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Atlas / NTSB / WPR21LA239

NTSB CAROL · Event

Event WPR21LA239

2021-06-20 West Glacier, Montana, United States Airport · 2MT1 None 1 aircraft Status: Completed

Aircraft involved

Probable cause & findings

The pilot’s inadequate performance planning and decision to continue the takeoff which, resulted in a runway overrun and collision with terrain.

Factual narrative

The pilot reported that, he was departing to the south on a 2,500 ft long grass runway at a mountain airport with an estimated 5,000 ft mean sea level density altitude. The pilot calculated the airplane’s performance using the pilot’s operating handbook, which revealed a takeoff distance of 1,800 ft on grass. According to the pilot, during the takeoff run, the airplane lifted off the ground after traveling between 1,250 ft and 1,870 ft down the runway as the airplane reached 60 mph. However, the airplane touched back down to the runway surface near the end of the runway and impacted fallen timber before it came to rest. The airplane sustained substantial damage to the rudder and right wing. The pilot reported that there were no mechanical failures or malfunctions with the airplane that would have precluded normal operation. The pilot stated that, before his takeoff run, he observed the windsock, which indicated winds from the east at 9 kts. However, wind data retrieved from a nearby station and sounding information indicated that winds may have been from the north at 5 kt, which would have resulted in a tailwind. Source: NTSB Aviation Accident Database Retrieved: 2026-02-12

NTSB Findings

Hierarchical cause / factor breakdown from the FAA bulk avdata database. Each finding tagged C (Cause) or F (Factor).

  • Personnel issues-Action/decision-Info processing/decision-Decision making/judgment-Pilot
  • Environmental issues-Conditions/weather/phenomena-Wind-Tailwind-Effect on operation
  • Environmental issues-Conditions/weather/phenomena-Temp/humidity/pressure-High density altitude-Effect on operation
  • Personnel issues-Task performance-Planning/preparation-Performance calculations-Pilot

Verbatim from NTSB's published report. Source file NTSB_2021_WPR21LA239.txt. Findings + structured fields enriched from FAA avall.mdb. Full investigation docket on data.ntsb.gov ↗.