NAVWEPS 00-801-80  AIRPLANE  PERFORMANCE  (2) Gross weight.  (3) Temperature--an additional correc-  tion for nonstandard temperatures to ac-  count for the thrust loss associated with  high compressor inlet air temperature.  For this correction the ambient tempera-  ture at the runway conditions is appro-  priate rather than the ambient temperature  at some distant location.  (4) Wind.  In addition, corrections are necessary  to ac-  count for runway slope, engine power defi-  ciencies, etc.  will  cause these approximate increases in  takeoff distance:  3% percent for the supercharged  recipro-  cating airplane when below critical  altitude  7 percent for the turbojet with high thtust-  to-weight ratio  10 percent for the turbojet with  low  thrust-to-weight ratio  These approximate relationships show the  turbojet airplane to be much more sensitive to  density altitude than the reciprocating powered  airplane, This is an important fact which  must be appreciated by pilots in transition  from propeller type to jet type airplanes.  Proper accounting of pressure altitude (field  elevation is a poor substitute) and temperature  is mandatory for accurate  prediction of takeoff  roll distance.  LANDING  PERFORMANCE.  In many  cases, the landing distance of an airplane will  define the runway requirements for flying  operations. This is particularly the case of  high speed  ‘ jet airplanes at low altitudes where  landing distance is the problem rather than  takeoff performance. The minimum landing  distance is obtained by landing at some mini-  mum safe velocity which allows sufficient mar-  gin above stall and provides satisfactory,  con-  trol and capability for waveoff  Generally,  the landing speed is some fixed percentage of  the stall speed or minimum control speed for  the airplane in the landing configuration. As  such, the landing will  be accomplished at  some particuIar value of ~lift coefficient and  angle of attack.  The exact value of CL and  P for landing will  depend on the airplane  characteristics  but, once defined, the values are  independent of weight, altitude, wind, etc.  Thus, an angle of attack indicator can be a  valuable aid during approach and landing.  The most critical conditions of takeoff  performance  are the result of somecombination  of high gross weight, altitude, temperature  and unfavorable wind.  In a11 cases, ir be-  hooves the pilot to make an accurate prcdic-  tion of takeoff’ distance from the performance  data of the Flight Handboo& regardless of the  runway available, and to strive for.2 polished,  professional takeoff technique.  In the prediction of takeoff distance from  the handbook data, the following primary  considerations must be given:  (1) Pressure  altitude and temperature-  to define the effect of density altitude on  distance.  (2) Gross weight-a  large effect on dis-  tance.  (3) Specific humidity-to  correct cake-  off distance for the power loss associated  with water vapor.  (4) Wind-a large effect  due to the wind  or wind component along the runway.  (I) Pressure  altitude and temperature-  to define the effect of density altitude.  Turbine  powered  airplane  Reciprocating  powered  airplane  To obtain minimum landing distance at the  specified landing velocity, the forces which  act on the airplane must provide maximum  deceleration (or negative.acceIeration) during  the landing roll.  The various forces actin~g.  on the airplane during the landing roll may  require various techniques to maintain landing  deceleration at the peak value.  Figure 2.34 illustrates the forces acting on  the aircraft during landing roll.  The power-  plant thnrJt should be a minimum positive  192 