AutothrottleNavigation — Instrumentation — DGCA CPL practice questions
Question 1 of 6
The autothrottle THR HLD annunciation during take-off occurs at:
All 6 questions — Autothrottle
Navigation — Instrumentation · DGCA CPL. The correct option is marked on each.
Q1. The autothrottle THR HLD annunciation during take-off occurs at:
- A.60 knots IAS
- B.84 knots IAS✓
- C.400 ft RA
- D.V2 + 20 knots
Why: THR HLD annunciates at 84 kt (64 kt for aeroplanes with earlier A/T computers) to indicate that the A/T cannot change thrust level position — but the thrust levers can be manually repositioned. THR HLD remains until 400 ft RA and approximately 18 seconds after liftoff. See Section 6 . — THR HLD = autopilot-generated thrust hold. The A/T sets the thrust for T/O, then HOLDS it until the aircraft is safely airborne and established on climb.
Q2. During a dual channel approach with FLARE armed, the A/T will automatically disengage if thrust lever separation exceeds:
- A.5 degrees
- B.8 degrees
- C.10 degrees✓
- D.15 degrees
Why: Thrust levers separated by more than 10 degrees during a dual channel approach after FLARE is annunciated will cause A/T disengagement. See Section 5 . — Distinguish the two separation values: 8° = N1 equalization limit; 10° = A/T disengagement threshold during dual approach with FLARE armed.
Q3. What is the recommended A/T approach speed setting for the Boeing 737-400?
- A.VREF
- B.VREF + 5 kt✓
- C.VREF + 15 kt to allow for gusts
- D.VREF + 20 kt
Why: The recommended A/T approach speed setting is VREF + 5 kt . Adding extra speed for wind/gust corrections is NOT recommended — the A/T corrects for normal wind gusts through airspeed and acceleration sensing. Higher command speeds result in excessive approach speeds. See Section 6 . — VREF + 5 is the standard 737-400 A/T approach command speed. The A/T's acceleration sensing handles gusts — trusting it is part of the system philosophy.
Q4. During a go-around, pressing the TOGA switch a second time (after initial GA thrust has been set) will cause the A/T to:
- A.Disengage
- B.Advance thrust levers to idle
- C.Advance thrust levers to full GA N1 limit✓
- D.Remain at reduced GA thrust
Why: The first TOGA switch press advances thrust to reduced GA thrust (producing 1000–2000 fpm rate of climb). Pressing TOGA a second time, after reaching reduced GA thrust, signals the A/T to advance thrust to the full GA N1 limit . See Section 6 . — The two-step TOGA philosophy: first press = safe assured climb; second press = maximum go-around power. This gives crew a chance to assess before committing to full power.
Q5. FADEC stands for:
- A.Full Automated Digital Engine Computer
- B.Full Authority Digital Engine Control✓
- C.Fuel and Air Digital Engine Controller
- D.Flight Automated Digital Engine Computer
Why: FADEC = Full Authority Digital Engine Control. It provides complete engine management throughout all phases of flight, including gas generation control, engine limit protection, power management, and engine starting. See Section 10 . — "Full Authority" is the key distinguishing word — FADEC has complete control authority, unlike earlier partial authority engine management systems.
Q6. A flexible (reduced thrust) take-off is achieved with the autothrottle by:
- A.Manually setting thrust levers to a lower position before take-off
- B.Selecting a higher assumed temperature than the actual ambient temperature on the control panel✓
- C.Selecting a lower N1 limit directly on the EICAS display
- D.Reducing the fuel flow on the FMC CDU before take-off
Why: Selecting a temperature on the control panel that is higher than the ambient airfield temperature causes the thrust computation system to calculate a lower limiting EPR or N1. This produces reduced power for take-off — the "assumed temperature" method. See Section 8 . — The assumed temperature method is the standard industry technique. Higher assumed temperature = hotter day = less dense air = engine produces less thrust → lower N1/EPR limit computed.