AutolandNavigation — Instrumentation — DGCA CPL practice questions
Question 1 of 6
What is the minimum number of autopilots required for a fail-passive (LAND 2) autoland?
All 6 questions — Autoland
Navigation — Instrumentation · DGCA CPL. The correct option is marked on each.
Q1. What is the minimum number of autopilots required for a fail-passive (LAND 2) autoland?
- A.One
- B.Two✓
- C.Three
- D.Four
Why: Fail-passive (LAND 2) status requires a minimum of two independent autopilots. This allows the system to withstand a failure without endangering safety — but it removes the ability to complete an automatic landing. See Section 3 . — LAND 2 = 2 A/Ps = fail-passive; LAND 3 = 3 A/Ps = fail-operational. Commit this pairing to memory.
Q2. During an autoland sequence, at what approximate height does the FLARE mode engage?
- A.200 ft RA
- B.100 ft RA
- C.50 ft RA (45 ft gear altitude)✓
- D.10 ft RA
Why: The A/P flare manoeuvre starts at approximately 50 ft RA (computed as 45 ft gear altitude). FLARE mode is engaged, FD command bars retract, and stabilizer is trimmed further nose-up. The A/T begins retarding thrust at approximately 27 ft RA to reach idle at touchdown. See Section 5 . — The distinction between FLARE ARMED (1500 ft) and FLARE ENGAGED (~50 ft) is a common exam trap.
Q3. What is the ICAO Category 2 ILS approach decision height range?
- A.Not lower than 200 ft
- B.Lower than 200 ft but not lower than 100 ft✓
- C.Lower than 100 ft
- D.No decision height (to the surface)
Why: Category 2 is defined as a precision instrument approach and landing with a decision height lower than 200 ft but not lower than 100 ft , and a RVR not less than 300 m . See Section 10 . — Learn the DH values as a sequence: CAT 1 = ≥200 ft; CAT 2 = 100–200 ft; CAT 3A = <100 ft; CAT 3B = <50 ft; CAT 3C = none.
Q4. What is "de-crabbing" in the context of autoland?
- A.The automatic retraction of flaps after landing
- B.Applying rudder to align the aircraft with the runway centreline by removing drift before touchdown✓
- C.The automatic go-around manoeuvre initiated below 100 ft
- D.The nose-down pitch manoeuvre to lower the nose gear
Why: De-crabbing (also called drift kick-off) is the runway alignment mode. The yaw channel computes the difference between heading and track from 1500 ft. Below approximately 100 ft, align mode engages and the rudder deflects to align the aircraft with the runway centreline, removing any crab/drift angle before touchdown. See Section 6 . — "De-crabbing" and "drift kick-off" are the same manoeuvre — removing the crosswind crab angle before wheels touch down.
Q5. What is the Alert Height in the context of autoland?
- A.The height at which the Captain must visually assess the approach for continuation
- B.A specified radio height above which a failure in a redundant system causes a go-around; below which the failure is ignored✓
- C.The height at which the FLARE mode is armed
- D.The minimum visibility height for Category 3A operations
Why: The Alert Height is a specified radio height. Above the Alert Height, a failure in a required redundant operational system causes the approach to be discontinued. Below the Alert Height, such a failure is ignored and the approach continues to complete the autoland — because the remaining system is sufficient to complete it safely. See Section 11 . — Alert Height is a fail-operational concept — it's the boundary below which you commit to completing the autoland even with one system failed.
Q6. At what approximate radio altitude does the autothrottle begin retarding thrust during an autoland flare?
- A.50 ft RA
- B.27 ft RA✓
- C.10 ft RA
- D.5 ft RA
Why: The A/T begins retarding thrust at approximately 27 ft RA to reach idle at touchdown. The FLARE mode itself engages at approximately 50 ft RA / 45 ft gear altitude. See Section 5 . — FLARE at 50 ft, A/T RETARD at 27 ft, FLARE off at 5 ft, pitch to 2° at 1 ft. These heights are precise and frequently examined.