During an approach in icing conditions with the tailplane accumulating ice contamination, a pilot lowers flaps to the landing position and experiences an abrupt uncommanded nose-down pitch and reduced elevator authority. This is characteristic of which hazard?
- AWing stall due to leading-edge ice accumulation
- BTailplane (horizontal stabilizer) stall due to ice-disrupted airflow
- CMach tuck from transonic shock formation on the tail
- DDeep stall due to a T-tail being blanketed by wing wake
Show answer & explanationAnswer & explanation
Correct answer: B. Tailplane (horizontal stabilizer) stall due to ice-disrupted airflow
Ice accumulation on the tailplane can disrupt airflow over that surface, and increasing flap deflection increases the downwash angle at the tail; if the ice-contaminated tailplane stalls, it loses its download, resulting in an abrupt, often uncommanded, nose-down pitch and reduced elevator effectiveness. This is different from a wing stall, which typically produces buffet and a pitch break at high AOA, and is a well-documented icing-related hazard requiring specific recovery techniques (e.g., not immediately retracting flaps).
Why the other options are wrong
- A. Wing stall symptoms typically include buffet and reduced lift causing altitude loss, not this specific tail-driven nose-down pitch pattern.
- C. Mach tuck is a transonic high-speed phenomenon unrelated to low-speed icing/flap scenarios.
- D. Deep stall involves the T-tail being blanketed at very high AOA, not related to flap extension or ice on the tail specifically.
Tailplane Icing Stall
Ice contamination on the horizontal stabilizer can cause it to stall, especially when flaps are extended (increasing downwash), resulting in an abrupt nose-down pitch and reduced elevator control.
- Increasing flap deflection increases tail angle of attack/downwash
- Ice-contaminated tail can stall before the wing does
- Recovery technique differs from wing stall (may involve retracting flaps, not adding them)
Memory trick: Icy tail, sudden nose-fall