Engine Operation π¨ββοΈ Flashcards
Which pressure spool rotates for starting on a two or three spool engine
High pressure spool
In what order does the process of engine starting occur
Engine core rotates first
Igniters activated
Fuel introduced last
Light up means
The point at which combustion occurs
Indications of light up
Takes 20secs
Sharp rise in EGT
N2 (high pressure spool) rpm increase
When can you disconnect the starter
After self sustaining rpm
Then idle slightly above this rpm
Why do you idle the engine for 2-3 minutes then shut off fuel on shutdown
To allow temperatures to stabilise
Rpm isnβt increasing at the expected rate and the EGT indicates too high for the selected rpm What could this be
Hung start
Causes and Actions to take in a hung start
Causes - starter cutting out too early
-fuel flow insufficiency
Actions
Cut off fuel and dry motor by turning the engine to starve fuel
Hot start indications and causes
Indications
EGT beyond limits and slow rising rpm
Causes
Mixture is too rich meaning Not enough airflow Too much fuel
Starting in a strong tailwind
Hot start actions to take
Cut off fuel and dry motor the starter
What temperatures are we concerned with on starting
EGT Exhaust gas temperature
TIT Turbine inlet temperature
ITT interstate turbine temperature
What is EGT sometimes referred to as
TOT turbine outlet temperature
JPT jet pipe temperature
TGT turbine gas temperature
What is TIT turbine inlet temperature also known as
TET turbine entry temperature
On starting You have no EGT rise, there is fuel vapour coming from the tailpipe and the rpm shows the same as the starter motor.
What is this likely an indication of and what should you do
Wet start
Cut off fuel and dry motor to starve fuel
Causes of a wet start
Igniters not functioning properly
