Definition
Ice that accumulates on the empennage — the tail assembly of the aircraft, including the horizontal stabilizer, vertical stabilizer, and elevator. Because the tail surfaces are typically thinner than the wings, they collect ice faster and at a higher rate, and the resulting disturbance of airflow can lead to a sudden loss of pitch control known as a tailplane stall.
Plain English
Ice that builds up on the tail of the aircraft. The tail is thinner than the wings, so it picks up ice quickly, and even a small amount can disturb the airflow over it badly enough to cause a sudden nose-down pitch that the pilot may not be able to recover from.
Context Anchor
Seen in icing discussions, especially when flying in clouds or precipitation near freezing temperatures and when changing configuration for approach or landing.
Derivation
‘Empennage’ comes from the French empenner, meaning to feather an arrow. The tail of an aircraft serves the same purpose as the feathers on an arrow — it stabilizes the flight path. ‘Empennage ice’ is simply ice on that part of the aircraft.
Why Pilots Care
Ice on the tail can change its shape enough to cause a tailplane stall or sudden loss of pitch control.
Grounding Statement
Picture ice collecting on the tail’s small wing-like surface; even a rough layer can change how air flows over it and weaken its control effect.
Intuition Check
Do not assume icing is only a wing problem. Empennage ice is tail ice, and tail ice can affect pitch control even when the wings still seem to be flying.
Example Sentence 1
After picking up ice in the climb, the crew delayed extending full flaps on approach because of the risk of empennage ice causing a tailplane stall.
Example Sentence 2
Preflight checks confirmed no empennage ice had formed overnight on the parked aircraft.