Pilot Debrief

TRAVEL AIR C 4000 near Williams, CA — 2014-08-30

Final reportWPR14LA361
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Date
2014-08-30
Location
Williams, CA, USA
Airport
CN12
Aircraft
TRAVEL AIR C 4000
Registration
N9952
Category
Airplane
Highest injury
Serious
Fatalities
0
Phase of flight
Initial climb

Probable cause

The failure of the elevator control tube due to corrosion, which resulted in a loss of elevator control and collision with terrain.

NTSB narrative

A witness reported that during takeoff, the airplane reached about 8 ft above ground level, then suddenly pitched down and descended to ground contact. Postaccident examination of the airplane revealed a fractured and separated elevator control tube. A viscous liquid was inside the fractured tubing. A mixture analysis found signatures for emulsifiers, surfactants, and amines, which are often found in combination in corrosion-inhibiting compounds. The tubing fracture surfaces had features consistent with torsional overstress. A cross-section of the tube away from the fracture was examined. Corrosion was observed on the inner surfaces of the control tube, as well as significant thinning of the control tube wall thickness, which was 1/2 to 2/3 of the thickness of the least-corroded sections. The thinner wall thickness resulting from the corrosion likely could not support the same loading conditions as the full wall thickness, and likely led to the overstress separation of the control tube.

Analysis

Primary failure mode
Mechanical failure
First missed decision gate
Pilot could have checked control surfaces before takeoff.

NTSB coding

Evidence available

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

Docket documents6

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