Pilot Debrief

GREAT LAKES 2T-1A-2 near Kingsville, TX — 2011-02-26

Final reportCEN11LA209
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Date
2011-02-26
Location
Kingsville, TX, USA
Airport
IKG
Aircraft
GREAT LAKES 2T-1A-2
Registration
N6196L
Category
Airplane
Highest injury
None
Fatalities
0
Phase of flight
Approach

Probable cause

A pre-existing crack in the front spar of the right horizontal stabilizer near a riveted fitting, causing it to fail and separate from the airplane in flight. Contributing to the accident was the failure of maintenance personnel comply with existing service bulletins and to detect and repair the damaged spar.

NTSB narrative

The pilot took off to practice aerobatic maneuvers for an upcoming air show. After completing a hammerhead turn, he felt a slight vibration and the pitch control felt unusual. Returning to the airport, the vibration increased. The pilot landed but was unable to maintain directional control and the airplane ground-looped. The right horizontal stabilizer and elevator had separated from the airplane, striking the rudder and causing substantial damage. A postaccident examination revealed evidence of a pre-existing crack in the front spar near a riveted fitting. The spar moved outward and disengaged from the fitting. The inboard section rotated downward and separated from the airplane. The remaining portion of the stabilizer pivoted aft, separated from the airplane, and struck and damaged the rudder. A service alert from the airplane’s manufacturer outlined a similar previous occurrence. Another emphasized the importance of properly rigged tail wires, noting that if the tail wires were improperly rigged excessive torque loads could be applied to the horizontal stabilizer front spar, causing the attach fitting to fail. Examination of the last annual inspection entry disclosed no reference to the horizontal stabilizer spar being inspected, nor did it indicate that either service bulletin had been complied with.

Analysis

Primary failure mode
Mechanical failure
First missed decision gate
Inspection of the horizontal stabilizer prior to the flight could have prevented the failure.

NTSB coding

Evidence available

  • 6 docket documents
View NTSB final reportView NTSB docket

Docket documents6

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