Narrative:Two co-pilots were preparing for an upgrade flight. The instructor disabled the student's attitude indicator and an engine failure was simulated in the procedure turn for an instrument approach. The student became disoriented and asked the instructor to take control, which he refused. The aircraft later struck the sea.
Probable Cause:PROBABLE CAUSE: "The instructor pilot's loss of altitude awareness and possible spatial disorientation, which resulted in the loss of control of the airplane at an altitude too low for recovery; and company management's lack of involvement in and oversight of its Beechcraft 1900 flight training program. Contributing to the accident was the instructor pilot's exercise of poor judgment in establishing a flight situation and airplane configuration conducive to spatial disorientation that afforded the pilots little or no margin for error."
The ALPA did not agree with the probable cause adopter by the NTSB. In a 1997 ALPA petition they claim that a whirl mode flutter was induced to the right engine and propeller assembly, due to pre-existing right engine truss tube failures. This whirl mode flutter caused a catastrophic failure within the truss mount system. This failure allowed the right engine and nacelle to depart the right wing. The right engine struck and removed the right horizontal stabilizer. The propeller probably damaged the left horizontal stabilizer. The aircraft then pitched over violently and instantly and crashed.
Loss of control
» Aircraft Damage Detection From Acoustic Signals Found By A Cockpit Voice Recorder / Ronald O. Stearman et al
» Air Safety Week 3.5.1993 (p. 3)
» ICAO Adrep Summary 4/94 (#14)
» Petition for Reconsideration of Probable Cause, N811BE (The Investigation Process Research Resource Site)
Official accident investigation report
|investigating agency: ||National Transport Safety Bureau (NTSB) - United States of America |
|report status: ||Final|
|report number: ||NTSB/AAR-93-01-SUM|
|report released:||27 April 1993|
|duration of investigation: ||1 year and 4 months|
|download report: ||
Follow-up / safety actions