On March 15, 1984, a Hiller UH-12B (registration N1021Y) was involved in an aviation accident near Ulysses, KS. Investigators recorded the probable cause as: Fatigue in the attachment fittings of the anti-torque rotor and gearbox. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
A pilot performed an autorotative precautionary landing after feeling vibrations in the anti-torque pedals. The aircraft landed hard in a field, and upon exiting, the pilot found the anti-torque rotor and gearbox missing, later located 100 yards away. Analysis revealed fatigue in the attachment fittings.
Event Details
The pilot conducted an autorotative precautionary landing after experiencing vibrations in the anti-torque pedals. The aircraft was turned into the wind but landed hard in a field. Upon exiting the aircraft, the pilot discovered that the anti-torque rotor and gearbox were missing. They were found approximately 100 yards away, back along the flight path.
Findings
Analysis of the failed components revealed an area of fatigue in the attachment fittings of the anti-torque rotor and gearbox. This fatigue led to the separation of those components during flight, which likely caused the vibrations felt in the anti-torque pedals.
Probable cause
Fatigue in the attachment fittings of the anti-torque rotor and gearbox.
Frequently asked questions
What happened in the 15 Mar 1984 Hiller UH-12B accident near Ulysses, KS?
A pilot performed an autorotative precautionary landing after feeling vibrations in the anti-torque pedals. The aircraft landed hard in a field, and upon exiting, the pilot found the anti-torque rotor and gearbox missing, later located 100 yards away. Analysis revealed fatigue in the attachment fittings.
What aircraft was involved and where did it happen?
The accident on 15 Mar 1984 involved a Hiller UH-12B, registration N1021Y, at Ulysses, KS.
What was the probable cause of the accident?
Fatigue in the attachment fittings of the anti-torque rotor and gearbox.
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