02-15662. 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 a one-time inspection to identify all alloy steel bolts on the body station 1480 bulkhead splice, and corrective action if necessary; and provides for optional terminating action for certain requirements of that AD. This proposed AD would require accomplishment of the previously optional terminating action. The actions specified by this proposed AD are intended to prevent cracked or broken bolts, which could result in structural damage and rapid depressurization of the airplane. This action is intended to address the identified unsafe condition.

DATES:

Comments must be received by August 5, 2002.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2002-NM-84-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. 2002-NM-84-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:

Technical Information: Rick Kawaguchi, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone [phone]; fax [phone].

Other Information: Sandi Carli, Airworthiness Directive Technical Editor/Writer; telephone [phone], fax [phone]. Questions or comments may also be sent via the Internet using the following address: [e-mail]. Questions or comments sent via the Internet as attached electronic files must be formatted in Microsoft Word 97 for Windows or ASCII text.

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 the specific change to the proposed AD 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 2002-NM-84-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. 2002-NM-84-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

On April 12, 2002, the FAA issued AD 2002-08-10, amendment 39-12718 (67 FR 19641, April 23, 2002), applicable to certain Boeing Model 747 series airplanes, to require a one-time inspection to identify all alloy steel bolts on the body station (BS) 1480 bulkhead splice, and corrective action if necessary. That action also provides for optional terminating action for certain requirements. That action was prompted by reports of broken alloy steel bolts on the BS 1480 bulkhead splice. Alloy steel bolts have been found to be susceptible to stress corrosion and consequent cracking and breakage. The requirements of that AD are intended to detect and correct cracked or broken bolts, which could result in structural damage and rapid depressurization of the airplane.

Actions Since Issuance of Previous Rule

In the preamble to AD 2002-08-10, the FAA indicated that the actions required by that AD were considered “interim action” and that further rulemaking action was being considered. The FAA now has determined that further rulemaking action is indeed necessary, 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 2002-08-10 to continue to require a one-time inspection to identify all alloy steel bolts on the BS 1480 bulkhead splice, and corrective action if necessary and to require the previously optional replacement of all alloy steel bolts on the splice, which would terminate the requirements of the AD. The actions would be required to be accomplished in accordance with Boeing Alert Service Bulletin 747-53A2477, described previously, except as discussed below.

Differences Between Proposed AD and Alert Service Bulletin

Although the alert service bulletin specifies that the manufacturer may be contacted for disposition of certain repair conditions, this proposed AD would require the repair of those conditions to be accomplished in accordance with a method approved by the FAA, or per data meeting the type certification basis of the airplane approved by a Boeing Company Designated Engineering Representative who has been authorized by the Manager, Seattle Aircraft Certification Office, to make such findings.

Explanation of Change Made to Existing Requirements

The FAA has clarified the inspection requirement contained in AD 2002-08-10. Whereas that AD specifies a detailed visual inspection, this proposed AD specifies a detailed inspection. Additionally, a note is included in this proposed AD to define that inspection.

Cost Impact

There are approximately 582 airplanes of the affected design in the worldwide fleet. The FAA estimates that 178 airplanes of U.S. registry would be affected by this proposed AD.

The inspection that is currently required by AD 2002-08-10 takes approximately 58 work hours per airplane to accomplish (including access and close), at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the currently required actions on U.S. operators is estimated to be $619,440, or $3,480 per airplane.

The terminating action proposed in this AD action would take approximately 86 work hours per airplane to accomplish, at an average labor rate of $60 per work hour. Required parts could cost as much as approximately $1,414 per airplane. Based on these figures, the cost impact of the proposed requirements of this AD on U.S. operators is estimated to be $1,170,172, or $6,574 per airplane.

The cost impact figures discussed above are 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.

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 39-12718 (67 FR 19641, April 23, 2002), and by adding a new airworthiness directive (AD), to read as follows:

Boeing: Docket 2002-NM-84-AD. Supersedes AD 2002-08-10, Amendment 39-12718.

Applicability: Model 747 series airplanes, certificated in any category, line numbers 1 through 750 inclusive, excluding airplanes on which the bulkhead splice areas have been modified in accordance with Plan “B” of AD 2001-11-06, amendment 39-12248.

Note 1:

This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been otherwise 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 (g) 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 cracked or broken bolts, which could result in structural damage and rapid depressurization of the airplane, accomplish the following:

Restatement of Certain Requirements of AD 2002-08-10

Inspection

(a) At the applicable time specified by paragraph (a)(1) or (a)(2) of this AD: Inspect the BS 1480 bulkhead splice to identify all alloy steel bolts by using a magnet or, if applicable, detailed methods, in accordance with Boeing Alert Service Bulletin 747-53A2477, dated February 28, 2002.

Note 2:

For the purposes of this AD, a detailed 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.”

(1) For airplanes on which the bulkhead splice inspection specified by AD 2001-11-06 has NOT been accomplished within 15 months before May 8, 2002 (the effective date of AD 2002-08-10, amendment 39-12718): Inspect within 90 days after May 8, 2002.

(2) For airplanes on which the bulkhead splice inspection specified by AD 2001-11-06 HAS been accomplished within 15 months before May 8, 2002: Inspect within 18 months since the most recent inspection.

Corrective Actions

(b) For each alloy steel bolt found during the inspection required by paragraph (a) of this AD: Before further flight, inspect those bolts using torque test or ultrasonic methods to detect cracks or breakage, in accordance with Boeing Alert Service Bulletin 747-53A2477, dated February 28, 2002, except as required by paragraph (e) of this AD.

(1) For each uncracked and unbroken alloy steel bolt found: Repeat the inspection specified by paragraph (b) of this AD thereafter at least every 18 months, until the terminating action of paragraph (d) of this AD is accomplished.

(2) For any cracked or broken bolt found: Before further flight, replace it with an Inconel 718 bolt. Such replacement terminates the requirements of this AD for that bolt only.

(3) If any cracked or broken bolt is found anywhere along the splice during any inspection required by paragraph (b) of this AD: Before further flight, reinspect, using ultrasonic methods, any remaining alloy steel bolts that were initially inspected using torque test methods, and replace any cracked or broken bolt with an Inconel 718 bolt. Such replacement terminates the requirements of this AD for that bolt only.

Magnetic Particle Inspection

(c) Plan “A” inspections required by AD 2001-11-06 are acceptable for compliance with the inspection requirements of paragraph (b) of this AD, provided a magnetic particle inspection and applicable corrective actions are performed on any alloy steel bolt removed during any Plan “A” inspection before the bolt is reinstalled. The magnetic particle inspection and corrective actions must be performed in accordance with Boeing Alert Service Bulletin 747-53A2477, dated February 28, 2002, except as required by paragraph (e) of this AD.

New Requirements of this AD

Terminating Action

(d) Within 6 years after the effective date of this AD: Replace all alloy steel bolts in the BS 1480 bulkhead splice with Inconel 718 bolts, in accordance with Boeing Alert Service Bulletin 747-53A2477, dated February 28, 2002, except as required by paragraph (e) of this AD. Replacement of all alloy steel bolts terminates the requirements of this AD.

Exceptions to Service Information

(e) If Boeing Alert Service Bulletin 747-53A2477, dated February 28, 2002, specifies to contact Boeing for appropriate action: Before further flight, repair in accordance with a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA; or per data meeting the type certification basis of the airplane approved by a Boeing Company Designated Engineering Representative who has been authorized by the Manager, Seattle ACO, to make such findings. For a repair method to be approved, the approval must specifically reference this AD.

Spares

(f) As of the effective date of this AD, no person may install an alloy steel bolt on the BS 1480 bulkhead splice on any airplane.

Alternative Methods of Compliance

(g) 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, 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 3:

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

(h) 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 June 14, 2002.

Ali Bahrami,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.