# Airworthiness Directives; McDonnell Douglas Model DC-10 Series Airplanes and Model KC-10A (Military) Airplanes

> Briefs, arguments, decisions, and more.

URL: https://www.frixlaw.com/law-library/documents/fr%3A94-13627

## Record

- **Collection:** Federal Register
- **Document type:** Uncategorized Document
- **Published:** June 13, 1994

## Text

DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 93-NM-90-AD; Amendment 39-8933; AD 94-12-05]

Airworthiness Directives; McDonnell Douglas Model DC-10 Series
Airplanes and Model KC-10A (Military) Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

-----------------------------------------------------------------------

SUMMARY: This amendment adopts a new airworthiness directive (AD),
applicable to all McDonnell Douglas Model DC-10 series airplanes and
Model KC-10A (military) airplanes, that requires inspections to detect
cracks in wing stringer number 41; installation of a repair, if
necessary; and modification of that stringer. This amendment is
prompted by reports of fatigue cracks in outer wing stringer number 41.
The actions specified by this AD are intended to prevent reduced
structural integrity of the wing.

DATES: Effective July 13, 1994.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of July 13, 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: Maureen Moreland, Aerospace Engineer,
Airframe Branch, ANM-120L, FAA, Transport Airplane Directorate, Los
Angeles Aircraft Certification Office, 3229 East Spring Street, Long
Beach, California 90806-2425; telephone (310) 988-5238; 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 all McDonnell Douglas Model DC-10 series airplanes and
Model KC-10A (military) airplanes was published in the Federal Register
on September 24, 1993 (58 FR 49946). That action proposed to require
inspections to detect cracks in wing stringer number 41; installation
of a repair, if necessary; and modification of that stringer.
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 members, requests that the FAA include a flow diagram in the
proposal since its provisions are complex. The FAA does not concur. The
FAA considers that the requirements of this AD are presented in a
reasonably clear manner in the text of the final rule. In addition,
McDonnell Douglas DC-10 Service Bulletin 57-114, Revision 1, dated July
26, 1993, which is referenced in the AD as the appropriate source of
service information, provides corresponding guidance for accomplishment
of the actions required by this AD.
ATA also suggests that, prior to issuance of the final rule, the
FAA should verify that the service bulletin will not create problems
for operators, and that accomplishment of the service bulletin should
be verified by an operator before the AD is finalized. One ATA member
experienced difficulty accomplishing the permanent repair specified in
the service bulletin because parts listed did not fit, drawings were
erroneous, and fastener grip lengths were inadequate for the repair.
The FAA concurs with the commenter's request. The FAA has conveyed
these concerns to the manufacturer, and has verified that the initial
problems expressed by the commenter have been corrected in Revision 1
of the service bulletin. Since Revision 1 of the service bulletin was
cited in the proposal as the appropriate source of service information,
the FAA finds that no change to the AD is necessary.
One commenter requests that the FAA allow visual inspection methods
to be used in lieu of the proposed eddy current inspection methods. The
commenter indicates that fastener accessibility enables accomplishment
of a visual inspection and provides an equivalent level of crack
detection. The FAA does not concur. Based on the results of crack
growth analysis, the FAA has determined that a visual inspection of the
stringer cannot provide an acceptable level of crack detection. In
addition, the FAA based the repetitive inspection intervals on the
crack growth analysis results based upon the minimum crack length
detectable by eddy current inspection.
The commenter also requests that credit be given for general visual
inspections accomplished previously. A second commenter supports the
proposed rule, but requests that the AD be revised to state that
inspections accomplished within 1,500 landings prior to the effective
date of the AD are acceptable in lieu of the initial inspection. The
commenters provide no justification for these requests. Since the FAA
has determined that a visual inspection of the stringer does not
provide an acceptable level of crack detection, as discussed
previously, the FAA considers that the requirement for eddy current
inspections is appropriate and credit cannot be extended for general
visual inspections accomplished previously. However, the phrase
``unless accomplished previously,'' which appears in the ``Compliance''
paragraph of the final rule, provides credit for operators that have
accomplished the required inspection prior to the effective date of
this AD in accordance with McDonnell Douglas DC-10 Service Bulletin 57-
114, Revision 1, dated July 26, 1993.
One commenter requests that the first inspection accomplished to
comply with this AD be required during the airplane's next heavy
maintenance visit if a general visual inspection has been accomplished
prior to the effective date of the AD. The FAA does not concur. A
general visual inspection of the stringer does not provide an
acceptable level of crack detection, as discussed previously. In
developing an appropriate initial compliance time for this action, the
FAA considered the safety implications and normal maintenance schedules
for timely accomplishment of the inspection. In consideration of these
items, the FAA has determined that 6,500 total landings or 1,500
landings after the effective date of the AD, whichever occurs later,
represents the maximum interval of time allowable wherein the
inspection can reasonably be accomplished and an acceptable level of
safety can be maintained.
The same commenter states that the service bulletin cited in the AD
specifies that one reason for accomplishing the actions described in
the service bulletin is to prevent unscheduled maintenance downtime for
replacement of a cracked stringer; therefore, the commenter questions
the need for this AD. The commenter adds that, to date, stringer 41
cracking has not impacted its maintenance due to the viable maintenance
program currently in place. The commenter states that imposing an AD at
this time would only complicate its maintenance program and would
contribute little toward ensuring that the airplane wing structure is
operating in good condition.
The FAA does not concur. As explained in the preamble of the
proposal, the FAA has received reports of fatigue cracks in outer wing
stringer number 41 and, in one case, complete failure of the stringer.
Such fatigue cracking presents an unsafe condition in airplanes, since
it could eventually lead to failure of the stringer and reduced
structural integrity of the wing. The FAA has determined that this
unsafe condition could exist or eventually develop on Model DC-10
series airplanes and Model KC-10A (military) airplanes, and that
repetitive inspections of the affected area must be mandated to ensure
that safety is not degraded. The appropriate vehicle for mandating such
action to correct an unsafe condition is the airworthiness directive.
One commenter requests that the proposed compliance time for
accomplishment of the initial inspection specified in paragraph (b)(1)
of the proposal be changed from ``[p]rior to the accumulation of 6,500
total landings, or within 1,500 landings after the effective date of
the AD, whichever occurs later,'' to ``[p]rior to the accumulation of
6,500 total landings, or within one year after the effective date of
this AD, whichever occurs later.'' The commenter operates Model DC-10-
40 series airplanes of non-U.S. registry for training flights for
cockpit crews. The commenter explains that, during one training flight
period of a few weeks, the number of flight cycles accumulated may be
more than 1,500 landings. The commenter adds that the proposed
inspections and modifications require entry into the fuel tanks;
therefore, the commenter plans to accomplish the initial inspections
and the modifications during regularly scheduled maintenance.
The FAA does not concur with the commenter's request. Compliance
times for AD's are normally based on a parameter related to failure of
a particular component. In this case, fatigue cracking in outer wing
stringer number 41 and subsequent failure of the stringer are
undoubtedly related to the number of landings. The FAA has determined,
in this case, that there is no apparent direct relationship between
failure of the stringer and calendar time. In light of this, and in
consideration of the average utilization rate of the affected U.S.
operators and the practical aspects of orderly inspections of the U.S.
fleet during regular maintenance periods, the FAA established the
compliance times specified in this AD. The FAA maintains that those
compliance times are appropriate. However, the FAA would consider a
request for adjustment of the compliance time, in accordance with the
provisions of paragraph (c) of this AD, provided that, for example,
continued operational safety of the airplane could be assured until the
required action is accomplished.
One commenter requests that, in order for the AD requirements to
align with the actions described in the service bulletin,
accomplishment of the preventative modification should be considered
optional, and that operators should be permitted to accomplish
repetitive inspections at intervals of 4,000 landings in lieu of the
preventative modification. The FAA does not concur. The degree of
assurance necessary as to the adequacy of inspections needed to
maintain the safety of the aging transport airplane fleet, coupled with
a better understanding of the human factors associated with numerous
repetitive inspections, has caused the FAA to place less emphasis on
repetitive inspections and more emphasis on design improvements and
material replacement. Thus, in lieu of its previous position of
continual inspection, and repair or modification on condition if cracks
are found, the FAA has decided to require, whenever practicable,
airplane modifications necessary to remove the source of the particular
aging phenomena.
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 changes previously
described. The FAA has determined that these changes will neither
increase the economic burden on any operator nor increase the scope of
the AD.
There are approximately 426 Model DC-10 series airplanes and Model
KC-10A (military) airplanes of the affected design in the worldwide
fleet. The FAA estimates that 121 Model DC-10-10 and -15 series
airplanes of U.S. registry will be affected by this AD, that it will
take approximately 13.6 work hours per airplane to accomplish the
required actions, and that the average labor rate is $55 per work hour.
Required parts for Model DC-10-10 and -15 series airplanes will cost
approximately $586 per airplane. Based on these figures, the total cost
impact of the AD on U.S. operators of Model DC-10-10 and -15 series
airplanes is estimated to be $161,414, or $1,334 per airplane.
The FAA estimates that 148 Model DC-10-30 and -40 series airplanes
and Model KC-10A (military) airplanes of U.S. registry will be affected
by this AD, that it will take approximately 13.6 work hours per
airplane to accomplish the required actions, and that the average labor
rate is $55 per work hour. Required parts for Model DC-10-30 and -40
series airplanes and Model KC-10A (military) airplanes will cost
approximately $1,420 per airplane. Based on these figures, the total
cost impact of the AD on U.S. operators of Model DC-10-30 and -40
series airplanes and Model KC-10A (military) airplanes is estimated to
be $320,864, or $2,168 per airplane.
Based on these figures, the total cost impact of the AD on U.S.
operators is estimated to be $482,278. The total cost impact figure 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:

94-12-05 McDonnell Douglas: Amendment 39-8933. Docket 93-NM-90-AD.

-Applicability: All Model DC-10-10, -10F, -15, -30, -30F, -40,
and -40F series airplanes and Model KC-10A (military) airplanes;
certificated in any category. -
Compliance: Required as indicated, unless accomplished
previously. -
To prevent reduced structural integrity of the wing, accomplish
the following: -
(a) For Model DC-10-10, -10F, and -15 series airplanes:
Accomplish paragraphs (a)(1), (a)(2), (a)(3), and (a)(4) of this AD
in accordance with McDonnell Douglas DC-10 Service Bulletin 57-114,
Revision 1, dated July 26, 1993. -
(1) Prior to the accumulation of 6,500 total landings, or within
1,500 landings after the effective date of this AD, whichever occurs
later: Perform an eddy current surface inspection or an eddy current
bolt hole inspection to detect cracks on stringer number 41 on the
left- and right-hand wings, in accordance with the service bulletin.
-
(2) If no crack is found, repeat the inspection thereafter at
intervals not to exceed 4,000 landings. -
(3) If any crack is found, prior to further flight, accomplish
paragraph (a)(3)(i), (a)(3)(ii), or (a)(3)(iii) of this AD, as
applicable. -
(i) If any crack is found that extends upward from the fastener
hole, and if that crack is outside the limits specified in Condition
2 of the service bulletin, accomplish a temporary repair in
accordance with Condition 2, Phase I of the service bulletin, or a
permanent repair in accordance with Condition 2, Phase II of the
service bulletin. If the temporary repair is accomplished, prior to
the accumulation of 5,000 landings after accomplishing that
temporary repair, accomplish the permanent repair in accordance with
Condition 2, Phase II of the service bulletin. After accomplishment
of the permanent repair, no further action is required by this AD. -
(ii) If any crack is found that extends downward from the
fastener hole, and if that crack is outside the limits specified in
Condition 2 of the service bulletin, accomplish the permanent repair
in accordance with Condition 2, Phase II of the service bulletin.
After such repair, no further action is required by this AD. -
(iii) If any crack is found in a fastener hole, and if that
crack is within the limits specified in Condition 2 of the service
bulletin, accomplish the preventative modification in accordance
with Condition 1, Option II of the service bulletin. If the crack
was detected using techniques other than the eddy current bolt hole
inspection described in the service bulletin, prior to accomplishing
the preventative modification, perform an eddy current bolt hole
inspection to detect cracks, in accordance with the service
bulletin, and accomplish paragraph (a)(3)(iii)(A), (a)(3)(iii)(B),
or (a)(3)(iii)(C) of this AD, as applicable. -
(A) If any crack is found that extends upward from the fastener
hole, and if that crack is outside the limits specified in Condition
2 of the service bulletin, accomplish the requirements of paragraph
(a)(3)(i) of this AD. -
(B) If any crack is found that extends downward from the
fastener hole, and if that crack is outside the limits specified in
Condition 2 of the service bulletin, accomplish the requirements of
paragraph (a)(3)(ii) of this AD.
(C) If any crack is found that is within the limits specified in
Condition 2 of the service bulletin, accomplish the preventative
modification in accordance with Condition 1, Option II of the
service bulletin. After accomplishment of the preventative
modification, no further action is required by this AD.
(4) Except for airplanes on which the preventative modification
(Condition 1, Option II) or the permanent repair (Condition 2, Phase
II) has been accomplished, prior to the accumulation of 6,500 total
landings, or within 5 years after the effective date of this AD,
whichever occurs later: Perform an eddy current bolt hole inspection
to detect cracks in the fastener holes in accordance with the
service bulletin.
(i) If no crack is found, or if any crack is found that is
within the limits specified in Condition 2 of the service bulletin,
prior to further flight, accomplish the preventative modification in
accordance with Condition 1, Option II of the service bulletin.
After accomplishment of the preventative modification, no further
action is required by this AD.
(ii) If any crack is found that exceeds the limits specified in
Condition 2 of the service bulletin, prior to further flight,
accomplish a permanent repair in accordance with Condition 2, Phase
II of the service bulletin. After accomplishment of the permanent
repair, no further action is required by this AD.
(b) For Model DC-10-30, -30F, -40, and -40F series airplanes and
Model KC-10A (military) airplanes: Accomplish paragraphs (b)(1),
(b)(2), (b)(3), and (b)(4) of this AD in accordance with McDonnell
Douglas DC-10 Service Bulletin 57-114, Revision 1, dated July 26,
1993. -
(1) Prior to the accumulation of 6,500 total landings, or within
1,500 landings after the effective date of this AD, whichever occurs
later: Perform an eddy current surface inspection or an eddy current
bolt hole inspection to detect cracks on stringer number 41 on the
left- and right-hand wings in accordance with the service bulletin.
(2) If no crack is found, repeat the inspection thereafter at
intervals not to exceed 3,200 landings.
(3) If any crack is found, prior to further flight, accomplish
paragraph (b)(3)(i), (b)(3)(ii), or (b)(3)(iii) of this AD, as
applicable.
(i) If any crack is found that extends upward from the fastener
hole, and if that crack is outside the limits specified in Condition
2 of the service bulletin, accomplish a temporary repair in
accordance with Condition 2, Phase I of the service bulletin, or a
permanent repair in accordance with Condition 2, Phase II of the
service bulletin. If the temporary repair is accomplished, prior to
the accumulation of 5,000 landings after accomplishing that
temporary repair, accomplish the permanent repair in accordance with
Condition 2, Phase II of the service bulletin. After accomplishment
of the permanent repair, no further action is required by this AD.
(ii) If any crack is found that extends downward from the
fastener hole, and if that crack is outside the limits specified in
Condition 2 of the service bulletin, accomplish the permanent repair
in accordance with Condition 2, Phase II of the service bulletin.
After such repair, no further action is required by this AD.
(iii) If any crack is found in a fastener hole, and if that
crack is within the limits specified in Condition 2 of the service
bulletin, accomplish the preventative modification in accordance
with Condition 1, Option II of the service bulletin. If the crack
was detected using techniques other than the eddy current bolt hole
inspection described in the service bulletin, prior to accomplishing
the preventative modification, perform an eddy current bolt hole
inspection to detect cracks, in accordance with the service
bulletin, and accomplish paragraph (b)(3)(iii)(A), (b)(3)(iii)(B),
or (b)(3)(iii)(C) of this AD, as applicable.
(A) If any crack is found that extends upward from the fastener
hole, and if that crack is outside the limits specified in Condition
2 of the service bulletin, accomplish the requirements of paragraph
(b)(3)(i) of this AD.
(B) If any crack is found that extends downward from the
fastener hole, and if that crack is outside the limits specified in
Condition 2 of the service bulletin, accomplish the requirements of
paragraph (b)(3)(ii) of this AD.
(C) If any crack is found that is within the limits specified in
Condition 2 of the service bulletin, accomplish the preventative
modification in accordance with Condition 1, Option II of the
service bulletin. After accomplishment of the preventative
modification, no further action is required by this AD.
(4) Except for airplanes on which the preventative modification
(Condition 1, Option II) or the permanent repair (Condition 2, Phase
II) has been accomplished, prior to the accumulation of 6,500 total
landings, or within 5 years after the effective date of this AD,
whichever occurs later: Perform an eddy current bolt hole inspection
to detect cracks in the fastener holes in accordance with the
service bulletin.
(i) If no crack is found, or if any crack is found that is
within the limits specified in Condition 2 of the service bulletin,
prior to further flight, accomplish the preventative modification in
accordance with Condition 1, Option II of the service bulletin.
After accomplishment of the preventative modification, no further
action is required by this AD.
(ii) If any crack is found that exceeds the limits specified in
Condition 2 of the service bulletin, prior to further flight,
accomplish a permanent repair in accordance with Condition 2, Phase
II of the service bulletin. After accomplishment of the permanent
repair, no further action is required by 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: 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
Federal Aviation Regulations (FAR) Sec. 21.197 and Sec. 21.199 to
operate the airplane to a location where the requirements of this AD
can be accomplished.
(e) The inspections, repairs, and modification shall be done in
accordance with McDonnell Douglas DC-10 Service Bulletin 57-114,
Revision 1, dated July 26, 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, 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.
(f) This amendment becomes effective on July 13, 1994.

Issued in Renton, Washington, on May 31, 1994.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 94-13627 Filed 6-10-94; 8:45 am]
BILLING CODE 4910-13-U

---

Source: Frix Law Library, https://www.frixlaw.com/law-library/documents/fr%3A94-13627. Public record. Not legal advice.