On May 27, 1983, a Bell 206B (registration N16937) operated by Beartooth Helicopters was involved in an aviation accident near Billings, MT. Investigators recorded the probable cause as: Error in the manufacture of the first stage turbine wheel, specifically an error in proper web thickness that escaped detection. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive; 8 related events involving the same aircraft type or operator are linked below.
A helicopter made a hard autorotative landing after an engine fire/explosion forced it down. The pilot extinguished the fire. Investigation revealed a manufacturing error in the first stage turbine wheel.
Accident Details
A helicopter experienced an engine fire and explosion shortly after takeoff from an off-airport landing site, forcing the pilot to execute a hard autorotative landing. The pilot was conducting a personal flight with family and friends aboard. Following the landing, the pilot successfully extinguished the fire.
Investigation Findings
Post-accident investigation determined that the failure was caused by an error in the manufacture of the first stage turbine wheel. According to an Allison spokesman, the error involved an incorrect web thickness in the turbine wheel that occurred during the manufacturing process and escaped detection.
Probable cause
Error in the manufacture of the first stage turbine wheel, specifically an error in proper web thickness that escaped detection.
What happened in the 27 May 1983 Bell 206B accident near Billings, MT?
A helicopter made a hard autorotative landing after an engine fire/explosion forced it down. The pilot extinguished the fire. Investigation revealed a manufacturing error in the first stage turbine wheel.
What aircraft was involved and where did it happen?
The accident on 27 May 1983 involved a Bell 206B, registration N16937, operated by Beartooth Helicopters, at Billings, MT.
What was the probable cause of the accident?
Error in the manufacture of the first stage turbine wheel, specifically an error in proper web thickness that escaped detection.
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