TM 1-1520-238-T-4
Change 7
6–17
6–7.
SYSTEM DESCRIPTION (cont)
6–7
(e) An engine NGB cooling fan forces cooling air around the engine NGB to maintain operating
temperatures at 250 to 275 F (121 to 135 C) at 100% NG. The vaneaxial fan pulls cooling air around the
cooling fins on the NGB housing. The air is forced through NGB fairings down to the transmission deck, and
exhausted through the IR suppression system.
(f) The oil pressure transducer monitors and transmits engine NGB operating oil pressure to FD/LS.
(g) The CPG can access a true temperature reading through the DATA ENTRY keyboard (DEK) (ADC)
or control display unit (CDU) (ADD). The reading is obtained from the oil temperature transducer and is displayed
on the CPG’s heads out display (HOD).
(h) The oil level sight plug permits flight and maintenance personnel to visually inspect the oil level
when the engines are not operating.
(i) Power to the main transmission assembly is received from engine NGB 1 via input drive shaft 1, and
engine NGB 2 via input drive shaft 2.
M58-176
CHIP DETECTOR/
TEMPERATURE SWITCH
OIL PUMP
ASSEMBLY
OIL PRESSURE
TRANSDUCER
OIL TEMPERATURE
TRANSDUCER
OIL LEVEL
SIGHT PLUG
OIL
PRESSURE
SWITCH
OIL FILTER
IMPENDING
BYPASS
INDICATOR
Figure 6–10.
Engine NGB Assembly
