NAVWEPS O&ROT-R0 
AIRPLANE PERFORMANCE 
specified speed may mean that the airplane may 
stall, be difhcult to control, or develop high 
rates of descent. On the other hand, an exces- 
sive speed at landing may improve the control- 
lability (especially in crosswinds) but will 
cause an undesirable increase in landing dis- 
tance. The principal effect of excess landing 
speed is described by: 
& v2 * -= - h 0 VI 
Thus, a 10 percent excess landing speed would 
cause a 21 percent increase in landing distance. 
The excess speed places a greater working load 
on the brakes because of the additional kinetic 
energy to be dissipated. Also, the additional 
speed causes increased drag and lift in the nor- 
mal ground attitude and the increased lift will 
reduce the normal force on the braking sur- 
faces. The acceleration during this range of 
speed immediately after touchdown may suffer 
and it will be more likely that a tire can be 
blown out from braking at this point. As a 
result, 10 percent excess landing speed will 
cause at JUJ; 21 percent greater landing dis- 
tance. 
The most critical conditions of landing per- 
formance are the result of some combination of 
high gross weight, density altitude, and un- 
favorable wind. These conditions produce the 
greatest landing distance and provide critical 
levels of energy dissipation required of the 
brakes. In all cases, it is necessary to make an 
accurate prediction of minimum landing dis- 
tance to compare with the available runway. 
A polished, professional landing technique is 
necessary because the landing phase of flight 
accounts for more pilot caused aircraft acci- 
dents than any other single phase of flight. 
In the prediction of minimum landing dis- 
tance from the handbook data, the following 
considerations must be given: 
(1) Pressure altitude and temperature-to 
define the effect of density altitude. 
(2)’ Gross weight-which define the CAS 
or EAS for landing. 
(3) Wind-a large effect due to wind or 
wind component along the runway. 
(4) Runway slope-a relatively small cor- 
rection for ordinary values of runway slope. 
IMPORTANCE OF HANDBOOK PER- 
FORMANCE DATA. The performance sec- 
tion or supplement of the flight handbook con- 
tains all the operating data for the airplane. 
For example, all data specific to takeoff, climb, 
range, endurance, descent and landing are in- 
cluded in this section. The ordinary use of 
these data in flying operations is mandatory 
and great knowledge and familiarity of the air- 
plane can be gained through study of this 
material. A complete familiarity of an air- 
plane’s characteristics can be obtained only 
through extensive analysis and study of the 
handbook data. 
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