ANC20CA018

NTSB accident investigation · Cessna 172 · Palmer, AK · February 6, 2020

Accident · No injuriesData collectionFinal report
Date
February 6, 2020, 12:30 local (21:30 UTC)
Place
Palmer, AK
Injuries
3 uninjured
Damage
Substantial damage
Phase of flight
Maneuvering
Aircraft
N817PSCessna 172
Defining event
Maneuvering-low-alt flying: Low altitude operation/event
Weather
Visual (VMC) · Day
Status
Completed · report July 27, 2020
Report
Approved by Office Director
NTSB office
Alaska Regional Office
FAA report
20200206000299A
Case key
100923

From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.

On this page

Probable cause

The pilot's failure to maintain clearance from snow-covered terrain while maneuvering at low altitude.

Findings · 4

NTSB’s coded findings. Those marked are part of the probable cause; the rest are factors or other findings. Under each, the cases with the same finding.

Performance/control parameters: altitudeAircraft › Aircraft oper/perf/capability · Not attained/maintainedCessna 172F: 3 casesAll aircraft: 1,310 casesProbable cause
Object/animal/substance: snow/iceEnvironmental issues › Physical environment · Effect on personnelCessna 172F: 1 caseAll aircraft: 67 casesProbable cause

Sequence of events

The events NTSB coded, in order, by phase of flight. The defining event is the one that best describes the accident. Under each, the cases with the same event anywhere in their sequence.

Analysis

According to the pilot, while conducting a low-altitude pass over a frozen, snow-covered lake in his wheel-equipped airplane, he misjudged the airplane's height above the lake. The landing gear contacted snow, and subsequently, the left wing and propeller struck the ground, and the airplane came to rest upright. The left wing sustained substantial damage. The pilot reported there were no preaccident mechanical malfunctions or failures with the airplane that would have precluded normal operation. The pilot added that the accident may have been prevented if he had done a better job of evaluating the flight scenario and had properly addressed the risks involved with low-level flight over a snow-covered landscape, including the importance of recognizing visual illusions and depth perception issues associated with those conditions.

Factual narrative

According to the pilot, while conducting a low altitude pass over a frozen, snow-covered lake in his wheel-equipped airplane, he misjudged the airplane's height above the ground. The airplane's landing gear contacted the snow and the airplane descended. Subsequently, the left wing and propeller struck the ground and the airplane came to rest upright on the snow-covered terrain, sustaining substantial damage to the left wing. The pilot stated there were no preaccident mechanical malfunctions or anomalies that would have precluded normal operation. In the recommendation section of the NTSB Accident/Incident Reporting Form 6120.1, the pilot stated that the accident may have been prevented if he had done a better job of evaluating the flight scenario and had properly addressed the risks involved with low level flight over a snow covered landscape. In addition to, the visual illusions associated with those conditions.

Aircraft

Registration
N817PS
Reported as
Cessna 172 (F)
Category
Airplane
Serial number
17252705
Built
1965
Engine
Continental O-300 SER, 145 horsepower, reciprocating
Damage
Substantial damage
Flight
Personal · Part 91
Airworthiness certificate
Standard, Normal
Last inspection
100 hour · January 28, 2020
Departed
MRI · Anchorage, AK
Destination
MRI · Anchorage, AK
Equipment
Stall warning system

Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.

Flight crew

As NTSB recorded them. NTSB leaves out names.

Role
Pilot
Age
33
Injuries
None
Certificates
Flight instructor, Commercial
Airplane ratings
Multi-engine land, Single-engine land
Instrument ratings
Airplane
Medical
Class 1, Without waivers/limitations
Last flight review
February 3, 2020
Seat
Left
Restraint
Lap only
Flight hours
714 total · 180 in this make and model · 619 as pilot in command · 80 in the last 90 days · 21 in the last 30 days · 5 in the last 24 hours

Weather

Conditions
Visual (VMC) · Day
Wind
Calm
Visibility
10 statute miles
Lowest ceiling
4,800 ft broken
Temperature
30 °F, dew point 27 °F
Altimeter
29.76 inHg

Docket · 1

The files NTSB released with the investigation on March 20, 2020, on NTSB’s docket system: statements, records, photos and specialists’ reports. 581 KB in all.

FAA reports on this event · 1

The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.