On September 15, 1984, a Cessna 170B (registration N3010A) was involved in an aviation accident near Anchorage, AK. Investigators recorded the probable cause as: The pilot's failure to perform pre-flight weight and balance computations, which resulted in inadequate climb performance and subsequent collision with terrain. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
A pilot failed to perform required weight and balance calculations prior to departure. The aircraft could not clear rising terrain shortly after takeoff, leading to a fatal crash.
What happened
The pilot reported that the takeoff performance was sluggish, preventing the aircraft from clearing oncoming rising terrain and obstacles shortly after departure. Approximately 2,500 feet from the departure end of the runway, the left wing struck the tops of trees that were approximately 100 feet tall. This impact caused the aircraft to yaw 180 degrees away from its intended flight direction.
The investigation
Post-accident analysis revealed a critical procedural failure by the pilot. The pilot had failed to perform necessary weight and balance computations before the flight. Subsequent calculations determined that the aircraft's gross weight was no more than 150 pounds below the certified maximum limit, indicating it was dangerously close to its performance envelope.
Findings
The primary contributing factor was the pilot's failure to conduct pre-flight weight and balance checks. This omission led to an overloaded or improperly balanced aircraft that lacked the necessary climb performance to clear the terrain during takeoff.
Probable cause
The pilot's failure to perform pre-flight weight and balance computations, which resulted in inadequate climb performance and subsequent collision with terrain.