[Federal Register Volume 59, Number 191 (Tuesday, October 4, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-24199]
Federal Register / Vol. 59, No. 191 / Tuesday, October 4, 1994 /
[[Page Unknown]]
[Federal Register: October 4, 1994]
VOL. 59, NO. 191
Tuesday, October 4, 1994
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 93-NM-221-AD; Amendment 39-9039; AD 94-20-10]
Airworthiness Directives; McDonnell Douglas Model DC-10-10, -15,
-30, and -40 Series Airplanes and KC-10A (Military) Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule; request for comments.
-----------------------------------------------------------------------
SUMMARY: This amendment adopts a new airworthiness directive (AD),
applicable to certain McDonnell Douglas Model DC-10-10, -15, -30, and -
40 series airplanes and KC-10A (military) airplanes, that requires
inspections to detect fatigue-related cracking in certain areas of the
horizontal stabilizer; and repair of cracked parts. It also requires
installation of terminating modifications, which, when accomplished,
would eliminate the repetitive inspections. This amendment is prompted
by reports of fatigue-related cracks found on the horizontal
stabilizer. The actions specified by this AD are intended to prevent
loss of the load carrying and fail safe capability of the horizontal
stabilizer, damage to the adjacent structure, and subsequent reduced
structural integrity of the airplane, due to the problems associated
with fatigue cracking.
DATES: Effective October 31, 1994.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of November 3, 1994.
ADDRESSES: The service information referenced in this AD may be
obtained from McDonnell Douglas Corporation, P.O. Box 1771, Long Beach,
California 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, Transport Airplane Directorate, Los Angeles
Aircraft Certification Office, 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: Wahib Mina, Aerospace Engineer,
Airframe Branch, ANM-121L, FAA, Transport Airplane Directorate, Los
Angeles ACO, 3229 East Spring Street, Long Beach, California 90806-
2425; telephone (310) 988-5324; fax (310) 988-5210.
SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal
Aviation Regulations (14 CFR part 39) to include an airworthiness
directive (AD) that is applicable to certain McDonnell Douglas Model
DC-10-10, -15, -30, and -40 series airplanes and KC-10A (military)
airplanes was published as a notice of proposed rulemaking (NPRM) in
the Federal Register on March 30, 1994 (59 FR 14800). That action
proposed to require inspections to detect fatigue-related cracking in
certain areas of the horizontal stabilizer; and repair of cracked
parts. It also proposed to require the installation of certain
terminating modifications that would eliminate the need for the
repetitive inspections.
Immediate Adoption of This Regulation
Since issuance of the NPRM, one operator has reported finding a
crack in the area of the forward spar upper cap on the horizontal
stabilizer on a Model DC-10-10 series airplane that had accumulated
approximately 16,000 landings. This evidence indicates that fatigue
cracking may begin in this area much earlier than what was previously
considered. In light of this, the FAA has reconsidered the compliance
time proposed for the initiation of inspections to detect cracking in
this subject area on these airplanes. The FAA now has determined that
the initiation of inspections of Model DC-10-10 and -15 series
airplanes must begin prior to the accumulation of 12,000 total landings
or 90 days after the effective date of this AD, whichever occurs later.
(The compliance time for this action that was proposed in the notice
was 18,000 total landings.) The lowered threshold of 12,000 total
landings is necessary to ensure that cracking is detected and corrected
in a timely manner, and to prevent the loss of load-carrying and fail
safe capability of the horizontal stabilizer due to the problems
associated with fatigue cracking. The compliance time for the
inspections specified in paragraph (a) of this final rule has been
revised accordingly.
In making this revision, the FAA finds that, with respect to the
reduced compliance threshold, a situation exists that requires the
immediate adoption of this regulation. Therefore, it is found that
notice and opportunity for prior public comment hereon are
impracticable, and that good cause exists for making this amendment
effective in less than 30 days.
Comments Invited
Although this action is in the form of a final rule that involves
requirements affecting flight safety and, thus, was not preceded by
notice and an opportunity for public comment, comments are invited on
this rule. Interested persons are invited to comment on this 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 under the caption ADDRESSES. All
communications received on or before the closing date for comments will
be considered, and this rule may be amended in light of the comments
received. Factual information that supports the commenter's ideas and
suggestions is extremely helpful in evaluating the effectiveness of the
AD action and determining whether additional rulemaking action would be
needed.
Comments are specifically invited on the overall regulatory,
economic, environmental, and energy aspects of the rule that might
suggest a need to modify the 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 that
summarizes each FAA-public contact concerned with the substance of this
AD will be filed in the Rules Docket.
Commenters wishing the FAA to acknowledge receipt of their comments
submitted in response to this rule must submit a self-addressed,
stamped postcard on which the following statement is made: ``Comments
to Docket Number 93-NM-221-AD.'' The postcard will be date stamped and
returned to the commenter.
Discussion of Comments Received to the NPRM
Interested persons have been afforded an opportunity to participate
in the making of a portion of this amendment. Due consideration has
been given to the comments received.
One commenter supports the proposal.
Several commenters request that the proposed rule be revised to
exclude the Models DC-10-30 and -40 from the applicability until more
information is gathered to substantiate that these airplanes are
subject to the addressed unsafe condition. These commenters point out
that cracks have been reported on Model DC-10-10 series airplanes only.
One commenter states that the airframe manufacturer previously had
requested that operators of Model DC-10 series airplanes inspect their
airplanes for cracking and, as a result, none was found on any models
other than the Model DC-10-10 and -15 series. Another commenter
suggests that the spar cap and skin panel installed on Models DC-10-30
and -40 are thicker than those on Models DC-10-10 and -15; therefore,
the possibility of these items cracking on the Model DC-10-30 and -40
airplanes is very low.
The FAA does not concur with these commenters' request. Although
fatigue cracking may not have been detected on in-service Model DC-10-
30 and -40 series airplanes, the airframe manufacturer has conducted
load, fatigue, and damage-tolerance analyses, which indicate that
fatigue-related cracking is likely to occur on all Model DC-10 series
airplanes as these airplanes accumulate flight cycles. The compliance
thresholds specified in this AD, as well as the compliance times for
the required initial and repetitive inspections, were developed in
consideration of these analyses and with the participation of the
airframe manufacturer.
Several commenters request that the rule be revised to give credit
for visual inspections of the area that were performed previously, and
to add a visual inspection as an option for accomplishment of the
initial eddy current inspection. These commenters state that a damage
tolerance assessment conducted by the airframe manufacturer has shown
that an initial visual inspection will ensure that the structural
integrity of the horizontal stabilizer spar cap and skin is maintained.
Additionally, by permitting a visual inspection to be performed, which
takes less time and materials than an eddy current inspection, the
economic impact of non-scheduled maintenance and removal of aircraft
from service would be reduced for operators, as well as the
corresponding inconvenience for the traveling public.
The FAA concurs with these commenters' request. Subsequent to the
issuance of the notice, the FAA reviewed and approved Revision 1 to
McDonnell Douglas DC-10 Service Bulletins 55-24 and 55-25, both dated
August 3, 1994. These revised service bulletins contain revised
instructions for accomplishing the eddy current inspection (to make it
less complicated), and instructions for performing an optional visual
inspection in lieu of the initial eddy current inspection to determine
if cracks exist in the horizontal stabilizer forward cap and skin
panel. The FAA has revised the final rule to permit operators to
perform this optional visual inspection as the initial inspection only.
All repetitive inspections must be performed using eddy current
techniques.
Several commenters request that the proposed rule be revised to
eliminate the compliance time for the terminating modifications. These
commenters consider that these modifications should be optional instead
of mandatory. Other commenters indicate that fatigue-related cracks are
cycle-dependent, not calendar time-dependent; therefore, it is
inappropriate to impose a calendar time compliance time on a cycle-
dependent phenomenon. The commenters also consider that the proposed
compliance time of five years for installation of the terminating
modifications could be unfair to operators of low-time airplanes,
since, in some cases, an operator could be required to install the
terminating modifications before the airplane has reached the threshold
for the initial inspection.
The FAA does not concur with the commenters' request to allow the
terminating action to be optional. The FAA has determined that long
term continued operational safety will 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 modifications required by this AD are in consonance
with these considerations.
The FAA does acknowledge, however, that the proposed compliance
time for installation of the terminating modifications could present an
unfair situation to operators of low-time airplanes. This was not the
FAA's intent. Therefore, the FAA has revised paragraph (d) of the final
rule to specify modification prior to the accumulation of a certain
number of cycles (depending upon airplane model) or within 5 years,
whichever occurs later.
The FAA has revised paragraphs (a)(1), (b)(1), and (c)(1) of the
final rule to delete the previously proposed requirement to continue
inspections after installation of a repair that has been approved by
the Manager of the Los Angeles Aircraft Certification Office. The FAA
has determined that deletion of this requirement is appropriate, since
some repairs that have been approved have incorporated a terminating
action, thereby eliminating the need for continuing repetitive
inspections.
Cost Impact
There are approximately 427 Model DC-10-10, -15, -30, and -40
series airplanes and KC-10A (military) airplanes of the affected design
in the worldwide fleet. The FAA estimates that 241 airplanes of U.S.
registry will be affected by this AD.
The accomplishment of the optional initial visual inspection will
take approximately 1 workhour per airplane per inspection, at an
average labor charge of $55 per workhour. Based on these figures, the
total cost impact of this optional inspection on U.S. operators who
elect to accomplish it is estimated to be $55 per airplane.
The accomplishment of the eddy current inspections will take
approximately 3 workhours per airplane per inspection, at an average
labor charge of $55 per workhour. Based on these figures, the total
cost impact of the inspection requirement on U.S. operators is
estimated to be $39,765, or $165 per airplane, per inspection cycle.
The accomplishment of the modification of the forward spar upper
cap will take approximately 248 workhours per airplane. Likewise, the
accomplishment of the modification of the forward upper skin panel will
take approximately 248 workhours per airplane. The average labor rate
is $55 per workhour. Required parts will cost approximately $10,600 per
airplane. Based on these figures, the total cost impact of the
modification actions AD on U.S. operators is estimated to be
$9,129,080, or $37,880 per airplane.
The FAA recognizes that the required modifications require a large
number of workhours to accomplish. However, the 5-year compliance time
specified in paragraph (d) of this proposed AD should allow ample time
for the modifications to be accomplished coincidentally with scheduled
major airplane inspection and maintenance activities, thereby
minimizing the costs associated with special airplane scheduling.
The total cost impact figures discussed above are 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.
Regulatory Impact
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.
The FAA has determined that this regulation is an emergency
regulation that must be issued immediately to correct an unsafe
condition in aircraft, and that it is not a ``significant regulatory
action'' under Executive Order 12866. It has been determined further
that this action involves an emergency regulation under DOT Regulatory
Policies and Procedures (44 FR 11034, February 26, 1979). If it is
determined that this emergency regulation otherwise would be
significant under DOT Regulatory Policies and Procedures, a final
regulatory evaluation will be prepared and placed in the Rules Docket.
A copy of it, if filed, 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 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. 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:
94-20-10 McDonnell Douglas: Amendment 39-9039. Docket 93-NM-221-AD.
Applicability: Model DC-10-10, -15, -30, and -40 series
airplanes and KC-10A (military) airplanes; as listed in McDonnell
Douglas DC-10 Service Bulletins 55-24 and 55-25, Revision 1, both
dated August 3, 1994; certificated in any category.
Compliance: Required as indicated, unless accomplished
previously.
To prevent reduced structural integrity of the airplane,
accomplish the following:
(a) For Model DC-10-10 and -15 series airplanes: Prior to the
accumulation of 12,000 total landings, or within 90 days after the
effective date of this AD, whichever occurs later, unless previously
accomplished within the last 4,500 landings, perform either an
initial an eddy current inspection or visual inspection to detect
fatigue-related cracking of the forward spar upper caps on the
horizontal stabilizer, in accordance with McDonnell Douglas DC-10
Service Bulletin 55-24, Revision 1, dated August 3, 1994.
Note 1: Eddy current inspections accomplished in accordance with
McDonnell Douglas DC-10 Service Bulletin 55-24, dated October 25,
1993, are considered acceptable for compliance with this paragraph.
(1) If any crack is detected, prior to further flight, repair
the crack in accordance with a method approved by the Manager, Los
Angeles Aircraft Certification Office (ACO), FAA, Transport Airplane
Directorate.
(2) If no crack is detected, perform repetitive inspections
thereafter in accordance with the service bulletin and in accordance
with the following schedule:
(i) If the initial inspection was performed using visual
techniques, perform an eddy current inspection within 1,000 landings
after the visual inspection. Thereafter, repeat the eddy current
inspection at intervals not to exceed 4,500 landings.
(ii) If the initial inspection was performed using eddy current
techniques, repeat the eddy current inspection thereafter at
intervals not to exceed 4,500 landings.
(b) For Model DC-10-10 and -15 series airplanes: Prior to the
accumulation of 10,000 total landings, or within 120 days after the
effective date of this AD, whichever occurs later, unless previously
accomplished within the last 4,500 landings, perform either an
initial eddy current inspection or visual inspection to detect
fatigue-related cracking of the forward upper skin panel of the
horizontal stabilizer, in accordance with McDonnell Douglas DC-10
Service Bulletin 55-25, Revision 1, dated August 3, 1994.
Note 2: Eddy current inspections performed in accordance with
McDonnell Douglas DC-10 Service Bulletin 55-25, dated October 25,
1993, are considered acceptable for compliance with this paragraph.
(1) If any crack is detected, prior to further flight, repair
the crack in accordance with a method approved by the Manager, Los
Angeles ACO, FAA, Transport Airplane Directorate.
(2) If no crack is detected, perform repetitive eddy current
inspections thereafter in accordance with the service bulletin and
in accordance with the following schedule:
(i) If the initial inspection was performed using visual
techniques, perform an eddy current inspection within 1,000 landings
after the visual inspection. Thereafter, repeat the eddy current
inspection at intervals not to exceed 4,500 landings.
(ii) If the initial inspection was performed using eddy current
techniques, repeat the eddy current inspection thereafter at
intervals not to exceed 4,500 landings.
(c) For Model DC-10-30 and -40 series airplanes: Prior to the
accumulation of 17,500 total landings, or within 120 days after the
effective date of this AD, whichever occurs later, unless previously
accomplished within the last 4,500 landings, perform either an
initial eddy current inspection or visual inspection to detect
fatigue-related cracking of the forward upper skin panel of the
horizontal stabilizer, in accordance with McDonnell Douglas DC-10
Service Bulletin 55-25, Revision 1, dated August 3, 1994.
Note 3: Eddy current inspections performed in accordance with
McDonnell Douglas DC-10 Service Bulletin 55-25, dated October 25,
1993, are considered acceptable for compliance with this paragraph.
(1) If any crack is detected, prior to further flight, repair
the crack in accordance with a method approved by the Manager, Los
Angeles ACO, FAA, Transport Airplane Directorate.
(2) If no crack is detected, perform repetitive eddy current
inspections thereafter in accordance with the service bulletin and
in accordance with the following schedule:
(i) If the initial inspection was performed using visual
techniques, perform an eddy current inspection within 1,000 landings
after the visual inspection. Thereafter, repeat the eddy current
inspection at intervals not to exceed 4,500 landings.
(ii) If the initial inspection was performed using eddy current
techniques, repeat the eddy current inspection thereafter at
intervals not to exceed 4,500 landings.
(d) For all airplanes: Install the preventative modifications
specified in McDonnell Douglas DC-10 Service Bulletin 55-24,
Revision 1, dated August 3, 1994; and McDonnell Douglas DC-10
Service Bulletin 55-25, Revision 1, dated August 3, 1994; in
accordance with the following schedule. Accomplishment of these
preventative modifications constitutes terminating action for the
repetitive inspections required by this AD.
Note 4: Accomplishment of these preventative modifications in
accordance with McDonnell Douglas DC-10 Service Bulletin 55-24,
dated October 25, 1993; or McDonnell Douglas DC-10 Service Bulletin
55-25, dated October 25, 1993; as applicable; is considered
acceptable for compliance with this paragraph.
(1) For Model DC-10-10 and -15 series airplanes:
(i) Prior to the accumulation of 21,000 total landings, or
within 5 years after the effective date of this AD, whichever occurs
later, accomplish the preventative modifications of the forward spar
upper cap on the horizontal stabilizer in accordance with McDonnell
Douglas DC-10 Service Bulletin 55-24, Revision 1, dated August 3,
1994.
(ii) Prior to the accumulation of 19,000 total landings, or
within 5 years after the effective date of this AD, whichever occurs
later, accomplish the modification of the forward upper skin panel
on the horizontal stabilizer in accordance with McDonnell Douglas
DC-10 Service Bulletin 55-25, Revision 1, dated August 3, 1994.
(2) For Model DC-10-30 and -40 series airplanes:
(i) Prior to the accumulation of 44,250 total landings, or
within 5 years after the effective date of this AD, whichever occurs
later, accomplish the modification of the forward spar upper cap on
the horizontal stabilizer in accordance with McDonnell Douglas DC-10
Service Bulletin 55-24, Revision 1, dated August 3, 1994.
(ii) Prior to the accumulation of 26,500 total landings, or
within 5 years after the effective date of this AD, whichever occurs
later, accomplish the modification of the forward upper skin panel
on the horizontal stabilizer in accordance with McDonnell Douglas
DC-10 Service Bulletin 55-25, Revision 1, dated August 3, 1994.
(e) 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 5: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the Los Angeles ACO.
(f) 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.
(g) The inspections and modifications shall be done in
accordance with McDonnell Douglas DC-10 Service Bulletin 55-24,
Revision 1, dated August 3, 1994; and McDonnell Douglas DC-10
Service Bulletin 55-25, Revision 1, dated August 3, 1994. 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, California 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, Transport Airplane Directorate, Los Angeles Aircraft
Certification Office, 3229 East Spring Street, Long Beach,
California; or at the Office of the Federal Register, 800 North
Capitol Street, NW., suite 700, Washington, DC.
(h) This amendment becomes effective on October 31, 1994.
Issued in Renton, Washington, on September 26, 1994.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 94-24199 Filed 10-3-94; 8:45 am]
BILLING CODE 4910-13-U
