Failure Of The Landing Gear Float Due To Inadequate Maintenance Of The Floats And Corrosion

Location: Skwentna, Alaska Accident Number: ANC22LA080
Date & Time: September 25, 2022, 13:00 Local Registration: N9728B
Aircraft: Cessna 180A Aircraft Damage: Substantial
Defining Event: Sys/Comp malf/fail (non-power) Injuries: 1 Fatal
Flight Conducted Under: Part 91: General aviation - Personal

Analysis: The pilot was departing on a cross-country flight in a float-equipped airplane when the accident occurred. She had contacted a family member and stated she was departing; however, she did not arrive at the destination when expected. A search was initiated, and the airplane was located partially submerged in the departure lake.

Postaccident examination of the wreckage revealed that both floats were heavily corroded and separated from the fuselage. There was no evidence that either float had contacted a foreign object in the water. A portion of the hull on the right float tore open and bent back.

It is likely that tear in the float resulted in the airplane impacting the water during the takeoff. Maintenance records were not available for review during the investigation.

Though toxicology testing of the pilot’s tissue detected diazepam and venlafaxine and their metabolites in the pilot’s system, it is unlikely that the effects of these medications contributed to this accident.

Probable Cause and Findings: The National Transportation Safety Board determines the probable cause(s) of this accident to be -- The failure of the landing gear float due to inadequate maintenance of the floats and corrosion.

FMI: www.ntsb.gov