An AD that takes effect July 17 affects more than 41,000 turbocharged piston aircraft in service in the U.S. They’ll all have to be checked to see what kind of clamp is used to connect the turbocharger to the tailpipe. If it turns out to be a spot-welded, multi-segment exhaust pipe v-band coupling that has been in service more than 500 hours it will have to be replaced within a maximum of two years and inspected every 100 hours in the meantime.
Clamp failures have occurred in dozens of aircraft types and resulted in type-specific ADs but a General Aviation Joint Steering Committee working group figured out it was only the spot welded ones that were coming apart. Some clamps are riveted and those ones are not affected by this AD. When the clamps let go, they allow the venting of blazing hot exhaust gases into the engine compartment that can easily cause a fire. The FAA pegs the cost of the work at $570 per engine but AOPA says that’s light. FAA uses $85 an hour as the base labor rate but AOPA says its members are paying up to $180 for shop rates.
