What events caused previous FAA AD action? The FAA has received reports of (and is analyzing data from) cracks found in the wings of two Cessna Model 402C airplanes.
On the first airplane, early information indicates the airplane had severe cracking on its left wing in the vicinity of the forward spar and outboard engine beam. The main lower spar cap had completely failed at about Wing Station (WS) 114. The airplane also had cracks in the lower wing skin and the web splice doubler. Also found were two popped rivets: one between the heat shield and the wing skin and another between the factory installed web splice doublers and web. The airplane had 20,355 total hours time-in-service (TIS).
During the airplane's most recent flights before the cracking was found, the pilot noticed that roll trim was required. The flights required the pilot to use aileron trim for level flight to keep the wings level. The airplane landed safely and inspection revealed the cracks.
On the second airplane, fatigue cracks were found at about WS 114 in the main lower spar cap of another Model 402C airplane that had over 20,000 total hours TIS. Fatigue analysis shows that similar fatigue cracks could also develop in the wings of the Model 414A airplanes.
Airworthiness Directive (AD) 2000-23-01, Amendment 39-11971 (65 FR 70645), required repetitive visual inspections of the forward, aft, and auxiliary wing spars for cracks on Cessna Model 402C airplanes. These inspections are at intervals not to exceed 110 hours TIS.
Logbook records indicated that both airplanes with cracked spars were in compliance with AD 2000-23-01.
The FAA's analysis of the incidents presented above showed that, in the interim, the inspections of AD 2000-23-01 should be done more frequently and particular attention paid to certain areas.
Therefore, FAA issued Emergency AD 2005-05-51 to detect and correct cracking in the wing spars of the Cessna Models 402C and 414A airplanes before the cracks grow to failure. Such a wing failure could result in the wing separating from the airplane with consequent loss of control of the airplane.
Emergency AD 2005-05-51 superseded AD 2000-23-01 and:
Required the visual inspections of the forward, aft, and auxiliary wings spars for cracks more frequently on Model 402C airplanes including special emphasis areas;
Added inspection requirements for the Model 414A airplanes; and
Included provisions to position the airplane to a home base, hangar, maintenance facility, etc.
Emergency AD 2005-05-51 did not affect those airplanes that incorporate a spar strap modification on each wing following the original release of (or a later FAA-approved revision to) Cessna Service Bulletin MEB02-5 and Cessna Service Kit SK402-47 (currently at MEB02-5 Revision 2 and SK402-47B).
What has caused this particular AD action? Emergency AD 2005-05-51 was considered an interim action to immediately require visual inspection of the forward, aft, and auxiliary wing spars for cracks. The intent was to detect immediate and existing cracking before it grew to wing failure.
The FAA has also received a report of a third crack found at WS 112 on a Model 402C airplane.
Cessna has developed new inspection techniques (eddy current) for the forward spar that are more effective at detecting cracks before the structural integrity of the wing is compromised. These inspection techniques will allow for longer intervals between repetitive inspections than in emergency AD 2005-05-51.
Recent fatigue analysis that Cessna did (and the FAA reviewed) reveals that eddy current inspections of the forward wing spars combined with visual inspections of the aft and auxiliary spars will address the unsafe condition of these airplanes until long-term continued operational safety is assured through the Cessna-developed and FAA-approved spar strap modifications. Specifically:
The eddy current inspection will replace the visual inspection of the forward spar that emergency AD 2005-05-51 currently requires; and
The visual inspections of the aft and auxiliary spars will be maintained from emergency AD 2005-05-51, but will only be required repetitively every 100 hours TIS instead of every 15 hours TIS.
Cessna has issued the following service information to include procedures to eddy current inspect the Models 402C and 414A airplanes:
Cessna Service Bulletin MEB99-3, Revision 2, dated February 28, 2005 (Model 402C); or
Cessna Service Bulletin MEB00-7, Revision 2, dated February 28, 2005 (Model 414A).
The FAA's Determination
After careful review of all available information related to the subject presented above, including the above-referenced service bulletins, FAA has determined that:
The forward wings spars should be inspected using eddy current methods on Cessna Models 402C and 414A airplanes;
The visual inspections of the aft and auxiliary sparsshould be maintained from emergency AD 2005-05-51 (but not inspected as often); and
AD action should be taken to detect and correct cracking in the wing spars before the cracks grow to failure. Such a wing failure could result in the wing separating from the airplane with consequent loss of control of the airplane.
Consequently, we issued emergency AD 2005-05-52 to supersede emergency AD 2005-05-51.
Why is it important to publish this AD? The FAA found that immediate corrective action was required, that notice and opportunity for prior public comment were impracticable and contrary to the public interest, and that good cause existed to make the AD effective immediately by individual letters issued on March 2, 2005, to all known U.S. operators of Cessna Models 402C and 414A airplanes. These conditions still exist, and the AD is published in the Federal Register as an amendment to section 39.13 of the Federal Aviation Regulations (14 CFR 39.13) to make it effective to allpersons.
Comments Invited
Will I have the opportunity to comment before you issue the rule? This AD is a final rule that involves requirements affecting flight safety and was not preceded by notice and an opportunity for public comment; however, we invite you to submit any written relevant data, views, or arguments regarding this AD. Send your comments to an address listed under ADDRESSES. Include "Docket No. FAA-2005-20513; Directorate Identifier 2005-CE-07-AD" in the subject line of your comments. If you want us to acknowledge receipt of your mailed comments, send us a self-addressed, stamped postcard with the docket number written on it; we will date-stamp your postcard and mail it back to you. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the rule that might suggest a need to modify it. If a person contacts us through a nonwritten communication, and that contact relates to a substantive part of this AD, we will summarize the contact and place the summary in the docket. We will consider all comments received by the closing date and may amend the AD in light of those comments.
Authority for This Rulemaking
What authority does FAA have for issuing this rulemaking action? Title 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, section 106 describes the authority of the FAA Administrator. Subtitle VII, Aviation Programs, describes in more detail the scope of the agency's authority.
We are issuing this rulemaking under the authority described in subtitle VII, part A, subpart III, section 44701, "General requirements." Under that section, Congress charges the FAA with promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafecondition that is likely to exist or develop on products identified in this AD.
Regulatory Findings
Will this AD impact various entities? We have determined that this AD will not have federalism implications under Executive Order 13132. This AD will not have a substantial direct effect on the States, on the relationship between the National Government and the States, or on the distribution of power and responsibilities among the various levels of government.
Will this AD involve a significant rule or regulatory action? For the reasons discussed above, I certify that this AD:
1. Is not a "significant regulatory action" under Executive Order 12866;
2. Is not a "significant rule" under the DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and
3. Will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act.
We prepared a summary of the costs to comply with this AD and placed it in the AD Docket. You may get a copy of this summary by sending a request to us at the address listed under ADDRESSES. Include "Docket No. FAA-2005-20513; Directorate Identifier 2005-CE-07-AD" in your request.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.
Adoption of the Amendment
Accordingly, under the authority delegated to me by the Administrator, the Federal Aviation Administration amends part 39 of the Federal Aviation Regulations (14 CFR part 39) as follows:
PART 39--AIRWORTHINESS DIRECTIVES
1. The authority citation for part 39 continues to read as follows:
Authority: 49 U.S.C. 106(g), 40113, 44701.
Sec. 39.13 [Amended]
2. The FAA amends Sec. 39.13 by removing Airworthiness Directive (AD) 2000-23-01, Amendment 39-11971 (65 FR 70645), and adding the following new AD: