The concern sheet
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U.S. Department of Transportation
Federal Aviation Administration Airworthiness Concern Sheet Date: April 20, 2026
Reply to:
Name: Olivia Rasmussen Title: Aerospace Engineer Office: Central Certification Branch Street Address: 2300 E Devon Ave City, State, ZIP: Des Plaines, IL 60018-4696 Telephone: 847-294-7117 Electronic Mail: olivia.e.rasmussen@faa.gov Make/Model: Air Tractor: AT-802A, AT-802 Textron Aviation: 208 Pilatus: PC-6/B2-H4 DeHavilland: DHC-2, DHC-3, DHC-6 Float Models: 6000A, 6100A, 8000A, 10000A, 13000A Reason for Airworthiness Concern: Main landing gear actuators sticking due to corrosion on slide tube.
Federal Aviation Administration (FAA) Description of Airworthiness Concern The FAA recently received a report from the Australian Transport Safety Bureau (ATSB) of a water landing accident involving a DeHavilland DHC-2 Beaver installed with Wipline 6100A amphibious floats operating in a saltwater environment. One of the main gear wheels remained in the fully extended position and resulted in the aircraft becoming submerged after touchdown on water. The ATSB investigation reported that extensive corrosion was found on the contact surface of the main gear slide tube at the location where the main gear carriage sits when the main gear is in the fully extended position. The slide tube also exhibited wear consisting of longitudinal marks caused by movement of the main gear carriage. Further investigation found that the main carriage bushings exhibited wear of the PTFE layer, exposing the sintered bronze layer and exhibited evidence of scoring.
Affected STCs: SA610GL (6000A or 6100A floats on DeHavilland DHC-2 Mk. I), SA309CH (6000A floats on DeHavilland DHC-2 Mk. II), SA227CH (6100A floats on Pilatus PC-6/B2-H4), SA1311GL (8000A floats on Textron 208), SA331CH (8000A floats on DeHavilland DHC-
3), SA01795CH (10000A floats on Air Tractor AT-802 and AT-802A), and SA2CH (13000A floats on DeHavilland DHC-6)
Photos of the Slide Tube and Carriage Overview, Worn Carriage Bushings, and Corrosion and Scoring on the Slide Tube are shown on the following page.
The FAA and Wipaire are currently investigating this concern. Wipaire has released Service Letter 280 on their website in response to this issue.
Request for Information The FAA is interested in receiving any information on corrosion on main landing gear slide tubes and carriage assembly bushings in aircraft installed with Wipline model 6000A, 6100A, 8000A, 10000A, and 13000A amphibious floats. We recommend operators inspect this area and provide information including description of corrosion and available photos.
Please provide any other information you feel may be helpful for us to consider as a part of this evaluation.
This Airworthiness Concern Sheet (ACS) is intended as a means for FAA Aviation Safety Engineers to coordinate airworthiness concerns with aircraft owners/operators through associations and type clubs. At this time, the FAA has not made a determination on what type of corrective action (if any) should be taken. The resolution of this airworthiness concern could involve Airworthiness Directive (AD) action or a Special Airworthiness Information Bulletin (SAIB), or the FAA could determine that no action is needed at this time. The FAA’s final determination will depend in part on the information received in response to this ACS.
The FAA endorses dissemination of this technical information to all manufacturers and requests association and type club comments.
Attachments:
Service Difficulty Report Accident/Incident Data System Service Letter / Bulletin Special Airworthiness Information Bulletin Federal Aviation Administration or National Transportation Safety Board Transmittal:
Federal Aviation Administration Airplane Owners and Pilots Association Experimental Aircraft Association Type Club Type Certificate Holder Other:
Response Requested By:
Emergency (10 days) Alert (30 days) Information (90 days)
Safety Recommendation Airworthiness Directive Alternate Means of Compliance Risk Analysis
Figure 1: Slide Tube and Carriage Overview
Figure 2: Worn Carriage Bushings
Figure 3. Corrosion and Scoring on the Slide Tube