Definition
A rapid, uncommanded back-and-forth movement of the elevator control felt by the pilot, caused by airflow separation over an ice-contaminated horizontal tailplane. It is a recognized warning sign of an impending tailplane stall and indicates that the tail is no longer producing steady downward lift.
Plain English
The control yoke or stick starts twitching or jerking on its own in the fore-and-aft direction. The pilot did not cause the movement -- the airflow over an iced-up tail is breaking up and shaking the elevator.
Context Anchor
Seen in instrument flying and icing discussions, especially under tailplane stall symptoms after ice has formed on the aircraft.
Derivation
Pulsing comes from the Latin pulsare, meaning to beat or throb. It captures the rhythmic, repeating nature of the movement -- not a single jolt, but a steady throbbing felt through the controls.
Why Pilots Care
It provides an early physical warning of tailplane stall risk, allowing the pilot to exit icing conditions or configure the aircraft before a sudden uncommanded pitch-down occurs.
Analogy
It is like feeling a steering wheel shake in a repeating beat when something is wrong with the road contact. The shaking is not the main problem; it is a warning that the surface contact is no longer normal.
Grounding Statement
Picture flying in icing conditions and feeling the yoke start to pulse back and forth in your hand as the airflow over the tail becomes rough and unstable.
Intuition Check
Do not assume “pulsing” means normal engine vibration or the pilot moving the control. Here it means a repeated movement felt in the elevator control because airflow over the tail is breaking down.
Example Sentence 1
Shortly after extending flaps on approach in icing conditions, the pilot felt elevator control pulsing and immediately retracted the flaps one notch.
Example Sentence 2
During the approach briefing the instructor pointed out that elevator control pulsing often precedes a tailplane stall when ice has accumulated on the stabilizer.