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Repairing Aircraft Exhaust System Parts

Once inspection has been done, you should get one of three results: the system is okay or it needs repairs or part replacement, or the system is not fit for use anymore. We try to avoid the last one but since it is inevitable, we make sure to do immediate repairs or part replacements as soon as we find cracks or other defects to the exhaust system. Knisley Exhaust believes that doing timely remedies lengthens the life span of your aircraft exhaust systems, and makes sure that safety is never compromised.

When cracks, defects, or other problems are seen in muffler assembly of Knisley Aircraft exhaust systems, here are some options that can be done:

Option A: Replace Entire Muffler Assembly

You could choose to replace the entire muffler assembly – left, right, or both, depending on the case. It can then be replaced with new Knisley parts. To know the availability of the parts and the corresponding price, contact us by emailing us, and provide the aircraft’s model or serial number, date of manufacture, muffler and tailpipe configuration, and attach photos as well.

Option B: Recondition using Original Parts

Should you decide to retain the original configuration of the defective left, right, or both mufflers and tailpipes, you can pick option C. As long as you comply with the Federal Aviation Authority (FAA) and its approved methods and materials, this should be no problem.

When no crack, defects, or other problems are found, the muffler and the tailpipe assemblies can still be reassembled with the following process:

  1. Reassemble the ball joint.
  2. Secure the tailpipe attachments
  3. Secure heat exchanger shroud.

It is worth mentioning that in the Advisory Circular No 91-59A regarding the Inspection and Care of General Aviation Aircraft Exhaust Systems, there are also recommendations by the FAA regarding repairs and overhauls. These are the following:

  1. We recommended replacing any exhaust system component that either fails maintenance manual inspection procedures or is defective. This includes components that are burned, cracked, warped, or so worn that leakage occurs.
  2. Weld repairs to exhaust system components are complicated by contaminants and deposits that exist on any component after a short period of time, as well as problems with base materials, such as:
  • constant deterioration
  • proper identification
  • general thinness
  • changes in composition and grain structure,
  1. We encourage consultation with an appropriately rated FAA-certified repair station that has experience and demonstrated expertise in exhaust system inspection and repair prior to attempting the repair of any exhaust system component. We also recommend a pressure test after repairing a welded component of the exhaust system.
  2. Repairs of exhaust system components that are not in accordance with part 43 are a reason for rejection of approval for return to service.

For more information on repair that can be done by Knisley for your aircraft exhaust systems, contact us and we would gladly assist you.

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