[Federal Register Volume 66, Number 115 (Thursday, June 14, 2001)]
[Proposed Rules]
[Pages 32276-32279]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 01-14940]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-NM-90-AD]
RIN 2120-AA64


Airworthiness Directives; McDonnell Douglas Model DC-9 Series 
Airplanes and Model MD-88 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 McDonnell Douglas Model DC-9 
series airplanes and C-9 airplanes, that would have required 
modification of the electrical power center and modification and 
overhaul of certain alternating current power relays. That proposal was 
prompted by reports indicating that the alternating current (AC) cross-
tie relay shorted out internally, which caused severe smoke and burn 
damage to the relay, aircraft wiring, and adjacent panels. This new 
action revises the proposed rule by expanding the applicability to 
include additional airplanes; removing certain requirements; and 
revising certain requirements and service information. The actions 
specified by this new proposed AD are intended to prevent a short in 
the cross-tie relay, which may result in in-flight electrical fires.

DATES: Comments must be received by July 9, 2001.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 99-NM-90-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: [email protected]. Comments sent via fax or the Internet must contain

[[Page 32277]]

``Docket No. 99-NM-90-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 Aircraft Group, Long Beach Division, 
3855 Lakewood Boulevard, Long Beach, California 90846, Attention: Data 
and Service Management, Dept. C1-L5A (0800-0024); or Hamilton 
Sundstrand, Technical Publications, Mail Stop 302-9, Harrison Avenue, 
P.O. Box 7002, Rockford, IL 61125-7002. This information may be 
examined at the FAA, 1601 Lind Avenue, SW., Renton, Washington; or at 
the FAA, Los Angeles Aircraft Certification Office, 3960 Paramount 
Boulevard, Lakewood, California.

FOR FURTHER INFORMATION CONTACT: Elvin Wheeler, Aerospace Engineer, 
Systems and Equipment Branch, ANM-130L, FAA, Los Angeles Aircraft 
Certification Office, 3960 Paramount Boulevard, Lakewood, California 
90712-4137; telephone (562) 627-5344; fax (562) 627-5210.

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.
    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 99-NM-90-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-90-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 McDonnell Douglas Model DC-9 series airplanes and C-9 
airplanes, was published as a notice of proposed rulemaking (NPRM) in 
the Federal Register on August 30, 1999 (64 FR 47149). That NPRM would 
have required modification of the electrical power center and 
modification and overhaul of certain alternating current (AC) power 
relays. That NPRM was prompted by reports indicating that the AC cross-
tie relay shorted out internally, which caused severe smoke and burn 
damage to the relay, aircraft wiring, and adjacent panels. That 
condition, if not corrected, may result in in-flight electrical fires.

Comments

    Due consideration has been given to the comments received in 
response to the NPRM.

Support for the NPRM

    Two commenters support the NPRM.

Existing AD With Same Requirements

    Two commenters request that the modification requirements of 
paragraph (a) of the NPRM supersede those of AD 89-07-08, amendment 39-
6177 (54 FR 12589, March 28, 1989). One of the commenters also requests 
that a statement, ``unless previously accomplished,'' be added to 
paragraph (a) of the NPRM. The commenters state that the proposed 
modification duplicates the requirements of AD 89-07-08. One commenter 
states that the NPRM expands the effectivity of AD 89-07-08 to include 
airplane fuselage numbers up through 972.
    The FAA partially agrees. The commenters are correct that the 
modification (reference McDonnell Douglas DC-9 Service Bulletin 24-57, 
Revision 1, dated March 12, 1980) required by paragraph (a) of the NPRM 
is already required by AD 89-07-08. The commenter is incorrect that the 
effectivity of AD 89-07-08 was expanded in the NPRM; no additional 
airplane fuselage numbers were added. For these reasons, the FAA finds 
that the modification requirements of paragraph (a) of the NPRM are not 
necessary. We have deleted those requirements in the supplemental NPRM.

Wording of Unsafe Condition

    One commenter requests that the term ``cross-tie relay'' specified 
in the unsafe condition of the NPRM be revised to ``AC power relay.'' 
The commenter states that the unsafe condition should not single out 
one position of the affected AC power relays if the NPRM affects relays 
installed in any position (i.e., cross-tie relays, generator relays, 
auxiliary power relays, and external power relays) as indicated in 
paragraph (a)(1) of the NPRM.
    The FAA does not agree. In paragraph (a)(1) of the NPRM, the relay 
positions identified in the parenthetic are for clarification to 
identify the installed position of the relays. Most of the failures 
have occurred on the AC power relays installed in the cross-tie 
position. The six other relays (two each) at generators relays, 
auxiliary power relays, and external power relays are mounted in a 
vertical position; therefore, they are not as susceptible to the 
identified unsafe condition as the AC cross-tie relays. However, for 
interchangeability convenience, these six relays are modified to the P/
N 914F567-4 configuration.

Incorrect Reference to Service Information

    One commenter requests that the phrase ``in accordance with'' in 
paragraph (a)(2) of the NPRM be deleted. Paragraph (a)(2) of the NPRM 
reads, ``[r]eplace the Westinghouse alternating current power relays, 
P/N 914F567-3 or -4 with improved relays, P/N 9008D09 series, in 
accordance with McDonnell Douglas DC-9 Service Bulletin DC9-24-156, 
dated March 31, 1995.'' The commenter states Service Bulletin DC9-24-
156 recommends modifying the AC power relays per Sundstrand Aerospace 
Service Bulletin AVB79-24-2; however, the Sundstrand service bulletin 
only describes procedures for modification of AC power relays, part 
number (P/N)

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9008D09 series. The commenter also states that neither service bulletin 
addresses the modification or replacement of AC power relays, P/N 
914F567-3 or -4.
    The FAA agrees that neither McDonnell Douglas DC-9 Service Bulletin 
DC9-24-156, dated March 31, 1995, nor Sundstrand Aerospace Service 
Bulletin AVB79-24-2 describes procedures for doing the replacement 
required by paragraph (a)(2) of the NPRM. The correct source of service 
information for the required replacement is Chapter 24 of Boeing DC-9 
or MD-80 Airplane Maintenance Manual (AMM), as applicable. In addition, 
we find that this replacement alone addresses the identified unsafe 
condition, and thus, the modification required by paragraph (a)(1) of 
the NPRM (reference Westinghouse Aerospace Service Bulletin 75-703, 
dated June 1977) is not necessary. We have revised paragraph (a) of the 
supplemental NPRM accordingly.
    One commenter requests that the overhaul required by paragraph (b) 
of the NPRM be required per the applicable original equipment 
manufacturer overhaul maintenance manual (OMM). The commenter states 
that Westinghouse Service Bulletin 76-703, dated June 1977 (which was 
referenced in paragraph (b) of the NPRM as the appropriate source of 
service information), describes procedures for modification of AC power 
relays, P/Ns 914F567-3 and -4, but does not include overhaul 
instructions for AC power relays, P/N 9008D09 series.
    The FAA agrees. For Sundstrand (Westinghouse) AC power relays, P/N 
914F567-4, overhaul procedures are described in Chapter 24-20-46 of 
Westinghouse Overhaul Manual. For Sundstrand (Westinghouse) AC power 
relays, P/N 9008D09 series, overhaul procedures are described in 
Hamilton Sundstrand Component Maintenance Manual 24-20-87. We have 
revised paragraph (b) and added a new paragraph (c) of the supplemental 
NPRM accordingly.

Compliance Time of Overhaul

    Two commenters request that the compliance time specified in 
paragraphs (b)(1) and (b)(2) of the NPRM be revised. The commenters 
note the compliance times specified in those paragraphs do not take 
into consideration AC power relays that have been previously modified, 
installed as modified AC power relays, or exceeded the proposed 
overhaul limit. One commenter suggests to initially require the 
overhaul within 5,000 hours (or 4 years) after the effective date of 
the AD, or within 7,000 or 12,000 hours from the last overhaul or 
modification per paragraph (a) of the AD. The second commenter suggests 
that, for AC power relays previously installed, a compliance time of 
``prior to the accumulation of 7000 hours or 12000 hours (respectively) 
time since new or time since last overhaul and repeat at intervals not 
to exceed 7000 hours or 12000 hours (respectively).''
    The FAA agrees with the commenters that AC power relays modified or 
installed before the effective date of this AD can be overhauled within 
7,000 or 12,000 flight hours (respectively) after that modification or 
installation, or within 30 days after the effective date of this AD, 
whichever occurs later. We have revised paragraphs (b) and (c) 
(previously designated as (b)(1) and (b)(2) in the NPRM, respectively) 
of the supplemental NPRM accordingly. In addition, we have added a new 
paragraph (d) to the supplemental NPRM to allow airplanes on which the 
flight hours since modification or installation of the AC power relay 
cannot be determined, to overhaul within 30 days after the effective 
date of this AD.
    One commenter requests that the FAA require a life limit of 6,000 
flight hours on the affected AC power relays. The commenter believes 
that such a life limit would maintain an adequate level of safety for 
the affected fleet. The commenter states that it has deep concerns 
about the necessity of the NPRM. The commenter also states that ``The 
[overhaul] costs to industry would be overwhelming and the profit to 
Sundstrand would be tremendous.''
    The FAA does not agree. We find that the replacement and repetitive 
overhauls required by this supplemental NPRM adequately address the 
identified unsafe condition. In addition, we find that the compliance 
times for completing the proposed actions to be warranted, in that it 
represents an appropriate interval of time allowable for affected 
airplanes to continue to operate without compromising safety. No change 
to the supplemental NPRM is necessary with regards to this point.

Explanation of Change to Applicability Statement and Cost Impact

    The Westinghouse AC power relays on certain McDonnell Douglas Model 
DC-9-81, -82, -83, and -87 series airplanes, and Model MD-88 airplanes 
are identical to those on the affected Model DC-9 series airplanes and 
C-9 airplanes listed in the applicability of the original NPRM, and 
thus, may be subject to the identified unsafe condition of this 
supplemental NPRM. Therefore, the FAA has revised the applicability 
statement of the supplemental NPRM to include these additional 
airplanes. In addition, we have added the phrase ``equipped with 
Westinghouse alternating current power relays, part number (P/N) 
914F567-3'' to exclude airplanes that have other relays. Furthermore, 
since ``Model DC-9 series airplanes'' includes Model C-9 airplanes, we 
have determined that listing Model C-9 airplanes in the applicability 
of this AD is not necessary. Therefore, we have removed any reference 
to ``Model C-9 airplanes'' from the supplemental NPRM.
    Based on the changes described above, the FAA has revised the Cost 
Impact section of the supplemental NPRM accordingly.

Conclusion

    Since these changes expand 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 1,150 McDonnell Douglas Model DC-9 series 
airplanes and Model MD-88 airplanes of the affected design in the 
worldwide fleet. The FAA estimates that 690 airplanes of U.S. registry 
would be affected by this proposed AD.
    It would take approximately 20 work hours per relay (7 relays per 
airplane) to accomplish the proposed replacement, at an average labor 
rate of $60 per work hour. Required parts would cost approximately 
$1,965 per relay. Based on these figures, the cost impact of the 
replacement proposed by this AD on U.S. operators is estimated to be 
$15,286,950, or $22,155 per airplane.
    It would take approximately 56 work hours per relay (7 relays per 
airplane) to accomplish the proposed overhaul, at an average labor rate 
of $60 per work hour. Required parts would cost approximately $1,965 
per relay. Based on these figures, the cost impact of the overhaul 
proposed by this AD on U.S. operators is estimated to be $25,719,750, 
or $37,275, per airplane, per overhaul 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

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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.


Sec. 39.13  [Amended]

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

McDonnell Douglas: Docket 99-NM-90-AD.
    Applicability: Model DC-9 series airplanes and Model MD-88 
airplanes, equipped with Westinghouse alternating current (AC) power 
relays, part number (P/N) 914F567-3; 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 (e) 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 a short in the cross-tie relay, which may result in 
in-flight electrical fires, accomplish the following:

Replacement

    (a) Within 12 months after the effective date of this AD, 
replace the Westinghouse AC power relays, P/N 914F567-3 (i.e., 
cross-tie relays, generator relays, auxiliary power relays, and 
external power relays), to a -4 configuration or with a Sundstrand 
(Westinghouse) relay, P/N 9008D09 series, per Chapter 24 of Boeing 
DC-9 or MD-80 Airplane Maintenance Manual (AMM), as applicable.

Repetitive Overhauls

    (b) For airplanes equipped with Sundstrand (Westinghouse) relay, 
P/N 914F567-4: Overhaul the relay per Chapter 24-20-46 of 
Westinghouse Overhaul Manual at the applicable time specified in 
paragraph (b)(1) or (b)(2) of this AD. Repeat the overhaul every 
7,000 flight hours.
    (1) For AC power relays replaced per paragraph (a) of this AD: 
Overhaul within 7,000 flight hours after accomplishing that 
replacement.
    (2) For AC power relays modified or installed before the 
effective date of this AD: Overhaul within 7,000 flight hours after 
that modification or installation, or within 30 days after the 
effective date of this AD, whichever occurs later, except as 
provided by paragraph (d) of this AD.
    (c) For airplanes equipped with Sundstrand (Westinghouse) relay, 
P/N 9008D09 series: Overhaul the relay per Hamilton Sundstrand 
Component Maintenance Manual 24-20-87 at the applicable time 
specified in paragraph (c)(1) or (c)(2) of this AD. Repeat the 
overhaul every 12,000 flight hours.
    (1) For AC power relays replaced per paragraph (a) of this AD: 
Overhaul within 12,000 flight hours after accomplishing that 
replacement.
    (2) For AC power relays modified or installed before the 
effective date of this AD: Overhaul within 12,000 flight hours after 
that modification or installation, or within 30 days after the 
effective date of this AD, whichever occurs later, except as 
provided by paragraph (d) of this AD.
    (d) For airplanes on which the flight hours since modification 
or installation of the AC power relay cannot be determined: Overhaul 
within 30 days after the effective date of this AD. Repeat the 
overhaul at the times indicated in paragraph (b) or (c) of this AD, 
as applicable.

Alternative Methods of Compliance

    (e) 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, Los Angeles Aircraft Certification 
Office (ACO), FAA. Operators shall submit their requests through an 
appropriate FAA Principal Maintenance Inspector, who may add 
comments and then send it to the Manager, Los Angeles ACO.

    Note 2: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Los Angeles ACO.

Special Flight Permits

    (f) 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 June 7, 2001.
Donald L. Riggin,
Acting Manager,, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 01-14940 Filed 6-13-01; 8:45 am]
BILLING CODE 4910-13-U