NOTE: For JT8D engines incorporating the 15 or 40 micron main oil filter: Illumination of the differential oil pressure warning light may be caused by contaminant material in the filter, by cold, viscous oil, or by a combination of the two. In general, when oil temperature is above 250C (770F) at idle, illumination of the warning light indicates the presence of contaminants alone and the filter should be serviced immediately. If oil temperature is 250C or below, the warning light may remain on after start, but should go out as the oil warms. Normally the oil will warm sufficiently within 5 minutes to extinguish the warning light.
(13)
Allow engine to stabilize at idle rpm. For a standard day at sea level, check instrument readings as follows:
(a)
EPR: approximately 1.06
(b)
EGT: 300 to 3400C (4800C maximum) (Fig. 205)
(c)
N2 rpm: approximately 57% N2 (Fig. 206)
(d)
Fuel Flow: approximately 500 to 590 kilograms (1100 to 1300 pounds) per hour
(e)
Oil Pressure: 44 to 46 psi (55 psi maximum)
(f)
Oil Temperature: 40 to 600C (1200C maximum)
504
71-09-100 Page 222 BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details. Feb 01/96
NOTE: The instrument readings shown above are considered to be normal readings for the JT8D engine. See Fig. 205 for engine operating limits.
(14)
If noticeable drop in engine oil quantity occurs after starting engine, operate engine at IDLE for approximately 1 minute before servicing oil tank.
CAUTION: UP TO 2 GALLONS OF OIL MAY BE IN THE ENGINE SCAVENGE SECTIONS. TO ASSURE AN ACCURATE OIL LEVEL CHECK, OIL MUST NOT BE ADDED TO THE TANK UNTIL THE SCAVENGE SECTIONS ARE CLEARED. IF THE ABOVE PROCEDURE IS NOT FOLLOWED, EXCESS OIL ADDED MAY BUILD UP SUFFICIENT INTERNAL PRESSURE TO RUPTURE THE TANK DURING ENGINE OPERATION.
(15)
If no longer required, shut down APU or remove electrical power and pneumatic supply from airplane.
WARNING: OBSERVE ENGINE HAZARD AREAS DESCRIBED IN FIG. 201 WHEN WORKING WITH EXTERNAL ELECTRICAL OR PNEUMATIC SUPPLIES AT THE AIRPLANE DURING ENGINE OPERATION.
May 20/82 71-09-100 Page 222A/222B BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.
553 Idle Rpm Values
May 20/82 Figure 206 71-09-100
Page 223
BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.
B. Start Engine (Pneumatic - Cross-Start)
CAUTION: DURING FREEZING CONDITIONS CHECK FOR ICE IN ENGINE INLET AND EXHAUST. TURN ENGINE COMPRESSOR BY HAND AND CHECK FOR FREE ROTATION. IF ICE IS PRESENT, PREHEAT ENGINE WITH AIR HEATER UNTIL COMPRESSOR ROTOR TURNS FREELY.
CAUTION: IF THE AIRPLANE IS PARKED ON ICE OR SNOW, A LOW PRESSURE GROUND CART OR THE AIRPLANE APU IS RECOMMENDED FOR ENGINE STARTING SINCE ASYMMETRIC THRUST DURING CROSS-STARTS MAY CAUSE THE AIRPLANE TO SWING AROUND. ICE CHOCKS AND A HIGH AIRPLANE GROSS WEIGHT WILL TEND TO MINIMIZE THIS CONDITION.
(1)
Perform Engine Operation Preparations in par. 3 and Engine Prestart Procedure in par. 7.
(2)
Operate started engine at idle.
(3)
Check position of switches on forward overhead panel as follows:
(a) Fuel Pumps for Engine to be Started - ON.
Note: If you must use the fuel boost pumps in the center tank, you must have a maintenance person or observer in the flight compartment to continuously monitor the LOW PRESSURE lights. Turn the applicable fuel boost pump to the OFF position if the LOW PRESSURE light for the center tank stays on.
(b)
Engine Bleed Air Switches - ON.
(c)
Bleed Air Isolation Valve Switch - OPEN.
(d)
Hydraulic System B Electric Pump 1 - ON.
(e)
Hydraulic System A Pump (operating engine) - ON.
(f)
Hydraulic Ground Interconnect - CLOSE.
(4) Increase power on operating engine to 80-85% N2. Check that dual pressure gage, on forward overhead panel reads approximately 30 psig (minimum) to 48 psig (maximum). Do not exceed 85% N2.
CAUTION: INSUFFICIENT AIR PRESSURE TO THE PNEUMATIC STARTER MAY PRODUCE INADEQUATE STARTER TORQUE AND RESULT IN HOT, HUNG, OR TORCHING STARTS. WHEN AIRBLEED FROM AN OPERATING ENGINE IS USED TO OPERATE THE STARTER, CAUTION IS NECESSARY TO ENSURE THAT THE OPERATING ENGINE IS TURNING OVER FAST ENOUGH TO PROVIDE AN ADEQUATE SUPPLY OF PRESSURIZED AIR TO THE ENGINE BEING STARTED. IN THE EVENT OF TORCHING, HIGHER THAN NORMAL EXHAUST GAS TEMPERATURE, PROLONGED ENGINE ACCELERATION TIME, OR OTHER ABNORMALITIES, DISCONTINUE THE START AND INVESTIGATE.
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