CESSNA is questioning the US National Transportation Board (NTSB) call for an airworthiness directive (AD) requiring landing-gear inspections on several thousand piston singles.

The NTSB has recommended that the Federal Aviation Administration issue an AD requiring inspection of main gear spring struts for cracks and corrosion on tailwheel-configured Cessna 170s, 180s, 185s, 190s and 195s, requiring removal of the spring struts within 100h and regularly thereafter.

The recommendation was prompted by a September 1999 accident in Alaska, when the left main gear of a ski-equipped 185 collapsed on landing. The NTSB says 16 of 76,000 aircraft in service have experienced spring strut failures since 1984.

Cessna claims only 16,000 aircraft may be affected and that failures are to do with operational conditions: "Nine out of 10 of the incidents were in Alaska on aircraft fitted with skis or tundra tyres," it says.

Source: Flight International