P-3 Fuel System Procedures

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  1. 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
  2. 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.
  3. 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.
  4. 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
  5. 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.
  6. 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.
  7. 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.
  8. 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.
  9. 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
  10. 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
  11. 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.
  12. 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.
  13. 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
  14. 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.
  15. 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
  16. 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.
Card Set:
P-3 Fuel System Procedures
2012-05-02 03:41:24
Fuel System

P-3 Fuel System
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