15.13 Start And Ignition Flashcards
(52 cards)
Where is the engine turbine ignition system normally used?
Short period during the engine starter sequence and in the combustion chamber to ignite fuel
When would continuous ignition mode be used?
Uses at lower voltage and energy level, is used during certain flight conditions i.e if there is a possibility of an engine flame out, to relight the fuel and keep the engine from stopping
How do you start a GTE
Accelerate the high pressure compressor to provide sufficient airflow for combustion
Give some examples of when continuous ignition could be used?
Take off, landing and some abnormal or emergency situations, such as flying through a hailstorm or volcanic clouds
What are most turbine aircraft ignition system?
A high energy, capacitor-type ignition system and air cooled by a fan airflow
What is the order of starting a GTE
Ignition on, fuel, engine lights up, engine attains self-accelerating speed, ignition off, starter cuts out, engine reaches idle rpm
Why can working on a starter motor be dangerous ?
Starter motors generate high amounts of torque and are very heavy
What other ignition systems could turbine engines be equipped with?
Electronic type of ignition system
What can be left behind on the ignition exciter (igniter)?
High voltage and current, so it should not be touched if circuit breakers aren’t pulled or is the igniter lead is not connected
What tools should be used when disconnecting igniter leads?
Insulated tools and never bare hands
What should you always follow when or king on ignition systems ?
Manufacturer’s instructions and / or the AMM
What should be ensured before working on the ignition systems ?
There is no electricity left in the igniters
Should fuel be sprayed before ignition is on
No, ignition should be on before fuel
identical independent ignition units operating from a common low voltage (DC) electrical power source what are they?
Aircraft battery, 115 AC, permanent magnet generator
identical independent ignition units operating from a common low voltage (DC) electrical power source what are they?
Aircraft battery, 115 AC, permanent magnet generator
What is the generator turned by?
Directly by the engine through the accessory gearbox and produces power any time the engine is turning
Why is it imperative that the system can supply a high heat intensity spark?
Because they they often operate in low temp of high altitudes
What does a typical ignition system include?
Two exciter units two transformers, two intermediate ignition leads and two high tension leads. As a safety factor, the ignition system is a goal system designed to fire two igniter plugs
Before electrical energy reaches the exciter unit what does it pass through?
A filter that prevents noise voltage from being induced into the aircraft electrical system
What measures throttle position
Resolver (Boeing)
Potentiometer (Airbus)
From breaker points where do rapidly interrupted currents get delivered to?
Auto transformer
What are advantages of cartridge starting
Quick independent engine start by using compressed gas
What happens when the breaker closes and when it opens?
When closing the flow of current through the primary winding of the transformers establishes magnetic field. When breaker opens, flow of current stops and the collapse of the field induces a voltage in the secondary of the transformer
What are disadvantages of cartridge
Single use so need replacing
