Engine Starting and Auxiliary Power Units (APU)Aircraft & Engines — DGCA CPL practice questions

All 5 questions — Engine Starting and Auxiliary Power Units (APU)

Aircraft & Engines · DGCA CPL. The correct option is marked on each.

1. Q1. A 'hot start' is one in which:

   • A.EGT exceeds its maximum limit during start✓
   • B.The engine fails to light up
   • C.The engine accelerates too quickly
   • D.Oil temperature is high before start

   Why: Too much fuel for the available airflow sends EGT past its limit — the start must be aborted immediately.

2. Q2. A 'hung start' is one in which the engine:

   • A.Fails to rotate
   • B.Lights up but stabilises below idle RPM with rising EGT✓
   • C.Starts then flames out
   • D.Overspeeds

   Why: Usually insufficient starter power: light-up occurs but the engine won't accelerate to idle, while EGT climbs.

3. Q3. After a wet start (no light-up), before another attempt the engine must be:

   • A.Refuelled
   • B.Motored over to blow out unburnt fuel✓
   • C.Allowed to cool for 24 hours
   • D.Inspected by maintenance only

   Why: A blowout cycle clears pooled fuel so the next start doesn't torch.

4. Q4. Self-sustaining speed during a start is the point where:

   • A.The starter cuts out automatically at idle
   • B.The turbine produces enough power to drive the compressor without the starter✓
   • C.Fuel is first introduced
   • D.EGT peaks

   Why: Beyond self-sustaining speed the engine can accelerate on its own; the starter then drops out and the engine stabilises at idle.

5. Q5. A Ram Air Turbine (RAT) provides:

   • A.Cabin pressurisation
   • B.Emergency hydraulic or electrical power from a turbine deployed into the airstream✓
   • C.Engine starting air
   • D.Extra thrust

   Why: After a total power failure the RAT deploys and the airflow spins it to power essential flight controls and instruments.