December 8, 2003
Federal Aviation Administration Central Region - Office of the Regional Counsel ATTN: Rules Docket No. 2002-CE-05-AD 901 Locust - Room 506 Kansas City, MO 64106
RE: Airworthiness Directive 2002-CE-05-AD
The Aircraft Owners and Pilots Association (AOPA), on behalf of more than 400,000 pilots and aircraft owners, submits the following comments to proposed Airworthiness Directive (AD) 2002-CE-05-AD. This proposed AD, intends to preclude wing failure due to undetected fatigue cracks in Cessna 401, 401A, 401B, 402, 402A, 402B, 411, and 411A aircraft by mandating inspection of wing spar caps for fatigue cracks and installation of a spar strap modification kit on each wing spar.
While AOPA appreciates the FAA extending the comment period in October, the Association has not yet received access to the underlying data, which is necessary in order that we may provide complete and informed comments about the proposed AD. It is frustrating that the FAA has not fully responded to AOPA's request for this information made via a Freedom of Information Act (FOIA) request on September 24, 2003. The Association is concerned about the safety of these aircraft, but without this information, which the FAA maintains it has relied on in proposing the AD, we have no option but to request that the FAA delay rulemaking action until such time as the FAA responds to AOPA's FOIA request. We would then anticipate a reasonable period to analyze and comment on the data that the FAA is using to justify its rulemaking action.
The importance of this issue cannot be overstated because of the FAA's emphasis on the issue of "aging aircraft" and the FAA's reliance on a theoretical engineering analysis rather than real-world operational data as the basis for such a far-reaching airworthiness action. Given the fact that the theoretical engineering analysis used to substantiate these proposals was developed by Cessna (using FAA funds) and completed nearly 7 years ago, and given the fact that there have been no reports of failures or other service issues related to fatigue cracks in spar caps of subject aircraft during that time, there appears to be little, if any, real justification for such a costly and burdensome AD at this time. Furthermore, the fact that additional data that is directly relevant to the promulgation, or not, of this AD is still being gathered, further renders the FAA's proposed rulemaking, at the least, premature.
This lack of response has prohibited AOPA and others the ability to fully evaluate the basis for this AD. The FAA is asking the industry to pay for an expensive repair without providing the engineering justification data for evaluation. Our hope is the FAA understands how relying on theoretical engineering analysis troubles the Association. By allowing this to occur without proper evaluation of the theoretical data, the FAA is depriving the public of its opportunity to participate in this rulemaking, in contravention of the Administrative Procedures Act, which requires that the public be informed of the data and assumptions upon which an agency bases its proposed action. Apart from this resulting loss of statutory protections, we are concerned with the precedent that manufacturers may believe is being set as FAA's policy in proposing ADs in the future, a precedent that could effectively ground older aircraft with no publicly available justification.
We do believe the FAA can ensure the safety of the traveling public in Cessna 400 series aircraft used in commercial service under existing Cessna Service Bulletins. These require commercial operators to comply with the installation of the wing spar service kits.
If the FAA does not delay the proposed rulemaking action and issues an AD, AOPA is left no other recourse but to seek legal action to stop the implementation of this AD. By issuing this rule the FAA would deny the affected public the opportunity for meaningful participation in the rulemaking process contrary to procedural law.
Absent the requested information, a number of other concerns lead AOPA to oppose this rulemaking action. These additional concerns include the scope and nature of the fatigue cracks, possible degradation of safety as a result of wing spar service kit induced cracks, underestimation of the true cost of compliance (including time) and the FAA's reliance on theoretical engineering data.
Preliminary research by aircraft type-clubs such as Cessna Pilots Association (CPA), and Twin Cessna Flyer, AOPA, and several interested owners and operators, has raised serious questions regarding the true scope and nature of fatigue cracks in the wing spar caps of twin Cessna aircraft subject to this AD proposal. According to CPA, of 13 high-time aircraft that have undergone rivet removal and meticulous eddy-current inspection of the spar cap surface and rivet holes, not one has revealed any evidence of fatigue cracking. Very serious questions also surround the operating history and service conditions of the few aircraft exhibiting spar cap fatigue cracks. Initial research has revealed damage history common to several of the aircraft referenced in the AD proposal. Further, field application of the inspection and modification processes set forth in the proposed AD has raised serious doubt about the ability of mainstream general aviation service facilities to safely conduct the proposed AD required maintenance actions. The highly technical nature of the proposed inspection method, and the precision required to install the proposed spar strap modification kit without degrading the integrity of the wing structure require highly skilled personnel and specialized equipment.
Initial analysis has also revealed that FAA may have very seriously underestimated the true cost of complying with the provisions of the proposed AD. Economic estimates from several maintenance facilities have indicated that conducting the proposed inspections and spar strap modifications would require a dedicated staff of four highly skilled mechanics nearly one full work-month to complete. AOPA understands that the spar strap kit developed by Cessna may enhance the structural strength of Cessna 401, 402 and 411 wing spars. However, parts cost for the spar strap modification are estimated to be $13,000, and installation estimates range anywhere from $40,000 to $50,000 equating to a cost of nearly $70,000 per aircraft! Given the fact that the current inspections required by AD 79-10-15 R2 has provided an adequate level of safety in detecting cracked wing spars in Cessna 401, 402 and 411 airplanes, AOPA feels that mandatory installation of the Cessna spar strap kit is not warranted. Requiring installation of the Cessna spar strap kit will result in substantial cost (including parts and labor) and result in substantial aircraft downtime, with no corresponding safety enhancement. In fact, safety may be compromised as a result of installing the wing spar strap as required by Cessna's Service Bulletin MEB01-06 and Service Kit SK402-46. Reports from operators indicate that installation of the spar strap on Cessna 402B models alters the wing characteristics and causes cracks to develop where none existed before the installation.
An inventory of existing twin Cessna maintenance facilities has revealed that very few maintenance shops have the skills and equipment necessary to conduct the operations required by the proposed ADs. A total of 779 401, 401A, 401B, 402, 402A, 402B, 411 and 411A model aircraft are listed on the FAA aircraft registry. Industry estimates indicate that as few as 4-8 maintenance facilities in the country have the equipment and expertise necessary to safely conduct the operations required by the proposed AD - at the FAA estimated rate of one aircraft per 3-4 weeks, these facilities could complete only 96 aircraft per year. Assuming the number of capable maintenance facilities doubled during the first or second years - a service level that most in industry seriously doubt we may reach - a maximum of 338 aircraft may be completed at the FAA estimated rate of 3-4 weeks per aircraft.
Given the above, it is likely to take several years to comply with the provisions of the proposed AD! The resulting aircraft downtime (or loss of operational flexibility related to provisional aircraft operating limitations) will be devastating to owners and operators of affected aircraft, and will likely end the use of subject aircraft in a business or revenue generating capacity. Thus, the true economic implications of these proposals may be several orders of magnitude higher than FAA has estimated in the AD proposals. As a whole, by underestimating the costs of this AD, the FAA has erred in certifying that this AD, and the similar AD proposed in Docket No. 2002-CE-57-AD, does not constitute a significant regulatory action, that it is not a significant rule, and that it will not have a significant economic impact on a substantial number of small entities.
While AOPA, CPA, Twin Cessna Flyer, and several affected owners and operators continue to evaluate the FAA's proposal, research to date has raised more questions than answers. Given the highly technical nature of the FAA's proposed action, the scarcity of facilities capable of safely conducting the compliance actions required by the proposed AD, the gross underestimation of the true economic impact of the proposed AD, and the dire safety implications of improperly installing the proposed spar strap modification kit, it is imperative that the FAA more thoroughly evaluate this issue.
Thank you for your time and careful consideration in this matter - AOPA stands ready to assist the FAA in evaluating a more appropriate means to mitigate any safety concerns regarding the probability of fatigue cracks in spar caps of twin Cessna aircraft.
Luis Gutierrez Director Regulatory and Certification Policy
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