01-10344. Airworthiness Directives; Boeing Model 747 Series Airplanes

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

This document proposes the supersedure of an existing airworthiness directive (AD), applicable to certain Boeing Model 747 series airplanes, that currently requires repetitive detailed visual inspections to find discrepancies of the installation of the midspar fuse pins of the inboard and outboard struts, and follow-on actions, if necessary. The existing AD also provides an optional terminating modification for the repetitive inspections. This action would mandate accomplishment of the previously optional terminating modification. The actions specified by the proposed AD are intended to find and fix discrepancies of the installation of the midspar fuse pins, which could result in loss of the secondary retention capability of the fuse pins, migration of the fuse pins, and consequent loss of the strut and engine from the airplane.

DATES:

Comments must be received by June 11, 2001.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2001-NM-02-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. Comments may be inspected at this location between 9:00 a.m. and 3:00 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-02-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 for Windows 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:

Tamara Anderson, Aerospace Engineer, Airframe Branch, ANM-120S, 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-02-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-02-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

On February 26, 2001, the FAA issued AD 2001-05-05, amendment 39-12141 (66 FR 13424, March 6, 2001), applicable to certain Boeing Model 747 series airplanes, to require repetitive detailed visual inspections to find discrepancies of the installation of the midspar fuse pins of the inboard and outboard struts, and follow-on actions, if necessary. That action also provides for an optional terminating modification for the repetitive inspections. The requirements of that AD are intended to find and fix discrepancies of the installation of the midspar fuse pins, which could result in loss of the secondary retention capability of the fuse pins, migration of the fuse pins, and consequent loss of the strut and engine from the airplane.

Actions Since Issuance of Previous Rule

In the preamble to AD 2001-05-05, the FAA specified that the actions required by that AD were considered “interim action” and that we were considering requiring the optional terminating modification, which would constitute terminating action for the repetitive inspections required by that AD. The FAA has now determined that it is necessary to mandate the terminating modification, and this proposed AD follows from that determination.

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 supersede AD 2001-05-05 to continue to require repetitive detailed visual inspections to find discrepancies of the installation of the midspar fuse pins of the inboard and outboard struts, and follow-on actions, if necessary. This proposed AD also would mandate the previously optional terminating modification, which would end the repetitive inspections. The actions would be required to be done per the service bulletin referenced in the existing AD.

Cost Impact

There are approximately 1,111 airplanes of the affected design in the worldwide fleet. The FAA estimates that 256 airplanes of U.S. registry would be affected by this proposed AD.

The inspections that are currently required by AD 2001-05-05 take approximately 4 work hours per airplane to accomplish, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the currently required inspections on U.S. operators is estimated to be $61,440, or $240 per airplane, per inspection cycle.

The terminating modification that is proposed in this AD action would take approximately 4 work hours per airplane to accomplish, at an average labor rate of $60 per work hour. Required parts would cost approximately $1,000 per airplane. Based on these figures, the cost impact of the modification proposed by this AD on U.S. operators is estimated to be $317,440, or $1,240 per airplane.

The cost impact figures discussed above are based on assumptions that no operator has yet accomplished any of the current or proposed 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 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 removing amendment 39-12141 (66 FR 13424, March 6, 2001), and by adding a new airworthiness directive (AD), to read as follows:

Boeing: Docket 2001-NM-02-AD. Supersedes AD 2001-05-05, amendment 39-12141.

Applicability: Model 747 series airplanes, as listed in Boeing Service Bulletin 747-54A2206, Revision 1, dated February 22, 2001, 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 find and fix discrepancies of the installation of the midspar fuse pins of the inboard and outboard strut, which could result in loss of the secondary retention capability of the fuse pins, migration of the fuse pins, and consequent loss of the strut and engine from the airplane; accomplish the following:

Restatement of the Requirements of AD 2001-05-05

Inspections/Follow-On Actions

(a) At the time specified in paragraph (a)(1) or (a)(2) of this AD, as applicable: Do a detailed visual inspection to find discrepancies (e.g., incorrect thread protrusion, which is less than two threads protruding from the nut between the nut and the secondary retention washer; incorrect gap between the fuse pin primary nut and secondary retention washer; cracked or broken torque stripe) of the installation of the midspar fuse pins of the inboard and outboard struts, per Figure 2 of Boeing Service Bulletin 747-54A2206, Revision 1, dated February 22, 2001.

(1) For airplanes modified per the production equivalent of one of the AD's listed in Table 1 of this AD: Do the inspection at the later of the times specified in paragraphs (a)(1)(i) and (a)(1)(ii) of this AD.

(i) Before the accumulation of 8,000 total flight hours, or within 24 months since manufacture of the airplane, whichever occurs first.

(ii) Within 90 days after March 21, 2001 (the effective date of AD 2001-05-05, amendment 39-12141).

(2) For airplanes modified per one of the AD's listed in Table 1 of this AD: Do the inspection at the later of the times specified in paragraphs (a)(2)(i) and (a)(2)(ii) of this AD. Table 1 follows:

Table 1

AD No.	Amendment No.
AD 95-10-16	39-9233
AD 95-13-05	39-9285
AD 95-13-06	39-9286
AD 95-13-07	39-9287
AD 99-10-10	39-11163

(i) Within 8,000 flight hours, or within 24 months since doing the modification, whichever occurs first.

(ii) Within 90 days after March 21, 2001.

Note 2:

Where there are differences between the AD and the service bulletin, the AD prevails.

Note 3:

For the purposes of this AD, a detailed visual inspection is defined as: “An intensive visual examination of a specific structural area, system, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at intensity deemed appropriate by the inspector. Inspection aids such as mirror, magnifying lenses, etc., may be used. Surface cleaning and elaborate access procedures may be required.”

(A) If no discrepancy is found: Repeat the inspection at intervals not to exceed 8,000 flight hours or 24 months, whichever is first, until you do the terminating modification specified in paragraph (b) of this AD.

(B) If any discrepancy is found, and the primary nut has backed off and contacts the secondary retention washer: Before further flight, do the terminating modification specified in paragraph (b) of this AD.

(C) If any discrepancy is found, and the primary nut does not contact the secondary retention washer: Repeat the inspection at intervals not to exceed 90 days. Within 18 months after the initial finding, or March 21, 2001, whichever occurs later, do the terminating modification specified in paragraph (b) of this AD.

Note 4:

Inspections done prior to the effective date of this AD per Boeing Alert Service Bulletin 747-54A2206, dated October 19, 2000, are acceptable for compliance with the inspections required by paragraph (a) of this AD.

New Requirements of This AD

Terminating Action

(b) Within 6 years after the effective date of this AD: Do the terminating modification (replacement of the primary nut of the midspar fuse pin with a new nut, installation of torque stripe, a detailed visual inspection of the fuse pin threads for damage, and replacement, if necessary) per Figure 3 of Boeing Service Bulletin 747-54A2206, Revision 1, dated February 22, 2001. Doing this modification ends the repetitive inspections required by this AD.

Note 5:

Doing the terminating modification prior to the effective date of this AD per Boeing Alert Service Bulletin 747-54A2206, dated October 19, 2000, is acceptable for compliance with the terminating action required by paragraph (b) of this AD.

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. 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 6:

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.

Issued in Renton, Washington, on April 19, 2001.

Donald L. Riggin,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.