Agricultural Aircraft Overruns Runway in High-Density Conditions

Casualties unknown • Stanley, ND, US

An agricultural aircraft failed to clear a ditch at the end of the runway during takeoff, resulting in a fire. The pilot attempted to jettison his load but could not gain sufficient altitude due to high density altitude and heavy weight.

What happened

The aircraft departed from the end of the runway but failed to clear a ditch located just beyond the pavement edge. Upon impact with the ditch, the aircraft erupted in flames. The pilot had attempted to jettison his chemical load during the takeoff roll or initial climb phase, but the aircraft did not achieve enough height to safely clear the obstacle.

Weather conditions at the time included a temperature of 87 degrees Fahrenheit with light winds. The computed density altitude was 5000 feet, indicating significant performance degradation due to heat and elevation. Prior to this flight, other pilots operating in similar conditions had reported difficulty climbing out of ground effect and had reportedly attempted to radio warnings regarding the hazardous conditions.

The pilot had previously expressed concerns to his operator that the weather was too hot for safe spraying operations. Despite these reservations, the supervisor instructed him to proceed with the flight. The aircraft's fuel tanks were filled to the full mark, but the chemical hopper was loaded to approximately two-thirds capacity, contributing to the gross weight.

The investigation

Examination of the event focused on the performance limitations of the aircraft under high-density altitude conditions. The primary mechanical and operational factors involved the inability of the aircraft to generate sufficient lift to clear the ditch at the departure end of the runway. The combination of high temperature, density altitude, and partial load of chemicals exceeded the aircraft's takeoff performance capabilities.

Findings

Contributing factors included the decision to operate in high-density altitude conditions despite known performance limitations. The pilot's attempt to jettison the load was insufficient to prevent the overrun. The presence of a ditch at the end of the runway exacerbated the outcome, leading to the fire. The supervisor's directive to fly despite the pilot's concerns regarding heat played a role in the operational decision-making process.

Probable cause

The pilot's failure to ensure adequate climb performance during takeoff in high-density altitude conditions, resulting in an overrun of the runway and collision with a ditch.

Frequently asked questions

What happened in the 1986-06-18 Piper PA25-235 accident near Stanley, ND?

An agricultural aircraft failed to clear a ditch at the end of the runway during takeoff, resulting in a fire. The pilot attempted to jettison his load but could not gain sufficient altitude due to high density altitude and heavy weight.

What aircraft was involved and where did it happen?

The accident on 1986-06-18 involved a Piper PA25-235, registration N6535Z, at Stanley, ND.

What was the probable cause of the accident?

The pilot's failure to ensure adequate climb performance during takeoff in high-density altitude conditions, resulting in an overrun of the runway and collision with a ditch.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001213X33826. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.

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