Fuel System Flashcards
(23 cards)
What’s are the tanks of the main fuel system
- Nacelle tank
- Two wing leading edge tanks
- Two box section bladder tanks
- One integral wing tank
All of which gravity feed into the nacelle tank
What are the tanks of the Auxillary fuel system
Consists of only an auxiliary tank, located in the wing, inboard of the nacelle
Employs an automatic fuel transfer system to supply fuel to the main system
When aux tanks contain fuel, it is used first, and automatically transferred into the nacelle tank
What are the kinds of boost pumps
Each engine drives a:
1. High pressure fuel pump
2. Low pressure fuel pump
3. Electrically driven low-pressure standby boost pump (in the bottom of the nacelle tank)
What is the standby boost pump purpose
Serves three functions:
1. To serve as a backup for the engine-driven fuel boost pump
2. To pump aviation gasoline when above 20,000 feet
3. To pump fuel during crossfeed operation
If the electrical standby boost pump fails, crossed will not be possible from that side
How long can the engines run on Av Gas
150 hours before overhaul is needed
What is the Fuel Capacity of the Main Tank
386 Gallons
(@ 6.7 lb/g) 2586 lbs of useable fuel
What is the Fuel Capacity of the Auxiliary Tank
158 Gallons
(@ 6.7 lb/g) 1058 lbs of useable fuel
What is the Total Useable Fuel amount
544 galons
or 3644 lbs
Describe the Fuel Pumps
A High Pressure Pump and Low Pressure Boost Pump are engine driven through the accessory drive section.
The High Pressure Pump delivers fuel to the engine
The Engine Driven Low Pressure Boost Pump delivers low pressure fuel to the high pressure pump.
In the event that the Engine Driven Boost Pump fails, the Electric Standby Boost Pump should be actuated (located in the bottom of the nacelle tank)
If the electrically driven standby pump fails, can you crossfeed?
No. No fuel can be fed from that side
What PSI does the Low Pressure Engine Driven boost pump operate at?
25-30 PSI
What are the limitations of using AvGas?
Flight above 20,000 feet requires both standby pumps to be operational, and crossfeeed to be operational
Limited to 150 hours before overhaul
What cause a L or R Fuel Press light to come on
In the case of a low-pressure engine-driven fuel pump failure. The light illuminates when fuel press decreases below 10 +/- 1 PSI.
(Engine operation with Low Press light on is limited to 10 hours, before overhaul or replacement of high pressure fuel pump)
What happens if there is a failure of the high pressure fuel pump?
An immediate engine flameout
What pressure does the High Pressure pump operate at?
800 PSI
What is the minimum pressure required to open the “minimum-pressurizing valve” in engine start?
70 psi
How many fuel nozzles are there?
14
7 Primary
7 Secondary
Describe the fuel topping governor
The fuel topping (power turbine) governor protects against power turbine overspeed. If an overspeed occurs and the propeller goes beyond 106% of the requested RPM, the fuel topping governor vents air to reduce fuel flow. Reducing fuel flow decreases N1, and therefore power turbine speed.
With props in reverse, the FTG restricts fuel flow to approximately 95% of requested RPM
How many ignitors are in the combustion chamber
2
What % N1, will Low and High Idle maintain
Low = 61% N1
High = 70% N1
What is the max power air to fuel ratio
14.7:1
What is the most economic air to fuel ratio
16:1
