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Regulatory Brief -- FAA issues long-awaited twin Cessna exhaust ADRegulatory Brief -- FAA issues long-awaited twin Cessna exhaust AD

Regulatory Brief

FAA issues long-awaited twin Cessna exhaust AD

On January 19, 2000 the FAA published AD-2000-01-16, a final rule airworthiness directive (AD) affecting exhaust systems on turbocharged twin Cessna airplanes. The FAA originally proposed the AD on July 6 of last year as a Notice of Proposed Rulemaking (NPRM 97-CE-67-AD). The proposed AD required costly repetitive inspections of the exhaust system on turbocharged twin Cessna models T310 to 421C (except 337). The FAA cited several incidents/accidents in which cracks and corrosion caused exhaust system failure, uncontrollable in-flight fire, and in some cases, pilot and passenger injury.

The importance to our members:

According to the FAA, the AD affects approximately 6,500 turbocharged Cessna twins. To detect and correct cracks and corrosion on exhaust system components, the AD requires a series of repetitive inspections, replacement of unserviceable parts, and removal of the exhaust system for detailed inspections at engine overhaul. The FAA estimates that it will cost each affected aircraft owner nearly $4,400 to complete the required initial inspections. Although these figures fail to take into account the cost of complying with required repetitive inspections and associated parts repairs or replacements, the FAA has substantially reduced the compliance cost of the AD.

Significant provisions:

  • Currently, owners of Cessna 300 and 400 series aircraft must comply with AD 75-23-08-R5, which requires repetitive exhaust system inspections and the repair or replacement of unserviceable parts.
  • The new AD, (AD-2000-01-16) effective February 15, 2000, supercedes a previously issued AD (75-23-08-R5) and implements simplified inspection procedures, aligns inspection intervals with regularly scheduled maintenance, and unlike the original AD proposal, only requires removal of the exhaust system for inspections at engine overhaul.
  • The AD is the result of numerous incidents and accidents relating to the exhaust systems on Cessna 300 and 400 series airplanes dating from the middle 1970�s to the present, including six incidents since the issuance of AD 75-23-08-R5.
  • The actions specified by the AD are intended to prevent exhaust system failure and possible uncontrollable in flight fire with pilot and/or passenger injury.

AOPA position:

AOPA agrees that, in this particular situation, the potential for uncontrollable in-flight fire or in-flight structural wing failure warrants airworthiness action. AOPA thanks the FAA for affording the public an opportunity to comment on the provisions of the AD. The quality of public comments in response to the proposed AD are shining examples of how the real world knowledge and expertise of owner�s organizations, aircraft type-clubs, mechanics, and aircraft operators can result in practical and affordable alternatives to draconian AD actions. Although the FAA considered user comments, implemented an alternative means of compliance and significantly reduced the economic impact of this AD, AOPA feels that the agency has discounted the importance of a fair and complete economic analysis. In the future, AOPA hopes and expects that the FAA will more carefully consider the full economic impact of proposed AD actions.

AOPA analyzed the provisions of AD-2000-01-16 and submitted comments to the FAA on April 13, 2000. AOPA is awaiting a formal response from the FAA.


  • On July 6, 1999 the FAA issued 97-CE-67-AD. On July 8, 1999, AOPA sent a letter to all owners of affected aircraft recommending that they solicit the help of their mechanic, maintenance facility, or repair station, and submit comments to the FAA regarding the requirements of this AD.
  • Comments requested included: alternative means of compliance, inspection methods and associated failure rates, economic impacts resulting from repetitive inspections, safety impact of repetitive disassembly/reassembly, time-in-service vs. rate of deterioration of exhaust system, recommended inspection frequency, and method to benchmark current exhaust system integrity.
  • On August 6, 1999, AOPA submitted comments to the FAA regarding the provisions of the proposed AD.
  • On January 19, 2000, the FAA released final rule AD-2000-01-16, and afforded the public 90 days to comment.
  • On February 4, 2000, the FAA issued Special Airworthiness Information Bulletin (SAIB) CE-00-16. This SAIB clarifies the "Compliance Table" of AD 200-01-16 regarding removal or replacement of the exhaust system. The SAIB also provides a FAA point-of-contact for persons needing more information.
  • On April 13, 2000, AOPA submitted final comments to the FAA recommending several minor revisions to clarify the compliance action required by the AD. AOPA is awaiting a formal response from the FAA and will inform the membership as this situation develops.

Related documents:

AOPA final comments to final rule AD 2000-01-16, April 13, 2000

Special Airworthiness Information Bulletin CE-00-16 (requires Adobe Reader)

Preliminary AOPA analysis of AD 2000-01-16, January 20, 2000

Compliance schedule � AD 2000-01-16, January 20, 2000

AD 2000-01-16, January 19, 2000 (requires Adobe Reader)

AOPA comments to 97-CE-67-AD, August 6, 1999

AOPA letter to affected aircraft owners, July 9, 1999 (requires Adobe Reader)

FAA AD proposal, 97-CE-67-AD, July 6, 1999 (requires Adobe Reader)

AOPA press release, 99-2-071, June 25, 1999

Letter from AOPA President Phil Boyer to FAA Administrator Jane Garvey, June 24, 1999

AD 75-23-08