15.21 - Engine Monitoring and Ground Operations

Question 1

What precautions must you take when performing an Engine run?

Answer 1

• Ear protection – wear the appropriate rated ear protection to avoid hearing damage
• Inlet and exhaust danger areas – avoid standing behind or in the intake suction danger area of a running engine, if required only stand or approach through the entry corridor.
• FOD – before engine start, check the area ahead of the engine for Foreign Object Debris that may be ingested into the engine which would damage it.
• Weather – try to have the aircraft pointed into wind and ensure it is chocked with the parking brake engaged.

Question 2

What is a HOT START and give 3 causes?

Answer 2

A Hot Start is when the EGT (Exhaust Gas Temperature) rises above it’s allowable limit.

Causes: A compressor stall

Low starter air pressure

FOD (Foreign Object Damage)

Question 3

What is a Hung Start and give 3 causes?

Answer 3

A Hung Start is when the engine lights up but the engine speed does not increase. Identified by a light-off but an unusually slow acceleration and a below idle RPM stabilization.

Low starter air pressure

FOD (Foreign Object Damage)

Faulty starter valve

Question 4

What is SOAP and why is it performed ?

Answer 4

Spectrometric Oil Analysis Program (SOAP) is a method used to check the status of an engine. A sample of the engine oil is taken from the tank and the sample is sent to a laboratory. Small particles of the oil are filterd out and analysed to determine the overall health/status of the engine, if modular or component repairs are needed or if the engine is at risk of catasprophic failure.

Question 5

Describe how you would perform a boroscope and what testing is required afterwards?

Answer 5

Carry out the safety requirements as per the maintenance manual, open the cowling doors, remove the boroscope access plugs, if the engine was recently ran, check internal temperature before inserting borescope equipment. Insert the borescope, inspect for damage, rotate the core blades, record any damage found and check that is is within limits. Remove borescope, close access plugs and cowling door.

An engine run test is required afterwords.

Question 6

Which parameters are monitored on an engine for trend monitoring purposes?

Answer 6

Trend monitoring curves reveal much about the internal condition of a gas turbine engine.

N1

N2

EGT

Fuel flow

Question 7

Describe a motoring wash?

(RPM

psi)

Answer 7

15 - 25% RPM

20 - 50 psi

Question 8

Describe a running wash?

(RPM

psi)

Answer 8

60% RPM

15 - 25 psi

Question 9

What should an airport apron surface be made from and why?

Answer 9

concrete