The Direction Generale de l'Aviation Civile (DGAC), which is the airworthiness authority for France, notified the FAA that an unsafe condition may exist on certain Model A300 B2 and B4 series airplanes, and A300-600 series airplanes. The DGAC advises that cracks have been found on the lower outboard flange of gantry No. 4 in the main landing gear bay area on several Model A300-600 airplanes. During a maintenance inspection on one airplane, a 670-mm crack was found on the left side of gantry beam No. 4 between frame (FR) 52 and FR 53. The crack extended along the outboard flange of the beam. A 710-mm crack between FR 52 and FR 54 was found during an inspection done on another airplane after detection of an air leak. Subsequent to detection of the cracks, an emergency inspection was done by the manufacturer in a part of the structure between FR 52 and FR 53 that was not previously inspected, which revealed a 227-mm crack. Such cracking, if not found and fixed,could result in reduced structural integrity of the fuselage, and consequent rapid decompression of the airplane. This action is intended to address the identified unsafe condition.
The subject area on certain Model A300 B2 and B4 series airplanes is almost identical to that on affected Model A300-600 series airplanes. Therefore, those airplanes may be subject to the same unsafe condition revealed on the Model A300-600 series airplanes.
Explanation of Relevant Service Information
Airbus has issued All Operators Telex (AOT) A300-53A0371, Revision 01 (for Model A300 B2 and B4 series airplanes); and AOT A300-53A6145, Revision 01 (for Model A300-600 series airplanes); both dated September 10, 2003. The AOTs describe procedures for a detailed visual inspection of the left and right sides of the lower outboard flange of gantry No. 4 in the MLG bay area between FR 51 and FR 54. The AOTs recommend contacting Airbus if any cracks are found, in addition to specifying that flight with certain cracks is allowed and temporary repairs are available in case of large crack findings. The AOTs also recommend reporting inspection results to Airbus. The DGAC classified these AOTs as mandatory and issued French airworthiness directive 2003-356(B), dated September 17, 2003, to ensure the continued airworthiness of these airplanes in France.
FAA's Conclusions
These airplane models are manufactured in France and are type certificated for operation in the United States under the provisions of Sec. 21.29 of the Federal Aviation Regulations (14 CFR 21.29) and the applicable bilateral airworthiness agreement. Pursuant to this bilateral airworthiness agreement, the DGAC has kept us informed of the situation described above. We have examined the findings of the DGAC, reviewed all available information, and determined that AD action is necessary for products of this type design that are certificated for operation in the United States.
Explanation of Requirements of RuleSince an unsafe condition has been identified that is likely to exist or develop on other airplanes of the same type design registered in the United States, this AD is being issued to find and fix cracking of the lower outboard flange of gantry No. 4, which could result in reduced structural integrity of the fuselage, and consequent rapid decompression of the airplane. This AD requires a one-time inspection for cracking of the lower outboard flange of gantry No. 4 in the main landing gear bay area, and repair if necessary. The actions are required to be accomplished in accordance with the AOTs described previously, except as discussed below. This AD also includes a reporting requirement.
Differences Among This AD, AOTs, and French Airworthiness Directive
Unlike the procedures described in the AOTs, this AD will not permit further flight if cracks are detected in the lower outboard flange of gantry No. 4. We have determined that, because of the safety implications and consequences associated with such cracking, any cracked flange must be repaired or modified before further flight.
The French airworthiness directive and the AOTs recommend accomplishing the inspection before the accumulation of 8,000 flights "since new" or within 14 days after the effective date of the French airworthiness directive. However, this AD requires accomplishment of the inspection before the accumulation of 8,000 total flight cycles since the date of issuance of the original Airworthiness Certificate or the date of issuance of the Export Certificate of Airworthiness, whichever is first; with a grace period of 30 days after the effective date of this AD. This decision is based on our determination that "since new" may be interpreted differently by different operators. We find that our proposed terminology is generally understood within the industry and records will always exist that establish these dates with certainty. In addition, we have determined that a 30 day grace period will ensure an acceptable level of safety and is an appropriate interval of time wherein the inspection can be accomplished during scheduled maintenance intervals for the majority of affected operators.
Although the AOTs specify that operators may contact the manufacturer for disposition of certain repair conditions, this AD requires operators to repair those conditions per a method approved by either us or the DGAC (or its delegated agent). In light of the type of repair that would be required to address the unsafe condition, and consistent with existing bilateral airworthiness agreements, we have determined that, for this AD, a repair approved by either us or the DGAC will be acceptable for compliance with this AD.
Interim Action
This AD is considered to be interim action. The inspection reports that are required by this AD will enable the manufacturer to obtain better insight into the nature, cause, and extent of the cracking, and eventually to develop final action to address the unsafe condition. Once final action has been identified, we may consider further rulemaking.
Determination of Rule's Effective Date
Since a situation exists that requires the immediate adoption of this regulation, it is found that notice and opportunity for prior public comment hereon are impracticable, and that good cause exists for making this amendment effective in less than 30 days.
Comments Invited
Although this action is in the form of a final rule that involves requirements affecting flight safety and, thus, was not preceded by notice and an opportunity for public comment, comments are invited on this rule. Interested persons are invited to comment on this rule by submitting such written data, views, or arguments as they may desire. Communications shall identify the Rules Docket number and be submitted in triplicate to the address specified under the caption ADDRESSES. All communications received on or before the closing date for comments willbe considered, and this rule may be amended in light of the comments received. Factual information that supports the commenter's ideas and suggestions is extremely helpful in evaluating the effectiveness of the AD action and determining whether additional rulemaking action would be needed.
Submit comments using the following format:
Organize comments issue-by-issue. For example, discuss a request to change the compliance time and a request to change the service bulletin reference as two separate issues.
For each issue, state what specific change to the AD is being requested.
Include justification (e.g., reasons or data) for each request.
Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the rule that might suggest a need to modify the rule. All comments submitted will be available, both before and after the closing date for comments, in the Rules Docket for examination by interested persons. A report that summarizes each FAA-public contact concerned with the substance of this AD will be filed in the Rules Docket.
Comments wishing the FAA to acknowledge receipt of their comments submitted in response to this rule must submit a self-addressed, stamped postcard on which the following statement is made: "Comments to Docket Number 2003-NM-248-AD." The postcard will be date stamped and returned to the commenter.
Regulatory Impact
The regulations adopted herein 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. Therefore, it is determined that this final rule does not have federalism implications under Executive Order 13132.
The FAA has determined that this regulation is an emergency regulation that must be issued immediately to correct an unsafe condition in aircraft, and that it is not a "significant regulatory action" under Executive Order 12866. It has been determined further that this action involves an emergency regulation under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979). If it is determined that this emergency regulation otherwise would be significant under DOT Regulatory Policies and Procedures, a final regulatory evaluation will be prepared and placed in the Rules Docket. A copy of it, if filed, may be obtained from the Rules Docket at the location provided under the caption ADDRESSES.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.
Adoption of the Amendment
Accordingly, pursuant to 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.
39.13 [Amended]
2. Section 39.13 is amended by adding the following new airworthiness directive: