Control Restriction Due to Seat Cushion Shift Causes Crash

Casualties unknown • Clarks Hill, SC, US

A pilot lost control of the aircraft during a low-altitude maneuver after the rear seat cushion slid forward, restricting elevator travel and preventing recovery from a descent into trees.

What happened

The incident occurred while the aircraft was operating in close proximity to terrain. At the time of the event, the airplane was maintaining a circular pattern approximately 200 feet above the tree line. The pilot initiated a climbing turn to gain altitude. As the wings were leveled out of the turn, the aircraft unexpectedly began to descend.

In response to the loss of altitude, the pilot applied full engine power and moved the control stick forward to lower the nose slightly. However, when the pilot attempted to pull back on the flight controls to arrest the descent and level the aircraft, the airplane continued its downward trajectory into the trees. The pilot reported that during this critical phase, the control stick could only be moved through approximately 50% of its normal travel range.

The investigation

Post-accident examination focused on the cockpit configuration and potential obstructions to flight controls. The pilot stated that the bottom rear seat cushion had a history of sliding forward. It was determined that this cushion had shifted position, physically obstructing the full movement of the control stick. This mechanical restriction prevented the pilot from applying the necessary elevator input to recover from the low-altitude situation.

Findings

The primary factor in this accident was the inability to fully operate the flight controls due to an obstruction within the cockpit. The restricted travel of the control stick, caused by the displaced rear seat cushion, directly contributed to the aircraft's descent into the trees. This case highlights the importance of securing all movable items in the cabin to ensure unimpeded access to critical flight instruments and controls.

Probable cause

The pilot's inability to fully extend the elevator control due to obstruction by a rear seat cushion, which resulted in a loss of control and collision with trees.

Frequently asked questions

What happened in the 1987-10-18 Piper J-3 accident near Clarks Hill, SC?

A pilot lost control of the aircraft during a low-altitude maneuver after the rear seat cushion slid forward, restricting elevator travel and preventing recovery from a descent into trees.

What aircraft was involved and where did it happen?

The accident on 1987-10-18 involved a Piper J-3, registration N98806, operated by Augusta Aviation Inc, at Clarks Hill, SC.

What was the probable cause of the accident?

The pilot's inability to fully extend the elevator control due to obstruction by a rear seat cushion, which resulted in a loss of control and collision with trees.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001213X32260. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.

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