[Federal Register Volume 59, Number 77 (Thursday, April 21, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-6911]
[[Page Unknown]]
[Federal Register: April 21, 1994]
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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39
[Docket No. 93-NM-154-AD; Amendment 39-8860; AD 94-07-02]
Airworthiness Directives; McDonnell Douglas Model DC-10-30 and -
40 Series Airplanes and KC-10A (Military) Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule.
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SUMMARY: This amendment adopts a new airworthiness directive (AD),
applicable to certain McDonnell Douglas Model DC-10 series airplanes
and KC-10A (military) airplanes, that requires modification of the
cavity vent drain tube assembly at the center wing lower auxiliary fuel
tank cavity. This amendment is prompted by a report that the cavity
vent tube, if not properly grounded, could act as an electrical path in
the event of a lightning strike. The actions specified by this AD are
intended to prevent arcing in the tank cavity and possible resulting
fire.
DATES: Effective May 23, 1994.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of May 23, 1994.
ADDRESSES: The service information referenced in this AD may be
obtained from McDonnell Douglas Corporation, P.O. Box 1771, Long Beach,
CA 90801-1771, Attention: Business Unit Manager, Technical
Administrative Support, Dept. L51, M.C. 2-98. This information may be
examined at the Federal Aviation Administration (FAA), Transport
Airplane Directorate, Rules Docket, 1601 Lind Avenue SW., Renton,
Washington; or at the FAA, Los Angeles Aircraft Certification Office
(ACO), 3229 East Spring Street, Long Beach, California; or at the
Office of the Federal Register, 800 North Capitol Street, NW., suite
700, Washington, DC.
FOR FURTHER INFORMATION CONTACT: Raymond Vakili, Aerospace Engineer,
Propulsion Branch, ANM-140L, FAA, Transport Airplane Directorate, Los
Angeles Aircraft Certification Office, 3229 East Spring Street, Long
Beach, California 90806-2425; telephone (310) 988-5262; fax (310) 988-
5210.
SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal
Aviation Regulations to include an airworthiness directive (AD) that is
applicable to certain McDonnell Douglas Model DC-10 series airplanes
and KC-10A (military) airplanes was published in the Federal Register
on November 4, 1993 (58 FR 58807). That action proposed to require
modification of the cavity vent drain tube assembly at the center wing
lower auxiliary fuel tank.
Interested persons have been afforded an opportunity to participate
in the making of this amendment. Due consideration has been given to
the comments received.
One commenter supports the proposed rule.
The Air Transport Association (ATA) of America, on behalf of one of
its member operators, requests that the proposal be withdrawn. The
commenter maintains that the proposed modification will allow some fuel
leakage within specified limits into the lower auxiliary tank cavity.
This commenter asserts that, if this modification is not mandated by
the FAA, then fuel will not be permitted to leak into the cavity and,
unless fuel/vapor is present, there is no risk of fire in this cavity
in the event of a lighting strike. The commenter also points out that a
daily check to detect fuel leakage in the cavity drain valve is
currently specified in the On Aircraft Maintenance Planning (OAMP)
document for Model DC-10 series airplanes. The commenter concludes
that, since these inspections are performed on a daily basis, and since
fuel will not be permitted to leak into the cavity if the modification
is not mandated, then a lightning strike will not pose a threat to an
area containing fuel or fuel vapor.
The FAA does not concur that withdrawal of the proposal is
appropriate. First, the FAA points out that the OAMP document is not a
mandated, FAA-approved document; therefore, regardless of the number or
types of inspections that are contained in it, there is no assurance
that operators will strictly comply with those inspections or the
indicated inspection intervals. Additionally, there is always the
potential that a fuel leak could develop during flight between
inspection intervals. Second, the FAA has determined that, since the
required modification of the cavity vent drain tube assembly will
prevent the possibility of a lightning strike traveling up the cavity
vent tube, the possibility of arcing in the fuel tank cavity is thereby
eliminated (regardless of whether or not fuel/vapor is present).
Further, the FAA has determined that long term continued operational
safety will be better assured by actual modification of the cavity vent
drain tube assembly to remove the source of the problem, rather than by
continuous inspections. Long term inspections may not be providing the
degree of safety assurance necessary for the transport airplane fleet.
This, coupled with a better understanding of the human factors
associated with numerous continual inspections, has led the FAA to
consider placing less emphasis on inspections and more emphasis on
design improvements. The modification required by this AD is in
consonance with these considerations.
The ATA also requests that the proposed compliance time of 12
months for the modification be extended to 18 months. Such an extension
would permit accomplishment of the proposed modification during
regularly scheduled maintenance visits for most affected operators and
would preclude special scheduling at considerable expense. The FAA
concurs. Upon consideration of the information provided by the
commenter, and the fact that there have been no in-service incidents of
arcing or fire in the tank cavity (related to grounding problems in the
cavity vent drain tube assembly), the FAA has determined that extending
the compliance time by 6 additional months will not adversely affect
safety. Such extension will align with operators normal ``C'' checks,
and will allow the modification to be performed at a base during
regularly scheduled maintenance where special equipment and trained
maintenance personnel will be available if necessary. Paragraph (a) of
the final rule has been revised accordingly.
After careful review of the available data, including the comments
noted above, the FAA has determined that air safety and the public
interest require the adoption of the rule with the change previously
described. The FAA has determined that this change will neither
increase the economic burden on any operator nor increase the scope of
the AD.
There are approximately 294 McDonnell Douglas Model DC-10-30 and -
40 series airplanes and KC-10A (military) airplanes of the affected
design in the worldwide fleet. The FAA estimates that 127 airplanes of
U.S. registry will be affected by this AD, that it will take
approximately 3.5 work hours per airplane to accomplish the required
actions, and that the average labor rate is $55 per work hour. Required
parts will cost approximately $120 per airplane. Based on these
figures, the total cost impact of the AD on U.S. operators is estimated
to be $39,687.50, or $312.50 per airplane.
The total cost impact figure discussed above is based on
assumptions that no operator has yet accomplished any of the
requirements of this AD action, and that no operator would accomplish
those actions in the future if this AD were not adopted.
The regulations adopted herein will 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 final
rule does not have sufficient federalism implications to warrant the
preparation of a Federalism Assessment.
For the reasons discussed above, I certify that this action (1) is
not a ``significant regulatory action'' under Executive Order 12866;
(2) is not a ``significant rule'' under DOT Regulatory Policies and
Procedures (44 FR 11034, February 26, 1979); and (3) 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 final evaluation has been prepared for this action
and it is contained in the Rules Docket. A copy of it may be obtained
from the Rules Docket at the location provided under the caption
ADDRESSES.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by
reference, Safety.
Adoption of the Amendment
Accordingly, pursuant to the authority delegated to me by the
Administrator, the Federal Aviation Administration amends 14 CFR part
39 of the Federal Aviation Regulations as follows:
PART 39--AIRWORTHINESS DIRECTIVES
1. The authority citation for part 39 continues to read as follows:
Authority: 49 U.S.C. App. 1354(a), 1421 and 1423; 49 U.S.C.
106(g); and 14 CFR 11.89.
Sec. 39.13 [Amended]
2. Section 39.13 is amended by adding the following new
airworthiness directive:
94-07-02 McDonnell Douglas: Amendment 39-8860. Docket 93-NM-154-AD.
Applicability: McDonnell Douglas Model DC-10-30 and -40 series
airplanes, and KC-10A (military) airplanes; as listed in McDonnell
Douglas DC-10 Service Bulletin 28-204, dated August 5, 1993;
certificated in any category.
Compliance: Required as indicated, unless accomplished
previously.
To prevent arcing in the tank cavity and possible resulting
fire, accomplish the following:
(a) Within 18 months after the effective date of this AD, modify
the cavity vent drain tube assembly at the center wing lower
auxiliary fuel tank cavity in accordance with McDonnell Douglas DC-
10 Service Bulletin 28-204, dated August 5, 1993.
(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: 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
Federal Aviation Regulations (FAR) 21.197 and 21.199 to operate the
airplane to a location where the requirements of this AD can be
accomplished.
(d) The modification shall be done in accordance with McDonnell
Douglas DC-10 Service Bulletin 28-204, dated August 5, 1993. This
incorporation by reference was approved by the Director of the
Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part
51. Copies may be obtained from McDonnell Douglas Corporation, P.O.
Box 1771, Long Beach, CA 90801-1771, Attention: Business Unit
Manager, Technical Administrative Support, Dept. L51, M.C. 2-98.
Copies may be inspected at the FAA, Transport Airplane Directorate,
1601 Lind Avenue SW., Renton, Washington; or at the FAA, Los Angeles
ACO, 3229 E. Spring Street, Long Beach, California; or at the Office
of the Federal Register, 800 North Capitol Street NW., suite 700,
Washington, DC.
(e) This amendment becomes effective on May 23, 1994.
Issued in Renton, Washington, on March 18, 1994.
John J. Hickey,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 94-6911 Filed 4-20-94; 8:45 am]
BILLING CODE 4910-13-U
