Discussion
What events have caused this AD? The Luftfahrt-Bundesamt (LBA), which is the airworthiness authority for Germany, recently notified the FAA that an unsafe condition may exist on all Burkhardt Grob Model G103 TWIN ASTIR sailplanes. The LBA reports an instance of elevator lever failure on one of the affected sailplanes. Cracks in the elevator lever caused the elevator lever to fail.
The cracks are a result of inadequate design in the structural strength and durability.
The elevator lever, part number (P/N) 103-3521, is made from the same cast alloy as the airbrake over-center levers, P/Ns 103-4123 (left) and 103-4124 (right), used on Burkhardt Grob Model G103 TWIN ASTIR sailplanes. Cracks found on these parts caused us to issue AD 97- 24-10, Amendment 39-10217 (62 FR 62948, November 26, 1997), which requires replacing P/Ns 103-4123 and 103-4124 with improved design parts, P/N 103B-4123 and 103B-4124.
What is the potential impact if FAA took no action? If not prevented, cracks in the elevator lever could cause the elevator lever to fail. This failure could result in loss of control of the sailplane.
Has FAA taken any action to this point? We issued a proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an AD that would apply all Burkhardt Grob Model G103 TWIN ASTIR sailplanes. This proposal was published in the Federal Register as a notice of proposed rulemaking (NPRM) on September 14, 2005 (70 FR 54311). The NPRM proposed to require you to replace the aluminum cast alloy elevator lever, P/N 103-3521, with a sheet aluminum elevator lever, P/N 103-3523.
Comments
Was the public invited to comment? We provided the public the opportunity to participate in developing this AD. The following presents the comment received on the proposal and FAA's response to the comment:
Comment Issue No. 1: Address the Use of Parts Manufacturer Approval (PMA) Parts
What is the commenter's concern? The commenter states that the PMA part may often share the identical design data with the original part while carrying a completely different part number; therefore, it is possible the AD will not address certain defective PMA parts installed on the aircraft, allowing the unsafe condition to continue.
The commenter also states that it is possible that a "new and improved" PMA version of the defective original part may already exist in the marketplace. Therefore, specifying one approved part in preference to a different, but also approved part, will impart a commercial advantage to one manufacturer over the other.
The commenter requests that the final rule AD action be changed to address the replacement of identical, defective PMA parts and allow replacement with an identical, improved PMA part.
What is FAA's response to the concern? We agree with the commenter.
We will change the final rule AD action to include the phrase to cover the PMAreplacement parts and add information to clarify the phrase "or FAA-approved equivalent part number."
Conclusion
What is FAA's final determination on this issue? We have carefully reviewed the available data and determined that air safety and the public interest require adopting the AD as proposed except for minor editorial corrections. We have determined that these minor corrections: --Are consistent with the intent that was proposed in the NPRM for correcting the unsafe condition; and --Do not add any additional burden upon the public than was already proposed in the NPRM.
Changes to 14 CFR Part 39--Effect on the AD
How does the revision to 14 CFR part 39 affect this AD? On July 10, 2002, the FAA published a new version of 14 CFR part 39 (67 FR 47997, July 22, 2002), which governs the FAA's AD system. This regulation now includes material that relates to altered products, special flight permits, and alternative methods of compliance. This material previously was included in each individual AD. Since this material is included in 14 CFR part 39, we will not include it in future AD actions.
Costs of Compliance
How many sailplanes does this AD impact? We estimate that this AD affects 60 sailplanes in the U.S. registry.
What is the cost impact of this AD on owners/operators of the affected sailplanes? We estimate the following costs to do the replacement:
Labor cost
Parts cost
Total cost per sailplane
Total cost on U.S. operators
20 work hours $65 per hour = $1,300
$715
$2,015
60 $2,015 = $120,900.
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 unsafe condition 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 certifythat 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 other information as included in the Regulatory Evaluation) 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-2005-22156; Directorate Identifier 2005-CE-43-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. FAA amends Sec. 39.13 by adding a new AD to read as follows: