-
No. 1, 2, 3, or 4 primary fuel pump (parallel) light OFF during start (between 16% and 65%)
- Investigate
- (T) check FSOV cb on SEDC – may have popped after lightoff
- Inspect nacelle, lights check, try another start while CP watches light.
- Probable Cause: failure of secondary pump
-
No 1, 2, 3, or 4 primary fuel pump on, or momentarily ON then OFF, above 65% RPM
- Cause: Failure of primary pump or Fuel pumps are in parallel operation possibly due to a speed sense control malfunction.
- Action: Pull FUEL SHUTOFF VALVE CB on SEDC.
- If the light remains on, reset the CB, and assume the primary pump has failed.
- If the light goes out, leave the CB out, and assume a failure of either the 65% switch or the speed sense control.
- Note: if mission is continued:Do not use autofeather. Should maximum TIT be limited to ~830?C with or without the parallel light, assume a failure of the 94% switch or speed sense control. Place the affected TD switch to NULL.
- Do not shut down the affected engine with the intent to restart.
- Reset the CB prior to securing the engine with the fuel and ignition switch
- Lights ON – pump’s gone, Lights OUT – leave CB out.
-
FILTER light ON
- If engine continues to function normally, continue engine operation
- Cause: One or both of the low-pressure fuel filters are restricting flow.
- Tech: Consider possibility of bad gas – multiple filters lights necessitates immediate land.
-
PRESS LOW light on
- Check fuel quantity and fuel flow of corresponding engine
- Check engine operation normal
- Inspect nacelle for visible fuel (ask aft Obs)
- If fuel visible – secure engine
- In flight – If no fuel leak, continue operation, observing engine closely
- Ground OPS – if no fuel visible, cycle respective boost pump or shift engine to normal RPM and then back to low RPM. If light goes out and remains out, continue operation.
- Cause: Indicates diff pressure across the engine driven centrifugal pump is low (19psid) – flickering light indicates a partial obstruction of the fuel line. After start, possible faulty or stuck pressure switch
-
Fuel Boost Pump Failure – Climb
- Verify pump failure and establish crossfeed. (check CBs, pump pressure)
- Inoperative boost pump switch - OFF
- Boost pump CONTROL CB – Pull (MEDC)
- Continue climb
- After sufficient time a cruise altitude, discontinue crossfeed and monitor engine operation.
- If engine operates satisfactorily, continue the mission, if not:
- Return to crossfeed operation.
- Wait several more minutes and repeat step 5. If repeated attempts produce unsat results, continue crossfeed.
- Note: Adjust mission as necessary. If the mission can be accomplished at lower altitude, descend until the engine runs satisfactorily in the tank-to-engine configuration.
-
Fuel Boost Pump Failure – Cruise/Descent Conditions
- Verify pump failure (Check CBs, pump pressure)
- Inoperative boost pump switch - OFF
- Boost pump control CBs – PULL (MEDC)
- Monitor engine operation.
- If abnormal indications are observed during tank-to-engine operation, crossfeed engine from another tank, and proceed to step 5 of boost pump failure – climb procedures.
- Note: For tank-to-engine ops - avoid nose-down attitudes and excessive yawing. If a prolonged or high rate of descent is required, select crossfeed operation, as the scavenge section of the boost pump is also inoperative.
-
Transfer pump failure, Tank 5
- Inoperative transfer pump switch – OFF
- Transfer pump CBs – PULL (Bus A, Bus B, EMDC)
- Reduce tank 5 fuel to 3,000lb level with operating pump
- Close transfer valves and allow fuel quantity in each wing tank to drop 250lbs.
- Open all transfer valves and lower the fuel in tank 5 by 1000lbs
- Repeat steps 4 and 5 until tank 5 fuel is depleted.
- Note: It is possible that some fuel may have been trapped in the center section tank. Some of this fuel can be recovered by maneuvering the aircraft to a nosedown attitude.
-
Dual Transfer pump failure, Tank 5
- Turn both tank 5 transfer pumps off
- Ensure tank 5 transfer pump CBs are pulled (Bus A,B, EMDC)
- Determine zero fuel weight.
- If maximum zero fuel weight is not exceeded, adjust mission as necessary.
- If maximum zero fuel weight is exceeded, continue:
- Dump fuel until below max ZFW
- If max ZFW is exceeded, do not exceed 2.1gs, avoid turbulent air penetration, abort mission, and land.
-
Fuel Dump Procedure
- Airspeed – 140 to 300 knots.
- Aft observer – posted.
- Flaps (recommended) – UP
- Warning: Fuel dumping is prohibited with wing flaps extended beyond TAKEOFF/APPROACH position. Refer to fuel dumping limitations in Chapter 4.
- Affected equipment:
- VHF (OFF), HF-1,2 (Standby), TACAN (REC), IFF interrogator (OFF), IFF transponder (Standby), Radar (Standby), Chaff and Flare dispenser (OFF)
- Fuel transfer valves – Closed
- Note: close transfer valves for lower overall gross weight
- Fuel Dump switch – ON
- Tank 5 fuel gauge – Monitor. Dump rate ~1000ppm.
- Fuel Dump switch – OFF (when complete, prior to land)
- Tank 5 transfer pumps - OFF
-
TIT Limited to 830?C
- With or without the parallel light
- Assume failure of the 94% switch or speed sense control
- Place affected TD switch to null
- Do not shut down the affected engine with the intent to restart
- (T) Pull FSOV CB to isolate possible speed sense control malfunction
-
Stuck Fuel Quantity Indicator (w/out AFC-578)
- Caution: When testing the fuel quantity gauges with the press-to-test switch, do not allow the gauges to drive all the way to zero, or damage to gauge calibration may result.
- 1. TEST – fuel gauge test switch to test
- 2. TAP – lightly tap the fuel quantity indicator
- 3. CHECK CBs – fuel quantity cbs (MEAC/BUS A)
- Warning: If a quantity indicator cb trips, do not reset.
- Warning: Connecting or disconnecting connector plugs may cause a 115-volt electrical arc to be generated inside the fuel tank under certain system failure conditions.
- 4. Start a Fuel Log
- 5. Do not conduct further troubleshooting.
-
Fuel Quantity Indicator Goes Off Scale, High or Low or Fluctuates Abnormally
- 1. Both flight station and fueling panel quantity indicator cbs (MEAC/BUS A) - PULL
- Warning: Connecting or disconnecting connector plugs may cause a 115-volt electrical arc to be generated inside the fuel tank under certain system failure conditions.
- 2. Start a fuel log
- 3. Do not conduct further troubleshooting.
-
TIT, FF, SHP begin fluctuating abnormally
- TD system malfunction:
- TD switch to NULL
- If corrects the fluctuations – continue in NULL
- TIT must be monitored, no temp limiting protection
-
Considerations for adjusting mission (tech)
- If must crossfeed for proper engine operation, Fuel in tank with inop boost pump is unavailable.
- Consider fuel imbalance (including stores) 4389lbs tanks 1+4,
- Weather, crosswinds at destination
- If shutdown engine with failed boost pump, fuel is unavailable.
-
BOOST annunciator light cause
- Electrical boost pump pressure less than 2 psi
- Electrical cutout at case temperature of 400?F
- Check CB (BUS A or B, EMDC)
- Tech: Reset DC cb once, AC never
-
Fuel Quantity Indicator Failure (AFC-578)
- Individual indicators have BIT functions (figure 2-56)
- If BIT detects fault and “ERROR” light is flashing, there is some level of degradation to be expected in the fuel indicator quantity. A fuel log should be used to calculate the approximate amount of fuel remaining in the tank.
|
|
