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Proposed Rule

Airworthiness Directives; Boeing Model 747 Series Airplanes

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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 all Boeing Model 747 series airplanes, that currently requires periodic inspections and cleaning of the drainage system cavity of the canted pressure deck, aft of the wing center section. This action would add new repetitive tests and inspections for discrepancies of the drainage system of the canted pressure deck located in the wheel wells of the main landing gear (MLG) of the left and right wings; and corrective actions, if necessary. The action would also terminate the requirements of the existing AD. The actions specified by the proposed AD are intended to prevent ice accumulation on the lateral flight control cables due to water entering the wheel well of the MLG and freezing, which could restrict or jam control cable movement, resulting in loss of controllability of the airplane.

DATES:

Comments must be received by December 2, 2002.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2002-NM-28-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 (425) 227-1232. Comments may also be sent via the Internet using the following address: 9-anm-nprmcomment@faa.gov. Comments sent via fax or the Internet must contain “Docket No. 2002-NM-28-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.

Start Further Info

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 (425) 227-1153; fax (425) 227-1181.

Other Information: Sandi Carli, Airworthiness Directive Technical Editor/Writer; telephone (425) 687-4243, fax (425) 687-4248. Questions or comments may also be sent via the Internet using the following address: sandi.carli@faa.gov. Questions or comments sent via the Internet as attached electronic files must be formatted in Microsoft Word 97 for Windows or ASCII text.

End Further Info End Preamble Start Supplemental Information

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 2002-NM-28-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-28-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

On May 24, 1989, the FAA issued AD 89-12-07, amendment 39-6232 (54 FR 24161, June 6, 1989), applicable to all Boeing Model 747 series airplanes, to require periodic inspections and cleaning of the cavity aft of the wing center section. The requirements of that AD are intended to prevent ice accumulation in the aileron control system which could result in reduced lateral control capability.

Actions Since Issuance of Previous Rule

Since the issuance of AD 89-12-07, we have received several reports indicating ice accumulation on the lateral flight control cables in the wheel well of the main landing gear (MLG) on certain Model 747 series airplanes during flight. The ice buildup was attributed to debris blocking the drainage system for the canted pressure deck area, which caused water accumulation in the canted pressure deck. The accumulation of water also caused excessive corrosion of the upper skin of the wing center section and the Start Printed Page 63857rear spar. Cabin pressurization caused the water to enter the wheel well of the MLG and solidify during flight. Such ice accumulation could restrict or jam control cable movement, resulting in loss of controllability of the airplane.

Explanation of Relevant Service Information

We have reviewed and approved Boeing Alert Service Bulletin 747-51A2057, dated February 21, 2002, which describes procedures for repetitive tests and inspections for discrepancies of the drainage system for the canted pressure deck located in the wheel wells of the MLG in the left and right wings; and corrective actions, if necessary; as follows:

  • Work Package 1 describes procedures for repetitive testing of the drainage system of the canted pressure deck for proper drainage. The test includes a visual inspection of the external drains, reducer, and drain lines for discrepancies. The discrepancies include damage, holes, signs of frozen water, and signs of blockage (3 to 5 pounds per square inch (PSI) compressed air is sent through the drain line to check for blockage). The corrective actions include cleaning the drain system to remove blockage if the air does not flow freely, and replacing any damaged drain line with a new drain line. The procedures also specify contacting the manufacturer for repair instructions for damaged drain lines.
  • Work Package 2 describes procedures for repetitive cleaning and inspecting of the canted pressure deck drainage system as shown in the Boeing 747 Airplane Maintenance Manual.
  • Work Package 3 describes procedures for repetitive inspections of the canted pressure deck for discrepancies (loose or missing fasteners; loose, missing, or cracked sealant; and leak paths). The corrective actions include replacing any loose or missing fastener, or loose, missing, or cracked sealant; and repair of any leak found. For other discrepancies, the procedures specify contacting the manufacturer for repair instructions.
  • Work Package 4 describes procedures for repetitive cabin pressurization tests to check for leaks in the canted pressure deck, and repair of any leak found.

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 supersede AD 89-12-07 to continue to require periodic inspections and cleaning of the drainage system cavity of the canted pressure deck, aft of the wing center section. This new action would add repetitive tests and inspections for discrepancies of the drainage system of the canted pressure deck located in the wheel wells of the MLG of the left and right wings; and corrective actions, if necessary. The new actions would terminate the requirements of the existing AD. The actions would be required to be accomplished in accordance with the service bulletin described previously, except as discussed below.

Difference Between Service Information and Proposed Rule

Although the service bulletin specifies that the manufacturer may be contacted for disposition of certain repairs, this proposed AD would require such repairs to be accomplished per a method approved by us, 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.

Cost Impact

There are approximately 1,127 airplanes of the affected design in the worldwide fleet. The FAA estimates that 255 airplanes of U.S. registry would be affected by this proposed AD.

It would take approximately 1 work hour per airplane to accomplish the actions that are currently required by AD 89-12-07, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the currently required actions is estimated to be $60 per airplane, per inspection cycle.

It would take approximately 12 work hours per airplane to accomplish the test/inspection/cleaning of the drainage system specified in Work Packages 1 and 2 of Boeing Alert Service Bulletin 747-51A2057, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the test/inspection/cleaning proposed by this AD on U.S. operators is estimated to be $183,600, or $720 per airplane, per cycle.

It would take approximately 4 work hours per airplane to accomplish the inspection specified in Work Package 3 of the service bulletin, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the inspection proposed by this AD on U.S. operators is estimated to be $61,200, or $240 per airplane, per inspection cycle.

It would take approximately 4 work hours per airplane to accomplish the cabin pressurization test specified in Work Package 4 of the service bulletin, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the test proposed by this AD on U.S. operators is estimated to be $61,200, or $240 per airplane, per test cycle.

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 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.

Start List of Subjects

List of Subjects in 14 CFR Part 39

End List of Subjects

The Proposed Amendment

Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration proposes to amend part Start Printed Page 6385839 of the Federal Aviation Regulations (14 CFR part 39) as follows:

Start Part

PART 39—AIRWORTHINESS DIRECTIVES

1. The authority citation for part 39 continues to read as follows:

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Authority: 49 U.S.C. 106(g), 40113, 44701.

End Authority
[Amended]

2. Section 39.13 is amended by removing amendment 39-6232 (54 FR 24161, June 6, 1989), and by adding a new airworthiness directive (AD), to read as follows:

Boeing: Docket 2002-NM-28-AD. Supersedes AD 89-12-07, Amendment 39-6232.

Applicability: All Model 747 series airplanes, 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 (f)(1) 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 ice accumulation on the lateral flight control cables due to water entering the wheel well of the main landing gear and freezing, which could restrict or jam control cable movement, resulting in loss of controllability of the airplane; accomplish the following:

Restatement of Requirements of AD 89-12-07

Repetitive Inspections/Cleaning

(a) Within 15 months after July 10, 1989 (the effective date of AD 89-12-07, amendment 39-6232), unless accomplished 3 months before July 10, 1989, and thereafter at intervals not to exceed 18 months: Gain access to the cavity aft of the wing center section and remove all debris and foreign material, clean the cavity, and verify all drains are open and clean.

New Requirements of This AD

Repetitive Tests of the Drainage System/Corrective Action

(b) Within 18 months after the effective date of this AD, do the actions required by paragraphs (b)(1), (b)(2), and (b)(3) of this AD, as applicable, per the Work Instructions of Boeing Alert Service Bulletin 747-51A2057, dated February 21, 2002.

(1) Do a test (including a general visual inspection of the external drains, reducer, and drain lines, and sending 3 to 5 pounds per square inch (PSI) compressed air through the drain line) of the drainage system of the canted pressure deck for discrepancies (including damage, holes, signs of frozen water, and signs of blockage), per Work Package 1 of the service bulletin. Repeat the test at least every 18 months.

(2) Clean the drainage system for the canted pressure deck and do a general visual inspection of the system for discrepancies per Work Package 2 of the Work Instructions of the service bulletin. Repeat the cleaning and inspection at least every 18 months. Accomplishment of this paragraph terminates the requirements in paragraph (a) of this AD.

(3) Except as required by paragraph (e) of this AD: If any discrepancy is found during any inspection or test required by paragraphs (b)(1) and (b)(2) of this AD, before further flight, repair per the Work Instructions of the service bulletin.

Repetitive Inspections of the Canted Pressure Deck/Corrective Action

(c) Within 36 months after the effective date of this AD: Do a general visual inspection of the canted pressure deck for discrepancies (including loose or missing fasteners; loose, missing, or cracked sealant; and leak paths), per Work Package 3 of the Work Instructions of Boeing Alert Service Bulletin 747-51A2057, dated February 21, 2002. If any discrepancy is found, before further flight, repair (including replacing any loose or missing fastener or loose, missing, or cracked sealant; and repair of any leak found) per the service bulletin; except as required by paragraph (e) of this AD. Repeat the inspection at least every 36 months.

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 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.”

Repetitive Cabin Pressurization Tests/Corrective Action

(d) Within 72 months after the effective date of this AD: Do a cabin pressurization test to check for leaks in the canted pressure deck per Work Package 4 of the Work Instructions of Boeing Alert Service Bulletin 747-51A2057, dated February 21, 2002. If any leak is found, before further flight, repair per the service bulletin; except as required by paragraph (e) of this AD. Repeat the cabin pressurization test at least every 72 months.

Corrective Action per Seattle Aircraft Certification Office (ACO)

(e) If any discrepancy is found during any inspection or test required by this AD and the service bulletin specifies to contact Boeing for appropriate action: Before further flight, repair per a method approved by the Manager, Seattle 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.

Alternative Methods of Compliance

(f)(1) 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.

(2) Alternative methods of compliance, approved previously in accordance with AD 89-12-07, amendment 39-6232, are approved as alternative methods of compliance with paragraph (b)(2) of this AD.

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

(g) 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.

Start Signature

Issued in Renton, Washington, on October 8, 2002.

Ali Bahrami,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.

End Signature End Part End Supplemental Information

[FR Doc. 02-26203 Filed 10-15-02; 8:45 am]

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