Casualties unknown

Light aircraft crashes during takeoff attempt on county road due to high density altitude (N9666D)

Ellis, KS, US

On August 15, 1993, a Piper PA-22-150 (registration N9666D) was involved in an aviation accident near Ellis, KS. Investigators recorded the probable cause as: The pilot's inability to maintain sufficient airspeed and lift due to high density altitude and heavy loading, resulting in a loss of control during takeoff from an upward-sloping surface. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.

Sourcesthe U.S. National Transportation Safety Board (NTSB) historical archivePrimary reportUpdated 2026-06-10Data APIEditorial standards

A light airplane attempting to take off from an upward-sloping county road nosed over in a ditch after sinking and drifting left. High temperature and density altitude contributed to the loss of performance.

What happened

The pilot attempted to initiate a takeoff from a county road under hot weather conditions. The air temperature was recorded at approximately 93 degrees Fahrenheit, creating challenging atmospheric conditions for lift generation. The aircraft was loaded with four persons aboard and contained a full fuel load. The specific terrain presented an additional challenge as the road sloped upward in the direction of intended flight.

During the takeoff roll and initial climb, the airplane began to sink while remaining in ground effect. Simultaneously, the aircraft drifted toward the left side of the roadway. Unable to maintain altitude or correct the lateral drift, the airplane left the paved surface and entered a ditch adjacent to the road. The impact caused the nose of the aircraft to overturn.

Findings

The investigation highlighted several critical factors contributing to the accident. The estimated density altitude at the time of the event was 4,800 feet mean sea level (msl). This high density altitude significantly reduced engine power and aerodynamic efficiency. Combined with the full fuel load and four occupants, the aircraft's performance capabilities were severely compromised.

The upward slope of the county road further degraded takeoff performance by reducing the available ground roll distance for acceleration. The pilot was unable to achieve sufficient airspeed to sustain flight in these high-density-altitude conditions. Fuel exhaustion was not a factor, as the tank was full; rather, the primary issue was the inability to generate enough lift to overcome the weight and atmospheric density.

Safety message

High density altitude drastically reduces aircraft performance, particularly during takeoff and climb phases. Pilots must carefully calculate performance data for temperature and elevation before attempting operations in marginal conditions. Operating from unpaved or sloped surfaces like county roads adds complexity and risk, especially when the aircraft is near its maximum gross weight limit.

Probable cause

The pilot's inability to maintain sufficient airspeed and lift due to high density altitude and heavy loading, resulting in a loss of control during takeoff from an upward-sloping surface.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001211X13105. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.