Pilot Debrief

BEECH 65-A80-8800 near Alexandria, MN — 2020-12-29

Final reportCEN21LA101
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Date
2020-12-29
Location
Alexandria, MN, USA
Airport
AXN
Aircraft
BEECH 65-A80-8800
Registration
N134BA
Category
Airplane
Highest injury
None
Fatalities
0
Phase of flight
Takeoff roll

Probable cause

The pilot’s decision to attempt takeoff with frost covering the airplane and rotating below the published rotation speed, which led to exceedance of the airplane’s critical angle of attack and an aerodynamic stall.

NTSB narrative

The pilot reported that the takeoff was conducted below the airplane’s maximum gross weight. Although his written statement and interviews indicated that there was no frost on the airplane during his preflight examination, the police report of the accident stated that the pilot told the responding officer immediately after the accident that there could have been frost on the wings of the airplane. The airport manager who responded to the accident scene reported that all airplane surfaces were covered with frost when he arrived a short time after the accident. The pilot reported that during the takeoff the rotation speed was between 82 and 85 knots. The pilot’s reports of what happened after rotation were consistent, indicating that the airplane began to veer to the right and began shaking. The pilot stated that he did not hear a stall warning and that the airplane did not feel like it was in a stall. While the pilot tried to correct the veering to the right, the airplane pitched down, turned left, and the left wing struck the ground. The airplane then bounced, the right wing struck the ground, and the right main landing gear collapsed. The left wing sustained substantial damage. Airplane performance data indicated that the proper rotation speed for a maximum gross weight takeoff was 96 knots. The power-on stall speed at maximum gross weight for the airplane with landing gear extended and flaps retracted was not specifically listed but would have been between 78 and 91 knots based on available performance data from the airplane owner’s manual. In addition, the performance data would have been for an airplane without frost on it; frost would have increased the speed. Based on the available evidence it is likely that the airplane had frost contamination, which the pilot ignored. He then rotated the airplane during the maximum gross-weight takeoff at a speed below the airplane manufacturer’s recommended rotation speed. The slower speed in combination with degraded performance due to frost contamination of the airplane’s flying surfaces resulted in exceedance of the critical angle of attack, resulting in an aerodynamic stall and subsequent impact with the ground.

Analysis

Primary failure mode
Human factors
First missed decision gate
Pilot could have delayed takeoff due to potential frost on wings.

NTSB coding

Evidence available

  • Photos
  • 9 docket documents
View NTSB final reportView NTSB docket

Docket documents9

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