03-21873. Airworthiness Directives; Boeing Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747-400, 747SR, and 747SP 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 airplane models. This proposal would require a one-time inspection to identify all H-11 steel bolts installed in the latch fittings of the cargo doors, repetitive inspections for cracked or broken H-11 steel bolts, and follow-on and corrective actions if necessary. This proposal also would require eventual replacement of all H-11 steel bolts in the latch fittings of the cargo doors with Inconel bolts. This action is necessary to prevent broken bolts in the latch fittings, which could reduce the capability of the door latch to keep the door closed, and result in loss of a cargo door and consequent rapid depressurization of the airplane. This action is intended to address the identified unsafe condition.

DATES:

Comments must be received by October 14, 2003.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2001-NM-180-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-180-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:

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].

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-180-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-180-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

The FAA has received a report of five corroded and broken bolts common to two of the latch fittings for the main deck side cargo door on a Boeing Model 747-300 series airplane. The affected bolts are made from H-11 steel, a material that is susceptible to corrosion and subsequent stress corrosion cracking. Broken H-11 steel bolts in the latch fittings of the cargo door could reduce the capability of the door latch to keep the door closed. This condition, if not corrected, could result in loss of the cargo door and consequent rapid depressurization of the airplane.

The same H-11 steel bolts used in the latch fittings of the main deck side cargo door of Boeing Model 747-300 series airplanes are also used in the latch fittings of the main deck side cargo door, nose cargo door, and the forward and aft lower lobe cargo doors on certain Boeing Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-200C, 747-200F, 747-400, 747SR, and 747SP series airplanes. Therefore, the subject doors on all of these airplane models may be subject to the same unsafe condition.

Explanation of Relevant Service Information

We have reviewed and approved Boeing Alert Service Bulletin 747-53A2464, Revision 1, dated August 30, 2001. That service bulletin describes procedures for a one-time inspection to identify all H-11 steel bolts installed in the latch fittings of the main deck side cargo door, nose cargo door, and the forward and aft lower lobe cargo doors. The inspection procedures include checking the bolt part number, which is stamped on the bolt head; or using a magnet to verify that the bolt is made of steel. The service bulletin also describes procedures for repetitive ultrasonic inspections for cracked or broken H-11 steel bolts, and replacement of H-11 steel bolts with Inconel bolts. The procedures for replacement of H-11 steel bolts involve performing a detailed inspection of the bolt hole for corrosion; oversizing the bolt hole to remove any corrosion; installing a new bolt, nut, and washers; and applying sealant. Accomplishment of the actions specified in the service bulletin is intended to adequately address the identified unsafe condition.

Other Relevant Rulemaking

Boeing Alert Service Bulletin 747-53A2464, Revision 1, specifies that the actions in Boeing Alert Service Bulletin 747-52A2167 must have been accomplished previously or must be accomplished concurrently. The FAA has previously issued AD 80-14-11, amendment 39-3831. That AD applies to all Model 747 series airplanes equipped with nose cargo doors, and requires, before further flight (as of July 15, 1980, the effective date of that AD), an inspection for loose or missing bolts of the portal latch fittings of the nose cargo door, and corrective actions if necessary, per Boeing Alert Service Bulletin 747-52A2167, Revision 1, dated March 28, 1980. Because the initial compliance time of AD 80-14-11 has long passed, this AD does not specify a requirement for accomplishing that service bulletin.

Explanation of Requirements of Proposed AD

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 Boeing Alert Service Bulletin 747-53A2464, Revision 1, except as discussed below. The actions would be required to be accomplished in accordance with the service bulletin described previously.

Differences Between This Proposed AD and Boeing Alert Service Bulletin 747-53A2464, Revision 1

The service bulletin does not specify the type of inspection necessary to identify H-11 steel bolts or to find corrosion during accomplishment of the replacement of H-11 bolts with improved bolts. For the purposes of this proposed AD, we have determined that the procedures in the service bulletin constitute a “detailed inspection.” Note 1 of this proposed AD defines such an inspection.

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 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.

The service bulletin specifies that the actions therein should be accomplished prior to or concurrently with the actions in Boeing Service Bulletin 747-52-2197. We have determined that it is not necessary at this time to require accomplishment of Boeing Service Bulletin 747-52-2197. This determination is based on our decision that the inspection of the portal latch fitting of the nose cargo door described in that service bulletin does not address an immediate safety issue. Service history shows that there have been no significant adverse findings since the issuance of that service bulletin; thus, the subject of that service bulletin is not an area of concern.

Changes to 14 CFR Part 39/Effect on the Proposed AD

On July 10, 2002, the FAA issued a new version of 14 CFR part 39 (67 FR 47997, July 22, 2002), which governs the FAA's airworthiness directives system. The regulation now includes material that relates to altered products, special flight permits, and alternative methods of compliance (AMOCs). Because we have now included this material in part 39, only the office authorized to approve AMOCs is identified in this proposed AD.

Change to Labor Rate Estimate

We have reviewed the figures we have used over the past several years to calculate AD costs to operators. To account for various inflationary costs in the airline industry, we find it necessary to increase the labor rate used in these calculations from $60 per work hour to $65 per work hour. The cost impact information, below, reflects this increase in the specified hourly labor rate.

Cost Impact

There are approximately 566 airplanes of the affected design in the worldwide fleet. The FAA estimates that 179 airplanes of U.S. registry would be affected by this proposed AD, that it would take between 2 and 8 work hours per airplane (depending on the airplane's configuration) to accomplish the proposed inspection, and that the average labor rate is $65 per work hour. Based on these figures, the cost impact of the proposed AD on U.S. operators is estimated to be between $130 and $520 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. 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-180-AD.

Applicability: Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747-400, 747SR, and 747SP series airplanes; line numbers 1 through 721 inclusive, 976, and 982; certificated in any category.

Compliance: Required as indicated, unless accomplished previously.

To prevent bolts from breaking in the latch fittings of the cargo doors, which could reduce the capability of the door latch to keep the door closed, and result in loss of a cargo door and consequent rapid depressurization of the airplane, accomplish the following:

Service Bulletin References

(a) The following information pertains to the service bulletin referenced in this AD:

(1) The term “service bulletin” as used in this AD, means the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2464, Revision 1, dated August 30, 2001.

(2) Although the service bulletin referenced in this AD specifies to submit certain information to the manufacturer, this AD does not include such a requirement.

(3) Although the service bulletin specifies that the actions therein must be accomplished prior to or concurrently with the actions in Boeing Alert Service Bulletin 747-52A2167 and Boeing Service Bulletin 747-52-2197, this AD does not include such a requirement. AD 80-14-11, amendment 39-3831, already requires accomplishment of Boeing Alert Service Bulletin 747-52A2167, Revision 1, dated March 28, 1980.

(4) Inspections and replacements accomplished before the effective date of this AD per Boeing Alert Service Bulletin 747-53A2464, dated March 15, 2001, are considered acceptable for compliance with this AD.

Initial Inspection

(b) Within 1 year after the effective date of this AD: Do a one-time detailed inspection to identify all H-11 steel bolts installed in the latch fittings of the main deck side cargo door, nose cargo door, and the forward and aft lower lobe cargo doors, as applicable. Do the inspection by checking the bolt part number stamped on the bolt head, or verifying the bolt is steel by using a magnet, per the service bulletin. If no H-11 steel bolt is found, no further action is required by this paragraph. If any H-11 steel bolt is found, do the requirements of paragraph (c) of this AD.

Note 1:

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.”

Follow-On Inspections/Corrective Actions

(c) For any H-11 steel bolt found during any inspection required by paragraph (b) of this AD: Before further flight, do an ultrasonic inspection for cracked or broken bolts, or replace the H-11 steel bolt with an Inconel bolt, per the service bulletin. Replace any cracked or broken bolt with an Inconel bolt before further flight per the service bulletin. Repeat the ultrasonic inspection of remaining H-11 steel bolts in the latch fittings of the main deck side cargo door, nose cargo door, and the forward and aft lower lobe cargo doors, at intervals not to exceed 18 months until the terminating action required by paragraph (d) of this AD is done.

Terminating Action

(d) Within 6 years after the effective date of this AD: Replace, with Inconel bolts, all H-11 steel bolts in the latch fittings of the main deck side cargo door, nose cargo door, and the forward and aft lower lobe cargo doors, per the service bulletin. The procedures for this replacement include performing a detailed inspection of the bolt hole for corrosion; oversizing the bolt hole to remove any corrosion; installing a new bolt, nut, and washers; and applying sealant. Such replacement terminates the repetitive inspections required by paragraph (c) of this AD. If corrosion is found and oversizing the bolt hole within the limits specified in the service bulletin is not adequate to remove the corrosion, 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.

Parts Installation

(e) As of the effective date of this AD: No person may install, on any airplane, an H-11 steel bolt in the latch fittings of the main deck side cargo door, nose cargo door, or the forward and aft lower lobe cargo doors.

Alternative Methods of Compliance

(f) In accordance with 14 CFR 39.19, the Manager, Seattle ACO, is authorized to approve alternative methods of compliance for this AD.

Issued in Renton, Washington, on August 20, 2003.

Kyle L. Olsen,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.