Airworthiness Directives; Boeing Model 747 Series Airplanes

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Final rule.

SUMMARY:

This amendment adopts a new airworthiness directive (AD), applicable to certain Boeing Model 747 series airplanes, that requires replacement of any brake system accumulator that has aluminum end caps with an accumulator that has stainless steel end caps. This amendment is prompted by reports of fractures of aluminum end caps on brake system accumulators. The actions specified by this AD are intended to prevent high-velocity separation of a brake system accumulator barrel, piston, or end cap, which could result in injury to personnel in the wheel well area, loss of cabin pressurization, loss of certain hydraulic systems, or damage to the fuel line of the auxiliary power unit.

DATES:

Effective August 23, 2000.

The incorporation by reference of certain publications listed in the regulations is approved by the Director of the Federal Register as of August 23, 2000.

ADDRESSES:

The service information referenced in this AD may be obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, Washington 98124-2207. This information may be examined at the Federal Aviation Administration (FAA), Transport Airplane Directorate, Rules Docket, 1601 Lind Avenue, SW., Renton, Washington; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT:

Don Kurle, Aerospace Engineer, Systems and Equipment Branch, ANM-130S, FAA, Transport Airplane Directorate, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 227-2798; fax (425) 227-1181.

SUPPLEMENTARY INFORMATION:

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an airworthiness directive (AD) that is applicable to certain Boeing Model 747 series airplanes was published in the Federal Register on January 5, 2000 (65 FR 401). That action proposed to require replacement of any brake system accumulator that has aluminum end caps with an accumulator that has stainless steel end caps.

Comments

Interested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the comments received.

Support for the Proposed Rule

One commenter supports the proposed rule.

Request to Reference Corresponding Supplier Part Numbers in Spares Paragraph

One commenter, the airplane manufacturer, requests that the FAA revise paragraph (b) of the proposed rule (the “Spares” paragraph) to reference the supplier's part numbers for the brake system accumulator that correspond to the airplane manufacturer's part numbers listed in paragraph (b) of the proposed rule. The commenter states that including the supplier's part numbers in this AD will assist operators in identifying affected parts. The FAA concurs with the commenter's request, and has revised paragraph (b) of this final rule to reference the applicable supplier's part numbers that correspond to the airplane manufacturer's part numbers.

Request To Extend Compliance Time

Three commenters request that the FAA extend the compliance time for the actions in paragraph (a) of the proposed rule. The FAA proposed a compliance time of 3,000 flight hours after the effective date of this AD. The commenters' suggestions for extending the compliance time range from 10 months to 2 years or 6,000 flight hours. One commenter's justification for its request is the number of affected airplanes (estimated at 70 airplanes), the lead-time for modification kits (estimated at 10 months), and the lead-time for new parts (estimated at 4 months). Another commenter notes that the lead-time for new accumulators or modifications parts is 90 days for the initial production order; however, it will take two years to produce the quantity of new accumulators or modifications kits that will be necessary to accomplish the proposed replacement throughout the fleet. Another commenter states that the proposed actions are appropriate for accomplishment in a hangar environment and, with the proposed compliance time of 3,000 flight hours, special maintenance visits would be necessary to accomplish the proposed actions within that compliance time. That commenter suggests that a compliance time of 18 months would allow the proposed actions to be accomplished at a ``C''-check for most affected airplanes.

The FAA concurs that the compliance time for accomplishment of the replacement described in this AD may be extended somewhat, and that accomplishment of the required actions during a “C”-check is appropriate. In developing an appropriate compliance time for this AD, the FAA considered not only the degree of urgency associated with addressing the subject unsafe condition, but the availability of required parts and the normal intervals for operators' “C”-checks (as stated in Maintenance Review Board documents). The FAA has determined that 6,000 flight hours represents an appropriate interval of time wherein an ample number of required parts will be available for modification of the U.S. fleet, and wherein operators will be able to accomplish the replacement during a “C”-check. The FAA also finds that such a compliance time will not adversely affect the safety of the affected airplanes. Paragraph (a) of this final rule has been revised accordingly.

Conclusion

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 rule with the changes previously described. The FAA has determined that these changes will neither increase the economic burden on any operator nor increase the scope of the AD.

Cost Impact

There are approximately 1,217 Model 747 series airplanes of the affected design in the worldwide fleet. The FAA estimates that 324 airplanes of U.S. registry will be affected by this AD, that it will take approximately 1 work hour per accumulator (airplanes may have three, four, or five accumulators of various types) to accomplish the required actions, and that the average labor rate is $60 per work hour. Required parts will cost approximately between $7,650 and $13,418 per airplane (depending on the number and type of affected accumulators). Based on these figures, the cost impact of the AD on U.S. operators is estimated to be between $7,830 and $13,718 per airplane.

The cost impact figure discussed above is based on assumptions that no operator has yet accomplished any of the requirements of this AD action, and that no operator would accomplish those actions in the future if this AD were not adopted.

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.

For the reasons discussed above, I certify that this action (1) is not a “significant regulatory action” under Executive Order 12866; (2) is not a “significant rule” under 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. A final evaluation has been prepared for this action and it is contained in the Rules Docket. A copy of it 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.

2. Section 39.13 is amended by adding the following new airworthiness directive:

2000-14-01 Boeing: Amendment 39-11810. Docket 99-NM-335-AD.

Applicability: Model 747 series airplanes; as listed in Boeing Special Attention Service Bulletin 747-32-2461, dated August 19, 1999; certificated in any category.

Note 1:

This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For airplanes that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (c) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.

Compliance: Required as indicated, unless accomplished previously.

To prevent high velocity separation of a brake system accumulator barrel, piston, or end cap; which could result in injury to personnel in the wheel well area, loss of cabin pressurization, loss of certain hydraulic systems, or damage to the fuel line of the auxiliary power unit; accomplish the following:

Replacement

(a) At the next “C”-check, not to exceed 6,000 flight hours after the effective date of this AD, replace any brake system accumulator that has aluminum end caps with an accumulator that has stainless steel end caps in accordance with Boeing Special Attention Service Bulletin 747-32-2461, dated August 19, 1999.

Spares

(b) As of the effective date of this AD, no person shall install a brake system accumulator having part number (P/N) BACA11E1 (Parker P/N 2660472-1 or 2660472M1) or BACA11E5 (Parker P/N 2660472-5 or 2660472M5) on any airplane.

Alternative Methods of Compliance

(c) 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, Seattle Aircraft Certification Office (ACO), 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, Seattle ACO.

Note 2:

Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Seattle ACO.

Special Flight Permits

(d) 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.

Incorporation by Reference

(e) The actions shall be done in accordance with Boeing Special Attention Service Bulletin 747-32-2461, dated August 19, 1999. 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 Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, Washington 98124-2207. 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.

Effective Date

(f) This amendment becomes effective on August 23, 2000.