routes to fluctuate, with airlines subject to different policies. Costs are, of course, transferred to travellers, while airspace restrictions can significantly limit the options available to certain destinations.

Algeria uses France's ENNA to collect their fees

  Overflying navigation fees are generally imposed by the country’s civil aviation authority (CAA) although some countries have other entities responsible for their issuance, such as the airport authority, or specialist local government bureaux. In Algeria for example, responsibility lies with ENNA, the National Enterprise for Air Navigation.

As such, Algeria doesn't want in Israelis in their country, but probably doesn't mind their money to fly over nearly as much.


What is "Block burn" and how is it calculated?

I have no idea and no connection with the aviation industry so I looked it up. I found

Block Fuel / Ramp Fuel / Total Fuel On Board
Block fuel is the total fuel required for the flight and is the sum of the Taxi fuel, the Trip fuel, the Contingency fuel, the Alternate fuel, the Final Reserve fuel, the Additional fuel and any Extra fuel carried. Source: Skybrary.aero.

That in turn led me to look up 'aviation block' and I found

Perhaps you’ve noticed that flights flown on different airlines between the same airports take different amounts of time. You might reasonably ask: why would different flights, departing from and arriving to the same airport take different amounts of time? The total amount of time a flight takes — from pushing back from the departure gate (“off-blocks”), to arriving at the destination gate (“on-blocks”) — is called “block time”, and airline block times vary for the same routes. Source: FlightStats.

I guess that block burn is the amount of fuel burnt between the departure gate and the destination gate.

My second question is how is it calculated?

Start fuel - end fuel, I guess. This can then be tabulated and used for future flight block burn calculations.

I have also heard it depends on seasonal data.

Many operational factors will vary by season so this seems reasonable.


Can the FAA allow a foreign training center to add a type rating to an FAA license?

Training centers do not issue type ratings, examiners do. To validate foreign ratings in your FAA license you have to submit the request and supporting documentation to the FSDO closest to you. They will tell you if it is possible to add the rating to your license based on reciprocal agreements.


Why don't air-cooled radial engines use fuel to cool the oil?

The Fuel/Oil heat exchanger serves two purposes. It helps to dissipate some of the heat from the oil and warm the fuel up for combustion

  The fuel-cooled oil cooler acts as a fuel oil heat exchanger in that
  the fuel cools the hot oil and the oil heats the fuel for combustion.
  Fuel flowing to the engine must pass through the heat exchanger;
  however, there is a thermostatic valve that controls the oil flow, and
  the oil may bypass the cooler if no cooling is needed.

In piston radials you generally dont need this fuel pre-heat. Since Avgas is vaporous at a fairly low temperature you dont really need to pre heat it. On top of that preheating it may vaporize it in the lines which is also a fairly big issue in and of itself.

There are always concerns of cross leaking, and this applies in both cases. A leaky exchanger can add fuel to your oil or oil to your fuel. A potential issue in either direction.


For pilots, are the procedures different between airframes with different engine options?

I can only speak for the Boeing B787, but the 787 Flight Crew Operating Manual (FCOM) indicates that there are slight differences between different engine options. Three examples:

autostart modes (different failures can be automatically detected and corrected for during engine autostart),
warm-up times before take-off and cool-down times after landing,
take-off thrust setting ("GE engines: Advance the thrust levers to approximately 40% N1" vs "RR engines: Advance the thrust levers to approximately 20 TPR" - this also indicates that the primary engine indications are slightly different: N1 and EGT vs. TPR, N1 and EGT).

I don't know though how much these slight differences translate to different procedures, as I am not a pilot.


I think it's a fairly good match for the Rolls Royce F405 Ardour. I can't quite work out which version though....
Thanks to everyone who spent time looking.
Rolls-royce.com
here's an afterburner and nozzle for a variant:
Hunini


This is a GPS guidance indicator from AG-NAV, with the main unit visible onboard. Snapshot from your linked video:

Main unit

Using the main unit, different information can be displayed on the lightbar:

GPS cross-track
Angle of Intercept
Overlap in sprayed area
Area already treated
Spray height
Aircraft inside/outside area indicator
...

Basic data can also be shown (e.g. airspeed) See this video. The indicator itself:

Lightbar

More:

Lightbar brochure.
Main unit brochure.


Why do we need to know both groundspeed and airspeed?

Airspeed is critical for pilots, because it is what the airplane "feels" when it's flying. Too little airspeed and the wings won't generate enough lift to fly, too much and the plane can be damaged. (And you're right, the pitot tube, along with the "static port" is what allows airspeed to be measured.)

Groundspeed is how quickly you're getting where you're going. This is also important, because the engine (or engines) consumes an certain amount of fuel per hour. If you are flying between two airports that are 400 miles apart in a plane that goes 100MPH, with no wind your trip will take 4 hours. If you have a 20MPH headwind your airspeed will still be 100MPH but your groundspeed will be reduced to 80MPH, and your trip will take 5 hours instead of 4. If you've only got 4.5 hours worth of fuel, you're going to need to make a stop. It's really good to know this before you leave!

So airspeed is how fast the plane is flying through the air and groundspeed is, as you observed, how fast you're getting where you're going. Both are important!