Fuel System Flashcards
What is the purpose of an aircraft fuel system?
Supply the main aircraft engines with sufficient fuel at a given pressure, under all operating conditions.
Different types of tanks
Integral, flexible/bag, rigid/drum/fabricated.
Disadvantage of the rigid tank
Adds significant weight to the aircraft.
AVGAS 100LL
Blue, 0.72, low lead.
AVGAS 100
Green, 0.72, high lead
AVGAS80
Red.
FSII Icing Inhibitor
Suppresses fungal growth, and prevents icing
Where is the fuel flow measurement carried out?
After the high pressure valve
Which has a lower freezing temperature, and a lower flashpoint between Jet A and Jet B?
The freezing point for Jet A is at a higher temperature than that for Jet B.
The flash point for Jet A is at a higher temperature than that for Jet B.
The correct order of decreasing freezing points of the three mentioned fuels is:
Jet A, Jet A1, Jet B
On most transport aircraft, the low pressure pumps of the fuel system are:
Low Pressure Centrifugal Pumps
Role of the Fuel Heating Device
Prevent, at low fuel temperature, the risk of ice formation from water contained in the fuel.
What power are the LP Centrifugal Pumps supplied with?
Three Phase AC - 115V
Purpose of Baffles in the Wing Tank
Restrict unwanted movement of fuel, especially in banking attitudes.
How are fuel tanks pressurised?
Ram Air intakes on the underside of the wing.
Fuel Tank Air Pressure is maintained at ambient by:
Fuel Vent System
Where are fuel heaters located on a jet aeroplane?
In the engines, just before the fuel filters.
Automatic Fuelling Shutoff Valve
Stops fuelling as soon as a predetermined fuel mass./volume is reached inside the tank.
Cross-Feed System
Transfer fuel from any tank and feed the engine.
Adjusts fuel distribution.
Purpose of submerging the booster pumps in fuel
Cools them down.
Vapour Lock
Bubbling of fuel blocking the fuel feed link.
As aircraft fly higher the ambient pressure drops, this allows the fuel to more easily change state from a liquid to a vapour. If fuel changes into a vapour in a pipe, or if vapour enters a pipe, it can create a vapour lock which will reduce or stop the flow of fuel.
Functions of a LP Booster Pump
Avoid vapour locking, prevent cavitation of the HP Pump
Function of the Feed Box
Increase the fuel level at the boost pump location
Allows fuel into the box but prevent the fuel flowing out as the aircraft is manoeuvred. This ensures the pump is always submerged in fuel.
Integral fuel tanks:
Comprise a portion of the aircraft structure which has been sealed to form a fuel tank.
Fuel pressure is measured
In the line between the booster pump and the engine or at the outlet of the high pressure filter
From which tanks can the APU receive fuel?
All three tanks.
If the AC fuel pumps fail, how can fuel be supplied?
Gravity feed
Prior to starting, from where would the APU be supplied with fuel?
Tank #1 by LP pump
When would the Fuel Low Level warning activate?
When the fuel is low in any tank that is not expected to empty during flight
When using magnetic dipsticks, what else is required?
When using magnetic dipsticks to measure the quantity of fuel, what else is needed to establish the fuel quantity?
‘Wet wing’ with regards to fuel storage refers to:
Integral fuel tanks
Given the following parameters, in a capacitance fuel gauge, the correct formula is:
A = area of plates D = distance between plates E = dielectric permittivity
E x A / D
