The Federal Aviation Administration (FAA) has issued Airworthiness Directive (AD) 23-09-09, addressing concerns related to V-band clamp assemblies used in various turbocharged aircraft engines (this AD has been known to be a repeat offender!). These components, critical for securing exhaust system joints, have been linked to potential failures that could lead to exhaust gas leaks, engine damage, or even in-flight fire hazards.
In this piece, we’ll provide a comprehensive overview of all available resources related to AD 23-09-09. This includes manufacturer service bulletins, FAA guidance documents, inspection procedures, compliance aids, and engineering reference materials—all aimed at helping operators, maintenance providers, and aircraft owners ensure timely and effective compliance.
Before proceeding with the requirements of AD 23-09-09, it’s important to confirm whether your aircraft or component already meets the intent of earlier related directives. Reviewing maintenance records, logbook entries, and previous AD sign-offs can help determine if credit is available for prior inspections or replacements.
The V-Band Clamp Best Practices Guide (BPG) provides clear, practical instructions to ensure proper installation, inspection, and maintenance of V-band clamp assemblies. It consolidates industry and manufacturer recommendations into one reference, emphasizing correct torque procedures, alignment checks, inspection intervals, and replacement criteria. The guide is designed to help maintenance personnel reduce the risk of clamp fatigue or failure, improve reliability across exhaust systems, and support compliance with AD 23-09-09 requirements.
At TBX (Airworthy.com) we are huge fans of tips, tricks, and Do's & Dont's when it comes to aviation maintenance. Buried within the Best Practices Guide is a great list with 14 tips and tricks to complying with V-band clamp issues, inspections, and ADs:
1. New over Old: Installation and fit of new components is often much better than a mix of old (or worn) components and new components.
2. Mind the Gap: Align exhaust components prior to installation to minimize gaps or misalignment
3. Start Loose: Loosely soft-fit all components (including support brackets and clamps) to assist in proper alignment and in tailpipe support to preclude pre-loading the coupling/clamp inadvertently.
4. Get Assistance: Do not attempt to align things using the coupling/clamp alone, get assistance from someone
5. Ensure Airworthiness: Ensure all required seals (or gaskets as applicable, per the DAH ICA’s) are airworthy and in their proper position
6. Check Self-locking Nuts: Ensure the self-locking nuts are still serviceable and retain their locking capability, otherwise replace them.
7. Hands Off: Minimize opening, twisting or cycling of the coupling/clamp at any time.
8. Anti-Seize can Help: Use of a hi-temp, nickel based, anti-seize compound on all interfaces may assist in the initial installation process.
9. Seat & Tighten Together: Properly seat the coupling/clamp evenly around its circumference while tightening up exhaust installation fasteners (tailpipe, supports, hanger, etc.).
10. Tap that Clamp: If accessible, a tap around the circumference with a soft mallet while tightening may help seat the coupling/clamp
11. Get the Torque Right: Apply the proper torque as defined by the DAH Instructions for Continued Airworthiness
12. Beware Over-Torquing: More torque and subsequent over-torque is NOT better and will lead to deformation of the coupling/clamp and reduced service life.
13. Marine is Mean: In marine or saltwater environments or operations, be sure to include the V-band coupling/clamp in your airplane/engine washes and enhanced inspection programs.
14. Blast Media Tips: If using blast media for cleaning a coupling/clamp, use only blast media that is non-abrasive, non-ablative and non-peening when cleaning any coupling/clamp per approved or acceptable methods.
V-Band couplings and clamps are routinely exposed to extremely high exhaust temperatures and heat cycles, which can lead to cracks and failures in the V-band coupling/clamps. While 23-09-09 established a life limit of 500 hours on spot-welded, multi-segment V-band couplings, the safety working group also recommends 2,000 hour recommended life-limits on rivetted and single-piece clamps.
Just because you have a riveted V-band coupling or a single-piece clamp does NOT mean you are immune to the safety concern. The V-band clamp working group has attempted to put in place life-limits to help guide the community to better safety measures regarding ALL V-band clamps:
Note: substitution of a coupling/clamp part number, and/or type (spot-welded, riveted, or single-piece) for another coupling or clamp IS NOT ALLOWED without a specific FAA approval from the design approval holder (DAH).
Because the spot-welded V-band clamp inspection under 23-09-09 was required within 2-years of the AD, a surge in V-band clamp orders has made it hard to procure clamps. The AMOC from Continental grants a 9-month extension and increases the life limits (temporarily!) for V-band clamps installed on 11 of the 35 affected engine models.
Because of the surge in parts demand, there are simply not enough V-band clamps out there to go around. While tempting, using non-approved parts can have severe consequences! Some of the providers or folks that might be able to help you find a proper clamp are:
1. McFarlane (P/N CF600391-0000S) for Hartzell Exhaust Systems
2. RAM (P/N 2274-40) single piece clamp PMA replacement
3. Cessna/Textron (P/N 24540-300) for Lycoming TIO-540 series
4. Rayjay (P/N RJ0193) for Piper Seneca Rayjay STC's airplanes
5. Air Power (P/N 1015-70-03877)
6. Eaton/Aeroquip (P/N NH1009399-10) replaces the spot-welded Aeroquip 55677-340M in Saratogas and Mirages
7. Lycoming (P/N 40D23255-340M) replaces the spot-welded 40D21162-340M as per AD 2010-13-07 in Piper Lance, Saratogas, and Malibus
8. Cessna/Textron (P/N S1921-1) for the Seneca and Stationair clamps
9. Continental (P/N 653332) can be useful if AOG
10. Acorn Welding - tremendous amount of experience with clamps/ exhaust systems
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