[Federal Register Volume 61, Number 2 (Wednesday, January 3, 1996)]
[Proposed Rules]
[Pages 134-136]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-44]
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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39
[Docket No. 95-NM-177-AD]
Airworthiness Directives; McDonnell Douglas Model DC-10-10, -15,
-30, -40, and KC-10A (Military) Series Airplanes
AGENCY: Federal Aviation Administration, DOT.
[[Page 135]]
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 McDonnell Douglas Model
DC-10-10, -15, -30, -40, and KC-10A (military) series airplanes. This
proposal would require modification of the AC generator control units.
This proposal is prompted by reports of loss of electrical power from
two generators and an engine that flamed out due to an overfrequency
condition of a generator. The actions specified by the proposed AD are
intended to prevent an overfrequency condition of a generator, which
could lead to the loss of all electrical power of the airplane.
DATES: Comments must be received by February 28, 1996.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-103,
Attention: Rules Docket No. 95-NM-177-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 McDonnell Douglas Corporation, 3855 Lakewood Boulevard,
Long Beach, California 90846, Attention: Technical Publications
Business Administration, Department 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 90712.
FOR FURTHER INFORMATION CONTACT: Natalie Phan-Tran, Aerospace Engineer,
Systems and Equipment Branch, ANM-130L, FAA, Los Angeles Aircraft
Certification Office, 3960 Paramount Boulevard, Lakewood, California
90712; telephone (310) 627-5343; fax (310) 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.
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 95-NM-177-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-103, Attention: Rules
Docket No. 95-NM-177-AD, 1601 Lind Avenue, SW., Renton, Washington
98055-4056.
Discussion
The FAA has received reports of loss of electrical power from two
generators and an engine that flamed out on Model DC-10 series
airplanes, which resulted in multiple malfunctions of the electrical
system. Investigation revealed that the cause of the loss of electrical
power was attributed to an overfrequency condition in one of the three
generators, which resulted from certain failure modes of the constant
speed drive (CSD). Since all three generators are in parallel, the
overfrequency condition of one generator increased the speed of the
other two generators, which led to failure of the generator fans. If
the generator fans fail, all electrical power from the generators could
be lost; this situation could lead to loss of all electrical power of
the airplane.
The FAA has reviewed and approved McDonnell Douglas Service
Bulletin DC10-24-111 RO1, Revision 1, dated August 14, 1995, which
describes procedures for modification of the AC generator control units
(GCU). This modification adds a circuit that will provide overfrequency
protection. The circuit will isolate an overspeeding generator before
there is a perceptible power interruption on the other buses.
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 modification of the AC GCU's. The actions
would be required to be accomplished in accordance with the service
bulletin described previously.
There are approximately 419 Model DC-10-10, -15, -30, -40, and KC-
10A (military) series airplanes of the affected design in the worldwide
fleet. The FAA estimates that 276 airplanes of U.S. registry would be
affected by this proposed AD, that it would take approximately 5 work
hours per airplane to accomplish the proposed actions, and that the
average labor rate is $60 per work hour. Required parts would cost
approximately $2,896 per generator control unit; there are 4 units per
airplane. Based on these figures, the cost impact of the proposed AD on
U.S. operators is estimated to be $3,279,984, or $11,884 per airplane.
The cost impact figure discussed above is 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 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.
[[Page 136]]
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 USC 106(g), 40101, 40113, 44701.
Sec. 39.13 [Amended] -
2. Section 39.13 is amended by adding the following new
airworthiness directive:
McDonnell Douglas: Docket 95-NM-177-AD. -
Applicability: Model DC-10-10, -15, -30, -40, and KC-10A
(military) series airplanes, as listed in McDonnell Douglas Service
Bulletin DC10-24-111 RO1, Revision 1, dated August 14, 1995;
certificated in any category.
-Note 1: This AD applies to each airplane identified in the
preceding applicability provision, regardless of whether it has been
otherwise 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 use the authority
provided in paragraph (b) of this AD to request approval from the
FAA. This approval may address either no action, if the current
configuration eliminates the unsafe condition; or different actions
necessary to address the unsafe condition described in this AD. Such
a request should include an assessment of the effect of the changed
configuration on the unsafe condition addressed by this AD. In no
case does the presence of any modification, alteration, or repair
remove any airplane from the applicability of this AD.
-Compliance: Required as indicated, unless accomplished
previously. -
To prevent an overfrequency condition of the generator, which
could result in loss of all electrical power of the airplane,
accomplish the following: -
(a) Within 2 years after the effective date of this AD, modify
the AC generator control units (GCU) in accordance with McDonnell
Douglas Service Bulletin DC10-24-111 RO1, Revision 1, dated August
14, 1995. -
(b) 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, 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, 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. -
(c) 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 December 27, 1995.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 96-44 Filed 1-2-96; 8:45 am]
BILLING CODE 4910-13-U
