Pilot Debrief

Great Lakes 2T-1A-2 near San Diego, CA — 2019-03-15

Final reportWPR19LA114
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Date
2019-03-15
Location
San Diego, CA, USA
Airport
MYF
Aircraft
Great Lakes 2T-1A-2
Registration
N101GL
Category
Airplane
Highest injury
None
Fatalities
0
Phase of flight
Initial climb

Probable cause

The fracture of the aileron hinge strap due to fatigue crack propagation, which resulted in substantial damage to a wing rib aft of the spar at the outboard aileron cutout. Contributing to the accident was inadequate maintenance inspection.

NTSB narrative

About 5 minutes after taking off, the pilot observed that the left upper aileron had come loose from the inboard hinge. The pilot returned to the departure airport and landed uneventfully. A postaccident examination of the airplane revealed that a wing rib aft of the spar at the outboard aileron cutout was substantially damaged. Examination of the aileron hinge strap fracture surfaces revealed crack arrest marks and thumbnail-shaped patterns on the fracture surfaces, which emanated from both the top and bottom surfaces of the hinge strap. The fracture surfaces were consistent with asymmetric reverse-bending fatigue crack propagation. The fatigue cracking propagated from the top and bottom surfaces through almost the entire cross-section of the hinge strap. The pilot reported that while there were no inspection criteria from the manufacturer relative to the hinge straps, all hinge straps were inspected as part of each annual inspection.

Analysis

Primary failure mode
Mechanical failure
First missed decision gate
Pilot could have conducted a more thorough preflight inspection.

NTSB coding

Evidence available

  • Photos
  • 6 docket documents
View NTSB final reportView NTSB docket

Docket documents6

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