15.13 Starting and Ignition Systems Flashcards
(43 cards)
What are the 3 main engine controls?
- engine start controls
- forward thrust controls
- reverse thrust controls
How does the thrust lever control the thrust of the engines?
It informs the fuel control unit how much thrust is required by the pilot
What controls are used to start the engines?
The master switches
What is the purpose of the resolver?
It converts the thrust lever position (angular deflection) into an electrical signal
How is the engine and fuel supply switched on to the engines?
Via the engine start levers
What type of valve is the low pressure fuel shut-off valve?
An electric motor driven valve
When the low pressure fuel shut-off valve is open, is the indication illuminated or not illuminated in the cockpit?
It is not illuminated. It is only illuminated if the valve is closed
How is the high pressure fuel shut-off valve controlled?
Via the engine start levers - a mechanical input
What are the thrust control systems called in a mechanical thrust control system?
The throttles
How do the throttles transmit the thrust lever position to the FCU?
Via rods, pulleys, drums and flexible push-pull cables
What position would the power lever be in for a crank lever operated throttle if the pilot moves them to idle?
The mid position
Forward = thrust, Rearward = reverse thrust
What type of throttle transmission can be used instead of crank levers?
Rack and pinion
How do the throttles remain in a selected position?
A friction brake which is strong enough for preventing inadvertent movement from vibrations, but small enough to easily move
How does the auto throttle system move the throttle levers?
An electric servo motor moves the levers and the mechanical transmissions
What are the micro switches for that are connected to the throttle position?
They are used for warnings depending on position
- take off warnings
- cabin pressurisation
- thrust reverser activation
What are the 3 tasks for thrust reverser controls?
- to activate the thrust reverser
- to increase engine power
- to block the reverse thrust lever while the reverser moves to the deployed position
What is the purpose of the throttle interlock system?
It is the main difference between the forward thrust controls and the reverse thrust controls
Where is the mechanical throttle interlock system installed?
In the engine pylon
How are electrical thrust controls safer to use?
Two signals are sent from each thrust lever to the associated control units (Channel A/B)
How many resolvers are used for each thrust lever?
2
What is the difference between the levers of mechanical aircraft and fly-by-wire aircraft?
Mechanical = have a servo-mechanism which moves the throttles (autothrottle) Fly-by-wire = thrust levers don’t move; they use an autothrust system via the autoflight system sending the values direct to the F.A.D.E.C
What are the 3 main reverse thrust lever positions?
- normal position (stows the reversers)
- reverse idle (deploys the reversers)
- full reverse (increases engine power)
What is “start ignition”?
It is the continuous ignition for starting the engines only. After ignition, the igniters aren’t used unless required.
What is “continuous ignition”?
It is selected manually or can be automatic if there is a risk of engine flame-out
