[Federal Register Volume 64, Number 86 (Wednesday, May 5, 1999)]
[Proposed Rules]
[Pages 24092-24094]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-11225]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-NM-41-AD]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 747 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the adoption of a new airworthiness 
directive (AD) that is applicable to certain Boeing Model 747 series 
airplanes. This proposal would require a one-time inspection to 
determine whether latch pins on the lower lobe and main deck side cargo 
doors are installed backward, and corrective actions, if necessary. For 
certain airplanes, this proposal also would require eventual 
modification of the latch pin fittings on certain cargo doors. This 
proposal is prompted by reports that latch pins have been found 
installed backward on the cargo doors of several airplanes. The actions 
specified by the proposed AD are intended to prevent improper latching 
of latch pins and the mating latch cam on the cargo door, which could 
result in damage to the structure of the cargo door and doorway cutout 
and consequent opening of the cargo door during flight.

DATES: Comments must be received by June 21, 1999.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 99-NM-41-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.
    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: Julie Alger, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Transport Airplane Directorate, Seattle 
Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, 
Washington 98055-4056; telephone (425) 227-2779; fax (425) 227-1181.

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 notice may be changed in 
light of the comments received.
    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

[[Page 24093]]

proposal will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this notice must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 99-NM-41-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. 99-NM-41-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The FAA has received reports indicating that latch pins have been 
found installed backward on the forward and aft lower lobe cargo doors 
of Boeing Model 747 series airplanes. One operator found one latch pin 
installed backward, and another operator found three of eight latch 
pins installed backward. In the reported cases, the backward pins have 
all been found on the lower lobe cargo doors, though similar pins are 
installed on the main deck side cargo door on airplanes equipped with 
such a door. Investigation has revealed that latch pins that are 
removed during maintenance activities can be installed backward such 
that the pins extend from the wrong end of the latch pin fitting. 
Backward installation of the latch pins results in improper latching of 
the pins and the mating latch cam on the cargo door. Such improper 
latching increases load on the adjacent latch pins and fittings, latch 
cams, and support structure, which could lead to damage to the 
structure of the cargo door and doorway cutout. This condition, if not 
corrected, could result in the cargo door opening during flight.

Explanation of Relevant Service Infomation

    The FAA has reviewed and approved Boeing Alert Service Bulletin 
747-52A2258, dated June 1, 1995; as revised by Notices of Status Change 
747-52A2258 NSC 1, dated July 20, 1995; 747-52A2258 NSC 2, dated August 
31, 1995; and 747-52A2258 NSC 03, dated December 14, 1995. That alert 
service bulletin describes procedures for a one-time visual inspection 
to determine whether latch pins on the forward and aft lower lobe cargo 
doors and the main deck side cargo door are installed correctly, and 
corrective actions, if necessary. The corrective actions include 
reinstalling the pin correctly, and inspecting the affected cargo door 
and doorway cutout to detect damage. If any latch pins are found 
installed backward, the alert service bulletin specifies to contact 
Boeing for structural inspection procedures.
    The FAA also has reviewed and approved Boeing Service Bulletin 747-
52-2260, Revision 1, dated March 21, 1996, which describes procedures 
for modification of the latch pin fittings on the forward and aft lower 
lobe cargo doors. The modification will prevent backward installation 
of the latch pins. Accomplishment of the actions specified in the alert 
service bulletin and 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 require accomplishment of the actions specified in 
the alert service bulletin and service bulletin described previously, 
except as discussed below.

Differences Between Alert Service Bulletin and This Proposed AD

    Operators should note that, although Boeing Alert Service Bulletin 
747-52A2258 specifies that the manufacturer may be contacted for 
instructions for structural inspections, this AD would require such 
inspections to be accomplished in accordance with a method approved by 
the FAA.

Cost Impact

    There are approximately 990 airplanes of the affected design in the 
worldwide fleet. The FAA estimates that 235 airplanes of U.S. registry 
would be affected by the proposed AD.
    It would take approximately 2 work hours per to accomplish the 
proposed inspection, at the average labor rate of $60 per work hour. 
Based on these figures, the cost impact of the proposed AD on U.S. 
operators is estimated to be $28,200, or 120 per airplane.
    It would be approximately 3 work hours per airplane to accomplish 
the proposed modification, at the average labor rate $60 per work hour. 
Required parts would cost approximately $2,045 per airplane. Based on 
their figures, the cost impact of the proposed AD on U.S. operators is 
estimated to be $522,875, or $2,225 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 AD were not adopted.

Regulatory Impact

    The regulations proposed herein would not have substantial direct 
effects 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, in 
accordance with Executive Order 12612, it is determined that this 
proposal would not have sufficient federalism implications to warrant 
the preparation of a Federalism Assessment.
    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.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by adding the following new 
airworthiness directive:

Boeing: Docket 99-NM-41-AD.

    Applicability: Model 747 series airplanes, line positions 1 
through 1079 inclusive, 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

[[Page 24094]]

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 prevent improper latching of latch pins and the mating latch 
cam on the cargo door, which could result in damage to the structure 
of the cargo door and doorway cutout and consequent opening of the 
cargo door during flight, accomplish the following:

Inspection and Corrective Actions

    (a) Within 30 days after the effective date of this AD, perform 
a one-time visual inspection to determine whether latch pins on the 
forward and aft lower lobe cargo doors and the main deck side cargo 
door are installed backward, in accordance with Boeing Alert Service 
Bulletin 747-52A2258, dated June 1, 1995; as revised by Notices of 
Status Change 747-52A2258 NSC 1, dated July 20, 1995; 747-52A2258 
NSC 2, dated August 31, 1995; and 747-52A2258 NSC 03, dated December 
14, 1995. If any latch pin is found installed incorrectly, prior to 
further flight, accomplish the requirements of paragraphs (a)(1) and 
(a)(2) of this AD.
    (1) Reinstall the affected latch pin correctly, in accordance 
with the alert service bulletin.
    (2) Perform structural inspections to detect damage of the 
affected cargo door and doorway cutout, in accordance with a method 
approved by the Manager, Seattle Aircraft Certification Office 
(ACO), FAA, Transport Airplane Directorate.

Modification

    (b) For airplanes having line positions 1 through 1078 
inclusive: Within 2 years after the effective date of this AD, 
modify the latch pin fittings of the forward and aft lower lobe 
cargo doors, in accordance with Boeing Service Bulletin 747-52-2260, 
Revision 1, dated March 21, 1996.

    Note 2: Modification of the latch pin fittings accomplished 
prior to the effective date of this AD in accordance with Boeing 
Service Bulletin 747-52-2260, dated December 14, 1995, is considered 
acceptable for compliance with 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 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.

    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

    (d) Special flight permits may be issued in accordance with 
Secs. 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 28, 1999.
D.L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 99-11225 Filed 5-4-99; 8:45 am]
BILLING CODE 4910-13-U