Do US state governors have jurisdiction over their airspace?

State governors do not have any control over their airspace but may have control over landing sites (read airports). From the FAA's brief on drone regulations:

  Congress has provided the FAA with exclusive authority to regulate
  aviation safety, the efficiency of the navigable airspace, and air
  traffic control, among other things. State and local governments are
  not permitted to regulate any type of aircraft operations, such as
  flight paths or altitudes, or the navigable airspace.

  However, these powers are not the same as regulation of aircraft
  landing sites, which involves local control of land and zoning. Laws
  traditionally related to state and local police power – including land
  use, zoning, privacy, and law enforcement operations – generally are
  not subject to federal regulation.


Why is there a difference between the procedural track heading and final approach course at Fort Hood (KGRK)?

It's really only confusing because they are within one degree of each other, but this actually happens quite a bit with feeder routes.
The 151 Degree Course NW of STARN
The 151 degree course (and the OKEST intersection) is only used if you are using AGJ as the Initial Approach Fix (IAF). This is the course that you would fly from OKEST towards the GRK VOR (on the GRK 331 degree radial) in order to get to STARN.  After reaching STARN, you would fly the 150 degree bearing outbound from STARN and the rest of the approach using STARN to navigate.
The 150 Degree Bearing NW of STARN
If you were to use STARN as the IAF instead of AGJ, you would fly the procedure turn on the 150 degree bearing from it in order to get yourself established on the correct inbound course to fly the rest of the approach.  In this case, you would never use GRK at all.


How much do '1,500 total hours with 500 multi crew hours' cost in Europe?

You get to the 1500 hours by working in a flying job once you have your comm/group 1 IFR, which is where the 62k gets you.  Even if you wanted to spend a decade renting airplanes to get the time in, for the 500 multi-crew part you have no choice but to find a flying job since there is no other way to get those hours unless you are rich enough to afford your own multi-crew airplane.

The course gets you to a minimum employable level of flying hours (maybe 250-300 or so - hard to see 60k getting your any farther than that) and with the EASA ATPLs written, which allows you to copilot multi-crew aircraft as a greenhorn 300 hr copilot (normally you get a "multi-crew" license, which is a trimmed down version of the ATPL for low time pilots to serve on 2 pilot a/c) without having to write the exams again when you get the time in (that's the "frozen" part).  Most jurisdictions will "freeze" your exam validity for 3 years.

The "fast track" bit just means they cram the whole thing into one year.  That would be a pretty intense course, jamming 2-300 hours into 12 months with the ATPL ground school thrown in as well.


Should the pitching moment be up or down?

All points you mention are correct (for the nitpickers: Point 5 is only true below transsonic speeds). That the pitching moment of the wing is drawn nose-up is probably because it is positive this way - nothing more. The sketch you posted in your question is rather poor, with the center of gravity located behind mid-chord when it should be closer to the aerodynamic center.

Indeed, if you have positive camber, the center of pressure of the wing is behind the aerodynamic center, so the wing's pitching moment around the aerodynamic center should be nose-down. However, if you assume the center of gravity of the isolated wing to be at mid-chord, the center of pressure is normally between the quarter chord and mid points, so the wing all by itself will pitch up because it pitches around the center of gravity. The moment depends on the reference point.

Did you look at this answer for an explanation of static stability yet? Let me know if something is left unclear.


Is there a modern day "replacement" for the de Havilland Beaver?

As an ex DeHavilland employee I'll admit I'm a bit biased, but I'd say there isn't really a "direct" replacement so far.  Two reasons:
The Beaver was designed in Canada around a bush operator survey.  Outside Canada (and to a smaller extent Alaska), "bush operation" generally means remote land operations into dirt strips.  In Canada, "bush operation" meant almost exclusively seaplane operations, (and to a lesser extent ski operations in winter).  The survey provided the Dehavilland Canada designers with a wish list of features provided by seaplane operators running Norsemans and the like (sadly, helicopters and gravel strips to provide land plane access remote areas have replaced most seaplane use as basic transportation, and today most seaplane operations in Canada and Alaska support the tourist trade).
So, unlike its modern contemporaries, it is specifically designed to operate on floats, and is optimized for being serviced and loaded from a dock.  The fuel tanks in the belly, the placement and shape of the main doors, the battery location, etc. Easy to load, easy to service from a dock.  The Beaver's modern contemporaries aren't optimized for float operations quite the same way so the "fit" isn't quite as good for a seaplane operator. On the flying side, the very long wings and full span slotted flaps (the ailerons droop with the flaps) allows it haul loads out of very small lakes, with a decent rate of climb.
The other big reason is the engine.  The R-985 is one of the only large piston engines over 400 hp that is still commercially viable, that is, it's still feasible to keep running reliably in a commercial operation.  A piston engine is far cheaper to operate than a turbine.  Bush operators operate on very thin margins and direct operating costs have a direct impact on viability of an operation, so turbines are out of reach for most.
With the Petersen Mogas STC you can run an R-985 on aviation automotive fuel (Mogas) (like all 80 octane engines it's much happier on Mogas than 100LL), and in Canada at least some bush operators do this (the operator I worked for in the early 90s switched to Mogas when the supply of 80 octane in Canada dried up - 80 was still in production in Canada for some time after it disappeared in the US in the 1980s).
Add in the overall reliability of the design and ease of repair, and there you go.
The Beaver is kind of a single engine version of the DC-3. Its combination of features came together so well that after nearly 75 years, it's still the best choice for commercial seaplane operators to use as a business tool to make money. On top of that, it benefited from a large military order by the US Army that took roughly half of total production, 970 units, which has kept up the supply of used aircraft to keep prices in check (the story of the Army's adoption of the Beaver followed a trip to Alaska in the company demonstrator to take some generals fishing, and included a bizarre flyoff against a range of ill-suited contemporaries after US manufacturers complained about foreign sourcing - get the book the DeHavilland Canada Story for an interesting read).


Why are the wings of some modern gliders tadpole shaped?

The flaps and ailerons are "reflexed" on this glider. They have been raised to a setting above the normal zero position, above the airfoil's normal chord line. A number of flapped gliders have this feature.

Two main benefits are a reduction in pitching moment as the pressure distribution on the wing is moved forward, so less downforce work for the tail, reducing trim drag, and lower induced drag because with the trailing edge partially unloaded it has an effect like reducing wing area and moves the best L/D speed up a bit.  So overall, best glide angle is a bit better, and the speed it's achieved is a bit higher.

You use reflex for "penetration", going as flat as possible as fast as possible, for whatever reason, like getting through an area of sink in a hurry.


Why does the A320 still have this old fashioned nose?

Cockpit windows that sit flush with the fuselage can save a very small amount of drag, but they require large double curvature window panes. Manufacturing such panes is significantly more expensive and there was limited commercial availability for that product when the A320 was being designed.

You can see a few more examples of flat vs curved windows here: https://www.airliners.net/forum/viewtopic.php?t=754093

Cost and availability are a serious concern, as the A320 was already expensive compared to the competition. Paying more and risking delays if double-curved glass production couldn't be ramped up would not have been worth the savings. Airliners aren't just about performance, the very name "Airbus" hints that they're also a public conveyance.

In short, only the newest airframes get to make that small drag saving. Some older airframes had single curvature windows, which are between flat and double-curvature in complexity.

This has been explored in more detail in a broader question.


Which FARs does the Boeing 737 MAX conform to with respect to turbulence?

Testing standards for things like turbulence and fatigue are not related to any specific aircraft type certificate. Yes, the MAX shares the same type certificate as the first 737-100, but the TC only makes reference to the certification standards to which the design complies. If you look at the TC you will see that it references the advisory circular for fatigue and damage tolerance testing (AC 25.171-1x), but as new models are introduced the TC makes reference to the latest version of the AC at the time the modified TC is issued to include the new model. The latest version of the AC is -1D.


Its hard to tell from the picture, but assuming you are talking about the yellow airplane and the "wiggle" in the course, that was probably just an S-turn for spacing.  Sometimes the controllers don't get the spacing exactly right, or one airplane slows down early and messes things up.  In those cases, in visual conditions,  the controller can ask the following airplane to make an S-turn.  This causes the plane to take a bit more time to cover the same distance as flying straight and spaces the planes out.

This may be used instead of a speed assignment for a number of reasons

Planes on approach may not be able to slow down further as configured
There may already be a speed assignment but it wasn't enough
Slowing down takes time, and S turn may be more efficient.

An ATC instruction may assign a heading and follow up with a new heading and approach clearance or other instructions to join final, or they may simply ask for an "S turn to the right for spacing".  The vectors would be more likely in instrument conditions and the S-turn more likely in visual conditions.


Is it common for aircraft tugs to work from under the aircraft?

Yes, this is a perfectly normal practice, still used, especially for tight spaces, as seen in this video moving a 747 into the hangar for service. And no, it doesn't require any special equipment - the nose gear attachment is designed to be used either way.

A still from the video:


What other advantage(s) does an adjustable prop give you?

It's not just the operating RPM that is pertinent. It's also the pitch of the blades.
If your propeller blades' pitch is optimized for takeoff/climb performance, it's going to be aerodynamically inefficient at high true airspeeds, like taking little tiny footsteps on a treadmill that's going really fast. (It works, but it wastes energy.)
The opposite is true as well. If you have a "cruise" prop on your airplane, it's going to perform poorly on takeoff when the airspeed is slow, like taking large strides on a treadmill that's just barely moving.
If you want to optimize your body mechanics, you change your gait based on the speed you need to go, so you're not wasting energy. If you want optimize a propeller, you change it's pitch based on the speed of the air that's entering it, so you're not wasting energy.


What are the primary and secondary flight controls for the SEPECAT Jaguar?

According to  airvectors.net, the flight controls of the SEPECAT Jaguar are:

The Jaguar A had a high-mounted wing with a sweep of 40 degrees and an anhedral droop of 3 degrees, with relatively small wing area for a smoother ride at low altitude. There was a leading-edge flap along the outboard section of each wing, and large, double slotted trailing edge flaps on both the outboard and inboard sections of each wing. There was a "dogtooth" between the outboard and inboard sections of the wing.
There were no ailerons, roll control being provided by a two-section spoiler on top of each wing, just forward of the outboard flaps. There was a prominent "fence" between the inboard and outboard sections of the wing. Along with a conventional tail assembly, with all-moving one-piece tailplanes, there were two ventral fins. There were twin hydraulically-operated perforated airbrakes ahead of the ventral fins, under the wings. The hydraulic system was dual-redundant.

(Emphasis mine)
The omission of ailerons from a ground attack fighter might seem odd, as one might presume this makes the plane less  maneuverable. But, as described in the first sentence of the quote, the Jaguars main mission was to (or at least it often had mission critical sections with) flying fast and low, which often translates into a very choppy ride. This was mitigated by the use of a smaller wing = higher wing loading. To achieve low enough approach and landing speed with such a small wing, efficient and large flaps were needed. As sufficient and consistent roll control is somewhat hard to achieve with flaperons (or at least it was when Jaguar was designed), the Jaguar had to make do with full span flaps and use spoilers for roll control.


How Military to Civil Aircraft Transition is made by National Authorities?

In the US, ex-military aircraft must be issued a special airworthiness certificate before they can be flown as civilian aircraft. Some aircraft may be denied the certificate outright, but most can be flown this way. The hard part is maintaining them, the cost of operating them, and finding qualified people to crew them, including a qualified flight instructor and even a Designated Examiner if the FAA requires a type rating to fly it.

In some very rare cases, it is possible to get a standard or utility airworthiness certificate, but the aircraft must have been previously approved that way before you can do that.

In the majority of cases, the aircraft is given a special airworthiness certificate under the Experimental category, Exhibition subcategory. This means the aircraft can only be operated to exhibit the aircraft’s flight capabilities, performance, or unusual characteristics for air shows, motion pictures, television, and similar productions, and for the maintenance of exhibition flight proficiency. To fly it, you must meet certain experience requirements and in some cases you need to obtain a pilot type rating for that aircraft.

In other cases, if you want to race the aircraft in air races, you can get a special airworthiness certificate for that purpose, to operate the aircraft in air races, practice for air races, and to fly to and from racing events.

To get the airworthiness certificate in the first place you have to submit a maintenance plan for the aircraft to the FAA (often derived from maintenance plans others have drafted) and have it approved by the FAA, and the aircraft must be subject to regular inspections as per the plan.

Source: FAA Experimental Airworthiness Certificates home page

In yet other cases, some military cargo aircraft are converted for missions such as firefighting. Those are exceptional cases, almost unique to the US in that they are not required to comply with many federal aviation regulations.

  The Federal Aviation Administration (FAA) has abrogated any
  responsibility to ensure the continued airworthiness of "public-use"
  aircraft, including ex-military aircraft converted to firefighting air
  tankers. Although these aircraft are awarded FAA type certificates,
  the associated certification processes do not require testing and
  inspection to ensure that the aircraft are airworthy to perform their
  intended missions. Source

For other countries I suggest you list the ones you are interested in. I only know the rules for the US/FAA.


Could an amateur build a full-scale UAV?

You sure can,

The FAA provides a special airworthy cert for this kind of thing. There are a few types that you can apply for depending on what you are trying to fly. You can find the relevant info here

You can find the full Special Order that covers it here.

  Airworthiness Certification of Unmanned Aircraft Systems and Optionally
  Piloted Aircraft

  Purpose of This Order. This order establishes procedures for issuing special airworthiness certificates in the experimental
  category or special flight permits to unmanned aircraft systems (UAS)
  and manned aircraft integrated with UAS technology. For the purposes
  of this directive, manned aircraft integrated with UAS technology are
  referred to as optionally piloted aircraft (OPA).

In your specific example if it was an RV-8 (built as it usually is) with the ability to remote pilot it added in, it would be classified as an "optionally piloted aircraft"


Is prior clearance into Class B airspace revokable?

Every clearance can be cancelled or revoked, irrespective of the type of clearance.


Who manages International Airspace Traffic?

Global ATC in general
In the civil aviation domain, international rules are proposed by ICAO. The foundations of these laws have been agreed in 1944 under the Chicago Convention, in particular its Annex 2, Rules of the Air. Nearly all countries are signatories of this convention.
ICAO global airspace structure is divided into large Flight Information Regions (FIR -- their upper layer being conventionally named UIR). A FIR over a domestic airspace is under the responsibility of the country below. A FIR over the international airspace (e.g. airspace over international waters) is under the responsibility of a single ICAO member state which has received a delegation from ICAO.
Within a FIR, enroute services are provided by Area Control Centers or ACC (ARTCC is the FAA local name for ICAO ACC). The first services available (and guaranteed) are information and alerting. Control services like separation can be provided, depending on the FIR.
(That's unfortunately a lot of acronyms, and more are coming soon... I give them only for precision in case someone wants to dig further into details, but you don't need to remember them to understand the system.)
Specificity of Oceanic Control
When a FIR provides control services over an ocean area, such area is named Oceanic Control Area or OCA, and the corresponding ACC are named Oceanic Area Control Centers (OAC). OAC and ACC differ by the procedures they can use to provide their services: ACC are able to track aircraft using reliable radars, while OAC mostly work with voice/data position reports from crews over unreliable long distance communications (that's less and less true with modern means like space-based ADS-B and ACARS/CPDLC/DCPC (see Guidance Material for ATS Data Link Services in NAT Airspace here).
North Atlantic case
All flights which want to maximize (eastbound) or minimize (westbound) the effects of high altitude jet streams of the day over the Atlantic Ocean must use the crowded North Atlantic Organized Track System (NAT-OTS, not to be confused with NATS Holdings, the UK ANSP) when flying at or above FL55. They must obtain an oceanic clearance from the first OAC before reaching their entry point into the NAT-OTS. So to answer directly your question:

The crew using the track system will be in contact with the OCA/OAC controllers during the flight between domestic areas. However to bear with possible unreliability of HF radio transmissions, this contact doesn't have to be permanent. Instead it may occur only at intermediate reporting points spaced by 10° longitude.

They will also be in contact with FIR/ACC controllers prior to entering and after leaving the OCA/OAC.

Transition areas (OTA) exist to bridge between ACC and OAC: See areas ending in "OTA" in the Shanwick FIR/OCA, like BOTA for Brest OTA, bridging Shanwick OTA (UK) with Brest FIR/UIR (domestic France). In OTA, traffic is handled by the regular domestic FIR (actually its UIR, given the altitude flown at this stage) rather than the OCA.

North Atlantic ocean is covered by 6 OCA managed by different ICAO member States: UK (Shanwick), Iceland (Reykjavik), Canada (Gander), Norway (Bodø), USA (NY West) and Portugal (Santa Maria).

North Atlantic OCAs (source ICAO, now removed from the site)
A common route for the flight you mention will cross Shanwick and Gander OCA.

(source FlightAware)
FIRs and their boundaries worldwide can be displayed with this ICAO GIS viewer (be patient at the first use, background resources take time to load):

(source: ICAO FIR viewer)


If you don't crawl underneath and breathe in the exhaust fumes from the engine, you'll be fine.  If you do crawl underneath and breathe in the exhaust fumes, you'll be dead from carbon monoxide poisoning long before any harmful effects from the tetraethyl lead combustion byproducts in the fuel.
While you don't want to ingest lots of lead, that won't really happen being around airplanes with engines running.  The old saying in toxicology is, "The poison is the dose", and whatever dose you get from casual exposure is too microscopic to matter.
My advice, as an old-timer who likes a clean world as much as the next guy, is don't become so hyper-sensitized (by mostly media coverage) to environmental exposure to chemicals that you can't enjoy life. It's not worth it.


How should passengers report SOS signal sightings?

There is a procedure, at least for the aircraft crew.

It is appropriate for a flight crew to transmit a "pan pan" or even a "mayday relay" so a passenger should immediately inform the senior cabin crew member, usually by asking to  speak to the "purser".  SOS is an internationally recognised distress signal.  If the purser did not act upon it, I would politely, but assertively request that they inform the captain since these procedures are part of standard pilot training and flight crews are required to respond to potentially life threatening situations.

Reporting emergencies or urgent situations is not restricted to the aircraft itself.  It can, and should be used, where any threat to life or safety  is real or possible.  ATC in turn can contact the appropriate local resources depending on the situation.

An example would be if I was flying and witnessed a fire or perhaps a road crash and emergency services were not already in attendance, I would not hesitate
to contact ATC and be prepared to offer assistance if possible, for example relaying position or exact circumstances.

You did the right thing.  Perhaps you could have been a bit more assertive at the time, when the cabin crew member incorrectly told you that there is no procedure, since minutes can count.


Are there any aircraft with a 4-wheel nose landing gear and a 16-wheel main landing gear?

The Il-76:

4 main bogies with 4 wheels each, nose gear with 4 wheels.

this one has a better view of the wheels, but it's a CGI:

4-wheel nose gear is rare, 16-wheel mains are more common: Boeing 747 (4 trucks with 4 wheels each in 2x2 config), Avro Vulcan (main trucks with 2 axles with 4 wheels each), HP Victor (same as Vulcan), Shorts Belfast (same as Vulcan).


How would you get certified for the AgustaWestland AW609 as a rotorcraft pilot or without any previous certification?

I know nothing about powered-lift aircraft, but according to 14 CFR 61.5 they're a separate category for licensing, like airplane, rotorcraft or glider. It is therefore possible to get a "private pilot powered-lift" certificate without having any flying experience in any other aircraft type. 14 CFR 61.109, 61.129 and 61.163 state the flying requirements for private, commercial and ATP powered-lift ratings respectively and 61.65 has the requirements for a powered-lift instrument rating.

61.109(e)(5) does allow substituting some limited airplane (i.e. fixed-wing) experience for powered-lift time:

  (5) 10 hours of solo flight time in an airplane or powered-lift
  consisting of at least—

There are also allowances for using simulator and military experience in lieu of powered-lift flight time, but I couldn't see anything that directly allows rotorcraft experience to count towards powered-lift certification. The fact that powered-lift is a category of its own suggests that the FAA considers them to be significantly different from rotorcraft.

So yes, you could theoretically start from zero and work to get your private, instrument, commercial and/or ATP ratings with flying time in powered-lift aircraft only. If, that is, you can find a powered-lift aircraft and an instructor: an ATP requires 1500 hours of experience and doing them all in powered-lift aircraft may not be practical (61.163 only requires 250 of them to be in a powered-lift aircraft).

In reality, I suspect that any civilian powered-lift pilots who are not ex-military are (or will be) people with extensive rotorcraft and/or fixed-wing experience who then follow a training program provided by the aircraft manufacturer. Your insurance company will probably also have a say in who you hire and what experience they have.

Finding and training those people won't be cheap, but if you're buying up new AW609s then you can probably afford it :-)


How do I achieve a lower stall speed, and capture potential CLmax without enough elevator control authority?

It depends, partially on what you precisely mean with "trim".

Pilots use a rather narrow definition where trimming means to zero the control forces for a specific control surface deflection and speed. This is achieved by tabs or springs in the control linkage.

Engineers use it more broadly and include the ability to deflect control surfaces such that the desired attitude can be stabilized. I guess that you refer to this line of thought.

Long before the lift coefficient of a stalling airplane peaks, the flow over part of the wing will start to separate. Ideally it will do so near the trailing edge of the wing root, and the separation will slowly progress forward and outward as angle of attack increases. This separation will shift the local center of pressure back, such that the aircraft will experience an increasing nose-down moment as it approaches stall. To stabilize it at higher angles of attack will, therefore, need nonlinearly increasing elevator deflections. Depending on the position of the center of gravity, the installed elevator authority might not be sufficient to trim the aircraft all the way into the fully developed stall.

If you mean the first interpretation of "trim", then yes, most aircraft will not allow you to zero stick forces into the stationary stall. The trim range should cover the speed for steepest climb, not more. However, if the center of gravity range is wide enough, you should be able to trim an aircraft with rear c.o.g. all the way into the stall. After all, with neutral stability you can ideally trim (second interpretation) any angle of attack with the same elevator deflection angle (note that the nonlinearity explained above will require more negative elevator deflections as you approach stall even in a statically neutral aircraft).

I would rule out that the control forces are too high - after all, when stalling in level flight at 1g the aircraft will fly as slowly as possible, so stick forces should be small.

The effects of thrust depend on the engine installation. With a propeller, more power will add torque and increase the dynamic pressure at the tail. Now it depends whether the prop blast will hit the empennage - if it doesn't, the effect of adding power will at best be be an asymmetric stall.

In case you have a configuration change where the older configuration is known and the new should give the same flight characteristics, use tail volume as a sizing parameter. Horizontal tails of the same volume should give the same control power. Volume is the product of area and the lever arm between tail neutral point and the center of gravity. If the new tail has a different dihedral angle, don't forget to add the cosine of the dihedral angle.

When comparing elevators of the same size but of different flap chords, use the square root of the relative flap chord for comparison. Say the old elevator has a 20% flap and the new one 30%. The new one will have 22.5% more control power for the same deflection ($\sqrt\frac{0.3}{0.2}$).

Depending on elevator chord, at some point more deflection will not help much (typically 20° for a 25% elevator - going higher will add little control power). Now several options can be employed to increase control power:

Change the incidence of the stabilizer. That is what airliners do to compensate the massive trim changes caused by Fowler flaps.
Add leading edge devices on the stabilizer to make the elevator more effective. This adds a lot of complexity for a small gain, however.
Use slotted flaps and double flaps to eke more control power and higher useful deflection angles from an existing elevator. Again, airliners with their wing flaps should point the way.

In damping, both the dihedral angle and the lever arm have a quadratic influence while they have a linear influence on control power. This way one can adjust damping and control characteristics individually.


Are NPRMs published in the Federal Register?

Since posting my question, I've learned that the answer is "yes".  For example, the following URL opens to a FAA NPRM published in the Federal Register: https://www.federalregister.gov/citation/57-FR-18954


Why is an ATC operational error called a "deal"?

The first time some of us heard this term was from a controller at a fly-in breakfast, perhaps in the early 80's.  One of the people in the group asked for clarification, and was essentially told that a "deal" was a "big deal" and that a report had to be written and reviewed, and it had the potential of being a factor in a performance rating.

The "deal" in this case was a maintenance truck which was still on a runway, after a 727 was cleared for takeoff.  The 72 driver saw the issue and delayed takeoff, but it was on the tapes, and there were people in the cab who saw it. So paperwork was filed.

Rumor had it that the processes for deviations were relaxed for the new controllers after the strike/firing of controllers under the Regan administration.


Does the FAA maintain pilot records from before 1998?

If you took a checkride the FAA has your 8710 (form you would have filled out) which will have your flight times and can be used as proof of time.  Follow these steps to get your records.

You can search the airman database.  My father's and grandfather's records are in there from the 1970s and 1980s.  This just lists certificates though, no times.

You can also request a replacement certificate.  If you are a PPL then they will send you one.  You'll need to do this anyway to get the new plastic card.  Also, no times...just a certificate...which prove that you have at least the minimum flight time required to hold the certificate.

Good luck.


What is the gray zigzag line over V154 between Dublin VORTAC and LOTTS intersection?

According to the “Airspace Information” section of FAA Aeronautical Chart User’s Guide, it is a low-altitude unusable route. The high-altitude flavor is similar in shape with a smaller amplitude.

See also page 62 of the Guide PDF, if you prefer.

  UNUSABLE ROUTE

In this particular case, observe the overprint on 110 in the compass rose surrounding DBN, which indicates abnormal status. The Airport/Facility Directory entry for Dublin VORTAC (as of the 31 MAR 2016 publication) reads, with added emphasis:

  DUBLIN N32°33.81′ W82°49.80′ NOTAM FILE MCN.
    (L) VORTAC
   113.1   DBN   Chan 78   276º 7.9 NM to W H 'Bud' Barron. 306/5W.
  HIWAS.
      VOR portion unusable:
        215°–285° byd 10 NM blo 3,500’
        001°–139° byd 33 NM
        001°–139° blo 5,000’
  RCO
   122.1R 122.6 113.1T (MACON RADIO)

Note that the DBN 110 radial falls within the 001-139° unusable range. Beyond LOTTS intersection, V154 is defined with reference to the Savannah VORTAC.


What is the buzzing noise generated by the engines in this 777 takeoff video?

That buzzing sound is from the tips of the fan blades breaking the sound barrier.  When you're sitting farther back in the airplane, that sound is overpowered by the sound of the exhaust, which is the roaring part of a jet engine's sound.

So in general, sit forward of the wing, you'll hear the fan sound (the buzz), sit aft of the wing and you'll hear the exhaust sound (roar).  It'll vary from airplane to airplane of course, and when thrust is reduced and the fan speed slows, the buzz will subside.


Does the cockpit have an alarm to warn about fuel leakage?

In a typical trainer aircraft (in this case, a C172), you have an annunciator panel that includes a "Low Fuel" light:

These lights only come on when fuel is low if the lights are functioning properly. This panel is located prominently, and is easy to notice. This is only one aircraft, but when you consider it is an entry level aircraft that is less sophisticated, it gives a baseline idea of what you could expect to see.
Also, there are fuel gauges displayed with all engine instruments that will indicate accordingly. While this isn't a leak detector, pilots are trained to monitor all instruments regularly and cross check the values - which is how a leak is identified in aircraft with low amounts of technology.
It is worth noting that checking the "LOW FUEL" annunciator is off is a regular checklist item that occurs before you start your actual flight.
As GdD mentions in the comments - you are taught not to rely on any one instrument indication, and panel lights are no exception.


Would it have been feasible to install 'conformal fuel tanks' on the Mercure?

Adding conformal tanks will add drag and weight. Each on its own will impact performance but both together will definitely have a huge impact and I doubt that it would even get airborne.

The reason that jet fighters have these is for ferry flights eg deployment overseas.. and since they usually leave the bombs/missiles/etc behind on these ferry trips there is not a big increase impact in take-off weight.


What is the significance of Slip-Skid Indicator in PFD?

The slip/skid indicator is the small bar under the roll pointer. The image below should clarify that.

Image from flightlearnings.com

The Slip/Skid Indicator (sometimes called turn-and-bank indicator) moves left and right relative to the roll pointer in proportion to lateral acceleration and helps the pilot correct for any deviations in a turn.

In a level flight, the indicator is centered. Assume that the pilot is executing a left turn (the roll pointer would've moved left)- if the indicator is in center, it means that the turn is coordinated i.e. the aircraft is not slipping or skidding.

If the indicator (bar) is moving right, it shows that the aircraft is skidding. Movement in the opposite side (i.e. towards the left, same direction of turn) indicates that the aircraft is slipping. This enables the pilot to take corrective action. This is one of the necessary flight instruments.


Why is the temperature of the cabin so low during a flight?

On the 737, I can make the cabin as hot as I want to; the challenge is more often adequate cooling if the aircraft got hot on the ground. With the insulation that the aircraft has, the generated heat of 100+ people in a confined space overwhelms the cooling of the outside air. (Yeah, it's utterly counter-intuitive, and I can't explain the why, but that is the way it goes. With the loss of all bleed air, the cabin will get hot -- although that's at 10,000', where you descended after the depressurization.)

I've never been told to run the temperature hot or cold as a fuel-saving measure. In theory, you save a little gas by not running the AC packs in "High", but again, that's mostly used to get more cooling air. Or to quickly warm a jet that sat unheated all night in freezing temperatures.

If the cabin was unbearably cold on a particular flight, somebody just wasn't attentive to the temperature. On any modern airliner, we have the tools to warm things up. Maybe the flight attendants prefered a cold cabin & had sweaters to wear; maybe "really cold" to the OP is actually pretty comfortable to others; maybe the thermostat was indicating erroneously high temperature in the cabin so the automatic system kept putting out cold air; or, maybe the pilots were being jerks and "freezing out" the flight attendants (and passengers) for some reason. Unlikely, that last, but not impossible or unheard of.

As far as a preference to run slightly warm or cool, cool will generally win, simply because warm tends to make airsickness worse, while cool has the opposite effect. On a bumpy flight, the last thing you want is a warm cabin; the saying goes that "popsicles don't puke," and it is accurate.


What is this wire going from mid-fuselage to the tail on this 737?

It is the HF antenna. It was mostly used in older aircraft, which used them in trans-oceanic flights or in areas without UHF or VHF communications facilities.Modern 737s (and other aircraft in general) have done away with them. On later versions it was fitted in the leading edge of the Vertical fin of B737-200s, as shown in the figure below.

Image from b737.org.uk

Note that these aircraft were delivered in 1982-83. Newer 737s don't have these.


What is the stress tolerance of landing gear of commercial aircraft?

First off, the thud and deceleration may be more related to the conditions as well as the runway length than pilot skill, but lets discuss some of your questions.

  1) Please elaborate on the stress tolerances built into various parts of the landing gear of common commercial aircraft, such as the Airbus
  A320 and Boeing 737?

This is a complex question to answer simply as airplane gear sees lost of loads and some compromises are made for simplicity of operation. For one the rubber used on the tires is quite thick since some of it does wear away on every landing since the gear is not spinning when the plane touches down (you can read more on why not here) The tradeoff here is weight (you need to haul the tires around with you) but they can be used for many cycles. The vertical load is generally handled by an Oleo Strut these allow for a margin of error but they (or the gear system) can be bottomed out and a hard enough landing can result in a bounce. The last serious load that gear sees is usually side loads when a crosswind landing is made. These are tough to mitigate and its generally the job of the pilot to reduce these loads they will manifest them selves as tire wear and mechanical wear. Perhaps the coolest solution to this was the B-52's full rotating gear.

(Source)

One of the more interesting non Oleo designs for GA gear is the rubber disks used on Mooneys. These are said to require less maintenance and are easier to replace but are far less forgiving than Oleo struts.

(source)

Some of the vertical force is absorbed by the tire its self when the plane touches down the tire does ballon out a bit. As such it is of vital importance that the tire pressure is within a small margin since low pressure can cause excessive ballooning which would lead to side wear depending on gear design.

  2) What kind of stress testing is done on crucial parts of the landing
  gear, such as tyres, wheels, axles and hydraulic parts?

These parts are generally made by different manufactures and are designed to comply with the aircrafts specs as set fourth by the builder (Boeing etc). Like everything else on a plane these parts have a cycle life (TO/LD) and are replaced when necessary. Since they are high impact I would assume the life is on the shorter side generally speaking. Here is some info from Goodyear on how to care and maintain tires for aircrafts. Heres some good info on Oleo struts as well.

  3) What are the backups and fail-safe measures designed into such
  landing gear?

This depends on the plane, bigger planes generally need to spread the load out over more axles/tires which gives them greater redundancy a plane like a 747 has 2 sets of twin axle main gear on each side of the plane so you could lose an axle and still be ok (relatively speaking)

(source)

compare this with a 737 and you will see that the main gear is less redundant as its a single axle only system. In this case losing one of two tires would be less catastrophic than losing all the gear.

(source)

Compare this all to a smaller GA plane where you generally have a single wheel situation

(source)

The one thing all these planes have in common is that the nose wheel is the most delicate part of the landing gear. Hard landings on the nose wheel can collapse the gear or cause porpoising both of which are bad. This is what happens if the gear does not rotate properly in other words that nose gear saw complete side loads. Planes have be successfully landed with collapsed nose gear or nose gear that wont come down. Its a sight but generally speaking its not the worst thing to happen.

Sensors: The only sensor I know of on the gear (and this is plane dependent) is the squat sensor which is a simple on off for being on the ground or not. The FDR will record 3-axis acceleration but that will be of the airframe which is behind the Oleo struts so the gear its self may see higher loads.


Is the word “bomb” muted in inflight movies?

This might be dependent on the airline?

I usually fly Emirates and the movies are not muted for the word "bomb". Maybe because each seat has its own entertainment console?

In the old days when there was one giant projector that displayed movies (which was later replaced by TVs that articulated from the ceiling) - I suppose in these scenarios it might be prudent to mute words or scenes.


Can a zero hour pilot actually launch a Bombardier Q400 with only simulator experience?

You don't even need your own simulator. Here is a good video of how to start a Q400 (taken from a sim game) and here is one from a tech going through an actual cockpit. There is even a chance there were checklists in the aircraft when he arrived.

To get off the ground he really just needed to know how to gun the throttles and roughly when to pull back on the yoke to get airborne. These numbers can be found pretty readily around the web. Considering his fuel and cargo load and depending on the trim of the aircraft it may have even started flying with almost no control inputs.

Whats important to understand about some of the maneuvers he did was the fact that the aircraft was empty and flying on a partial fuel load which will make it easier to do some of those things. I will refrain from diving deep here until the NTSB report is out but at full throttle planes are capable of quite a bit. Rolling an airliner is not out of the question in the right scenario.


How can flying high minimize drag and increase fuel efficiency?

Flying higher means less drag because the air is thinner; therefore, you can fly faster at altitude and hence travel farther on less fuel.

However, flying higher also means less oxygen available to burn your fuel, so available horsepower decreases with altitude.

There is a special altitude at which these two effects (drag reduction and available power reduction) achieve a crossover point. This is called the critical altitude and it is there where you achieve optimum cruise and best economy.

If you want to fly higher than critical altitude, you will fly slower because the power loss is greater than the drag reduction and you will spend more time in the air.


Why was the 307’s pressurisation system removed when it was modified into the C-75, despite the fuel-burn advantage of higher-altitude flight?

Pressurization is primarily for crew and passenger comfort. The B307 was a very early attempt at cabin pressurization and the marginal pressurization differential of only 2.4 psi did not allow much of an increase in cruising altitude.

The difference between 8,000’ and 12,000’ did not really justify the added expense and weight.

When the B307s were converted to C-75 military cargo configuration, there was even less justification for pressurization as military crew and passengers would not expect the comfort of pressurization. The C-75 could still fly at altitudes up to 23,000’ but the crew and passengers would just need to use supplemental oxygen.

The B307 had Wright R-1820 engines which were similar to B-17 engines except they were only supercharged and lacked turbochargers. Cabin pressurization was supplied by compressors mechanically driven by the engine. These compressors would rob the engines of power so removing them would allow the aircraft to fly higher but with less comfort.


Has a small airplane ever been air launched from a heavy-lift helicopter?

November 2017 the Dream Chaser shuttle craft was dropped from a Chinook helicopter
from over 12,000 feet.  The automated glide test back to a runway near Mojave, California
was a success.


No.

Think about what you are asking.

Scenario:

You're a captain at the pointy end.  All your instruments have failed.  Maybe let's add in some extra emergency element for good measure.

You need to land at the nearest usable airfield using little more than the good old Mk1 Eyeball.

Your concept of an "IFR only" airfield can shout "IFR only" down the radio all they like until they are blue in the face.  But in line with the rules of the air, the captain has the ultimate authority, if he's got clear VFR, he'll be landing there as he has no other options.

Keeping the spam-can brigade out of the way of busy airfields is not the job of airfield policy, its the job of airspace policy. And that works perfectly well.

Conclusion:

Even if they might be rarely used on a daily basis, having VFR procedures in place is important whether you are a major airfield or some grass strip.

That way, everyone knows what is expected of everyone else.


What effect do slats have on descent rate?

If the slats would increase L/D, they would not be retracted in cruise.

TomMcW is right, any high lift device increases drag when compared to a polar point that is within the regular operating envelope of the clean wing. How much so can be answered when looking at old wind tunnel data published by Sighardt Hörner in his classic "Fluid Dynamic Drag":

Figure 6-20 from Fluid Dynamic Drag comparing different versions of the Fieseler Fi-156 "Storch" slat. Although it is not explicitly stated (and the original report in the Jahrbuch der deutschen Luftfahrt-Forschung of 1940 is not available online), it must be assumed that the lift coefficients of (a), (b) and (c) are similar. After all, Mr Hörner worked at Fieseler in Kassel and contributed to the aerodynamic design of the Fi-156, so he should have been intimately familiar with this airfoil.

Version (a) at the bottom is with a gapless slat and produces a drag coefficient of 0.015. Version (b) is with a gapped slat but blocked flow, and the drag coefficient shows a small increase to 0.018. Once the gap is opened (c), the drag coefficient jumps to 0.03. Note that at a higher angle of attack and lift coefficient (d), the drag coefficient is slightly reduced (0.028). But it is safe to assume that a deployed slat roughly doubles the airfoil drag.

If thrust and speed are not changed, deploying slats will increase sink speed. If I further assume that this descent is done at optimum L/D (zero-lift drag equals induced drag), then a doubling of the zero-lift drag of the wing will increase total drag by maybe 17%, details depending on the share the wing has in overall drag (I assume for the figure above that this share is ⅓).


How frequently do civilian aircraft have mechanical issues to which passengers are oblivious?

I don't think you'll find a definitive answer because most will be just considered routine items, but if you're including non-safety-critical items then I imagine the answer is "lots". Passenger aircraft are huge, complex, mechanical devices with many many parts. It is accepted and expected that some of these things will occasionally fail.
Most of these can fail gracefully without impacting the flight in any way beyond a note in the tech log. Not only that, but lots of things can be known to have failed but still allow the flight to go ahead as normal.
You may wish to explore the idea of Minimum Equipment Lists. These provide exhaustive lists of items which can fail and flights can still be dispatched as normal. Note this isn't the same as an in-flight failure occurring and continuing to the destination - items in these lists can be failed before you even take off.
For example, here's one for the Airbus A320: https://fsims.faa.gov/wdocs/mmel/a-320%20r21.pdf
Everything listed in that document can be failed in some way, but a flight still operate as normal (with exceptions, as per the remarks column)
For example, and to highlight the level of detail, an Airbus A380 does not need to be grounded because the "PA In Use" notification light doesn't work.


How is structural damage to a composite fuselage detected?

I can't personally speak for the Airbus, or Boeing methodology regarding damage diagnosis, however speaking as an A&P IA FCC, experienced in the Business, and General Aviation Industry, the diagnosis will employ, one or a combination of all of the following inspection methods:

Visual
Coin-Tap
X-Ray
Ultrasonic


Do instrument approach procedures sometimes have a minimum temperature?

There are procedures with temperature restrictions, related to altitude constraints. An example is Innsbruck:

The text in the red box says:

  Procedure N/A below AD temp -7°

For effect of temperature on altimeter: How will the altimeter read in air colder than ISA?


What variant of Mi-8/Mi-17 is this near Kennedy Space Center?

I have a better candidate than the Mi-17MD now:  what I think is the next version after that, the Mi-17V-5.  The feature that really prompted the question was the heater not being in the place I'm used to; the V5s have an enlarged right-side door, and that apparently necessitates moving the heater to the top-right position (from where the KO-50 used to be, right, extending from the same bulge that extends forward from the right main gear).  Oddly, it's not clear to me if all V-5s share the door or not--Airforce Technology makes the right-side door sound optional, and it's tough to tell if various internet sources are just using stock of any Mi-8 when they refer to some country or other purchasing V5s or if they're making sure they're getting it right.  Mi-17MDs in the service of the Colombian Air Force seem to delete the heater unit altogether.

The only other thing I'm wondering about now is the large open hatch above the right-side landing gear.  Most Hips have round windows there.  That might some kind of optional equipment though.

...there also may be a roundel just behind that hatch, but I can't tell what it is.  The CH-178s had similar roundels there, but I really really don't think it's one of those.


What are the advantages of the Airbus New Engine Option (NEO) program?

How does adding more options for engines for potential customers act as an advantage for the Aircraft Manufacturer?

There are a couple of ways of looking at this

Why new options?
Why multiple options

Change

The A320 has been around a while, engines have improved a lot and newer types of engine exist now that were not available before, even though the A320 type airframe is still competetive.

According to Airbus, new choice of engines allow for

Lower fuel costs
Lower maintenance costs

  Airbus is working on offering a new engine for the A320 known as the New Engine Option (NEO). The choice for new engines include the CFM International LEAP-X and the Pratt & Whitney PW1400G/PW1500G. The new engines will burn 16% less fuel: the actual fuel gain on an A320 installation will be slightly less, since 1-2% is typically lost upon installation on an existing aircraft. Airbus CEO said to be "comfortable" with the projections of 20% lower maintenance cost for the Pratt & Whitney's PW1000G family, compared with today's engines.

From Airbus

Choice

Speculating a little:

The people who buy and operate aircraft like having a choice of engine manufacturers. It helps keep the engine market competitive and it means they can, if they want, operate a range of aircraft all using engines from one maker - potentially allowing for savings in engine maintenance infrastructure.

Aircraft operators sometimes don't actually buy engines with their aircraft, they buy thrust from an engine maker and the engine maker (effectively) install their engines on the operators aircraft. The engines might remain the property of the maker.

It may also be that aircraft makers don't wish the future of their aircraft to be tied to a single supplier of engines. It makes negotiating harder and it makes their future prosperity dependent on the continued existence of one manufacturer.


Are there technical means to enforce aircraft speed limits as well as regulatory means?

Some aircraft have flight envelope protections which, among other things, aim to prevent the aircraft exceeding a predefined maximum airspeed.

High Speed Protection:
Prevents exceeding VMO or MMO by introducing a pitch up load factor demand.
The pilot can NOT override the pitch up command.

- AirbusDriver.net
Note that these are structural safety limits, people on the ground cannot use this feature to impose arbitrary speed limits by geographic area, time of day etc.


How can I mount my iPhone 6 in the cockpit to record my flights?

UPDATE  9/4/2017
I'm thrilled this post has been so helpful for so many people. As such, I wanted to  update it with more details and more current links in case people are interested. Enjoy!

You could have a lot of fun, and get a lot out of reviewing the footage of your lessons. I'd look into a suction cup mount as you are already considering. When buying a suction cup mount, make sure you get one that is "beefier" than you expect you need. Whatever you do, make sure you share your videos online, your video might even get someone else interested in aviation!
Below are the details of doing what you asked. You might be able to buy a used, older model gopro for a comparable price - but I'd actually argue your phone is probably a better option.
What to buy:
(this all actually gets kind of expensive, but is still cheaper than buying a go pro and accessories)
Must have:
To get GoPro functionality from your iphone, you'd need a mount and a case:

http://amzn.to/1ZQDx7q (Optrix Super Sucker Mount)
http://amzn.to/1MyN1uc (Case)

This is a mount that mimics the functionality of a go-pro mount. It also let's you know if pressure is dropping in the suction cup as you climb.
If you ever feel brave enough you could even stick this to your wing!

http://amzn.to/1GmeYbU

The view angle probably is not wide enough. This inexpensive kit will apply a wide angle to your iphone. I'd make sure your case/mount doesn't preclude using one of these.
Best alternative camera to GoPro:

http://amzn.to/2vZsQEx (Garmin Ultra Virb 30)

I love the aviation data overlay of this camera. It works very well and helps debriefing a lot. I personally prefer this over my GoPro because it includes that data.
Best GoPro options:

http://amzn.to/2xJKn67 (GoPro Hero5 Black)

4k resolution @ 30FPS, 12MP quality is great. I use this mainly for wing mounted shots.

http://amzn.to/2eDiQi3 (GoPro Hero5 Session)

The nice thing about the session series is they are small and super simple to operate. I use this camera to point inside the cabin, on the side windows. It is nice because it doesn't block as much of my view outside, even in a mount on suction cups.
Important Accessories:

http://amzn.to/1ZQERqT (Zoom H1)

I use this to record ATC/Headset audio. It is easy to have it recorded to its own device and lets me have better control over the audio recordings than if it was part of a video file. The audio is oftentimes more useful than the video alone, especially with your instructor explaining things to you. Having a separate device also reduces your point of failure risk if you have a camera battery die.

http://amzn.to/2wAg29z (Headset cable to record audio)

You need this cable to "grab" audio from your headset jack to record it to a camera or external recorder. (Note- the Garmin Virb 30 Aviation bundle includes this)

http://amzn.to/2wAo1Uh (External Battery)

You will be running out of battery fast if you record HD video for any length of time. This external charger will keep you from running out of battery.

ND (Prop) Filters (remove the weird prop strobing from your footage)

(Note- the Garmin Virb 30 Aviation bundle includes this)

http://amzn.to/2xJhxm9 (GoPro Hero5 Black ND Filter)
http://amzn.to/2exTIFG (GoPro Hero5 Session ND Filter)

Placement:
The best place to put it would be between the seats on the ceiling pointing landscape style towards the instrument panel. This would give you a view of all of your instruments and maybe even a bit of the horizon. At first, we all struggle to use the horizon as a reference instead of instruments, so putting the camera close to head level might help develop a good sight picture.

Here's a video using the angle I am referring to.
Unless you set up a second camera, you are unlikely to get rudder input on film. This video shows a good example of that angle, but might be impossible while getting dual instruction.

Video showing rudder control input on takeoff
Words of caution:

Make sure your filming doesn't distract you. This is really serious and not something to shrug off. Remember, you don't want the FAA to have footage to shove in your face of you being reckless.
Make sure you don't damage the aircraft with the mount. The windshields in particular are vulnerable to being squeezed out of shape from the pressure in the suction cup, especially if they are hot. I have seen some indented windshields recently due to gopro mounts, which makes it very hard to get a normal sight picture (imagine looking through a fun house mirror).
UPDATE
Another issue I recently saw was a result of someone using this camera: http://amzn.to/1oos68G. The camera has a built in rare earth magnet which made mounting it very easy. The problem was, it was impacting the magnetic compass - so be aware if you get a magnetic mount to make sure your compass is not affected by it being placed in the cockpit! When attached to the overhead speaker we saw no visible impact on the compass, but worth keeping an eye on.

Take a look on youtube at some popular pilot channels to see how they record. From there, you can pick your favorite angles and splice a film together.


Why are autonomous vehicles not used at airports for on-ground services?

Many of the ground vehicles need to have a trained human to make it useful for the plane (for example the fuel truck, mobile stairs, ...) so it makes sense for it to cart the trained human around. If you do that you may as well make said human drive. This means there is a high ratio of human controlled vehicles mixed with the autonomous vehicles. There are also the firetrucks that need priority, giving it to them sometimes needs human intuition in where you stop or move to to make a path.

You don't want the vehicle to path underneath an airplane and cause damage, or potentially end up in the jetblast.

Someone needs to monitor them and coordinate with the ground controller whenever they need to access/cross the taxiways.


May a VFR-only pilot without high-performance or complex endorsements be the safety pilot for an IFR currency flight?

First, can a pilot without an HP endorsement act as safety pilot in an HP aircraft? Since 14 CFR 91.109 only requires a safety pilot to have category and class ratings, there's no need to have any additional endorsements.

That's confirmed in this FAA legal interpretation:

  there is no regulatory requirement that a safety pilot have a
  high performance endorsement to act as safety pilot

The same document says that safety pilots are "encouraged to be thoroughly familiar and current in the aircraft that is used" - which is great advice - but that's it.

As for the flight conditions (IMC/VMC) and rules (IFR/VFR), I'm not sure what you're asking. Is either pilot IFR current? If not, then the flight can only be VFR. This question might be relevant.


Do crews look for "Dr." on a passenger manifest to identify medical doctors?

You are correct that it is done by PA rather than by reference to the manifest, at least at my carrier in my type of aircraft. As you surmise, the "Dr" notation has too many opportunities for both false positive AND false negative results to be where you want to start when time is of the essence.

Besides, if you need medical help at 40,000', you're probably much better off in the hands of a good E.R. nurse or paramedic than with a radiologist who hasn't done hands-on emergency care since his residency.

Most airlines use a service that's reachd by a phone patch to an E.R. doctor who specializes in evaluating these sorts of situations (and recommending, divert now or continue on), so any medical professional on the aircraft is working under his direction. He is also familiar with the contents of a medical kit carried on the aircraft just for these situations, so he can say "have the (nurse/paramedic/doctor/etc) administer ___ out of the medical kit" already knowing what is & isn't available.

Interestingly, a veterinarian can also administer the same medications the other medical professionals can in this sort of situation!


What exactly is tower enroute control? Is this similar to 'preferred routes'?

Tower enroute control is similar to the preferred route in that both are designed to improve the system effeciency. FAA defines the Tower En  Route Control (TEC) (in AIM section 4-1-19) as:

  TEC is an ATC program to provide a service to aircraft proceeding to and from metropolitan areas. It links designated Approach Control Areas by a network of identified routes made up of the existing airway structure of the National Airspace System.

Preferred routes, on the other hand (from Instrument Procedures Handbook) are defined as:

  Preferred IFR routes are established between busier airports to increase system efficiency and capacity. They normally extend through one or more ARTCC areas and are designed to  achieve  balanced  traffic  flows  among  high  density terminals.

This outlines one of the major differences between the two: in TEC route, you never 'talk' to the ARTCC. As flyingmag notes:

  TEC flights are intended to be relatively short — generally two hours or less, and are conducted below 10,000 feet. Throughout the route, communications are managed through tower controllers, and departure and approach controllers at a TRACON facility. You will never talk to ARTCC.

Another important thing is that the TEC is essentially equivalent of getting a pop-up IFR clearance, as already noted (from AIM section 4-1-19):

  There are no unique requirements upon pilots to use the TEC program. Normal flight plan filing procedures will ensure proper flight plan processing. Pilots should include the acronym “TEC” in the remarks section of the flight plan when requesting tower en route control.

The TEC is established only in areas with Radar coverage. US DoT WP AT 7110.5A specifically notes:

  TEC should be established/expanded only within areas of radar coverage. In areas without radar coverage ... an equivalent level of safety is maintained, TEC may be established and/or expanded.

TECs basically are published preferred IFR routes that are entirely in TRACON airspace. As a result, most of the TECs are in the northeast and the west coast (which can be found here), where the airspaces are close enough that one can fly with Radar coverage the whole way.


What are the factors behind increasing aircraft window sizes?

In the early years of the jet age, which followed closely on the introduction of pressurized hulls, there was much fear of stresses specifically in the area of the window openings due to the loss of two DeHavilland Comets. Subsequent Comet hulls had different shaped, rounded, smaller windows and that trend continued in other pressurized, typically jet-powered, aircraft.

Only with modern CAD systems and new materials knowledge could windows be made larger again. The newest aircraft designs reflect that progress.


Why didn't planes land from the sea in the old Kai Tak Hong Kong airport?

Reading up on the old Hong Kong airport Kai Tak, I'm left with the question as to why the planes didn't land from the sea?

It's a small point, but Kai Tak was not next to the open sea but rather alongside Victoria Harbor. Most of the rwy 31 final approach was over the harbor but with mountainous terrain on either side. The rwy 13 final approach was over Hong Kong island, then Victoria Harbor, then Kowloon.

Both rwy 13 and rwy 31 were used for takeoffs and landings depending on the wind, and winds in Hong Kong were often strong right down to ground/water level. Generally the prevailing winds favored rwy 13. By that I mean that when tracking the runway just before touchdown or when taking off you would have a headwind component. However, because most of the time there was a crosswind, it often meant that when approaching for landing but before you made the 47 degree right turn from the IGS course to short final, you had a tailwind component.

Both runways could be very turbulent. If ceiling and visibility were poor, that always meant a rwy 13 approach, at least that was my experience. The worst turbulence, though, was in severe clear conditions to rwy 31 when the wind was coming off the Chinese mainland.

I have a blog item about operating into Kai Tak on my website. You can look at it here.


What drives the design decision of where to place the refueling receptacle?

Usually just a matter of constraints on where the engineer can physically fit the fueling port with the limits that it must be an upper surface, not too near critical components that may be damaged, and have minimal aerodynamic impact. The plane must also deal with the substantial change in center of mass and angle of attack[required lift] during the fueling. All these factors vary with the design goals of each model.

The drogue and probe method is used by the US navy and most international air forces. This is a very adaptable system that can fuel multiple small planes from wing mounted hoses on one tanker or small plane to small plane, and even works with helicopters(using a very long probe); the down side is that maneuvering to couple is more difficult and each drogue design has a narrow speed range. The probe must be in located view of the pilot.

The port and flying boom method is used by the United States air force; it was developed by the strategic air command early in the cold war for strategic bombers. As such the flow rate of the flying boom is an order of magnitude larger than the hose and probe, and it can be used across a very wide speed range without changing parts, with added benefit of no probe to effect drag, radar signal, or to get damaged; the downside is the tanker can only serve one plane at a time, the port must be on an upper surface, and the tanker needs a boom operator.


Why does load shedding still occur in jetliners (e.g., 787) when there is so much power available?

Load shedding always occurs during engine start, according to the FCOM of the B789. Both engines are allowed to start simultaneously. The B789 engines are started using both VFSGs of each engine, which are mechanically connected to the N2 shaft via the accessory gearbox. So, the VFSGs are using power instead of delivering during engine start. The APU cannot provide enough power to prevent load shedding.

If the engines are started using external power, at least two 90 kVA external power sources are required. Optimal start performance is achieved using 3 external power sources (2 on the left forward fuselage and 1 behind the left wing on the fuselage). If only 2 external power sources are used, significant load shedding can occur (e.g. First Officers displays blanks and even the audio control panel receive and trasmit selections may be lost).

The APU is normally switched off during flight, unless e.g. one VFSG is U/S.

Load shedding should normally not occur when both engines are running and all VFSGs are operational (I haven’t experienced load shedding during flight).


How to not converge or diverge from the runway when there aren't checkpoints?

I'd like to add something to Ron's answer.  Use of geographic checkpoints is used a lot in initial training but it can become a debilitating crutch that leaves you in the lurch as soon as you go to another airport.  I teach in gliders where getting the circuit right is fairly critical the first time, there being only one chance to land.

The really important checkpoint or turnpoint is the turn from downwind to base.  Learn to recognize the presentation of the runway when at a 45 degree aspect to it, which is normally the proper turn point for downwind-to-base unless you are extending or shortening your downwind for a specific reason.  I always weaned my glider students from dependence on geographic points as soon as possible, and certainly before solo.

You are at 45 degrees to the runway when the extended line of the lengthwise edge and an extended line of the threshold are "even" relative to the horizon.   This can be pretty tricky to discern at first but over time you'll learn to recognize this just by the appearance from your vantage point, and you will no longer care about ground landmarks.


Is there a way to avoid the effects of turbulence?

There are currently no production anti-turbulence devices or control systems that I know of. It should however be noted that auto-pilot (to an extent) will hold a course in turbulence within a margin but will or may constantly be auto-correcting.  However there is some research going on at RMIT into the matter and it looks like they have at least a small working prototype. The issue you have in the matter is positive control, to avoid turbulence and/or be ready to correct for it before it happens you need to be able to see it/predict it ahead of time. There is some more research going into Laser based Radar systems for detecting clear air turbulence but as far as I know nothing has made it to market. So yes it may be/is almost possible but the systems are still in research and development at best.


Why did Boeing keep using yokes while Airbus moved on to sidestick?

There are very good reasons to implement coupled column/yokes for aeroplane control: they are right in front of you, you can apply force with both hands, and you can feel immediately what input the other crew member is giving. The force sensors in our hands are very precise feedback instruments that should and can be fully utilised.

The upside of the side stick for passenger aircraft is...actually, what was the problem that needed to be solved? More room for the lunch table?

The F16 used side sticks because of the 9g accelerations that accelerate arms all over the place and can be the source of Pilot Induced Oscillations - best to support the arm with the armrest and control the aircraft by wrist movement. Not a lot of movement because the sticks are almost fixed, and use the force sensors in the hands for pilot feedback.

Column/yoke combinations provide the clearest feedback on what the condition of the aeroplane is: hydraulics ON, autopilot ON, trim position. The 737 is about the largest plane that can handle manual reversion, and one requires a column/yoke or a centre stick for that.


Where can I find more information about my grandfather's crashed B-18a bomber on Mt. Redoubt Alaska?

What is the terrain/glacier situation [on the southeast side of Mt Redoubt]?

The southeast side is all glacier, forming in the valleys formed by previous formative eruptions, which have deepened significantly due to glacier flow. These glaciers do move and churn, so unless the plane crashed on top of one of the prominent ridges then the position of the plane's remains is changed, and they are likely mixed/buried within the glacier.

It's been 75 years though, and while the glaciers sped up during eruptive periods (or melted, as on the north face during the 1989 eruption), the average annual glacier speed is 20 meters per year.  So the wreckage would have moved at least 1.5km down the mountain slope over time, buried under new snow (and occasional ash), and always moving down into the drift glacier.

These reports on Mt. Redoubt's glaciers should provide significant help in determining the location, thickness, and movement of each glacier present:

https://pubs.usgs.gov/wri/1997/4187/report.pdf

https://www.igsoc.org/journal/32/112/igs_journal_vol32_issue112_pg355-362.pdf

In a normal crash if you have the location to within 100 meters it can be found with a simple search, even decades later, even though the plane may have undergone environmental extremes.  In this situation, though, not only will the wreckage have been moved, but it will have been torn apart and spread over a much larger area than the original crash.

  Is landing possible at this location?

You can land on glaciers in general, and these are no exception, but you can't land on the side of Mt. Redoubt any easier than any other mountain.  You may be able to land at the base of the mountain, but you'd have to decide which glacier flow to land on, and as explained below it's unlikely that you will find anything to help you decide which one.

The pilot will have to make the final decision, though, as conditions may vary, not just in the weather, but on the glacier itself.

  Has anyone seen an accident site at this location?

Only the rescuers would have.  Once consumed by the snow and glacier over years it would have remained only as small parts of the whole.  Any pieces remaining visible to the eye would also act as solar collectors - they would melt the snow beneath them, sinking lower into the glacier, and then be covered by another fresh layer of snow.

I commend you and your father for your dedication to this aspect of your family history, and wish you luck!


It is a matter of power source (and engine aspiration in case of air breathing engines), wing loading and aerodynamic efficiency. With current technology, the limit is around 100.000 ft (30 km), as proven by Pathfinder and especially Helios. I doubt that much more is possible with really useable aircraft.
Aerodynamics first: The altitude factor of $c_l \cdot Ma^2$ tells you how much lift can be produced at a given flight Mach number, and the wing loading then gives you the minimum density for sustained flight. 0.4 is a good value for subsonic $c_l \cdot Ma^2$, and 30 kg/m$^2$ is a feasible wing loading for flight at 30 km. See this answer for more detail.
If the power source needs ambient air (piston engine), the plane needs triple-stage compressors or turbochargers, which have been tested up to 20 km altitude and should be good for maybe 24 km. They are finicky devices; Boeing Condor rarely flew at its maximum power because the stages of the turbochargers would oscillate in an alternating sequence of surges. One stage would race ahead, causing the other to surge, which made the first surge and free up the other to race ahead, and so on.
Above approximately 24 km, solar-electric propulsion looks like the best option currently. In all cases you can only fly subsonic, so the minimum practical wing loading will limit the maximum altitude. Aircraft like Helios are very delicate already, so they can only be launched in calm weather and are at risk of being blown away by high altitude winds. Payload is minimal, and depending what the aircraft is supposed to do besides flying high will give you a limit on the maximum altitude between 24 and 30 km.
Going to orbit in a propeller driven device is completely illusory. There is not enough matter to push against at higher altitudes, and the theoretical propeller diameter would be measured in Kilometers (or miles, if you prefer that unit). The structural mass would be prohibitive. Also, propeller thrust is inversely proportional to flight speed, and there is no way to accelerate with a propeller to escape velocity. The thrust would be just a rounding error away from zero at 7.9 km/s.
This speed is required to escape earth's gravity by flying fast enough around it so that the centripetal force equals the aircraft's weight and is called orbital velocity. The higher the orbit becomes, the more energy is required to reach it. In order to gain enough energy, a propeller aircraft would accelerate in the atmosphere to a speed quite a bit higher than the desired orbital velocity and then convert that kinetic energy to potential energy to lift its trajectory above at least 100 km, the internationally recognized altitude where spaceflight starts. Note that this phase of the flight requires inverted flight if the acceleration takes some time. The maximum flight Mach number would need to be maybe 12 or even 15 so this maneuver is possible at all.
In short: Going to orbit with a propeller? Forget it!


Is a supertransporter considered a different aircraft type than the one it is derived from?

Such aircraft require separate certification. The Beluga XL has just completed its certification process.

From the Wikipedia articles you linked to:

  The 747 LCF was granted FAA type certification on June 2, 2007.

and

  Following a total of 335 flight hours being performed during the test program, restricted certification of the type was awarded by the European Aviation Safety Agency (EASA) in October 1995, enabling the A300-600ST "Beluga" to enter service shortly thereafter.

and

  The Beluga XL made its first flight on 19 July 2018, and received its type certification on 13 November 2019.


Is it possible to add "planets" to the gearbox of a Trent 1000?

The fundamental question you seem to be asking is whether adding more planets to a planetary gear improves the load carrying capability of the gearbox.  The answer to that question is yes... to a point.

Take a look at a picture of the PW geared turbofan gearbox.  You'll note that there are five planets in there, and they are packed in pretty tightly.  There's really no room to add any more.  Although adding more planets would distribute the load such that each planet takes less load, it's impossible in this configuration because there is no space.  Let's say that you really really wanted to make it six planets instead of five. The only way to make enough room would be make the planets smaller. As you make the planets smaller, then either the ring gear has to get smaller too, or the sun gear has to get larger.  Either way, that is going to change the gear ratio (see formulas here). Specifically, the gear ratio is going to get closer to 1, which means the gearbox no longer does the job it was intended to do (namely reduce speed and increase torque).

So you can't have your cake and eat it too.  If you want 16 planets in a planetary gear, you can do it, but the gear ratio will be something like 1.02:1 which is not useful.  You might as well forget the gearbox and just do direct drive at that point.  If you need a decently high reduction ratio like 2:1, you can do it, but you will be limited on the number of planets that you can fit in.


What kind of certifications are required for a plane manufactured for personal use?

As Andy pointed out, this question is very broad (even if we're only talking about India). Your starting point should be the Directorate General of Civil Aviation (DGCA) because they can tell you definitively what would be involved in getting a "homebuilt" aircraft approved to fly under Indian law.

Information about this is available on the DGCA website and is broadly similar to the FAA's "Experimental: Amateur-Built" certification requirements:

The aircraft needs to be constructed in accordance with the DGCA's acceptable methods, techniques, and practices. Basically this means you can't use chewing gum as a structural fastener: The aircraft needs to be safe to fly.
The aircraft will be inspected by a DGCA representative prior to being allowed to fly.

  Note that the DGCA inspection is mainly looking for "obviously unsafe" conditions - they don't do a teardown inspection so if you used chewing gum as a structural fastener and subsequently that area is covered up by a wing skin the inspector won't know, but you will when the wing falls off on your test flight.

You will need the DGCA to issue you a Certificate of Airworthiness before you can fly the aircraft around - that certificate is contingent on completing required test flights at the airport where the aircraft is based/built.
You will need an appropriate pilot's license (and medical certificate if applicable) in order to fly the aircraft (this is also required to conduct  the Certificate of Airworthiness test flights mentioned previously).


Is a biplane without dihedral more stable than a low wing monoplane without dihedral?

Narrow answer: Yes, it is.

But no aircraft designer in his right mind would build an unswept low wing aircraft without dihedral. So this question is misleading.

Please look here why low wing aircraft need more dihedral.

Please read here why a low wing aircraft is just as stable as a high wing aircraft. The high wing does not entail more stability!


What are the rules for "see and be seen" when you suspect a potential conflict in class G airspace?

In the USA, RW aircraft are supposed to avoid the flow of FW traffic and FW traffic have the right of way for landing.

So I would have descended to 500ft instead of climbing. Slight differences in altimeters make 1,200 and 1,000ft too close for comfort. But  500ft AGL (noise abatement be damned in a safety situation) is a perfectly acceptable altitude in a heli.

Also, I would have adjusted my downwind so that I was fairly close to the runway where airplanes are rarely found.

So now I have both vertical and horizontal separation, and I am in a continuous position to land, at my convenience.


What is the physical definition of turbulence?

Image source

Turbulence is merely the measure of Reynolds number of a fluid at rest or motion ( (turbulence occurs when fluid is in motion) let's say you light up a cigarette and when the smoke is at the tip of cigarette you see it flows upwards uniformly and this is because the fluid is in laminar flow and as it expands into its vicinity it becomes turbulent. so what is the physics here? basically, reynolds number defines if a fluid is laminar or turbulent. Reynolds number is defined as the ratio of inertial to viscous forces experienced on a body. when divided it gives a number without any units. If the Reynolds number is less than 2100 then the flow is laminar and greater than 4000 it's turbulent and if it's between 2100 and 4000 its transitional flow (which is rare and instantaneous)


What does "still air" mean when planning alternative airports?

The latter - it means you don't need to take winds into account for that portion of the takeoff alternate selection.


Why don't planes fly directly to their destination?

There are many reasons why planes don't fly direct to their destination.

Mountains (for smaller piston aircraft)
Traffic capacity and traffic flow considerations for the ATC center
Weather along the route
Preferred airway routings

For an analogy, cars don't drive direct to their destination for the same reasons.  Roads, I would venture to guess, would be preferred routings to your destinaiton.

There would be a traffic jam if everyone wanted to get to the closest airport for the Olympics at the exact same time.  Traffic flow considerations would dictate planes slow down or fly a different routing or wait till there is a time slot for them to land at their destination.


What has been done to provide security for remote wireless updating of in-aircraft software components?

Boeing claims in this document:

  The 787 uses wireless (802.11 b/g) technology while at the gate to
  transfer maintenance data and update the Electronic Flight Bag (EFB).
  This is referred to as “e- Enabling” and it will allow airlines flying
  the 787 to operate more efficiently.

So, yes, they use a regular WLAN connection for transmitting data while on the ground.

The document continues:

  Upon weight on wheels the 787 attempts to authenticate specific ground
  access points. Information regarding the key configuration
  requirements and how the 787 authentication occurs requires the
  signing of a PIA.

I interpret PIA as Proprietary Information Agreement, a form of secrecy agreement. Boeing uses security through obscurity to safeguard the integrity of the connection.

If you want to know more, Boeing advises to contact 787terminalwireless@boeing.com. However, I doubt they will talk to you or me unless we are airport representatives with a credible need to know.


What is the metal plating on the back of the A-6 for?

It is a speed brake, a plate hinged at the forward edge which can be hydraulically extended to increase aerodynamic drag. It had been used on early models, and the speed brakes were mostly replaced by firmly riveted plates later, because flight test revealed handling problems. The wake of the speed brake disturbed the flow around the horizontal tail especially during approach and landing. They were replaced by wing tip brakes, and from the 304th aircraft on were completely omitted.

See here for further details.

Below is a picture of an A-6 with the wing tip speed brakes (circled red) extended:

(Source: navy.mil)


Why does climb gradient at Changi be at minimum of 6 and 7 percent?

Geographical location of Changi airport

Singapore is on the Straits of... Singapore. This straits is the southern continuation of the Straits of Malacca, both form an international maritime road between Indian Ocean and Pacific Ocean, on a par with Suez and Panama.

(Source)

To add to the bustle, the Changi Naval Base, opened in 2004, is a mere 2 km East of the runways:

(Source)

If that was not enough, there is a shipping channel at the North of the airport, with two terminals near the runways: A ferry terminal, and a cargo terminal.

View of the waters South of Changi airport:

(Source)

Obstructions and climb gradient

Very large ships, including military ones can be close to the runway ends. When this happens, and to take a long takeoff into account, a large climb gradient is in use.

AIP for Changi includes instruction for obstacle clearance calculation.

On the North the climb gradient is at least 3.3%, but is increased based on ships actual height when ships exceed a specified height, and depending on the runway e.g. for RWY 02C:

  When there are no reports of vessel movement along the northern
  shipping channel, or where the reported vessel height is less than 70m
  (230 ft) AMSL, the aircraft minimum net climb gradient shall be at
  3.3%.

  Where the reported vessel height is 70m (230 ft) AMSL or higher, ATC
  shall advise pilots of the vessel height. Pilots, on receipt of this
  information, shall apply the minimum net climb gradient in
  accordance with the following table.

For RWY 02L, the height threshold is as small as 35 m and the gradient for a 110 m ship will be 10.7%, i.e. the gradient is twice.

On the South, because the traffic is larger and permanent, the guidance is different:

  All departures on Runway 20C/20R shall be on a minimum net climb
  gradient of 5% until reaching or passing 400 ft. Thereafter, the
  minimum net climb gradient shall be 3.3%.

So what happened for this NOTAM to be published, requiring a higher gradient of 6 and 7% for RWY 20C/20R? Note this is only 1 or 2% steeper than it is usually. Different possibilities, no certainty:

The South protected area border is temporarily closer to the coast.
There is a very tall ship in the vicinity.
There is an obstacle on the land.

The general formula used for MOC calculation, for North and South departures:

  For the above calculations, operators shall use the following
  information:

  a. The most penalizing obstacle is a tall vessel which is
  on the extended center line of the runway. (ATC shall advise pilots of
  the height of the tall vessel.)

  b. The required MOC is 0.8% of the
  distance (d) from the departure end of runway (DER) to the obstacle,
  in accordance with Volume II of ICAO Doc 8168 -  Procedures for Air
  Navigation Services Operations (PANS-OPS)  where, in the case of
  Singapore Changi Airport, the DER is defined as the end of the
  clearway.

  c. The distance (d) for departure Runways 02L/02C is
  measured from the DER to the shipping channel north of Changi. The
  distance (d) for departure Runways 20C/20R is measured from the DER to
  the boundary of the restricted waters south of Changi wherein tall
  vessels of height above 49m (161 ft) AMSL are not permitted. The
  distance (d) for the various departure runways is as follows

The procedure above can be used by crews to calculate an optimized climb gradient, in case the default 5% is not retained. This procedure is used to provide pre-calculated MOC for North departures.

Now I want to see the actual departure from RWY 02C! Fly me!


Getting data from Existing ADSB Receivers

ADSB Exchange and OpenSky Network both provide access to the data they receive from their contributors.  Terms (and payment) may vary depending on whether your use is research or commercial.


Triple engine failure; which would you choose to keep left?

Using the inner engines allows you to maneuver easier as the yaw moment is smaller in comparison to the outboard engine which also means you need less rudder inputs to keep the course. The big advantage of needing less rudder to keep a straight path of flight is that you can react better because the rudder can move a bit more.

Which sides engine to use is depending on the wind situation (I would use the engine on the side the wind is coming from as you can turn into the wind better to keep your course) and other influences like if you need to turn left or right more often; avoid turning into a dead engine as Terry already mentioned).


How can I get General Aviation flight data on smartphone and/or tablet?

Garmin has a product called Connext that allows you to stream in-flight avionics data to mobile devices. They are pushing that product as a move towards connected components and a "Bring your own device" approach to cockpit automation.

So is it possible in general to receive it? No, not really. Not unless the avionics package was designed to broadcast it out. As other answers have said, a simple GPS and AHRS integration of the sensors in your tablet/smartphone can give a pretty good approximation of the data you are asking for, but things like airspeed, navigation waypoints, and other on-board sensor data are not generally available without a product like Connext.

The other side of it is that if you are a passenger you still probably won't be able to pair with the avionics. Connext allows you to modify the flight plan via a mobile device, and I'm not sure I would want any of my passengers doing that. On top of that, pilots are trained to interpret the data at hand, you don't want a passenger seeing a faulty artificial horizon after a vacuum failure and think that the aircraft is tumbling out of the sky.

There is a lot of security concerns as it is over being able to hack into commercial aircraft (I know you are talking about GA), but I still don't want a passenger to have the ability to connect to my avionics.


Can a commercial airline continue its flight if its landing gear fails to retract after take-off?

Usually not. It depends on various factors, most importantly the available fuel. If the pilot decides that enough fuel is available even after accounting for the extra drag due to extended landing gear, he can decide to continue, though this will rarely be the case as the drag penalty is too high and the aircraft speed is limited.

A case in point is the Hapag-Lloyd Flight 3378, which crash landed due to fuel starvation caused by the extended landing gear (which was kept that way as a precaution). The pilot was criticized for his decision to keep on flying instead of diverting to another airfield, and given a suspended prison sentence.


Why not tow aircraft instead of single-engine taxi?

Single-engine taxi is used for taxiing out (to the runway) and taxiing in (after landing) when the aircraft/operator allows it.

It is usually done when the taxi time is big, which means at big and busy airports. Use Google Earth to see how complicated big airports are in case you're not familiar with the airport layouts. But for the purposes of your question, let's consider a simple airport.

(wikimedia.org)

As shown, there is a single runway and one major parallel taxiway. Typically airplanes land and takeoff in the same direction.

First off too many tow trucks is too much traffic, too much money, and an increased chance of accidents on the ground.

Let's say in the above picture the plane is towed to where it says (11) for takeoff, the tow truck will detach, then what? It will have to occupy the runway and exit (delaying departures and arrivals).

Same thing for arrivals, tow trucks will need to wait by the exits, and with the time it takes to attach, the exit will be occupied. If not the exit but farther down, then you're already almost at the gate.

So the why not is basically: more traffic that doubles when the tow truck detaches, expenses (trucks, drivers, maintenance), reduced runway capacity, bigger chance for ground accidents, and a very complicated coordination task.


All rivets that are properly set will eventually "smoke" given a structure subjected to vibration that has been under-engineered, meaning not enough rivets per inch. The other cause would be improperly installed rivets. What looks like smoke is aluminum oxide produced by the movement of the surface, and the rivet rubbing a bit of it and sloughing it out and back along the airstream direction.


Can cruise pilots/second officers go for years without doing a takeoff or landing?

Every airline pilot is required to maintain currency. In a 2nd officers case most of this will probably be in a full motion simulator.


Why B-52 was not re-engined as a more efficient 4-engine?

There were several proposals to do just that, none of them ever went beyond the proposal phase.

Part of the reason is almost certainly the large stockpile of spare engines the USAF had (and maybe still has), taken in part from re-engined KC-135s.

Part of the reason no doubt is also that there have been near constant plans to retire the B-52 "soon" and a major project like this was never deemed economical.


Why were "pattern a" and "pattern b" removed from the Instrument Flying Handbook?

I can't say for sure, but I would assume that the pattern-based drills were removed because of the new emphasis on scenario-based ("real world") training the FAA has been moving toward: While Pattern A and Pattern B are useful for honing your skills (and I'll even admit they're kind of fun to fly) they're not something you'll fly in the "real world" - you are unlikely to string together that particular set of elements in that particular order on any kind of regular basis.

That doesn't mean the Pattern A / Pattern B maneuvers are not useful tools or that the FAA "frowns on" them - they really don't care how you acquire the skills necessary to pass your checkride and if flying Pattern A / Pattern B helps then by all means fly your heart out! Just know that when you take your checkride you will not be asked to "Fly Pattern B" - it's not an element of the practical test.

A copy of the maneuver diagrams for Pattern A and Pattern B can be found in Gleim's Additional Instrument Flight Maneuvers handout, which also has some valuable notes on how the maneuvers should be performed.

Personally I prefer the diagrams from Privilege Aero because I find them a little easier to read (Patterns A & B are listed as Patterns D & E respectively, except the Gleim version of Pattern B includes a descent & go-around at the end of the hold).

I've reproduced the Pattern E diagram below in case any of the links above break.


Was there a design flaw in the fuel tanks of the MiG-15/17/19/21?

I found a reference to exploding fuel tanks on Mig-21's caused by overheating engines.

 "it had an unfortunate tendency to explode in mid-air. The problem was finally traced to a fuel tank placed under the engines that could cook up when the engines overheated."

  Like its forebear, the MiG-17 inherited the major design deficit which
  could cause the fuel tanks develop to under-pressure if more than half
  the fuel had been used, which could easily lead to tank implosions,
  crushing the main fuselage of the aircraft mid-fight, with almost
  always fatal results.

Tank implosion implies negative tank pressure. Under pressure or negative pressure is caused by improper fuel tank venting.

High pressure pumps sucking fuel out of an improperly vented tank can quickly develop negative pressure which can cause a tank collapse. If the tank was integral to the fuselage it could also cause an airframe failure. A collapsed tank could also leak fuel which could lead to catastrophic failure if the fuel found an ignition source.