AD 94-13-08

This amendment adopts a new airworthiness directive (AD) that is applicable to certain Airbus Model A310 and A300-600 series airplanes. This action requires inspections and replacement or reinstallation of certain aft engine mount link assemblies. This amendment is prompted by reports of cracking in the aft engine mount link assemblies. The actions specified in this AD are intended to prevent loss of the capability of the aft engine mount to support engine loads, and possible separation of the engine from the airplane.

Final rule; request for comments.

94-13-08 AIRBUS INDUSTRIE: Amendment 39-8948. Docket 93-NM-187-AD.

Applicability: Model A310 and A300-600 series airplanes; equipped with Pratt & Whitney (PW) JT9D-7R4 series engines or PW 4000 series engines; certificated in any category.

Compliance: Required as indicated, unless accomplished previously.

To prevent the loss of the capability of aft engine mount to support engine loads, and possible separation of the engine from the airplane, accomplish the following:
(a) Within 120 days after the effective date of this AD, perform a visual inspection of the aft engine mount link assembly, part numbers 221-0262-501 and 221-0262-503, at all three link positions (left outboard, right outboard, and inboard) to determine the serial numbers of the links and to identify any suspect link that is installed, in accordance with Airbus Service Bulletin A310-71-2021, dated March 16, 1994 (for Model A310 series airplanes), or Airbus Service Bulletin A300-71-6019, dated March16, 1994 (for Model A300-600 series airplanes), as applicable. Suspect links are those links having serial numbers WPC0001 through WPC1063 inclusive, or M1064 through M1255 inclusive. If no suspect link is installed, no further action is required by this AD.

NOTE 1: Links having serial numbers M1255 and below with the "M" prefix are from the same forging supplier as links having the "WPC" prefix.

(b) If any suspect link is found during the inspection required by paragraph (a) of this AD, prior to further flight, remove the suspect link, and perform a fluorescent penetrant inspection and an eddy current inspection to detect cracks or other defects in the suspect link, in accordance with Airbus Service Bulletin A310-71-2021, dated March 16, 1994 (for Model A310 series airplanes), or Airbus Service Bulletin A300-71-6019, dated March 16, 1994 (for Model A300-600 series airplanes), as applicable.
(1) If any crack or defect is found in the link, prior to further flight, replaceit with a link having a serial number that is not within the suspect serial number groups, in accordance with the service bulletin.
(2) If no crack or defect is found in the link, prior to further flight, replace it with a link having a serial number that is not within the suspect serial number groups, or reidentify and reinstall the uncracked suspect link in accordance with the service bulletin. No further action is required by this AD for that link.

(c) Within 10 days after accomplishing the inspection required by paragraph (a) of this AD, submit a report of inspection findings, including the information specified in paragraphs (c)(1), (c)(2), and (c)(3) of this AD, to the Manager, Standardization Branch, ANM-113, FAA, Transport Airplane Directorate, 1601 Lind Avenue SW., Renton, Washington 98055-4056; fax (206) 227-1320. Information collection requirements contained in this regulation have been approved by the Office of Management and Budget (OMB) under the provisions of the Paperwork Reduction Act of 1980 (44 U.S.C. 3501 et seq.) and have been assigned OMB Control Number 2120-0056.
(1) The serial number of any suspect link found.
(2) The aircraft fuselage serial number on which the suspect link was found.
3) The results of inspections required by paragraph (b) of this AD.

(d) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Standardization Branch, ANM-113, FAA, Transport Airplane Directorate. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Standardization Branch, ANM-113.

NOTE 2: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Standardization Branch, ANM-113.

(e) Special flight permits may be issued in accordance with sections 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the airplane to a location where the requirements of this AD can be accomplished.

(f) The inspection and replacement shall be done in accordance with Airbus Service Bulletin A310-71-2021, dated March 16, 1994 (for Model A310 series airplanes); or Airbus Service Bulletin A300-71-6019, dated March 16, 1994 (for Model A300-600 series airplanes); as applicable. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from Airbus Industrie, 1 Rond Point Maurice Bellonte, 31707 Blagnac Cedex, France. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

(g) This amendment becomes effective on July 8, 1994.

The Direction G n rale de l'Aviation Civile (DGAC), which is the airworthiness authority for France, recently notified the FAA that an unsafe condition may exist on certain Airbus Model A310 and A300-600 series airplanes. The DGAC advises that there have been three reports of cracking in the aft engine mount link assemblies, part numbers 221-0262-501 and 221-0262-503. Link assemblies having those part numbers are installed on Model A310 and A300-600 series airplanes in conjunction with Pratt & Whitney (PW) JT9D-7R4 and PW 4000 series engines.

Metallurgical analysis and close examination of the cracked links has indicated a similar mode of cracking among the four cracked links reported. This cracking is the result of physical defects, which were caused during the forging process by one supplier. Specifically, the cracking is a result of alloy segregation in a defective material ingot. Two of the cracked links came from the same heat lot of 215 parts; the third cracked link came from a separate heat lot of 75 parts. Due to the random nature of alloy segregation, not all of these 290 suspect links will exhibit alloy segregation and resultant cracking; however, cracking potentially could develop in any of them.

Cracks in the aft engine mount link assemblies, if not detected and corrected in a timely manner, could result in loss of the capability of the aft engine mount to support engine loads, and possible separation of the engine from the airplane.

Airbus Industrie has issued Service Bulletin A310-71-2021, dated March 16, 1994 (for Model A310 series airplanes), and Service Bulletin A300-71-6019, dated March 16, 1994 (for Model A300-600 series airplanes). These service bulletins contain general information concerning procedures to inspect for and replace the suspect engine mount links. These service bulletins also reference Pratt & Whitney Service Bulletins APW7R4 71-126 (for PW JT9D-7R4 series engines) and APW4NAC 71-138 (for PW 4000 series airplanes) for additional service information. The Pratt & Whitney service bulletins describe procedures for:
1. A visual inspection to determine the serial numbers of the aft engine mount link assembly, part numbers 221-0262-501 and 221-0262-503, at all three link positions (left outboard, right outboard, and inboard); and to determine the serial numbers of the links.
2. Removal of any suspect link found during the visual inspection; a fluorescent penetrant inspection and an eddy current inspection to detect cracks in the suspect link; and replacement of any cracked or defective suspect link with a link having a serial number that is not within the suspect serial number groups.
3. Replacement of any suspect link that is not cracked or defective with a link having a serial number that is not within the suspect serial number groups, or reidentification and reinstallation of the uncracked suspect link.

The DGAC classified the Airbus service bulletins as mandatory and issued French Airworthiness Directive 94-074-159(B), dated March 30, 1994, in order to assure the continued airworthiness of these airplanes in France.

These airplane models are manufactured in France and are type certificated for operation in the United States under the provisions of section 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 the FAA informed of the situation described above. The FAA has 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.

Since 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 prevent loss of the capability of the aft engine mount to support engine loads, and possible separation of the engine from the airplane.

This AD requires a visual inspection of the aft engine mount link assembly, part numbers 221-0262-501 and 221-0262-503, at all three link positions (left outboard, right outboard, and inboard) to determine the serial numbers of the links. If any suspect link is found, operators are required to remove the link and perform both a fluorescent penetrant inspection and an eddy current inspection of it to detect cracks and other defects, and to replace any cracked or defective suspect link with a link having a serial number that is not within the suspect serial number groups. If no crack or defect is found in the link, it may either be replaced with a non-suspect link, or reidentified and reinstalled. The actions are required to be accomplished in accordance with the Airbus service bulletin described previously.

This AD also requires that operators report certain inspection findings to the FAA.The FAA has initiated a similar rulemaking action that is applicable to McDonnell Douglas Model MD-11 series airplanes on which the suspect links may also be installed.

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 datefor comments will be 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.

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.

Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this notice must submit a self-addressed, stamped postcard on which the following statement is made: "Comments to Docket Number 93-NM-187-AD." The postcard will be date stamped and returned to the commenter.

The regulations adopted herein will not have substantial direct effects 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, in accordance with Executive Order 12612, it is determined that this final rule does not have sufficient federalism implications to warrant the preparation of a Federalism Assessment.

The FAA has determined that this regulation is an emergency regulation that must be issued immediately to correct an unsafe condition in aircraft, and 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. App. 1354(a), 1421 and 1423; 49 U.S.C. 106(g); and 14 CFR 11.89.
39.13 - [Amended]
2. Section 39.13 is amended by adding the following new airworthiness directive: