# SDR 2022FA0000179

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: September 26, 2021
- Submitted: March 31, 2022
- Operation: General aviation
- Aircraft: [N4810](https://openairdocs.org/aircraft/N4810), registered now
- Make and model: Cessna 185F
- Registry model: [Cessna 185F](https://openairdocs.org/model/cessna-185f) (OpenAirDocs)
- Aircraft serial: 18504111
- Aircraft time: 3,995 hours
- Engine: Cont IO550D
- Propeller: Hartzl HCC3YF1
- System (JASC): [7800 · Engine Exhaust System](https://openairdocs.org/jasc/7800)
- Part: Exhaust Stack
- Condition: Cracked
- Part time: 60 hours
- Stage of operation: IN
- How discovered: V
- Nature of condition: G, O
- Precautionary procedure: O
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/2022FA0000179

## Discrepancy

INSTALLED NEW ACORN WELDING LTD. EXHAUST STACKS AND MUFFLER ON FACTORY NEW IO-550D ENGINE.  BOTH EXHAUST STACKS CRACKED WITHIN 60 HOURS; REPLACED BOTH STACKS WITH NEW ACORN STACKS; ONE OF THE NEW STACKS CRACKED (1" HOLE) WITHIN 30 HOURS.  REMOVED FROM AIRCRAFT. I HAVE HEARD OF 10 OTHER INSTANCES OF ACORN EXHAUST STACKS CRACKING; ONE WITHIN 10 HOURS OF INSTALL ON A NEW ENGINE. THIS IS A POTENTIALLY VERY DANGEROUS FAILURE.  A CRACKED EXHAUST CAN CAUSE CARBON MONOXIDE IN THE CABIN, OR A FIRE IN THE ENGINE COMPARTMENT. PLEASE INVESTIGATE.

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