The Air InletAircraft & Engines — DGCA CPL practice questions

All 4 questions — The Air Inlet

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

1. Q1. A subsonic engine intake is shaped as a:

   • A.Convergent duct
   • B.Divergent duct✓
   • C.Convergent-divergent duct
   • D.Straight pipe

   Why: The divergent intake slows ram air and raises its pressure before the compressor — ram pressure recovery.

2. Q2. Supersonic intakes use movable ramps or spikes to:

   • A.Increase the airflow velocity
   • B.Control shockwave position and slow the air to subsonic speed✓
   • C.Filter out foreign objects
   • D.Generate extra thrust

   Why: Compressors cannot accept supersonic flow; the intake geometry manages shockwaves to decelerate the air efficiently.

3. Q3. Engine intake anti-icing typically uses:

   • A.Electrical heater mats only
   • B.Hot bleed air from the compressor✓
   • C.De-icing boots
   • D.Glycol spray

   Why: Hot compressor bleed air heats the intake lip to stop ice forming and being ingested into the compressor.

4. Q4. FOD refers to:

   • A.Fan Overspeed Detection
   • B.Foreign Object Damage from debris entering the intake✓
   • C.Fuel On Demand
   • D.Flight Operations Directive

   Why: Stones, birds and other debris entering the intake can severely damage compressor blades — Foreign Object Damage.