[Federal Register Volume 63, Number 58 (Thursday, March 26, 1998)]
[Proposed Rules]
[Pages 14654-14656]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-7879]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 97-NM-288-AD]
RIN 2120-AA64
Airworthiness Directives; McDonnell Douglas Model DC-10 Series
Airplanes and KC-10A (Military) Airplanes
AGENCY: Federal Aviation Administration, DOT.
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 series airplanes and KC-10A (military) airplanes. This proposal
would require repetitive inspections to detect cracking of the lower
cap of the wing rear spar, and repair, if necessary. This proposal is
prompted by reports of fatigue cracks found in the lower cap of the
wing rear spar. The actions specified by the proposed AD are intended
to detect and correct fatigue cracking of the lower cap of the wing
rear spar, which could result in reduced structural integrity of the
airplane.
DATES: Comments must be received by May 11, 1998.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-114,
Attention: Rules Docket No. 97-NM-288-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 The Boeing Company, Douglas Products Division, 3855
Lakewood Boulevard, Long Beach, California 90846, Attention: Technical
Publications Business Administration, Dept. C1-L51
[[Page 14655]]
(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: Ron Atmur, Aerospace Engineer,
Airframe Branch, ANM-120L, FAA, Transport Airplane Directorate, Los
Angeles Aircraft Certification Office, 3960 Paramount Boulevard,
Lakewood, California 90712-4137; telephone (562) 627-5224; 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.
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 97-NM-288-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. 97-NM-288-AD, 1601 Lind Avenue, SW., Renton, Washington
98055-4056.
Discussion
The FAA has received reports of four instances of crack development
in the lower cap of the wing rear spar. In all four instances, a single
crack on the left or right wing had propagated from the aft leg into
both the vertical and forward legs of the spar cap. All affected
airplanes had accumulated over 32,000 flight hours and over 18,000
landings. The cause of the cracking has been attributed to fatigue.
Such fatigue cracking, if not detected and corrected in a timely
manner, could result in reduced structural integrity of the airplane.
Other Relevant Rulemaking
The subject area is designated as Principal Structural Element
(PSE) No. 57.10.007/.008 in McDonnell Douglas Report No. L26-012, ``DC-
10 Supplemental Inspection Document (SID),'' Volume I, Revision 5,
dated October 1994; Volume II, Revision 5, dated October 1994; and
Volume III-94, dated November 1994. Inspections of that PSE are
required by AD 95-23-09, amendment 39-9429 (60 FR 61649, December 1,
1995). The inspections required for this PSE follow the fleet leader
sampling criteria with a fatigue life threshold (Nth) greater than
34,000 landings, which corresponds to a probability of failure per
flight of 10-9; i.e., failure is extremely improbable. All
of the cracks have been detected on airplanes with fewer than 34,000
landings. Additionally, a PSE is defined as structure on which
undetected failure could lead to loss of the structural integrity of
the airplane. Therefore, the FAA has determined that an additional AD
is warranted to require inspection of the lower cap of the wing rear
spar on Model DC-10 series airplanes and KC-10A (military) airplanes
after accumulation of 7,000 total landings. Such inspections would
ensure that fatigue cracking is detected in a timely manner, well in
advance of cracking reaching a critical length.
Explanation of Relevant Service Information
The FAA has reviewed and approved McDonnell Douglas Alert Service
Bulletin DC10-57A137, dated July 31, 1997, which describes procedures
for repetitive eddy current surface inspections to detect cracking in
the lower cap of the wing rear spar.
Explanation of Requirements of Proposed Rule
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 accomplishment of the actions specified in
the alert service bulletin described previously, except as discussed
below.
Differences Between the Alert Service Bulletin and This Proposed AD
Operators should note that, although the alert service bulletin
specifies that the manufacturer may be contacted for disposition of
repair conditions, this proposal would require the repair of those
conditions to be accomplished in accordance with a method approved by
the FAA.
Operators also should note that, although the alert service
bulletin recommends a compliance time of 60 days for accomplishment of
the initial inspection for airplanes that have accumulated more than
7,000 total landings, this proposed AD would require that the initial
inspection be accomplished within 18 months after the effective date of
the AD. In developing the proposed compliance time, the FAA determined
that a compliance time of 18 months is appropriate in consideration of
the safety implications, the average utilization rate of the affected
fleet, and the practical aspects of an orderly inspection of the fleet
during regular maintenance periods.
Cost Impact
There are approximately 283 airplanes of the affected design in the
worldwide fleet. The FAA estimates that 201 airplanes of U.S. registry
would be affected by this proposed AD, that it would take approximately
8 work hours per airplane to accomplish the proposed inspection, and
that the average labor rate is $60 per work hour. Based on these
figures, the cost impact of the proposed AD on U.S. operators is
estimated to be $96,480, or $480 per airplane, per inspection cycle.
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.
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''
[[Page 14656]]
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 97-NM-288-AD.
Applicability: Model DC-10 series airplanes and KC-10A
(military) airplanes, as listed in McDonnell Douglas Alert Service
Bulletin DC10-57A137, dated July 31, 1997; 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 detect and correct fatigue cracking of the lower cap of the
wing rear spar, which could result in reduced structural integrity
of the airplane, accomplish the following:
(a) Conduct an eddy current surface inspection to detect
cracking of the lower cap of the wing rear spar, in accordance with
the Accomplishment Instructions of McDonnell Douglas Alert Service
Bulletin DC10-57-A137, dated July 31, 1997; at the later of the
times specified in paragraphs (a)(1) and (a)(2) of this AD.
Thereafter, repeat this inspection at intervals not to exceed 1,500
landings.
(1) Prior to the accumulation of 7,000 total landings, or within
18 months after the effective date of this AD, whichever occurs
later. Or
(2) Within 1,500 landings after the accomplishment of the
inspection of Principal Structural Elements 57.10.007 and 57.10.008,
in accordance with AD 95-23-09, amendment 39-9429.
(b) If any crack is found during any inspection required by this
AD, prior to further flight, repair in accordance with a method
approved by the Manager, Los Angeles Aircraft Certification Office
(ACO), FAA, Transport Airplane Directorate.
(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, 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.
(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 March 19, 1998.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 98-7879 Filed 3-25-98; 8:45 am]
BILLING CODE 4910-13-U