[Federal Register Volume 63, Number 91 (Tuesday, May 12, 1998)]
[Proposed Rules]
[Pages 26100-26102]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-12520]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 96-NM-171-AD]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 747-400, -400D, and -400F 
Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Supplemental notice of proposed rulemaking; reopening of 
comment period.

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SUMMARY: This document revises an earlier proposed airworthiness 
directive (AD), applicable to certain Boeing Model 747-400, -400D, and 
-400F series airplanes, that would have required modification of the 
P212 and P213 panels of the cabin pressure control system. That 
proposal was prompted by a report of in-flight loss of cabin 
pressurization control due to a single failure of the auxiliary power 
unit (APU) battery. This action revises the proposed rule by adding new 
requirements, for certain airplanes, to modify the P5, P6, and P7 
panels, and the W4701, W4703, and W4908 wire bundles, as applicable. 
The actions specified by this proposed AD are intended to prevent loss 
of control of the cabin pressurization system, which could result in 
rapid depressurization of the airplane. Such rapid depressurization 
could result in deleterious physiological effects on the passengers and 
crew; and airplane diversions, which represent an increased risk to the 
airplane, passengers, and crew.

DATES: Comments must be received by June 8, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 96-NM-171-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: Clayton R. Morris, Jr., Aerospace 
Engineer, Systems and Equipment Branch, ANM-130S, FAA, Seattle Aircraft 
Certification Office, 1601 Lind Avenue, SW., Renton, Washington; 
telephone (425) 227-2794; 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 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

[[Page 26101]]

statement is made: ``Comments to Docket Number 96-NM-171-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. 96-NM-171-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    A proposal to amend part 39 of the Federal Aviation Regulations (14 
CFR part 39) to add an airworthiness directive (AD), applicable to 
certain Boeing Model 747-400, -400D, and -400F series airplanes, was 
published as a notice of proposed rulemaking (NPRM) in the Federal 
Register on April 1, 1997 (62 FR 15433). That NPRM would have required 
modification of the P212 and P213 panels of the cabin pressure control 
system. That NPRM was prompted by a report of in-flight loss of cabin 
pressurization control due to a single failure of the auxiliary power 
unit (APU) battery. That condition, if not corrected, could result in 
rapid depressurization of the airplane. Such rapid depressurization 
could result in deleterious physiological effects on the passengers and 
crew; and airplane diversions, which represent an increased risk to the 
airplane, passengers, and crew.

Actions Since Issuance of Previous Proposal

    Since the issuance of that NPRM, the FAA has given due 
consideration to the comments received in response to the NPRM. One 
comment and the information it provides has led the FAA to consider 
making a significant change to the proposal. The comment and the 
changes prompted by it are explained below.

Request to Include Actions Specified in Additional Service Bulletin

    One commenter (the manufacturer) requests that the FAA revise the 
proposed AD to additionally require accomplishment of the actions 
specified in Boeing Service Bulletin 747-24-2193, dated January 25, 
1995; as revised by Notices of Status Change (NSC) 747-24-2193 NSC 1, 
dated April 13, 1995, 747-24-2193 NSC 2, dated October 5, 1995, 747-24-
2193 NSC 3, dated November 22, 1995, 747-24-2193 NSC 4, dated December 
21, 1995, 747-24-2193 NSC 5, dated May 2, 1996, and 747-24-2193 NSC 6, 
dated March 13, 1997; or Alert Service Bulletin 747-24A2193, Revision 
1, dated June 19, 1997.
    The FAA concurs with the commenter's request to add the actions 
described in the service bulletins to the requirements of the 
originally proposed AD. Since issuance of the NPRM, the FAA has 
reviewed and approved these service bulletins, which describe 
procedures for modification of the wiring of the P5, P6, and P7 panels, 
and modification of the wiring in the W4701 and W4908 wire bundles; 
installation of diodes in the P6 panel; and, for certain airplanes, 
modification of the wiring in the W4703 wire bundles. Accomplishment of 
the actions described in the service bulletins would provide backup 
power for the control and indication of the cabin pressurization system 
in the event of a single-source failure of the main battery bus.
    The FAA finds that accomplishment of the actions specified in 
Service Bulletin 747-24-2193 (including notices of status change), 
Alert Service Bulletin 747-24A2193, and Alert Service Bulletin 747-
21A2381 (the appropriate source of service information for 
accomplishment of the actions specified in the originally proposed AD) 
would adequately address the identified unsafe condition by providing 
an additional power source in the event of loss of the primary power 
source. Therefore, the FAA has revised the proposed AD to add the 
actions specified in Boeing Service Bulletin 747-24-2193 or Alert 
Service Bulletin 747-24A2193.

Conclusion

    Since this change expands the scope of the originally proposed 
rule, the FAA has determined that it is necessary to reopen the comment 
period to provide additional opportunity for public comment.

Cost Impact

    There are approximately 351 airplanes of the affected design in the 
worldwide fleet.
    The FAA estimates that 43 airplanes of U.S. registry would be 
affected by this proposed AD. For all airplanes, it would take 
approximately 8 work hours per airplane to accomplish the proposed 
modification of the P212 and P213 panels, at an average labor rate of 
$60 per work hour. Required parts would cost approximately $389 per 
airplane. Based on these figures, the cost impact of this modification 
proposed by this AD on U.S. operators is estimated to be $37,367, or 
$869 per airplane.
    For certain airplanes, it would take approximately 47 work hours 
per airplane to accomplish the proposed modification of the P5, P6, and 
P7 panels, and the W4701, W4703, and W4908 wire bundles, at an average 
labor rate of $60 per work hour. Required parts would cost 
approximately $1,529 per airplane. Based on these figures, the cost 
impact of this modification proposed by this AD on U.S. operators is 
estimated to be $4,349 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.


[[Page 26102]]




Sec. 39.13  [Amended]

    2. Section 39.13 is amended by adding the following new 
airworthiness directive:
Boeing: Docket 96-NM-171-AD.

    Applicability: Model 747-400, -400D, and -400F series airplanes; 
as identified in Boeing Alert Service Bulletin 747-21A2381, dated 
June 27, 1996; 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 (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 loss of control of the cabin pressurization system, 
which could result in rapid depressurization of the airplane and 
consequent deleterious physiological effects on the passengers and 
crew; and airplane diversions, which represent an increased risk to 
the airplane, passengers, and crew; accomplish the following:
    (a) Within 180 days after the effective date of this AD: Modify 
the P212 and P213 panels of the cabin pressure control system as 
specified in paragraph (a)(1) or (a)(2) of this AD, as applicable, 
in accordance with Boeing Alert Service Bulletin 747-21A2381, dated 
June 27, 1996.
    (1) For Groups 1 through 7 airplanes, as identified in the alert 
service bulletin: Change the wiring in the P212 and P213 panels; 
replace the existing two-pole relays with new four-pole relays; and 
perform a test of both panels.
    (2) For Group 8 airplanes, as identified in the alert service 
bulletin: Change the wiring in the P212 panel; replace the existing 
two-pole relays with new four-pole relays; replace the existing P213 
panel with a new P213 panel; and perform a test of both panels.
    (b) For airplanes having line positions 696 through 1021 
inclusive: Within 180 days after the effective date of this AD, 
accomplish paragraphs (b)(1) and (b)(2), as applicable, of this AD; 
in accordance with Boeing Service Bulletin 747-24-2193, dated 
January 25, 1995; as revised by Notices of Status Change (NSC) 747-
24-2193 NSC 1, dated April 13, 1995, 747-24-2193 NSC 2, dated 
October 5, 1995, 747-24-2193 NSC 3, dated November 22, 1995, 747-24-
2193 NSC 4, dated December 21, 1995, 747-24-2193 NSC 5, dated May 2, 
1996, and 747-24-2193 NSC 6, dated March 13, 1997; or Alert Service 
Bulletin 747-24A2193, Revision 1, dated June 19, 1997.
    (1) For all airplanes: Modify the wiring of the P5, P6, and P7 
panels; modify the wiring in the W4701 and W4908 wire bundles; and 
install diodes in the P6 panel.
    (2) For Groups 1 and 2 airplanes identified in paragraph I. of 
the Accomplishment Instructions of the service bulletin or alert 
service bulletin: Modify the wiring in the W4703 wire bundle.
    (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 Aircraft Certification 
Office (ACO), FAA, Transport Airplane Directorate. 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 2: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Seattle ACO.

    (d) 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 May 5, 1998.
D. L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 98-12520 Filed 5-11-98; 8:45 am]
BILLING CODE 4910-13-U