PHI GOM S-92A - FUEL Flashcards
S-92 Fuel System
Which tank supplies fuel to run the Auxiliary Power Unit (APU)?
1 (left) FUEL TANK
How much fuel is unusable?
4.8 gallons (2.4 each side)
What are the approved fuels for the S-92?
Jet A (JP-5)
Jet A-1 (JP-8)
Jet B (JP-4)
No. 3 Jet Fuel
How much fuel can be loaded using pressure refueling in gallons and pounds?
764 gallons / 5175 pounds
How much fuel can be loaded using gravity refueling in gallons and pounds?
713 gallons / 4830 pounds.
What component controls which of the two prime pumps is used to prime the fuel system during engine start?
Maintenance Data Computer (MDC)
What is the recommended pressure for refueling?
55 psig (120GPM)
What is the maximum defuel rate?
90 GPM
How is fuel quantity measured?
Two fuel quantity probes in each tank (4 total) send information to the Fuel Conditioning Unit computer which averages the two probes per tank and provides quantity information to the EICAS.
What fuel level does the fuel low indication come on and what is the limitation?
215 +/- 45 pounds
No steady state pitch attitudes above 10 degrees or below 5 degrees.
What does the caution
SOV 1 WRNG POSN indicate?
1 Fuel prime shutoff valve is in disagreement;
either open when it should be closed,
or closed when it should be open.
During APU start with an inoperative MDC, will the fuel system be primed during start?
Yes, default pump is #1.
Which electrical bus powers the fuel high level pre-check circuits?
Battery Utility
Describe the fuel pre-check procedure for pressure refueling.
Begin pressure fueling and select PRI on the fuel precheck panel. Observe the flow of fuel stop indicating the high level sensor is operational. Release switch to NORM and allow fuel to flow, then select SEC on the precheck panel and observe the flow of fuel stop again indicating the secondary high level sensor is operational.
When 1 hour of fuel remains, based on current fuel consumption, the fuel quantity symbology will change to _________?
Green/Yellow barber pole in color
When the fuel quantity reaches _____ lbs of remaining fuel, the associated lettering and numbers turns _______?
215 +/- 45 lbs.
Yellow
The fuel prime pump only runs when the _______ is on or during_____.
APU is on
Engine starting
During pressure refuel will all fueling stop to both tanks if the right tank high level shut off activates?
No.
Fuel will stop for that tank and continue for the other.
MAINTENANCE MANUAL 28-21-00
Why does the fuel system have a LOW level shutoff valve?
For pressure defuel
When in crossfeed does the engine being started have positive prime pump fuel supplied or negative from the engine?
Negative
from the low pressure engine driven fuel pump.
Although a prime pump operates when each engine starts, the Prime SOV only opens to the engine being started when in DIRECT.
In Crossfeed the opposite Prime SOV opens. see RFM for Ref. Also, in the 28-00 Maint Manual page 620 you will see that a jumper has to be used during the #1 Engine prime fuel Crossfeed test so that the system thinks the #2 engine is starting.
Lastly, you can see this in the wiring diagram where the prime SOV relay is only powered by the on-side starter relay.
Can the S-92 be pressure refueled without the battery switch on?
Yes, however PHI does not allow this.
The high level shutoffs/prechecks are on the Utility bus so the battery does not have to be on.
