Stall during initial climb at high density altitude

Casualties unknown • Akron, CO, US

An aircraft stalled shortly after takeoff from an airport with a density altitude of 7011 feet. The pilot, unfamiliar with high-altion operations, rotated late and failed to maintain sufficient airspeed.

What happened

The flight involved a departure from an airfield characterized by significant elevation pressures, resulting in a density altitude of approximately 7,011 feet. Although the aircraft was loaded to roughly 200 pounds below its maximum gross weight limit for takeoff, the environmental conditions presented unique challenges. The pilot noted that his previous experience had been limited to operations near sea level, and he admitted to having little familiarity with the performance characteristics required for high-density-altitude departures.

During the takeoff roll, the aircraft reached rotation speed approximately three-quarters of the way down the runway. The pilot lifted the nose into a slightly elevated attitude to become airborne. Upon reaching an altitude of 100 feet above ground level (AGL), standard post-takeoff procedures were initiated: the landing gear was retracted and the flaps were partially raised to 10 degrees.

Immediately following these configuration changes, the aircraft's performance degraded rapidly. It began to settle back toward the runway surface rather than continuing a positive climb. The aircraft lost lift completely and entered a stall at an altitude of approximately 15 feet AGL. Upon impact with the ground, the aircraft was in a nose-low attitude. The force of the collision caused the airframe to flip over onto its back.

The investigation

Post-accident examination focused on the mechanical integrity of the airframe and the operational context of the flight. Investigators noted the discrepancy between the pilot's usual operating environment and the current high-density conditions. The rapid loss of altitude following gear and flap retraction suggested a critical lack of airspeed margin during the transition from takeoff to climb configuration.

Findings

The primary factors contributing to the accident included the pilot's inability to maintain adequate airspeed during the critical phase of flight immediately after liftoff. The combination of high density altitude, which reduces engine power and propeller efficiency, and the pilot's inexperience with these specific performance parameters led to a stall at an unsafe altitude. The decision to raise the flaps and gear while already struggling for altitude exacerbated the loss of lift.

Safety message

Pilots operating from airports with high density altitudes must carefully calculate takeoff performance data and ensure sufficient runway is available. It is critical to maintain recommended climb speeds, especially during the initial climb phase, to provide adequate margin against stalls. Pilots unfamiliar with high-altitude operations should seek specific training or guidance before attempting such departures.

Probable cause

The pilot's failure to maintain adequate airspeed after takeoff in high-density altitude conditions, which resulted in a stall and subsequent impact with the ground.

Frequently asked questions

What happened in the 1984-08-22 Cessna 185 accident near Akron, CO?

An aircraft stalled shortly after takeoff from an airport with a density altitude of 7011 feet. The pilot, unfamiliar with high-altion operations, rotated late and failed to maintain sufficient airspeed.

What aircraft was involved and where did it happen?

The accident on 1984-08-22 involved a Cessna 185, registration N1980U, at Akron, CO.

What was the probable cause of the accident?

The pilot's failure to maintain adequate airspeed after takeoff in high-density altitude conditions, which resulted in a stall and subsequent impact with the ground.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001214X40684. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.

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