T-45C TS, ADV & IUT ENG-18
OBOGS & ECS/Pressurization System Malfunctions
C. Effects on flight safety
1. Potential equipment failure if overheated (if occurred on ground)
2. Canopy fogging, especially during a penetration into hot and humid
areas
3. May require turning off pressurization
III. Cabin pressurization failure 1.8.1.4.2.1
Fig 1: Cockpit
Pressurization Schedule
A. Indications
1. System failure above 24,500 +/- 500 ft: MSL
a. CABIN ALT warning light will illuminate
b. MASTER ALERT flashes
c.
Warning tone sounds
2. System failure below 24,500 +/- 500 ft: MSL cabin altimeter
increases to aircraft altitude, above 5000 ft MSL
B. Verifications
1.
Cabin altitude gauge increases to aircraft altitude,
above 5000 ft MSL
2.
Confirm with aft cockpit, if possible
3.
Possible discomfort in ears and sinuses if cabin altitude
abruptly climbs
C. Effects on flight safety
1. Safest altitude below 25,000 ft MSL
2. At higher cockpit altitudes, pilot must closely monitor oxygen supply
3. Possible hypoxia if oxygen system lost
4. Lower altitude will increase fuel consumption
NOTE: Failure of OBOGS and pressurization may require an
immediate descent and use of emergency oxygen.
Original (9-98)
Page 18-4
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