On January 17, 1987, a Beech A-36 (registration N7688N) operated by Roscoe Brown Sales Co. was involved in an aviation accident near Corning, IA. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
A flight from Champaign, IL, experienced an altimeter unwinding on final approach to runway 17. The aircraft struck trees about one mile from the runway. Post-accident inspection revealed binding of the altimeter's 100-foot needle at the tang.
Flight Progress
The flight originated from Champaign, Illinois, and progressed normally under an IFR flight plan. The IFR clearance was canceled at the Lamoni VOR, after which the flight continued under visual flight rules (VFR).
Accident Sequence
While on final approach to runway 17, approximately one mile from the runway, the altimeter suddenly unwound. The aircraft subsequently struck trees. According to the pilot, the altimeter had functioned normally up to that point. Airport lighting was reported to be functioning properly during the approach.
Post-Accident Inspection
Examination of the altimeter after the accident revealed binding of the 100-foot needle at the tang. Investigators noted that only slow movement of the needle produced a significant binding problem. Testing of the altimeter reproduced a similar malfunction to that experienced by the pilot during the approach.