Tuesday, March 09, 2021

Cessna A185F Skywagon, N1848R: Accident occurred March 04, 2021 in Skwentna, Alaska

This is preliminary information, subject to change, and may contain errors. Any errors in this report will be corrected when the final report has been completed. 

The National Transportation Safety Board did not travel to the scene of this accident.

Additional Participating Entity:
Federal Aviation Administration / Flight Standards District Office; Anchorage, Alaska
Location: Skwentna, AK
Accident Number: ANC21LA022
Date & Time: March 4, 2021, 15:00 Local 
Registration: N1848R
Aircraft: Cessna A185F 
Injuries: 4 None
Flight Conducted Under: Part 91: General aviation - Personal

On March 4, 2021, about 1500 Alaska standard time, a Cessna 185F, N1848R, was substantially damaged when it was involved in an accident near Skwentna, Alaska. The pilot and three passengers were not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight.

The pilot reported that, after takeoff from a remote frozen snow-covered lake, with the hydraulic-wheel / ski-equipped airplane, the right rear check cable “came loose” from the fuselage attach fitting. The right ski then rotated to a nose high position as he maintained control of the airplane. His initial decision was to fly to the Lake Hood Airport (LHD) Anchorage, Alaska, however a “very serious” vibration was noted in the right horizontal stabilizer and he decided to return to the departure lake to land.

During the landing, he decided to land on untracked snow, and as the ski was coming down “into its normal landing position”, the airplane veered hard to the right. Subsequently the right main landing gear separated from the fuselage and the right wing impacted the snow. The fuselage sustained substantial damage.

The airplane was equipped with Airglas LH4000 hydraulic wheel-skis. The pilot reported that the skis equipped on the airplane were manufactured in 2010 or 2011.

The manufacturer issued a service bulletin (SB) on the skis in March 2018. The service bulletin states, in part: “Airglas has received 4 reports of the LH4000 yoke (PN LH3600-5) of the welds shearing off the outboard arm of the yoke. The common thread between all occurrences is a heavy side load is applied to the skis. This sideways load appears to happen in a turn. In three cases, pilot reported to Airglas that they hit an obstruction in a turn.

The yokes Airglas manufactured up until 2014 were manufactured differently than current yoke. The older yokes were welded and then post heat-treated, followed by a mag-particle inspection. We have also seen some evidence that yokes may have been partially cracked, prior to final heavy side load occurrence. The yokes are powder coated, and this may be masking partial cracks.”

The pilot stated that he and his mechanic were unaware of the SB. He added that, if he would have known of the SB, he “would have been the first in line for the upgraded, beefed up yoke”.

The airplane has been recovered and a detailed examination is pending.

Aircraft and Owner/Operator Information

Aircraft Make: Cessna 
Registration: N1848R
Model/Series: A185F 
Aircraft Category: Airplane
Amateur Built: No
Operator: On file
Operating Certificate(s) Held: None
Operator Designator Code:

Meteorological Information and Flight Plan

Conditions at Accident Site: 
Condition of Light:
Observation Facility, Elevation: PAWS,354 ft msl 
Observation Time: 14:56 Local
Distance from Accident Site: 55 Nautical Miles
Temperature/Dew Point: -2°C /-11°C
Lowest Cloud Condition:
Wind Speed/Gusts, Direction: 3 knots / , 290°
Lowest Ceiling: 
Visibility: 10 miles
Altimeter Setting: 29.74 inches Hg 
Type of Flight Plan Filed:
Departure Point: Skwentna, AK
Destination: Wasilla, AK (4AK6)

Wreckage and Impact Information

Crew Injuries: 1 None 
Aircraft Damage: Substantial
Passenger Injuries: 3 None 
Aircraft Fire: None
Ground Injuries: 
Aircraft Explosion: None
Total Injuries: 4 None
Latitude, Longitude: 61.60208,-151.45001 (est)

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