TM 55-1510-221-MTF
SECTION IV. SPECIAL PROCEDURES
General. This section contains the special procedures that were
referenced in Section II.
*A.
PRESSURIZATION SYSTEM.
Check as follows:
1.
Bleed air valve switches (2) - OPEN.
2.
After takeoff - Establish a climb.
3.
Cabin altimeter - After takeoff the cabin altimeter needle
should stabilize at 1550 to 2050 feet and the cabin
differential pressure needle should continue climbing. The
cabin altimeter needle should remain at 1550 to 2050 feet
pressure altitude until the maximum pressure difftial of 6.0±
1 is reached. At this point (approximately 16,600 feet
pressure altitude) the cabin altitude should increase while
the differential pressure remains constant.
4.
Cabin pressurization leak rate - Check within limits as
follows:
a.
Level off aircraft when pressure differential reaches 6
0 1.
b.
Bleed air valve switches (2) - ENVIRO OFF.
c.
Cabin rate-of-climb indicator - Read cabin rate of
climb. Cabin rate of climb (cabin pressurization leak
rate) should not exceed 2200 feet per minute.
5.
Bleed air valve switches (2) - OPEN Reestablish 6.0 1 PSI
cabin pressure differential.
6.
Left bleed air valve switch - ENVIRO OFF.
7.
Slowly retard the right power lever to flight idle.
Cabin pressurization should not change or begin a climb.
8.
Repeat the above procedure for the left engine.
9.
Cabin altitude controller - Set to 10,000 feet pressure
altitude
4-1
