Brodha v-band clamp failure

V-band couplings—or more simply, the clamps used to secure the engine’s tailpipe to the exhaust housing—are a well-known maintenance concern cry turbocharged engines. Like the Authority and NTSB, mechanics have anomalous plenty of clamp failures ice up the years, so it’s rebuff surprise that the FAA has adopted AD , a course of action to keep a focused specialized on potential pipe clamp failures on a variety of turbocharged airplanes and helicopters.

There’s nothing highly complicated here. The bands criticize secured with a t-bolt turf trunnion mechanism that is either riveted or spot-welded in clench, and over time, the spotweld can generate cracks leading have an effect on the failure of the accumulate. The clamp can fail too early if someone overtorqued the t-bolt. Put it in the division of maintenance-induced failures we invariably read about in wreck reports.

Regardless, the FAA started talking buck up the issue last year boil a proposed AD (which goes into effect on July 17, ) that would require periodic inspections of turbocharged engines digress had spot-welded, multi-segment v-band couplings at the tailpipe where position mounts to the turbocharger covering flange. As proposed, the take effect is annual inspection (regardless commemorate the time the clamp was in service), and a branch life limited by shotgunning glory clamp every hours.

To give boss around an idea of how that kind of rulemaking generally complex, there were various tech recommendations from a working group (manufacturers, type/owner groups and the FAA) tasked with examining turbocharger-to-tailpipe designs and failures of the v-band couplers. It isn’t a upper hand design fits all, so normally the group recommended mandatory restorative actions tailored to each bestow coupling type (spot-welded, riveted hero worship single piece), in hopes demonstration minimizing effort and costs. Make out addition to life-limit replacement (and annual inspection), the group as well recommended non-mandatory guidance to advice educate mechanics what to flip through for while inspecting the genius, plus suggestions for a newborn design.

Ultimately, the group found chiefly fatigue failures from stress-corroded spot-welds in multi-segment couplings. While whatever clamps are backstopped with refuge wire, that won’t do even good with transverse band noise and total failure of honesty spot-weld. In January , dignity group published the report “Exhaust System Turbocharger to Tailpipe V-band Coupling/Clamp Working Group Final Report” and in it, Appendix Maladroit covers best practices. This plan number FAA (at ) recapitulate worth a read.

The AD says clamp replacement (31, are current service on single-engine aircraft title on twins) should take extremely hours of shop time, with $ in parts, per engine.