[Federal Register Volume 64, Number 73 (Friday, April 16, 1999)]
[Rules and Regulations]
[Pages 18802-18804]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-9253]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-NM-197-AD; Amendment 39-11131; AD 99-08-22]
RIN 2120-AA64


Airworthiness Directives; McDonnell Douglas Model DC-10 Series 
Airplanes and KC-10 (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-10 (military) airplanes, that requires repetitive inspections to 
detect fatigue cracking of the rear spar cap of the horizontal 
stabilizer; and repair, if necessary. The amendment 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 amendment is prompted by reports of 
fatigue cracking of the rear spar cap of the horizontal stabilizer. The 
actions specified by this amendment 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: Effective May 21, 1999.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of May 21, 1999.

ADDRESSES: The service information referenced in this AD 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 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, 3960 Paramount Boulevard, 
Lakewood, California; or at the Office of the Federal Register, 800 
North Capitol Street, NW., suite 700, Washington, DC.

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: 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 series airplanes and KC-10 (military) airplanes was published in 
the Federal Register on August 4, 1998 (63 FR 41479). That action 
proposed to 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. That action 
also proposed to require a preventive modification of the rear spar cap 
of the horizontal stabilizer, which would constitute terminating action 
for the repetitive inspections.
    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received.

Support for the Proposal

    One commenter supports the proposed rule.

Request To Revise the Compliance Time of the Terminating Action

    One commenter requests that the proposed compliance time for 
accomplishment of the terminating modification be revised from ``within 
5 years'' to ``within 5 years or prior to the accumulation of 18,000 
landings after the effective date of the AD, whichever occurs later.'' 
The commenter contends that such a revision of the compliance time 
would allow the preventive modification installation on low-time DC-10 
series airplanes to be consistent with the initial inspection threshold 
of the proposal.
    The FAA concurs partially. It is appropriate to specify an 18,000-
landing compliance time for accomplishment of the terminating action. 
However, to be consistent with the compliance time specified in 
paragraph (a) of this AD, that threshold must include total landings 
accumulated on the airplane, not just those accumulated after the 
effective of this AD, as requested by the commenter.

Requests for Credit for Previous Accomplishment of the AD 
Requirements

    One commenter requests that credit be given for previous 
accomplishment of the proposed initial inspection. That commenter 
specifically requests that credit for the initial inspection be given 
if it was accomplished in accordance with McDonnell Douglas Comtwx DC-
10-COM-0047/SFY, dated December 11, 1997. Another commenter requests 
that credit be given for initial inspections and installation of the 
preventive modification that were accomplished prior to the effective 
date of the AD in accordance with the service bulletin specified in the 
proposal.
    The FAA has reviewed the referenced comtwx and concurs that credit 
may be given for the accomplishment of the initial inspection required 
by this AD if it was done in accordance with the comtwx referenced by 
the commenter. The FAA also notes that the comtwx is referenced in 
McDonnell Douglas Alert Service Bulletin DC10-55A028, dated April 27, 
1998, (which is the appropriate service information for this AD), as an 
additional source of service information. Therefore, the FAA has 
revised the final rule to add a new ``Note 2'' to give credit to 
operators that may have accomplished previously the initial inspection 
in accordance with McDonnell Douglas Comtwx DC-10-COM-0047/SFY, dated 
December 11, 1997.
    The FAA also concurs with the request to allow credit for 
accomplishment of actions specified in McDonnell Douglas Alert Service 
Bulletin DC10-55A028, dated April 27, 1998, that were accomplished 
prior to the effective date of this AD. The FAA notes that operators 
are generally given credit for work accomplished previously if the work 
is performed in accordance with the final rule by means of the phrase 
in the compliance section of the

[[Page 18803]]

AD that states, ``Required as indicated, unless accomplished 
previously.'' Therefore, no change in the final rule is necessary in 
this regard.

Request To Justify That Unsafe Condition Exists on Certain 
Airplanes

    One commenter notes that the horizontal stabilizer center section 
of Model DC-10-30/40 series airplanes is different than that of Model 
DC-10-10 series airplanes, and that reports of cracking of the rear 
spar cap of the horizontal stabilizer have only occurred on Model DC-
10-10 series airplanes. Therefore, the commenter questions the need to 
require installation of the proposed modification on DC-10-30/40 series 
airplanes, and requests that the FAA provide justification that an 
unsafe condition actually exists on the Model DC-10-30/40 series 
airplanes. The FAA infers that the commenter is requesting the FAA 
remove Model DC-10-30/40 series airplanes from the applicability of the 
proposal if the FAA cannot justify that an unsafe condition exists for 
that model.
    The FAA does not concur that further justification of an unsafe 
condition on DC-10-30/40 series airplanes is necessary, or that Model 
DC-10-30/40 series models should be removed from the applicability of 
this AD. Although the structure of the horizontal stabilizer center 
section is thicker on Model DC-10-30/40 series airplanes than the same 
structure on Model DC-10-10 series airplanes, the FAA finds that the 
thicker structure is necessary because of the higher loads sustained by 
Model DC-10-30/40 series airplanes. The airplane manufacturer also 
concurs that fatigue cracking of the horizontal stabilizer is as likely 
to develop on a Model DC-10-30/40 series airplane as on a Model DC-10-
10 series airplane. Therefore, no change to the final rule is 
necessary.

Conclusion

    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.

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) will be affected by this 
AD.
    It will take approximately 2 work hours per airplane to accomplish 
the required inspections, at an average labor rate of $60 per work 
hour. Based on these figures, the cost impact of the inspections 
required 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 will take approximately 34 work hours per airplane to accomplish 
the terminating modification, at an average labor rate of $60 per work 
hour. Required parts will 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 required 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 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.
    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 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:

99-08-22  McDonnell Douglas: Amendment 39-11131. 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.

    Note 2: Accomplishment of 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 Comtwx DC-10-COM-0047/SFY, dated December 11, 
1997, prior to the effective date of this AD, is acceptable for 
compliance with the initial inspection requirements required by 
paragraph (a) of this AD.

    (1) If no cracking is detected, repeat the inspection thereafter 
at intervals not to exceed 2,200 landings until accomplishment

[[Page 18804]]

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 or prior 
to the accumulation of 18,000 total landings, 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, 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.

Alternative Methods of Compliance

    (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 3: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Los Angeles ACO.

Special Flight Permits

    (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.

Incorporation by Reference

    (e) The actions shall be done in accordance with McDonnell 
Douglas Alert Service Bulletin DC10-55A028, dated April 27, 1998. 
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 The Boeing Company, Douglas Products 
Division, 3855 Lakewood Boulevard, Long Beach, California 90846, 
Attention: Technical Publications Business Administration, Dept. C1-
L51 (2-60) 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, 3960 Paramount Boulevard, Lakewood, 
California; or at the Office of the Federal Register, 800 North 
Capitol Street, NW., suite 700, Washington, DC.
    (f) This amendment becomes effective on May 21, 1999.

    Issued in Renton, Washington, on April 7, 1999.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 99-9253 Filed 4-15-99; 8:45 am]
BILLING CODE 4910-13-P