AEROGRAPHER'S MATE 3 & 2 



-ALTIMETER READS 

 LOW 



7\ 



rALTIMETER REAOS 

 CORRECTLY 



■"^^"J* 



— '^|^—- ALTITUDE -£—- 



ALTIMETER READS 

 HIGH 



SAME SEA LEVEL PRESSURE 



Figure 2-10.— Altimeter errors due to nonstandard air temperatures. 



209.378 



back to a receiver that presents them on a 

 calibrated cathode-ray tube. 



Altimeters of this type are generally used 

 for pressure-pattern and jet-stream flying along 

 with bombing, due to their high altitude capability. 



PRESSURE COMPUTERS 



To enable reporting stations to calculate 

 pressure information in support of aviation re- 

 quirements, several types of computers have 

 been devised to meet these needs. Two of these 

 computers, the Pressure Reduction Computer 

 CP-402/UM, and the Density Altitude Computer 

 CP-718/UM, are discussed in the following 

 paragraphs. 



PRESSURE REDUCTION 

 COMPUTER CP-402/UM 



The Pressure Reduction Computer, CP- 

 402/UM, is primarily used for computing sea 

 level pressure and altimeter settings from the 

 observed station pressure at sites that do not 

 have a constant reduction factor computed and 

 authorized. It may also be used to compute 



Figure 2-11.— Pressure reduction 

 CP-402/UM. 



209.379 

 computer 



30 



