03-29340. Airworthiness Directives; Boeing Model 767-200 and -300 Series Airplanes

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Boeing Model 767-200 and -300 series airplanes. This proposal would require replacement of certain door-mounted escape slides and slide-raft assemblies with new slide-raft assemblies; replacement of certain escape system latches with new latches; and modification or replacement of certain counterbalance assemblies with new counterbalance assemblies; as applicable. This action is necessary to prevent the escape slides and slide-rafts of the forward and mid-cabin entry and service doors from being too short to reach the ground in the event that the airplane rotates onto the aft fuselage, resulting in an extreme tip-back position, which could result in injury to passengers and crewmembers during an emergency evacuation. This action is intended to address the identified unsafe condition.

DATES:

Comments must be received by January 9, 2004.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2001-NM-237-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. Comments may be inspected at this location between 9 a.m. and 3 p.m., Monday through Friday, except Federal holidays. Comments may be submitted via fax to [phone]. Comments may also be sent via the Internet using the following address: [e-mail]. Comments sent via fax or the Internet must contain “Docket No. 2001-NM-237-AD” in the subject line and need not be submitted in triplicate. Comments sent via the Internet as attached electronic files must be formatted in Microsoft Word 97 or 2000 or ASCII text.

The service information referenced in the proposed rule may be obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, Washington 98124-2207. This information may be examined at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington.

FOR FURTHER INFORMATION CONTACT:

Susan Rosanske, Aerospace Engineer, Airframe Branch, ANM-150S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone [phone]; fax [phone].

SUPPLEMENTARY INFORMATION:

Comments Invited

Interested persons are invited to participate in the making of the proposed 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 above. All communications received on or before the closing date for comments, specified above, will be considered before taking action on the proposed rule. The proposals contained in this action may be changed in light of the comments received.

Submit comments using the following format:

• Organize comments issue-by-issue. For example, discuss a request to change the compliance time and a request to change the service bulletin reference as two separate issues.
• For each issue, state what specific change to the proposed AD is being requested.
• Include justification (e.g., reasons or data) for each request.

Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the proposed 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 summarizing each FAA-public contact concerned with the substance of this proposal will be filed in the Rules Docket.

Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this action must submit a self-addressed, stamped postcard on which the following statement is made: “Comments to Docket Number 2001-NM-237-AD.” The postcard will be date stamped and returned to the commenter.

Availability of NPRMs

Any person may obtain a copy of this NPRM by submitting a request to the FAA, Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2001-NM-237-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

The FAA has received reports indicating that the original analysis of the highest sill heights for the forward and mid-cabin entry and service doors is no longer valid on certain Boeing Model 767-200 and -300 series airplanes. The original analysis showed that, in the event of a main landing gear (MLG) failure, the engine nacelle strut would shear off due to the weight of the airplane; however, the results of further testing revealed that the engine nacelle strut has a higher strength than originally calculated. This higher strength could result in higher-than-expected sill height values ocurring at the forward and mid-cabin doors with the airplane resting on one MLG and the opposite engine. In this instance, the airplane could rotate onto the aft fuselage (i.e., an extreme tip-back position). We have received two reported incidents of a single MLG collapsing, which resulted in a partial tip-back position due to the degree of rotation of the airplane. No injury resulted to passengers using the evacuation slides during the emergency.

This condition, if not corrected, could cause the escape slides and slide-rafts of the forward and mid-cabin entry and service doors to be too short to reach the ground in the event that the airplane rotates onto the aft fuselage, resulting in an extreme tip-back position. This tip-back position could result in injury to passengers and crewmembers during an emergency evacuation.

Explanation of Relevant Service Information

The FAA has reviewed and approved Boeing Service Bulletin 767-25-0266, dated September 14, 2000, which describes procedures for replacing certain door-mounted escape slides and slide-raft assemblies with new slide-raft assemblies; replacing certain door latches with new latches; and modifying or replacing certain counterbalance assemblies with new counterbalance assemblies; as applicable. Accomplishment of the actions specified in the service bulletin is intended to adequately address the identified unsafe condition.

Explanation of Requirements of Proposed Rule

Since an unsafe condition has been identified that is likely to exist or develop on other products of this same type design, the proposed AD would require accomplishment of the actions specified in the service bulletin described previously, except as discussed below.

Differences Between Proposed Rule and Service Bulletin

Operators should note that, although Boeing Service Bulletin 767-25-0266 recommends that the affected parts be replaced at the end of the “useful service life” (approximately 15 years) of the slides and slide-rafts, the FAA has determined that the “useful service life” interval would not address the unsafe condition in a timely manner. Therefore, this proposal would require that the affected parts be replaced within five years from the effective date of this AD. In developing an appropriate compliance time for this AD, the FAA considered not only the manufacturer's recommendation, but also the degree of urgency associated with addressing the subject unsafe condition, the average utilization of the affected fleet, and the time necessary to perform the replacement. In light of all of these factors, the FAA finds a five-year compliance time for completing the required actions to be warranted, in that it represents an appropriate interval of time allowable for affected airplanes to continue to operate without compromising safety.

Cost Impact

There are approximately 745 airplanes of the affected design in the worldwide fleet. The FAA estimates that 261 airplanes of U.S. registry would be affected by this proposed AD. The work hours and required parts per airplane vary according to the configuration group to which the affected airplane belongs.

The following table shows the estimated cost impact for airplanes of U.S. registry affected by this proposed AD:

Cost Impact

Airplane configuration group	Number on U.S. register	Work hours per airplane	Parts cost per airplane	Cost per airplane	Total cost for U.S.-registered airplanes
1	208	6	$1,236	$1,626	$338,208
2	12	12	2,472	3,252	39,024
3	41	11	98,858	99,573	4,082,493
4 (none on U.S. register)	0	11	50,400	51,115	0
5 (none on U.S. register)	0	17	51,636	52,741	0

Based on the figures in the above table, the cost impact of the proposed AD on U.S. operators is estimated to be $4,459,725.

The cost impact figure discussed above is based on assumptions that no operator has yet accomplished any of the proposed requirements of this AD action, and that no operator would accomplish those actions in the future if this proposed 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 proposed herein would 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 proposal would not have federalism implications under Executive Order 13132.

For the reasons discussed above, I certify that this proposed regulation (1) is not a “significant regulatory action” under Executive Order 12866; (2) is not a “significant rule” under the DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and (3) if promulgated, 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 copy of the draft regulatory evaluation prepared for this action is contained in the Rules Docket. A copy of it may be obtained by contacting the Rules Docket at the location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• Safety

The Proposed Amendment

Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration proposes to amend 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:

Boeing: Docket 2001-NM-237-AD.

Applicability: Model 767-200 and -300 series airplanes, line numbers 1 through 793 inclusive, certificated in any category.

Compliance: Required as indicated, unless accomplished previously.

To prevent the escape slides and slide-rafts of the forward and mid-cabin entry and service doors from being too short to reach the ground in the event that the airplane rotates onto the aft fuselage, resulting in an extreme tip-back position, which could result in injury to passengers and crewmembers during an emergency evacuation, accomplish the following:

Replacement

(a) Within five years from the effective date of this AD, perform the actions specified in Table 1 of this AD for the applicable airplane configuration group, on the applicable doors, per the Accomplishment Instructions in Boeing Service Bulletin 767-25-0266, dated September 14, 2000.

Table 1.—Replacement Requirements

For airplanes identified in the service bulletin as group—	Perform the following action—	At these affected doors—
1	Replace the escape slides or slide-raft assemblies with new escape slide-raft assemblies, and replace the escape system latches with new latches	Forward entry and service doors.
2	Replace the escape slides or slide-raft assemblies with new escape slide-raft assemblies, and replace the escape system latches with new latches	Forward and mid-cabin entry and service doors.
3	Replace the escape slides or slide-raft assemblies with new escape slide-raft assemblies; replace the escape system latches with new latches; and replace the counterbalance assemblies with new counterbalance assemblies	Forward entry and service doors.
4	Replace the escape slides or slide-raft assemblies with new escape slide-raft assemblies; replace the escape system latches with new latches; and modify or replace the counterbalance assemblies with new counterbalance assemblies	Forward entry and service doors.
5	Replace the escape slides or slide-raft assemblies with new escape slide-raft assemblies; replace the escape system latches with new latches	Forward and mid-cabin entry and service doors.
5	Modify or replace the counterbalance assemblies with new counterbalance assemblies	Forward entry and service doors.

Replacements Accomplished Previously per the Service Bulletin

(b) Replacements accomplished before the effective date of this AD per Boeing Service Bulletin 767-25-0266, dated September 14, 2000, are considered acceptable for compliance with the corresponding actions specified in this AD.

Alternative Methods of Compliance

(c) 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.

Issued in Renton, Washington, on November 17, 2003.

Kalene C. Yanamura,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.