[Federal Register Volume 65, Number 113 (Monday, June 12, 2000)]
[Proposed Rules]
[Pages 36799-36801]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-14795]


=======================================================================
-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-NM-329-AD]
RIN 2120-AA64


Airworthiness Directives; McDonnell Douglas Model MD-90-30 Series 
Airplanes

AGENCY: Federal Aviation Administration, DOT.

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

-----------------------------------------------------------------------

SUMMARY: This document revises an earlier proposed airworthiness 
directive (AD), applicable to certain McDonnell Douglas Model MD-90-30 
series airplanes, that would have required replacement of certain 
ground block screws with new screws; and retermination of the circuit 
ground wires of the electrical power control unit (EPCU) to separate 
grounding points. That proposal was prompted by reports of complete 
loss of the primary electrical power on an airplane during flight. This 
new action revises the proposed rule by expanding the applicability of 
the proposed AD to include additional airplanes. The actions specified 
by this new proposed AD are intended to prevent a loose electrical 
ground block of the circuit ground wires of the EPCU, which could 
result in complete loss of the primary electrical power of an airplane 
during flight.

DATES: Comments must be received by July 7, 2000.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 99-NM-329-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. Comments may also be sent via the Internet using the 
following address: [email protected]. Comments sent

[[Page 36800]]

via the Internet must contain ``Docket No. 99-NM-329-AD'' in the 
subject line and need not be submitted in triplicate.
    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: 
Technical Publications Business Administration, Dept. C1-L51 (2-60). 
This information may be examined at the FAA, Transport Airplane 
Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the FAA, 
Transport Airplane Directorate, Los Angeles Aircraft Certification 
Office, 3960 Paramount Boulevard, Lakewood, California.

FOR FURTHER INFORMATION CONTACT: George Mabuni, Aerospace Engineer, 
Systems and Equipment Branch, ANM-130L, FAA, Transport Airplane 
Directorate, Los Angeles Aircraft Certification Office, 3960 Paramount 
Boulevard, Lakewood, California 90712-4137; telephone (562) 627-5341; 
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 notice must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 99-NM-329-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-329-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 MD-90-30 series airplanes, was 
published as a notice of proposed rulemaking (NPRM) in the Federal 
Register on December 7, 1999 (64 FR 68302). That NPRM would have 
required replacement of certain ground block screws with new screws; 
and retermination of the circuit ground wires of the electrical power 
control unit (EPCU) to separate grounding points. That NPRM was 
prompted by reports of complete loss of the primary electrical power on 
an airplane during flight. That condition, if not corrected, could 
result in a loose electrical ground block of the circuit ground wires 
of the EPCU, which could result in complete loss of the primary 
electrical power of an airplane during flight.

Comments

    Due consideration has been given to the comment received in 
response to the NPRM:
    One commenter requests that the FAA revise paragraph (b) of the 
NPRM to reference McDonnell Douglas Service Bulletin MD90-24-062, dated 
February 3, 2000, as the appropriate source of service information for 
accomplishing the proposed retermination rather than a method approved 
by the Manager, Los Angeles Aircraft Certification Office (ACO), FAA, 
Transport Airplane Directorate. The commenter states that referencing 
the service bulletin will eliminate the requirement for the ACO to 
approve an alternative method of compliance (AMOC), and that the 
proposed retermination could be accomplished easily in accordance with 
the service bulletin.
    The FAA concurs with the commenter. Since issuance of the NPRM, the 
FAA has reviewed and approved McDonnell Douglas Service Bulletin MD90-
24-062, dated February 3, 2000. The service bulletin describes 
procedures for relocating the ground wires of the EPCU system and 
installing a new ground stud bracket. Accomplishment of this 
modification will minimize the possibility of electrical power loss of 
an airplane during flight. Therefore, the FAA has revised paragraph (b) 
of the supplemental NPRM to reference the subject service bulletin as 
the appropriate source of service information for accomplishing the 
proposed retermination. In addition, the FAA has revised the work hour 
estimate of the final rule for accomplishing the retermination to 
conicide with the estimates in the subject service bulletin.

Explanation of Changes to the Applicability of the NPRM

    The applicability statement of the NPRM referenced McDonnell 
Douglas Alert Service Bulletin MD90-24A060, Revision 01, dated 
September 2, 1999, as the appropriate source of service information for 
determining the affected airplanes. However, the FAA has revised the 
applicability statement of the supplemental NPRM to also reference 
McDonnell Douglas Service Bulletin MD90-24-062, dated February 3, 2000. 
McDonnell Douglas Service Bulletin MD90-24-062 (described above) 
includes additional airplanes that are subject to the identified unsafe 
condition of this AD. As a result of this change, the FAA also has 
revised the applicability of paragraphs (a) and (b) accordingly.

Conclusion

    Since these changes 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 104 Model MD-90-30 series airplanes of the 
affected design in the worldwide fleet. The FAA estimates that 21 
airplanes of U.S. registry would be affected by this proposed AD.
    It would take approximately 1 work hour per airplane to accomplish 
the proposed replacement, at an average labor rate of $60 per work 
hour. Required parts would be procured from the operator's stock. Based 
on these figures, the cost impact of the replacement proposed by this 
AD on U.S. operators is estimated to be $1,260, or $60 per airplane.
    It would take approximately 1 work hour per airplane to accomplish 
the

[[Page 36801]]

proposed retermination of the circuit ground wires of the EPCU, at an 
average labor rate of $60 per work hour. The manufacturer has committed 
previously to its customers that it will bear the cost of replacement 
parts. As a result, the cost of those parts is not attributable to this 
proposed AD. Based on these figures, the cost impact of the 
retermination proposed by this AD on U.S. operators is estimated to be 
$1,260, or $60 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 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-329-AD.
    Applicability: Model MD-90-30 series airplanes, as listed in 
McDonnell Douglas Alert Service Bulletin MD90-24A060, Revision 01, 
dated September 2, 1999, and McDonnell Douglas Service Bulletin 
MD90-24-062, dated Feburary 3, 2000; 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 a loose electrical ground block of the circuit ground 
wires of the electrical power control unit (EPCU), accomplish the 
following:

Replacement

    (a) For airplanes listed in McDonnell Douglas Alert Service 
Bulletin MD90-24A060, Revision 01, dated September 2, 1999: Within 
30 days after the effective of this AD, replace the electrical 
ground block screws with new screws in accordance with McDonnell 
Douglas Alert Service Bulletin MD90-24A060, Revision 01, dated 
September 2, 1999.

    Note 2: Accomplishment of the replacement of electrical ground 
block screws prior to the effective date of this AD in accordance 
with McDonnell Douglas Alert Service Bulletin MD90-24A060, dated 
July 28, 1999, is acceptable for compliance with the requirements of 
paragraph (a) of this AD.

Modification of the Electrical Power Control Unit

    (b) For airplanes listed in McDonnell Douglas Service Bulletin 
MD90-24-062, dated February 3, 2000: Within 12 months after the 
effective date of this AD, reterminate the circuit ground wires of 
the EPCU to separate grounding points to ensure that a single point 
failure does not occur, in accordance with McDonnell Douglas Service 
Bulletin MD90-24-062, dated February 3, 2000.

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, Los Angeles ACO. 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 3: 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

    (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 June 6, 2000.
Donald L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 00-14795 Filed 6-9-00; 8:45 am]
BILLING CODE 4910-13-U