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Proposed Rule

Airworthiness Directives; Boeing Model 747-200C and 747-200F Series Airplanes

Document Details

Information about this document as published in the Federal Register.

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Start Preamble

AGENCY:

Federal Aviation Administration (FAA), Department of Transportation (DOT).

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The FAA proposes to adopt a new airworthiness directive (AD) for all Boeing Model 747-200C and 747-200F series airplanes. This proposed AD would require repetitive inspections for cracking of the left and right C-3 frame upper closure fittings of the nose cargo door, and corrective actions if necessary. This proposed AD also provides an optional modification that, if done, would terminate inspections in certain areas. This proposed AD is prompted by reports indicating that fatigue cracking was found in the inboard flange above the flight deck floor on the C-3 frame upper closure fittings of the nose cargo door. We are proposing this AD to detect and correct cracking of the C-3 frame upper closure fittings, which could extend and result in rapid depressurization of the airplane.

DATES:

We must receive comments on this proposed AD by March 4, 2005.

ADDRESSES:

Use one of the following addresses to submit comments on this proposed AD.

  • DOT Docket Web site: Go to http://dms.dot.gov and follow the instructions for sending your comments electronically.
  • Government-wide rulemaking Web site: Go to http://www.regulations.gov and follow the instructions for sending your comments electronically.
  • Mail: Docket Management Facility, U.S. Department of Transportation, 400 Seventh Street, SW., Nassif Building, room PL-401, Washington, DC 20590.
  • By fax: (202) 493-2251.
  • Hand Delivery: Room PL-401 on the plaza level of the Nassif Building, 400 Seventh Street, SW., Washington, DC, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

For service information identified in this proposed AD, contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207.

You can examine the contents of this AD docket on the Internet at http://dms.dot.gov, or in person at the Docket Management Facility, U.S. Department of Transportation, 400 Seventh Street, SW., room PL-401, on the plaza level of the Nassif Building, Washington, DC.

Start Further Info

FOR FURTHER INFORMATION CONTACT:

Ivan Li, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 917-6437; fax (425) 917-6590.

End Further Info End Preamble Start Supplemental Information

SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to submit any written relevant data, views, or arguments regarding this proposed AD. Send your comments to an address listed under ADDRESSES. Include “Docket No. FAA-2005-20024; Directorate Identifier 2004-NM-66-AD” in the subject line of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the proposed AD. We will consider all comments submitted by the closing date and may amend the proposed AD in light of those comments.

We will post all comments we receive, without change, to http://dms.dot.gov, including any personal information you provide. We will also post a report summarizing each substantive verbal contact with FAA personnel concerning this proposed AD. Using the search function of that website, anyone can find and read the Start Printed Page 2827comments in any of our dockets, including the name of the individual who sent the comment (or signed the comment on behalf of an association, business, labor union, etc.). You can review DOT's complete Privacy Act Statement in the Federal Register published on April 11, 2000 (65 FR 19477-78), or you can visit http://dms.dot.gov.

Examining the Docket

You can examine the AD docket on the Internet at http://dms.dot.gov, or in person at the Docket Management Facility office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Management Facility office (telephone (800) 647-5227) is on the plaza level of the Nassif Building at the DOT street address stated in the ADDRESSES section. Comments will be available in the AD docket shortly after the DMS receives them.

Discussion

We have received reports indicating that fatigue cracking was found in the inboard flange above the flight deck floor on the C-3 frame upper closure fittings of the nose cargo door on Boeing Model 747-200F series airplanes. The affected airplanes had accumulated approximately 20,000 to 23,500 total flight cycles. While cracks have been found previously in the C-3 frame upper closure fittings, these reports were of cracks in the inboard flange of a fitting. This condition, if not corrected, could result in the cracks extending, which could result in rapid depressurization of the airplane.

The C-3 frame upper closure fittings of the nose cargo door on Model 747-200C series airplanes are identical to those on Model 747-200F series airplanes. Therefore, these airplanes may be subject to the same unsafe condition.

Relevant Service Information

We have reviewed Boeing Alert Service Bulletin 747-53A2495, dated December 18, 2003. The service bulletin describes procedures for performing a detailed visual inspection for cracking of the C-3 frame upper closure fittings, including the flight deck floor tang, and corrective actions if necessary. The corrective actions include repairing, or replacing the fitting with a new fitting. The service bulletin describes procedures for repairs; however, if you find cracking that is outside certain limits, the service bulletin recommends that you contact Boeing for instructions for repairing the upper closure fitting, or replacing it with a new fitting. The compliance times for the initial inspection vary depending on the number of flight cycles that the airplane has accumulated as of the date of the initial release of the service bulletin (December 18, 2003), and whether certain modifications have been accomplished. Accomplishing the actions specified in the service information is intended to adequately address the unsafe condition.

The service bulletin also describes procedures for modifying the upper closure fittings. This modification involves doing an open-hole high frequency eddy current (HFEC) inspection for cracking of certain fastener holes, repairing if necessary, cold-working uncracked fastener holes, and installing new fasteners. If you do this modification, you do not need to continue inspecting the upper part of the closure fitting, though you must continue to inspect the flight deck floor tang.

Other Relevant Rulemaking

We previously issued AD 91-11-01, amendment 39-6997 (56 FR 22306, May 15, 1991). That AD requires repetitive inspections for cracking of the frame structure and skin in the fuselage Section 41, and repair if necessary. That AD refers to Boeing Alert Service Bulletin 747-53A2265, Revision 7, dated January 25, 1990, as the appropriate source of service information for the required actions. That AD also states that installing new, improved body frame structure in accordance with Boeing Service Bulletin 747-53-2272, dated January 12, 1987, constitutes terminating action for the required repetitive inspections for the structure replaced and other adjacent structure.

Explanation of Compliance Times

Paragraph (f) of this proposed AD refers to Boeing Alert Service Bulletin 747-53A2495, Figure 1 (for Group 1 and 2 airplanes) or Figure 2 (for Group 3 and 4 airplanes), as applicable, as the source for the compliance time for the initial inspection required by that paragraph (except as discussed under “Differences Between the Proposed AD and Service Bulletin”). For airplanes in Groups 1 and 2 in Boeing Alert Service Bulletin 747-53A2495, the compliance threshold for the initial inspection is based on whether the Zone 7 modification in accordance with Boeing Service Bulletin 747-53-2272 (the optional terminating action provided by AD 91-11-01) has been accomplished. If that modification has not been accomplished, the service bulletin specifies that the inspection in Boeing Alert Service Bulletin 747-53A2495 must be accomplished at the same time as the next scheduled inspection in accordance with Boeing Alert Service Bulletin 747-53A2265 (which is currently required by AD 91-11-01). If the Zone 7 modification in accordance with Boeing Service Bulletin 747-53-2272 has been accomplished, the service bulletin specifies a compliance threshold of 3,000 flight cycles after the Zone 7 modification was installed. If the applicable threshold has passed, the service bulletin provides a grace period ranging from 250 to 1,000 flight cycles after the initial release of Boeing Alert Service Bulletin 747-53A2495, depending on the number of flight cycles the airplane has accumulated as of the initial release of that service bulletin.

For airplanes in Groups 3 and 4, the service bulletin specifies a compliance time of prior to the accumulation of 16,000 total flight cycles, or within 1,000 flight cycles after the initial release of Boeing Alert Service Bulletin 747-53A2495, whichever is later.

FAA's Determination and Requirements of the Proposed AD

We have evaluated all pertinent information and identified an unsafe condition that is likely to exist or develop on other airplanes of this same type design. Therefore, we are proposing this AD, which would require the actions in Boeing Alert Service Bulletin 747-53A2495, described previously, except as discussed under “Differences Between the Proposed AD and Service Bulletin.”

Differences Between the Proposed AD and Service Bulletin

Boeing Alert Service Bulletin 747-53A2495 specifies that you may contact the manufacturer for instructions on how to replace or repair any cracked upper closure fitting, but this proposed AD would require you to replace or repair any cracked upper closure fitting in one of the following ways:

  • Using a method that we approve; or
  • Using data that meet the certification basis of the airplane that have been approved by an Authorized Representative for the Boeing Delegation Option Authorization Organization who has been authorized by the FAA to make those findings.

Where Boeing Alert Service Bulletin 747-53A2495 specifies compliance times relative to the date of the initial release of the service bulletin, this proposed AD would require compliance relative to the effective date of the AD.

Boeing Alert Service Bulletin 747-53A2495 provides the following information in Note 4 of the Start Printed Page 2828Accomplishment Instructions: “For the purposes of this service bulletin, do not count flight-cycles with a cabin pressure differential of 2.0 [pounds per square inch (psi)] or less. However, any flight-cycle with momentary spikes in cabin pressure differential above 2.0 psi must be included as a full-pressure flight-cycle. Cabin pressure records must be maintained for each airplane. Fleet averaging of cabin pressure is not allowed.” We have determined that an adjustment of flight cycles due to a lower cabin differential pressure is not substantiated and will not be allowed for use in determining the flight cycle threshold for this proposed AD.

Clarification of Inspection Terminology

In this proposed AD, the “detailed visual inspection” specified in Boeing Alert Service Bulletin 747-53A2495 is referred to as a “detailed inspection.” We have included the definition for a detailed inspection in a note in the proposed AD.

Costs of Compliance

This proposed AD would affect about 78 airplanes worldwide. The following table provides the estimated costs for U.S. operators to comply with this proposed AD.

Estimated Costs

ActionWork hoursAverage labor rate per hourPartsCost per airplaneNumber of U.S.-registered airplanesFleet cost
Inspection2$65None$130, per inspection cycle20$2,600, per inspection cycle.

Authority for this Rulemaking

Title 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, Section 106, describes the authority of the FAA Administrator. Subtitle VII, Aviation Programs, describes in more detail the scope of the Agency's authority.

We are issuing this rulemaking under the authority described in Subtitle VII, Part A, Subpart III, Section 44701, “General requirements.” Under that section, Congress charges the FAA with promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this rulemaking action.

Regulatory Findings

We have determined that this proposed AD would not have federalism implications under Executive Order 13132. This proposed AD 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.

For the reasons discussed above, I certify that the 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. 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.

We prepared a regulatory evaluation of the estimated costs to comply with this proposed AD. See the ADDRESSES section for a location to examine the regulatory evaluation.

Start List of Subjects

List of Subjects in 14 CFR Part 39

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The Proposed Amendment

Accordingly, under the authority delegated to me by the Administrator, the FAA proposes to amend 14 CFR part 39 as follows:

Start Part

PART 39—AIRWORTHINESS DIRECTIVES

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

Start Authority

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

End Authority
[Amended]

2. The FAA amends § 39.13 by adding the following new airworthiness directive (AD):

Boeing: Docket No. FAA-2005-20024; Directorate Identifier 2004-NM-66-AD.

Comments Due Date

(a) The Federal Aviation Administration (FAA) must receive comments on this AD action by March 4, 2005.

Affected ADs

(b) None.

Applicability

(c) This AD applies to all Boeing Model 747-200C and 747-200F series airplanes, certificated in any category.

Unsafe Condition

(d) This AD was prompted by a report that a fatigue crack was found in the inboard flange of the left C-3 frame upper closure fitting above the flight deck floor. We are issuing this AD to detect and correct cracking of the C-3 frame upper closure fittings, which could extend and result in rapid depressurization of the airplane.

Compliance

(e) You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done.

Repetitive Inspections

(f) Do a detailed inspection of the left and right C-3 frame upper closure fittings of the nose cargo door, including the flight deck floor tang, according to the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2495, dated December 18, 2003. Do the initial inspection at the applicable compliance time specified in Figure 1 (Group 1 and 2 airplanes) or 2 (Group 3 and 4 airplanes) of the service bulletin, as applicable; except, where the service bulletin specifies a compliance time relative to the date of the initial release of the service bulletin, this AD requires compliance relative to the effective date of this AD. Repeat the inspection thereafter at intervals not to exceed 3,000 flight cycles, except as provided by paragraph (h) of this AD.

Note 1:

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

Repair/Replacement

(g) If any cracking is found during any inspection required by this AD: Before further flight, do applicable repairs or replace the fitting with a new fitting, according to the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2495, dated December 18, 2003; except, where the bulletin specifies to contact Boeing for appropriate action, before further flight, repair in accordance with a method approved Start Printed Page 2829by the Manager, Seattle Aircraft Certification Office (ACO), FAA; or in accordance with data meeting the certification basis of the airplane approved by an Authorized Representative for the Boeing Delegation Option Authorization Organization who the Manager, Seattle ACO, has authorized to make this finding. For a repair method to be approved by the Manager, Seattle ACO, as required by this paragraph, the Manager's approval letter must specifically reference this AD.

Optional Modification

(h) Doing all actions associated with the modification of the upper closure fitting, including performing an open-hole high frequency eddy current inspection for cracking of certain fastener holes and all applicable corrective actions; according to Figure 4 of the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2495, dated December 18, 2003; terminates the repetitive inspections of the upper part of the upper closure fitting required by paragraph (f) of this AD. However, inspections of the flight deck floor tang must continue, as required by paragraph (f) of this AD.

Note 2:

There is no terminating action available at this time for the inspections of the flight deck floor tang required by paragraph (f) of this AD.

No Threshold Adjustment

(i) While Note 4 of the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2495, dated December 18, 2003, provides for adjusting the flight cycle threshold specified in the service bulletin by not counting flight cycles with a cabin pressure differential of 2.0 pounds per square inch or less, this AD does not allow this adjustment.

Alternative Methods of Compliance (AMOCs)

(j)(1) The Manager, Seattle ACO, has the authority to approve AMOCs for this AD, if requested in accordance with the procedures found in 14 CFR 39.19.

(2) An AMOC that provides an acceptable level of safety may be used for any repair required by this AD, if it is approved by an Authorized Representative for the Boeing Delegation Option Authorization Organization who has been authorized by the Manager, Seattle ACO, to make those findings. For a repair method to be approved, the repair must meet the certification basis of the airplane and the approval must specifically refer to this AD.

Start Signature

Issued in Renton, Washington, on January 7, 2005.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.

End Signature End Part End Supplemental Information

[FR Doc. 05-900 Filed 1-14-05; 8:45 am]

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