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Aviation safety reports, made easier to study

NTSB Reports is an independent research and search tool for public aviation accident and incident records. It brings NTSB aviation reports, structured fields, docket files, extracted figures, photos, videos, and update history into one searchable interface.

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February 13, 2021 · Maule M-6-235 · N56517

Tyonek, AK

Overview

Report Status
Probable Cause
Event Type
Accident
Date
February 13, 2021
Injury Outcomes
2 injuries (2 minor injuries)
Location
Tyonek, AK
Aircraft
Maule M-6-235 (1983)
Tail Number
N56517
Operator
Paul Andrews
Injuries
Minor
Aircraft Damage
Substantial
NTSB Number
ANC21LA017

The pilot initially reported that before landing on a snow-covered glacier, he intended to fly a low pass over the snow-covered site and briefly touchdown to determine the condition of the snowpack, a maneuver commonly known as dragging the landing site. He said that during a second downhill pass over the site, he inadvertently allowed the tailwheel-ski equipped airplane to slow while attempting to “set the track more fully”. He added that, he mis-judged the snow depth and allowed the airplane to slow too much. Subsequently, the ski tips dug into the snow and the airplane came to rest inverted. The airplane sustained substantial damage to the fuselage, the wings, and the empennage. The pilot initially reported there were no preimpact mechanical failures or malfunctions with the airframe and engine that would have precluded normal operation. The pilot later reported that he believed the brake calipers had obstructed the movement of the skis. Two witness marks were observed on the skis that indicated the brake calipers had impacted the skis. A Federal Aviation Administration (FAA) aviation safety inspector (airworthiness) examined the airplane and stated that there were no preimpact mechanical failures or malfunctions found with the airplane. Based on the available evidence, it is likely that the damage to the skis from the brake calipers were from impact damage.

NTSB Probable Cause

The pilot’s selection of unsuitable terrain for landing, which resulted in the airplane encountering deep snow and coming to rest inverted.

Full Narrative

The pilot initially reported that before landing on a snow-covered glacier, he intended to fly a low pass over the snow-covered site and briefly touchdown to determine the condition of the snowpack, a maneuver commonly known as dragging the landing site. He said that during a second downhill pass over the site, he inadvertently allowed the tailwheel-ski equipped airplane to slow while attempting to “set the track more fully”. He added that, he mis-judged the snow depth and allowed the airplane to slow too much. Subsequently, the ski tips dug into the snow and the airplane came to rest inverted. The airplane sustained substantial damage to the fuselage, the wings, and the empennage. The pilot initially reported there were no preimpact mechanical failures or malfunctions with the airframe and engine that would have precluded normal operation. The pilot later reported that he believed the brake calipers had obstructed the movement of the skis. Two witness marks were observed on the skis that indicated the brake calipers had impacted the skis. A Federal Aviation Administration (FAA) aviation safety inspector (airworthiness) examined the airplane and stated that there were no preimpact mechanical failures or malfunctions found with the airplane. Based on the available evidence, it is likely that the damage to the skis from the brake calipers were from impact damage.

Flight

Event TypeAccident
Event Time13:00 AKST
Nearest Airport0nm
Flight Plan FiledNone
Aircraft FireNo
Aircraft ExplosionNo

Aircraft

AircraftMaule M-6-235
Tail NumberN56517
Aircraft CategoryAir
DamageSubstantial
OperatorPaul Andrews
Operating RulePart 91
Engines1
Engine TypeReciprocating
Engine DetailsLycoming · IO-540-W1A5 · Reciprocating · 235
Seats4

People & Injuries

Injury Summary2 injuries (2 minor injuries)
Fatal0
Serious0
Minor2
Uninjured0
Total2
Crew 1Age 53 · Third Class · Minor

Conditions

ConditionsVMC
LightDaylight
Wind30° @ 5 kt
Visibility10 sm
CeilingNone
Temperature / Dew Point16 F / 7 F
Altimeter29.83 inHg
Observation Time12:53
Weather SourceWFAC

Appendix: Source Data