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 a one-time inspection to determine whether latch pins on the lower lobe and main deck side cargo doors are installed backward, and corrective actions, if necessary. This amendment also requires eventual modification of the latch pin fittings on certain cargo doors. This amendment is prompted by reports that latch pins have been found installed backward on the cargo doors of several airplanes. The actions specified by this AD are intended to prevent improper latching of latch pins and the mating latch cam on the cargo door, which could result in damage to the structure of the cargo door and doorway cutout and consequent opening of the cargo door during flight.

DATES:

Effective March 13, 2000.

The incorporation by reference of certain publications listed in the regulations is approved by the Director of the Federal Register as of March 13, 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:

Julie Alger, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Transport Airplane Directorate, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 227-2779; 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 May 5, 1999 (64 FR 24092). That action proposed to require a one-time inspection to determine whether latch pins on the lower lobe and main deck side cargo doors are installed backward, and corrective actions, if necessary. For certain airplanes, that action also proposed to require eventual modification of the latch pin fittings on certain cargo doors.

Explanation of Change Made to the Final Rule

The FAA has revised the applicability statement of the final rule to reference “line numbers” instead of “line positions.” The airplane manufacturer has informed the FAA that “line numbers” is the proper reference, although some Boeing service bulletins still refer to “line positions.”

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 Proposal

One commenter supports the proposed rule, and two commenters state no objection to the proposed rule. An additional commenter supports the proposed modification.

Requests To Revise Applicability

One commenter requests that the applicability of the AD be revised to remove the airplane having line number 1079. The commenter points out that that airplane was modified in production and was removed from the effectivity of Boeing Alert Service Bulletin 747-52A2258, dated June 1, 1995, by Notice of Status Change 747-52A2258 NSC 03, dated December 14, 1995. The FAA concurs and has revised the applicability of the final rule accordingly.

In addition, one commenter requests that the one-time inspection of the latch pins of the main deck side cargo door be made applicable only to airplanes having line numbers 1 through 307 inclusive. The commenter states that the latch pins on airplanes having line numbers 308 and subsequent were modified in production with a bracket that prevents the latch pins from being installed backward. The FAA concurs with the commenter's request and has revised paragraph (a) of the final rule accordingly. [Also, as a result of the revision of paragraph (a) of this final rule, a new paragraph (b) has been added to incorporate the corrective actions specified in paragraphs (a)(1) and (a)(2) of the proposal, and all other paragraphs have been renumbered accordingly.]

Request for Credit for Previously Accomplished Actions

One commenter requests that a statement be added to the proposed rule to clarify that no further action is required for airplanes inspected in accordance with the proposed rule prior to the effective date of this AD. The FAA agrees that no further inspection is required for these airplanes. Operators are always given credit for previously accomplished actions by means of the phrase in the compliance section of the AD that states, “Required * * * unless accomplished previously.” Therefore, no change to the final rule is necessary in this regard.

Request for Extension of the Compliance Time

One commenter requests that the compliance time for the modification required by paragraph (b) of the proposed rule [paragraph (c) of the final rule] be extended from two years after the effective date of this AD to six years or at the next removal of the latch pins. The commenter states that the immediate safety concern is addressed once the one-time inspection specified in paragraph (a) of the proposed rule is accomplished, and that the modification does not need to be accomplished until the next time the latch pins are removed.

The FAA does not concur with the commenter's request to extend the compliance time for the modification. In developing an appropriate compliance time for this action, the FAA considered the safety implications, parts availability, and normal maintenance schedules for timely accomplishment of the modification. In consideration of these items, as well as the possibility that a latch pin may be misinstalled during maintenance until the modification is accomplished, the FAA has determined that two years represents an appropriate interval of time allowable wherein an acceptable level of safety can be maintained. No change to the final rule is necessary in this regard.

Request To Revise Structural Inspection Requirements

One commenter requests that the proposed rule be revised to allow a Boeing Company Designated Engineering Representative to approve procedures for the structural inspection specified in paragraph (a)(2) of the proposed rule [paragraph (b)(2) of the final rule]. The commenter states that, in the event that a latch pin is installed backward, an airplane would be grounded until inspection methods are approved and accomplished, because no structural inspection methods are currently approved by the Manager of the FAA's Seattle Aircraft Certification Office [as specified in paragraph (a)(2) of the proposed rule].

The FAA does not concur with the commenter's request. To date, the airplane manufacturer has not provided the FAA with structural inspection criteria. The extent of the area that must be inspected for damage is not defined because the extent of the inspection depends on the number and location of latch pins found to be installed backward. Procedures for the structural inspections are also not defined, and there are no published standards that can be used as a basis for a compliance finding. The FAA is not authorized to delegate a function for which there is no established standards [i.e., in accordance with Part 25 (“Airworthiness Standards: Transport Category Airplanes”) of the Federal Aviation Regulations (14 CFR part 25)]. No change to the final rule is necessary in this regard.

Request To Revise Service Information

One commenter requests that Boeing Alert Service Bulletin 747-52A2258 be revised to include the structural inspection methods specified in paragraph (a)(2) of the proposed rule [paragraph (b)(2) of the final rule]. The commenter states that this would reduce the number of requests for approvals of alternative methods of compliance that the FAA would have to review.

The FAA does not concur. As stated previously, the airplane manufacturer has not provided structural inspection procedures for inclusion in the final rule. The FAA has determined that further delay in issuance of this AD while the airplane manufacturer revises Boeing Alert Service Bulletin 747-52A2258 would not provide an acceptable level of safety. However, the airplane manufacturer may request approval of an alternative method of compliance for structural inspection procedures on behalf of all affected operators, thereby limiting the number of requests for approval of alternative methods of compliance from individual operators. No change to the final rule is necessary in this regard.

Request To Add One-Time Inspection of Interchanged Latch Pins

One commenter, the airplane manufacturer, recommends that the proposed rule be revised to require accomplishment of Boeing Service Bulletin 747-52-2142, dated May 6, 1977. That service bulletin recommends a one-time inspection to detect interchanged latch pins between the lower lobe cargo doors and the main deck side cargo door, and installation of a pin stop bracket. The commenter provides no technical justification for its request.

The FAA does not concur with the commenter's request. To require this modification would necessitate issuance of a supplemental notice of proposed rulemaking and reopening of the comment period. The FAA finds that to further delay the issuance of this rule in this way would be inappropriate. Furthermore, though two interchanged latch pins were found during production, the FAA has not received any reports that operators have found such interchanged latch pins. Therefore, the FAA finds that mandatory action is not necessary. No change to the final rule is necessary in this regard.

Explanation of Change Made to Proposal

The FAA has clarified the inspection requirement contained in the proposed AD. Whereas the proposal specified a visual inspection, the FAA has revised this final rule to clarify that its intent is to require a general visual inspection. Additionally, a note has been added to the final rule to define that inspection.

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 990 airplanes of the affected design in the worldwide fleet. The FAA estimates that 235 airplanes of U.S. registry will be affected by this AD.

It will take approximately 2 work hours per airplane to accomplish the required inspection, at the average labor rate of $60 per work hour. Based on these figures, the cost impact of the AD on U.S. operators is estimated to be $28,200, or $120 per airplane.

It will take approximately 3 work hours per airplane to accomplish the required modification, at the average labor rate of $60 per work hour. Required parts will cost approximately $2,045 per airplane. Based on these figures, the cost impact of the AD on U.S. operators is estimated to be $522,875, or $2,225 per airplane.

The cost impact figures discussed above are 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 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.

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:

2000-02-37 Boeing: Amendment 39-11555. Docket 99-NM-41-AD.

Applicability: Model 747 series airplanes, line numbers 1 through 1078 inclusive, 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 (d) 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 improper latching of latch pins and the mating latch cam on the cargo door, which could result in damage to the structure of the cargo door and doorway cutout and consequent opening of the cargo door during flight, accomplish the following:

One-Time Inspection

(a) Within 30 days after the effective date of this AD, accomplish the requirements of paragraph (a)(1) or (a)(2) of this AD, as applicable, in accordance with Boeing Alert Service Bulletin 747-52A2258, dated June 1, 1995; as revised by Notices of Status Change 747-52A2258 NSC 1, dated July 20, 1995; 747-52A2258 NSC 2, dated August 31, 1995; and 747-52A2258 NSC 03, dated December 14, 1995.

(1) For airplanes having line numbers 1 through 307 inclusive: Perform a one-time general visual inspection to determine whether latch pins on the forward and aft lower lobe cargo doors and the main deck side cargo door are installed backward.

(2) For airplanes having line numbers 308 through 1078 inclusive: Perform a one-time general visual inspection to determine whether latch pins on the forward and aft lower lobe cargo doors are installed backward.

Note 2:

For the purposes of this AD, a general visual inspection is defined as: “A visual examination of an interior or exterior area, installation, or assembly to detect obvious damage, failure, or irregularity. This level of inspection is made under normally available lighting conditions such as daylight, hangar lighting, flashlight, or drop-light, and may require removal or opening of access panels or doors. Stands, ladders, or platforms may be required to gain proximity to the area being checked.”

Corrective Actions

(b) If any latch pin is found installed incorrectly during any inspection required by paragraph (a) of this AD, prior to further flight, accomplish the requirements of paragraphs (b)(1) and (b)(2) of this AD.

(1) Reinstall the affected latch pin correctly, in accordance with Boeing Alert Service Bulletin 747-52A2258, dated June 1, 1995; as revised by Notices of Status Change 747-52A2258 NSC 1, dated July 20, 1995; 747-52A2258 NSC 2, dated August 31, 1995; and 747-52A2258 NSC 03, dated December 14, 1995.

(2) Perform structural inspections to detect damage of the affected cargo door and doorway cutout, in accordance with a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate.

Modification

(c) Within 2 years after the effective date of this AD, modify the latch pin fittings of the forward and aft lower lobe cargo doors, in accordance with Boeing Service Bulletin 747-52-2260, Revision 1, dated March 21, 1996.

Note 3:

Modification of the latch pin fittings accomplished prior to the effective date of this AD in accordance with Boeing Service Bulletin 747-52-2260, dated December 14, 1995, is considered acceptable for compliance with paragraph (c) of this AD.

Alternative Methods of Compliance

(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, Seattle ACO. 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 4:

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

(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.

Incorporation by Reference

(f) Except as provided by paragraph (b)(2) of this AD, the actions shall be done in accordance with Boeing Alert Service Bulletin 747-52A2258, dated June 1, 1995; as revised by Notices of Status Change 747-52A2258 NSC 1, dated July 20, 1995; 747-52A2258 NSC 2, dated August 31, 1995; and 747-52A2258 NSC 03, dated December 14, 1995; and Boeing Service Bulletin 747-52-2260, Revision 1, dated March 21, 1996. 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.

(g) This amendment becomes effective on March 13, 2000.