Pilot Debrief

STINSON 108 near Palmer, AK — 2015-09-20

Final reportGAA15LA265
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Date
2015-09-20
Location
Palmer, AK, USA
Aircraft
STINSON 108
Registration
N6066M
Category
Airplane
Highest injury
Serious
Fatalities
0
Phase of flight
Approach

Probable cause

The pilot's failure to maintain adequate airspeed and his exceedance of the airplane’s critical angle-of-attack during final approach to landing, which resulted in an aerodynamic stall and impact with terrain.

NTSB narrative

The private pilot was conducting a personal flight and was on final approach to land at a remote backcountry airstrip. The pilot reported that he applied carburetor heat for the approach and that he observed 60 mph (52.1 knots) on the airspeed indicator. He subsequently "pushed the throttle forward, but the engine sound remained constant." According to the pilot-rated passenger, as the pilot began to level the wings to align with the runway, the right wing "instantly…dropped to a 45 degree angle." He then observed the pilot immediately reach for the throttle but saw him inadvertently grab the carburetor heat lever instead. The airplane impacted terrain in a nose-low, right-wing-down attitude and came to rest on a hillside about 100 yards short of the landing area. The airplane sustained substantial damage to both wings and the fuselage. The pilot reported no mechanical malfunctions or failures with the airplane that would have precluded normal operation. It is likely that, during the final approach, the pilot did not maintain adequate airspeed and exceeded the airplane's critical angle-of-attack, which resulted in an aerodynamic stall. Although the pilot attempted to add power to recover from the stall, he inadvertently grabbed the carburetor heat lever instead of the throttle.

Analysis

Primary failure mode
Loss of control
First missed decision gate
Pilot could have maintained airspeed and avoided the stall during final approach.

NTSB coding

Evidence available

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

Docket documents8

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