The discovery of fatigue cracks in the wings of a second twin-engine Cessna prompted the FAA to issue an Emergency Airworthiness Directive for two Cessna 400 series aircraft Feb. 21. The AD requires more frequent inspections for wing-spar cracks on the 402C and 414A models.
According to AD, the most recent incident happened Feb. 11 aboard a Cessna 402C used by a commuter airline. The pilot reported that the roll trim became progressively worse, and that he had to use aileron trim to keep the aircraft level.
“This is an aging aircraft issue, not a Cessna issue,” stressed John Frank, executive director of the Cessna Pilots Association. “The instance of fatigue crack and spar issues on older aircraft is not uncommon. This one just happens to involve the Cessna wet wing 400 series.”
The AD targets aircraft with more than 20,000 hours in service and those that have not been fitted with spar straps.
According to Frank, fatigue cracks in older Cessna twin-engine aircraft have been a topic of discussion for several years.
“A fatigue analysis of those aircraft was done and it was determined that, at a certain number of hours, these cracks can happen,” he explained, adding that Cessna developed a kit to do inspections and a strap for the spar to allow the aircraft to continue to fly.
Frank estimated the AD impacts approximately 400 aircraft, but observed that although two aircraft have been discovered to have cracks, another 50 that were inspected were crack-free.
The AD requires inspections be done when the 402C airframe has accrued 10,000 hours Time in Service and for intervals after that not to exceed 110 hours. The 414A AD requires inspections to begin at 8,500 hours and, after that, not to exceed 15 hours TIS.
The 414A AD also prohibits anyone but minimum flight crew on board for flights to get the aircraft to service centers. The crew has just three hours to move the aircraft and cannot fly if moderate turbulence has been reported or is forecast.