15.21, 15.14, 15.20 Flashcards
What’s a hot start and give 3 causes
When EGT rise above allowable limit
Compressor stall
Low starter air pressure
FOD
What’s a hung start and give 3 causes
When engine lights up but speed doesn’t increase
Low starter air pressure
FOD
Faulty starter valve
SOAP
spectrometric oil analysis program is a method to check engine status , sample of oil is taken and analysed
Which parameters are monitored on an engine for trend monitoring purposes
N1 , N2 , EGT , fuel flow
Describe a monitoring wash
RPM
PSI
15-25% RPM
20-50psi
Describe a running wash
RPM
PSI
60% RPM
15-25 psi
What’s runway made of
Concrete
Decibels of sound from engine test
140db
Appropriate distance from inlet
Nobody within 20m
Temperature of a hot wash for engine gas path washing
60-90 degrees
Anti freeze mixtures …. 5 to -5 degrees
25% isopropyl, 75% water
Anti freeze mixtures …. -5 to -10 degrees ?
35% isopropyl 65% water
When should you not wash engine gas path
Below -10 degrees
What’s used to measure EGT for purpose of temp indication
Thermocouples
What’s EPR and what does it measure
Engine pressure ration
It measures turbine discharge pressure / intake pressure
Sensors used to measure speed
Tachometer generator ( older aircraft ) Magnetic pickup ( phonic wheel )
What is it when engine is measured for performance
Condition monitoring
Secondary engine indications
Oil pressure , oil temp , fuel pressure , fuel temp , oil quantity
What metal is EGT probes
Chrome lane Alumel
Chromel= white
Alumel= green
Where is EPR normally measured
Pt2 probe from intake bullet
Pt7 probe in manifold aft of turbine final stage
Sensors used to measure oil temp
Most common is the resistance bulb
It’s made of pure nickel
How are engine oil contents measured
Reed switch transmitter
Variable capacitance transmitter
How is fuel temp measured
Measured by a temp bulb
How is fuel pump tank pressure monitored
A simple pressure switch
How is fuel flow monitored
The synchronous mass flow meter
The motor less mass flow meter
2 methods used to monitor engine speed on N1 and N2
N1= magnetic pickup ( phonic disk ) N2= tachometer generator
2 devices used to monitor engine vibration
Sprung magnet type ( older engines )
Piezoelectric type
How is power of engine expressed
Turbo prop= RPM
Gas turbine= EPR
Fire protection system consists of what systems
Detector circuit , alarm circuit , test circuit
Fire bottle made from?
Steel
Why are C02 bottles charged with nitrogen
To provide pressure to complete discharge of agent
Indication given in event of fire
Bell and fire warning light
What type of detectors are fenwal
Continuous loop detectors
Describe a Walter kidde fire detector
Continuous loop detector with 2 conducting cores
Systron donner?
A pneumatic fire loop ( filled with helium )
