AM Troubleshooting & Diagnostics 3

Question 1

A turbine engine's exhaust gas temperature (EGT) is higher than normal at takeoff power. Which fault is least likely to be the cause?

Accepted Answer

Engine oil level low by one quart

Answer

Oil level has little effect on EGT; high EGT is typically caused by reduced compressor efficiency, turbine degradation, or abnormal combustion.

Question 2

When a continuity check on a wire harness shows zero ohms between two conductors that should be separate, this indicates:

Accepted Answer

A short circuit between the two conductors

Answer

Zero ohms between conductors that should be isolated means they are shorted together, creating an unintended electrical path.

Question 3

During ground testing, fuel is found in the engine oil. What is the MOST likely cause on a reciprocating engine?

Accepted Answer

Failed primer system or leaking fuel injection nozzle flooding the intake

Answer

Fuel can enter the crankcase via a leaking primer or flooded injection nozzle, allowing raw fuel to pass the rings into the oil.

Question 4

An autopilot system causes repeated uncommanded roll inputs. After verifying the control surfaces are free, the technician should next check:

Accepted Answer

Rate gyro or attitude sensor outputs and autopilot servo feedback signals

Answer

Uncommanded autopilot roll inputs suggest erroneous sensor data from the rate gyro or attitude sensor, or servo feedback issues.

Question 5

A composite airframe shows a dull thud when tapped in an area that normally produces a sharp tap sound. This indicates:

Accepted Answer

Delamination or disbonding within the composite layers

Answer

A dull tap (coin-tap test) on composite structure indicates internal delamination or disbonding between layers.

(AM) Aircraft Maintenance Certification Practice Test