[Federal Register Volume 63, Number 149 (Tuesday, August 4, 1998)]
[Proposed Rules]
[Pages 41479-41481]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-20678]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 98-NM-197-AD]
RIN 2120-AA64
Airworthiness Directives; McDonnell Douglas Model DC-10 Series
Airplanes and KC-10 (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-10 (military) airplanes. This proposal
would require repetitive inspections to detect fatigue cracking of the
rear spar cap of the horizontal stabilizer; and repair, if necessary.
The proposed AD also would require a preventive modification of the
rear spar cap of the horizontal stabilizer, which would constitute
terminating action for the repetitive inspections. This proposal is
prompted by reports of fatigue cracking of the rear spar cap of the
horizontal stabilizer. The actions specified by the proposed AD are
intended to prevent fatigue cracking of the rear spar cap of the
horizontal stabilizer, which could result in reduced structural
integrity of the horizontal stabilizer, and consequent reduced
controllability of the airplane.
DATES: Comments must be received by September 18, 1998.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-114,
Attention: Rules Docket No. 98-NM-197-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 (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 98-NM-197-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. 98-NM-197-AD, 1601 Lind Avenue, SW., Renton, Washington
98055-4056.
Discussion
The FAA has received reports indicating that, on several in-service
McDonnell Douglas Model DC-10 series airplanes, cracking has been
discovered on the vertical leg of the rear spar cap of the horizontal
stabilizer, near the junction of the operating bulkhead. The cracking
originated in the counterbore transition area. The affected airplanes
had accumulated more than 46,000 total flight hours and 19,134 total
landings.
[[Page 41480]]
The cause of the cracking has been attributed to fatigue. Such
cracking, if not corrected, could result in reduced structural
integrity of the horizontal stabilizer, and consequent reduced
controllability of the airplane.
Explanation of Relevant Service Information
The FAA has reviewed and approved McDonnell Douglas Alert Service
Bulletin DC10-55A028, dated April 27, 1998, which describes procedures
for repetitive penetrant inspections or high frequency eddy current
inspections to detect fatigue cracking of the rear spar cap of the
horizontal stabilizer; and repair, if necessary. This alert service
bulletin also describes procedures for a preventive modification of the
rear spar cap of the horizontal stabilizer. The modification involves
the installation of doublers on the rear spar cap, which would
eliminate the need for the repetitive inspections. Accomplishment of
the actions specified in the alert service bulletin is intended to
adequately address the identified unsafe condition.
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 repetitive penetrant inspections or high
frequency eddy current inspections to detect fatigue cracking of the
rear spar cap of the horizontal stabilizer; and repair, if necessary.
The proposed AD also would require a preventive modification of the
rear spar cap of the horizontal stabilizer, which would constitute
terminating action for the repetitive inspections. The actions would be
required to be accomplished in accordance with the alert service
bulletin described previously, except as discussed below.
Differences Between Proposed Rule and Alert Service Bulletin
Operators should note that, for airplanes that have accumulated
18,000 or more total landings, although the alert service bulletin
recommends accomplishing the penetrant inspection or high frequency
eddy current inspection within 60 days (after the release of the alert
service bulletin), the FAA has determined that an interval of 1,500
landings would address the identified unsafe condition in a timely
manner, and would allow the airplanes to be inspected during a routine
maintenance period. In developing an appropriate compliance time for
this proposed AD, the FAA considered not only the manufacturer's
recommendation, but the fail-safe features of the Model DC-10 series
airplane, the degree of urgency associated with addressing the subject
unsafe condition, the average utilization of the affected fleet, and
the time necessary to perform the inspection (two hours). In light of
all of these factors, the FAA finds a 1,500-landing compliance time
(for airplanes that have accumulated 18,000 or more total landings) for
the required actions to be warranted, in that it represents an
appropriate interval of time allowable for affected airplanes to
continue to operate without compromising safety.
Operators should note that this AD proposes to mandate, within 5
years after the effective date of this AD, the preventive modification
described in the alert service bulletin, as terminating action for the
repetitive inspections. The alert service bulletin provides for
accomplishment of the preventive modification as an option only.
The FAA has determined that long-term continued operational safety
would be better assured by design changes to remove the source of the
problem, rather than by repetitive 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 proposed preventive modification
requirement is in consonance with these conditions.
Cost Impact
There are approximately 420 airplanes of the affected design in the
worldwide fleet. The FAA estimates that 242 airplanes of U.S. registry
(124 Group 1 airplanes; 118 Group 2 airplanes) would be affected by
this proposed AD.
It would take approximately 2 work hours per airplane to accomplish
the proposed inspections, at an average labor rate of $60 per work
hour. Based on these figures, the cost impact of the inspections
proposed by this AD on U.S. operators for Groups 1 and 2 airplanes is
estimated to be $29,040, or $120 per airplane, per inspection cycle.
It would take approximately 34 work hours per airplane to
accomplish the proposed modification, at an average labor rate of $60
per work hour. Required parts would cost approximately $6,236 per
airplane for Group 1 airplanes, or $6,349 per airplane for Group 2
airplanes. Based on these figures, the cost impact of the modification
proposed by this AD on U.S. operators of Group 1 airplanes is estimated
to be $1,026,224, or $8,276 per airplane; and, for Group 2 airplanes,
$989,902, or $8,389 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 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.
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.
[[Page 41481]]
Sec. 39.13 [Amended]
2. Section 39.13 is amended by adding the following new
airworthiness directive:
McDonnell Douglas: Docket 98-NM-197-AD.
Applicability: Model DC-10 series airplanes and KC-10 (military)
airplanes, as listed in McDonnell Douglas Alert Service Bulletin
DC10-55A028, dated April 27, 1998; 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 fatigue cracking of the rear spar cap of the
horizontal stabilizer, which could result in reduced structural
integrity of the horizontal stabilizer, and consequent reduced
controllability of the airplane, accomplish the following:
(a) Prior to the accumulation of 18,000 total landings, or
within 1,500 landings after the effective date of this AD, whichever
occurs later: Perform a penetrant inspection or a high frequency
eddy current inspection to detect fatigue cracking of the rear spar
cap of the horizontal stabilizer, in accordance with McDonnell
Douglas Alert Service Bulletin DC10-55A028, dated April 27, 1998.
(1) If no cracking is detected, repeat the inspection thereafter
at intervals not to exceed 2,200 landings until accomplishment of
the requirements of paragraph (b) of this AD.
(2) If any cracking is detected, prior to further flight, repair
in accordance with the alert service bulletin. Repeat the inspection
thereafter at intervals not to exceed 2,200 landings until
accomplishment of the requirements of paragraph (b) of this AD.
(b) Within 5 years after the effective date of this AD, perform
a penetrant inspection or a high frequency eddy current inspection
to detect fatigue cracking of the rear spar cap of the horizontal
stabilizer, in accordance with McDonnell Douglas Alert Service
Bulletin DC10-55A028, dated April 27, 1998.
(1) If no cracking is detected, prior to further flight, perform
the preventive modification of the rear spar cap of the horizontal
stabilizer, in accordance with the alert service bulletin.
Accomplishment of this modification constitutes terminating action
for the requirements of this AD.
(2) If any cracking is detected, prior to further flight,
repair, and perform the preventive modification of the rear spar cap
of the horizontal stabilizer, in accordance with the alert service
bulletin. Accomplishment of the modification constitutes terminating
action for the requirements of this AD.
(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 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.
(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 July 27, 1998.
S.R. Miller,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 98-20678 Filed 8-3-98; 8:45 am]
BILLING CODE 4910-13-U
