The v-band coupling illustrated in an FAA diagram included in the 2023 airworthiness directive, left, can now be replaced by a redesigned part. Photo courtesy of Hartzell Engine Technologies.
Since the 1970s the connection between the turbocharger and the exhaust system has been problematic, causing a significant number of incidents and accidents when the junction failed, allowing red-hot exhaust gases into the cowling. The weak point in the system was a clamp known as a v-band coupling. Under the stress of heat and vibration, the clamp could warp or fail, especially at the spot welds or riveted points in the assembly.
Over the years, the FAA issued a series of airworthiness directives (ADs) targeting various makes and models of aircraft in an effort to drive awareness and mitigate the risk for exhaust gas leaks, engine damage, or even in-flight fire. In 2023, the FAA decided that the issue was widespread and severe enough to warrant a significant action that focused on the couplings themselves, affecting nearly every turbocharged general aviation aircraft, estimated at 41,058 aircraft and engines. AD 2023-09-09 established a 500-hour life limit for the spot-welded, multi-segment exhaust tailpipe v-band couplings and 2,000 hours for riveted and single-piece units. The AD also requires repetitive inspections prior to reaching these life limits.
While the AD addressed a very real safety concern, the supply chain for the parts was woefully unprepared for the crisis that ensued. The number of aircraft with v-band couplings in service for more than the new life limits quickly depleted the available supply and finding parts became nearly impossible, grounding may otherwise airworthy aircraft. Continental Aerospace Technologies offered some temporary relief with an alternative method of compliance (AMOC) that granted extra calendar time and life limits to owners, but it was just a method of safely buying time as the underlying supply chain issued remained unresolved. The FAA approved Continental’s alternative method of compliance July 16, the day after the original AD deadline, extending the part replacement mandate to April 15 for some of the affected engines, though not all. Many aircraft owners found there were no replacement parts available.
Seeing the gravity of the issue when the original airworthiness directive was released, Hartzell Engine Tech quickly determined that its experience in exhaust systems and FAA-approved parts manufacturing made it uniquely qualified to develop a solution that could address this nearly 50-year-old issue, and prevent the grounding of thousands of aircraft in the process.
On February 27, the FAA approved Hartzell’s AeroForce V-Band Clamps for installation in both Continental and Lycoming engines. The approval provides operators with a certified replacement option that, according to Hartzell, terminates the recurring inspection requirement and life limit in the 2023 AD applied to spot-welded v-band couplings. The AeroForce V-Band Clamp is a unique design that reduces welds and rivets, using a braided wire cable and floating retainer improve durability and ease of installation.
“Operators have been managing legacy design issues, inspection burdens, and limited parts availability for some time,” said Marolous Cebulka, vice president of sales and marketing for Hartzell Engine Technologies. “This approval confirms AeroForce delivers a compliant and durable solution engineered to address known failure points in traditional clamps.
“Something as small as a clamp can ground an aircraft,” Cebulka added. “Our goal is to provide a certified option that restores confidence and supports long-term reliability.”
“We commend Hartzell for investing the time and resources required to design, test, and secure FAA approval for this critical part, and for achieving a viable alternative to grounding thousands of aircraft,” said AOPA Senior Vice President of Government Affairs and Advocacy Jim Coon. “This means a great deal to affected aircraft owners, and AOPA has worked with industry and the FAA for many years to achieve this kind of solution to a very difficult and potentially dangerous problem.”
The AeroForce V-Band Clamps are currently in production, with shipments expected to begin before the end of March. Pricing is approximately $1,495 for the Lycoming version and $805 for the Continental version of the clamp. Part numbers and ordering information are available through authorized Hartzell distributors.
By Jeff Simon
Jeff Simon is an A&P mechanic, IA, pilot, and aircraft owner. He has spent the last 22 years promoting owner-assisted aircraft maintenance and created the first inspection tool for geared alternator couplings available at ApproachAviation.com. Jeff is also the creator of SocialFlight, the free mobile app and website that maps more than 20,000 aviation events, hundred-dollar hamburger destinations, and also offers educational aviation videos. Free apps are available for iOS and Android devices, and users can also visit www.SocialFlight.com.
