Aircraft destroyed following loss of control during takeoff

Casualties unknown • Granite, OK, US

An aircraft was destroyed upon impact with terrain after experiencing a loss of control during the initial climb phase following takeoff.

What happened

During the takeoff and initial climb phase, the aircraft experienced a loss of control, resulting in an impact with the terrain. The accident resulted in the destruction of the aircraft.

The investigation

Investigators identified severe corrosion at two structural tube clusters. One of these clusters included a windshield pillar located directly beneath the forward and aft attach fittings of the right wing. Examination of the forward structure revealed that the portion available for carrying loads was less than 30% of the circumference of the pillar tube.

Analysis of the deformation related to the separation of the pillar tube indicated that the component failed under compression loads. According to a manufacturer's representative, the windshield pillar is typically subjected to tensile loads during flight. It was noted that compression loads generated during the takeoff roll may have caused the failure of the pillar. Because the separation point occurred directly below the forward attach fitting of the right wing, this structural failure likely altered the lift characteristics of the wing.

Maintenance records showed the most recent annual inspection took place in January 1999, with entries noting that steel tubing was treated as required. Additionally, a major repair had been performed on a tube cluster in the aft fuselage area in June 1999 due to external rust caused by a previous acid spill.

Probable cause

The failure of a structural windshield pillar due to compression loads, likely caused by corrosion and stresses during the takeoff roll, which altered the wing's lift characteristics and led to a loss of control.

Frequently asked questions

What happened in the 1999-10-11 Piper PA-18-150 accident near Granite, OK?

An aircraft was destroyed upon impact with terrain after experiencing a loss of control during the initial climb phase following takeoff.

What aircraft was involved and where did it happen?

The accident on 1999-10-11 involved a Piper PA-18-150, registration N4473A, at Granite, OK.

What was the probable cause of the accident?

The failure of a structural windshield pillar due to compression loads, likely caused by corrosion and stresses during the takeoff roll, which altered the wing's lift characteristics and led to a loss of control.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001212X19954. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.

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