04-1914. Airworthiness Directives; Boeing Model 737-300, -400, and -500 Series Airplanes

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Final rule.

SUMMARY:

This amendment adopts a new airworthiness directive (AD), applicable to certain Boeing Model 737-300, -400, and -500 series airplanes. This amendment requires, for certain airplanes, replacement of the hinge assemblies on certain escape slide compartments of the forward doors with new, stronger hinge assemblies; and, for certain other airplanes, an inspection for incorrectly crimped hinge assemblies, and corrective action if necessary. The actions specified by this AD are intended to prevent forward door escape slides from falling out of their compartments into the airplane interior and inflating, which could impede an evacuation in the event of an emergency. This action is intended to address the identified unsafe condition.

DATES:

Effective March 5, 2004.

The incorporation by reference of a certain publication listed in the regulations is approved by the Director of the Federal Register as of March 5, 2004.

ADDRESSES:

The service information referenced in this AD may be obtained from Boeing Commercial Airplanes, 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:

Keith Ladderud, Aerospace Engineer, Cabin Safety and Environmental Systems Branch, ANM-150S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone [phone]; fax [phone].

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 737-300, -400, and -500 series airplanes was published as a supplemental notice of proposed rulemaking (NPRM) in the Federal Register on September 19, 2003 (68 FR 54869). That action proposed to require, for certain airplanes, replacement of the hinge assemblies on certain escape slide compartments of the forward doors with new, stronger hinge assemblies; and, for certain other airplanes, an inspection for incorrectly crimped hinge assemblies, and corrective action if necessary.

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.

Agrees With the Proposed AD

One commenter generally agrees with the proposed AD and has no additional comments.

Allow for Reinstallation of the Hinges During Maintenance

One commenter requests that the proposed AD be revised to allow reinstallation of the existing hinge assemblies if a maintenance action not associated with the proposed AD requires the removal of the escape slide/hinge assemblies. This would allow normal operations until the replacement of the hinge assemblies is completed per planned maintenance. The commenter believes paragraph (c) of the proposed AD prohibits normal maintenance actions that require the removal and reinstallation of the escape slide/hinge assemblies. The commenter believes their proposal would allow for normal maintenance without disruption while replacing the hinge assemblies within the compliance time of the proposed AD and without any degradation of safety.

We agree with the commenter that clarification is necessary. The intent of paragraph (c) of the proposed AD is that when operators replace parts, they should replace them with good parts rather than bad parts. Doing normal maintenance where the escape slide assembly is removed does not warrant immediate replacement of the hinge assembly. By reinstalling the escape slide assembly, the operator is not “replacing” the hinge assembly. The hinge assembly replacement would be done within the compliance time of the AD. The final rule has been clarified 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.

Cost Impact

There are approximately 1,974 airplanes of the affected design in the worldwide fleet. The FAA estimates that 793 airplanes of U.S. registry will be affected by this AD.

Replacement of the hinge assemblies, if necessary, will take approximately 5 work hours per airplane, at an average labor rate of $65 per work hour. Required parts will cost approximately $1,569 per airplane. Based on these figures, the cost impact of the hinge replacement is estimated to be $1,894 per airplane.

The inspection, if necessary, will take approximately 1 to 3 work hours per airplane, at an average labor rate of $65 per work hour. Based on these figures, the cost impact of the inspection is estimated to be $65 to $195 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. The cost impact figures discussed in AD rulemaking actions represent only the time necessary to perform the specific actions actually required by the AD. These figures typically do not include incidental costs, such as the time required to gain access and close up, planning time, or time necessitated by other administrative actions.

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.

§ 39.13

[Amended]

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

2004-02-08 Boeing: Amendment 39-13443. Docket 2001-NM-88-AD.

Applicability: Model 737-300, -400, and -500 series airplanes; certificated in any category; as listed in Boeing Special Attention Service Bulletin 737-25-1430, Revision 1, dated April 10, 2003.

Compliance: Required as indicated, unless accomplished previously.

To prevent forward door escape slides from falling out of their compartments into the airplane interior and inflating, which could impede an evacuation in the event of emergency, accomplish the following:

Hinge Assembly Replacement

(a) For airplanes on which the hinge assemblies have not been replaced as of the effective date of this AD in accordance with Boeing Special Attention Service Bulletin 737-25-1430, dated February 22, 2001: Within 36 months after the effective date of this AD, replace the hinge assemblies on the escape slide stowage compartments of the forward doors with new, stronger hinge assemblies, in accordance with Part 1 of the Accomplishment Instructions of Boeing Special Attention Service Bulletin 737-25-1430, Revision 1, dated April 10, 2003.

Hinge Assembly Inspection

(b) For airplanes on which the hinge assemblies were replaced before the effective date of this AD in accordance with Boeing Special Attention Service Bulletin 737-25-1430, dated February 22, 2001: Within 36 months after the effective date of this AD, perform a general visual inspection for incorrectly crimped hinge assemblies, in accordance with Part 2 of the Accomplishment Instructions of Boeing Special Attention Service Bulletin 737-25-1430, Revision 1, dated April 10, 2003. If any hinge assembly is not correctly crimped, perform corrective action before further flight in accordance with Revision 1 of the service bulletin.

Note 1:

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 from within touching distance unless otherwise specified. A mirror may be necessary to enhance visual access to all exposed surfaces in the inspection area. This level of inspection is made under normally available lighting conditions such as daylight, hangar lighting, flashlight, or droplight 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.”

Part Installation

(c) As of the effective date of this AD, when replacing a hinge assembly, no person may install a hinge assembly, part number 65C30431-6 or 65C30431-7, on any airplane.

Alternative Methods of Compliance

(d) In accordance with 14 CFR 39.19, the Manager, Seattle Aircraft Certification Office, FAA, is authorized to approve alternative methods of compliance for this AD.

Incorporation by Reference

(e) The actions shall be done in accordance with Boeing Special Attention Service Bulletin 737-25-1430, Revision 1, dated April 10, 2003. 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 Airplanes, 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 March 5, 2004.

Issued in Renton, Washington, on January 20, 2004.

Kalene C. Yanamura,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.