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RULES and REGULATIONS DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14 CFR Part 39 [Docket No. 88
-NM
- 57
-AD; Amdt. 39
- 6230] Airworthiness Directives; Boeing Model 747 Series Airplanes Friday, June 2, 1989 AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final rule. SUMMARY: This amendment adopts a new airworthiness directive, applicable to certain Boeing Model 747 series airplanes, which requires replacement of certain underwing fuel tank access doors with stronger, fire
-resistant doors. This amendment is prom pted by several incidents of door penetration by tire and engine debris, which resulted in spillage of significant quantities of fuel. This condition, if not corrected, could result in a fire. DATES: Effective July 8, 1989. ADDRESSES: The applicable service information may be obtained from Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124. This information may be examined at the FAA, Northwest Mountain Region, Transport Airplane Directorate, 17900 Pacific Highway South, Seattle, Washington, or Seattle Aircraft Certification Office, FAA, Northwest Mountain Region, 9010 East Marginal Way South, Seattle, Washington. FOR FURTHER INFORMATION CONTACT:Mr. Michael E. Dostert, Propulsion Branch, ANM
- 140S, telephone (206) 431
- 1974. Mailing address: FAA, Northwest Mountain Region, 17900 Pacific Highway South, C
- 68966, S eattle, Washington, 98168. SUPPLEMENTARY INFORMATION: A proposal to amend Part 39 of the Federal Aviation Regulations to include an airworthiness directive, applicable to Boeing Model 747 series airplanes, which requires that certain fuel tank access doors be replaced with im proved types with more impact resistance, was published in the Federal Register on September 19, 198 8 (53 FR 36340). The comment period closed on November 10, 1988. Interested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the comments received. The only comments received were submitted by the Air Transport Association (ATA) of America on behalf of its member airlines. The ATA requested the proposed AD be withdrawn if the FAA planned to adopt a Federal Aviation Regulations (FAR) Part 121 rule, requiring replacement of the subject fuel tank access doors. The FAA does not concur that issuance of the proposed AD action should be deferred pending Part 121 rulemaking activity. A total of 1 6 fuel tank access door penetration incidents, including 3 of the inboard access doors, have been reported on Model 747 airplanes. In light of this service history and immediate safety implications, the FAA has determined that the need for timely action specific to the Model 747 airplane is appropriate.

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The ATA also re quested that the proposed 4
-month com pliance period be extended to at least one year after the e ffective date of the AD to allow operators to obtain parts and schedule retrofit of the fuel tank access doors. The FAA concurs in part with this request. The proposed compliance time of 4 months for replacement of the inboard fuel tank access doors and 30 months for the remaining 14 doors wa s established after careful consideration of the degree of risk, the number of airplanes affected, the predicted availability of parts, and the potential for disruption in operators' scheduled operations. Following issuance of the NPRM, the FAA has been advised that problems in access door production schedules have occurred, and, therefore, 8 months will be required to produce the required number of replacement doors. Accordingly, the FAA has revised paragraph A. to extend the compliance time from 4 months to 8 months for replacement of the four inboard access doors. However, the 30
-month compliance time for replacement of the remaining 14 doors per airplane has not been changed. Paragraph A. has also been revised to specify more accurately the number and location of access doors required to be replaced. After careful review of the available data, including the comments noted above, the FAA has determined that air safety and the public interest require the adoption of the proposed rule, with the changes noted above. The FAA has determined that these change s will neither increase the economic burden on any operator, nor increase the scope of the AD. There are approximately 700 Model 747 series airplanes of the affected design in the worldwide fleet. It is estimated that 208 airplanes of U.S. registry will b e affected by this AD, that it will take approximately 60 manhours per airplane to accomplish the required actions, and that the average labor cost will be $40 per manhour. Replacement door material costs, based on the manufacturer's kit price, are estimated to be $600 per door (18 doors total per airplane). Based on these figures, the total cost impact of the AD on U.S. operators is estimated to be $2,745,600. 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 p ower 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. For the reasons discussed above, I certify that this action (1) is not a “major rule” under Executive Order 12291 ; (2) is not a “significant rule” under DOT Regulatory P olicies and Procedures (44 FR 11034; February 26, 1979); and (3) will not have a significant economic im pact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act. A final evaluation has been prepared for this regulation and is contained in the regulatory docket. A copy of it may be obtained from the Rules Docket. List of Subjects in 14 CFR Part 39 Air transportation, Aircraft, Aviation safety, 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 as follows: PART 39

— [AMENDED] 1. The authority citation for Part 39 continues to read as follows: Authority: 49 U.S.C. 1354(a), 1421 and 1423; 49 U.S.C. 106(g) (Revised Pub. L. 97
-449, January 12, 1983); and 14 CFR 11.89
.

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14 CFR § 39.13 § 39.13 [Amended] 14 CFR § 39.13 2. Section 39.13 is amended by adding the following new airworthiness directive: Boeing: Applies to Model 747
- 100, 747
-200, 747
- 300, and 747
- SP series airplanes, certificated in any category. Com pliance required as indicated, unless previously accomplished. To minimize the fire hazard as a result of lower wing surface fuel tank access door penetration due to impact from lo w energy engine and tire debris, accomplish the following: A. Within the next 8 months after the effective date of this AD, replace the two inboard fuel tank access doors on each lower wing skin (Nos. 544AB and 545AB) on the left wing and (Nos. 644AB and 645AB) on the right wing, with doors having impact resistance equivalent to that of 2 024
- T3 aluminum 0.140
-inch thick, as approved by the Manager, Seattle Aircraft Certification Office, FAA, Northwest Mountain Region in accordance with the procedures described in Section 28
- 11
- 02 of the Boeing Model 747 Maintenance Manual. The replacement doors must also be fire resistant, as defined in the Federal Aviation Regulations, Part 1. B. Within the next 30 months after the effective date of this AD, replace the following 14 lower wing surface fuel tank access doors, seven on the left wing (Nos. 546AB, 546BB, 552AB, 552BB, 552CB, 552DB, and 552EB), and seven on the right wing (Nos. 646AB, 646BB, 652AB, 652BB, 652CB, 652DB, and 652EB), with doors having im pact resistance equivalent to that of 2 024
-T3 aluminum 0.140
-inch thick, as approved by the Manager, Seattle Aircraft Certification Office, FAA, Northwest Mountain Region, in accordance with the procedures described in Section 28
- 11
- 02 of the Boeing Model 747 Maintenance Manual. The replacement doors must also be fire resistant, as defined in the Federal Aviation Regulations, Part 1. C. An alternate means of com p liance or adjustment of

the compliance time, which provides an acceptable level of safety, may be used when approved by the Manager, Seattle Aircraft Certification Office, FAA, Northwest Mountain Region. Note: The request should be forwarded through an FAA Principal Maintenance Inspector (PMI), who will either concur or comment and then send it to the Manager, Seattle Aircraft Certification Office. D. Special flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate airplanes to a b ase in order to comply with the requirements of this AD. All persons affected by

this directive who have not already received the appropriate service documents from the manufacturer may obtain copies upon request to Boeing Commercial Airplanes, P.O. 3707, Seattle, Washington 98124. These documents may be examined at FAA, Northwest Mountain Region, Transport Airplane Directorate, 17900 Pacific Highway South, Seattle, Washington, or at the Seattle Aircraft Certification Office, 9010 East Marginal Way South, Seattle, Washington. This amendment becomes effective July 8, 1989. Issued in Seattle, Washington, on May 22, 1989. Leroy A. Keith, Manager, Transport Airplane Directorate, Aircraft Certification Service. [FR Doc. 89
- 13046 Filed 6
- 1
- 89; 8:45 am] BILLING CODE 4910
- 13
-M 54 FR 23643