[Federal Register Volume 61, Number 173 (Thursday, September 5, 1996)]
[Rules and Regulations]
[Pages 46704-46706]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-22262]


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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 95-NM-204-AD; Amendment 39-9735; AD 96-18-11]
RIN 2120-AA64


Airworthiness Directives; McDonnell Douglas Model DC-10-10 and -
15 Series 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-10-10 and -15 series 
airplanes, that requires repetitive inspections to detect cracks in the 
bulkhead tee caps, and repair and follow-on actions, if necessary. It 
also provides for an optional terminating modification for the 
repetitive inspections. This amendment is prompted by reports of 
cracking in the bulkhead tee caps at a fuselage station in the area of 
certain longerons due to fatigue. The actions specified by this AD are 
intended to prevent such fatigue cracking, which could result in loss 
of pressurization and damage to adjacent structure.

DATES: Effective October 10, 1996.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of October 10, 1996.

ADDRESSES: The service information referenced in this AD may be 
obtained from McDonnell Douglas Corporation, 3855 Lakewood Boulevard, 
Long Beach, California 90846, Attention: Technical Publications 
Business Administration, Department 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, Los Angeles Aircraft Certification Office, 
Transport Airplane Directorate, 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: Maureen Moreland, Aerospace Engineer, 
Airframe Branch, ANM-120L, FAA, Los Angeles Aircraft Certification 
Office, 3960 Paramount Boulevard, Lakewood, California 90712; telephone 
(310) 627-5238; fax (310) 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-10-10 and -15 series airplanes was published in the Federal Register 
on March 28, 1995 (61 FR 13787). That action proposed to require 
repetitive inspections to detect cracks in the bulkhead tee caps, and 
repair and follow-on actions, if necessary. The proposal would also 
provide for an optional terminating modification for the repetitive 
inspections.
    Interested persons have been afforded an opportunity to participate 
in the

[[Page 46705]]

making of this amendment. Due consideration has been given to the 
comments received.

Support for the Proposal

    Two commenters support the proposal.

Request to Ensure that Parts are Available

    One commenter who supports the proposal is concerned that enough 
replacement parts may not be available to support the repair 
requirements of the proposed rule.
    The FAA responds to this concern by stating that the manufacturer 
has advised that ample replacement tee cap splices will be available to 
the U.S. fleet in support of any necessary repair that may be required 
as a result of the inspection required by this rule.

Request for a Revision of Initial Inspection Interval

    Two commenters request that the proposed rule be revised to extend 
the initial inspection interval for airplanes on which the modification 
specified in the manufacturer's Structural Repair Manual (SRM), Chapter 
53-40-00, Volume 1, has been accomplished. This modification involves 
installing an arrowhead doubler at station Y=1156.000. For airplanes 
with this modification, the commenters request that the initial 
inspection interval be changed from the proposed 1,500 landings to 
2,200 landings. The commenters state that this extension will allow the 
inspection to be accomplished during regularly scheduled maintenance 
(i.e., a ``C'' check) at a main base. One commenter states that trying 
to accomplish a radiographic inspection at a field station (rather than 
at a main base) is very difficult and, if cracks are detected during 
the inspection, it is nearly impossible to repair them at a field 
station since trained personnel and appropriate equipment may not be 
available.
    The FAA does not concur with the commenters' request for two 
reasons:
    First, the accomplishment of the SRM modification specified by the 
commenters has been determined--via an assessment by both the airframe 
manufacturer and the FAA--to have no effect on the time that cracks may 
initiate and grow in the bulkhead tee caps at fuselage station 
Y=1156.00. Although the McDonnell Douglas service bulletin cited in 
this rule does refer to that SRM modification, the reference is made 
only to discuss the fact that the accomplishment of the SRM 
modification affects the methodology that must be used for the 
inspection and installation of a preventative modification of the 
bulkhead tee cap. Therefore, there is no basis to connect the 
inspection times required by this AD to whether or not the SRM 
modification has been accomplished.
    Second, the compliance time for the initial inspection required by 
this AD is based on the reports of fatigue cracking in the bulkhead tee 
caps on airplanes that had accumulated between 56,394 and 72,931 total 
flight hours and between 21,629 and 26,094 total landings. The FAA has 
determined that inspections of this area by the time the airplane has 
accumulated at least 20,000 total landings will ensure that fatigue 
cracking is detected before it reaches a critical length.
    The ``1,500 landings'' specified in the AD's compliance time is a 
``grace period'' that was established to preclude grounding airplanes 
that have exceeded the 20,000-landing threshold. In determining an 
appropriate ``grace period'' for this action, the FAA not only 
considered the degree of urgency associated with addressing the unsafe 
condition, but normal scheduled maintenance for the majority of 
affected operators, recommendations of the manufacturer, analysis of 
the rate of crack growth, and reports of cracking found in the in-
service fleet. In consideration of all of these factors, the FAA finds 
that the 1,500-landing ``grace period'' for initiating the required 
inspections on higher-time airplanes to be warranted, in that it 
represents an appropriate interval of time allowable for airplanes to 
continue to operate without compromising safety.

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 as proposed.

Cost Impact

    There are approximately 133 Model McDonnell Douglas Model DC-10-10 
and -15 series airplanes of the affected design in the worldwide fleet. 
The FAA estimates that 121 airplanes of U.S. registry will be affected 
by this AD, that it will take approximately 3 work hours per airplane 
to accomplish the required inspections, and that the average labor rate 
is $60 per work hour. Based on these figures, the cost impact of the AD 
on U.S. operators is estimated to be $21,780, or $180 per airplane, per 
inspection cycle.
    The cost impact figure discussed above 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.

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:

96-18-11 McDonnell Douglas: Amendment 39-9735. Docket 95-NM-204-AD.

    Applicability: Model DC-10-10 and -15 series airplanes, as 
listed in McDonnell Douglas Service Bulletin DC10-53-168, dated 
August 9, 1995; certificated in any category.

    Note 1: This AD applies to each airplane identified in the 
preceding applicability

[[Page 46706]]

provision, regardless of whether it has been otherwise 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, which could result in loss of 
pressurization and damage to adjacent structure, accomplish the 
following:
    (a) Prior to the accumulation of 20,000 total landings, or 
within 1,500 landings after the effective date of this AD, whichever 
occurs later, perform an eddy current and radiographic inspection, 
as applicable, to detect cracks in the bulkhead tee caps (left and 
right sides) in the area of longerons 38.0 through 41.0 at fuselage 
station Y=1156.000, in accordance with McDonnell Douglas Service 
Bulletin DC10-53-168, dated August 9, 1995.
    (1) If no cracks are detected, repeat the inspections thereafter 
at intervals not to exceed 2,600 landings until paragraph (b) of 
this AD is accomplished.
    (2) If any crack is detected, prior to further flight, 
accomplish the repair specified in either paragraph (a)(2)(i) or 
(a)(2)(ii) of this AD.
    (i) Splice in a new bulkhead tee cap section at cracked area of 
bulkhead tee cap in accordance with the service bulletin. Within 
20,000 total landings after accomplishing this repair, perform eddy 
current inspections to detect cracks in accordance with the service 
bulletin. Repeat the inspections thereafter at intervals not to 
exceed 2,600 landings until paragraph (b) of this AD is 
accomplished. If any crack is detected, prior to further flight, 
repair it in accordance with a method approved by the Manager, Los 
Angeles Aircraft Certification Office (ACO), FAA, Transport Airplane 
Directorate.
    (ii) Repair in accordance with a method approved by the Manager, 
Los Angeles ACO, FAA, Transport Airplane Directorate.
    (b) Terminating action for the repetitive inspections required 
by paragraphs (a)(1) and (a)(2)(i) of this AD is as follows:
    (1) Accomplish the preventative modification and eddy current 
open hole inspection in accordance with Condition 1 (no cracks in 
bulkhead tee cap), Option 2, of McDonnell Douglas Service Bulletin 
DC10-53-168, dated August 9, 1995. And
    (2) Within 14,450 total landings following accomplishment of the 
modification specified in paragraph (b)(1) of this AD, perform an 
eddy current and radiographic inspection to detect cracks, in 
accordance with Condition 1 (no cracks in bulkhead tee cap), Option 
2, of the service bulletin.
    (i) If no cracks are detected, repeat the inspections thereafter 
at intervals not to exceed 3,950 landings.
    (ii) If any crack is detected, prior to further flight, repair 
it in accordance with a method approved by the Manager, Los Angeles 
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 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.
    (e) The inspections shall be done in accordance with McDonnell 
Douglas Service Bulletin DC10-53-168, dated August 9, 1995. 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, 3855 
Lakewood Boulevard, Long Beach, California 90846, Attention: 
Technical Publications Business Administration, Department C1-L51 
(2-60). Copies may be inspected at the FAA, Transport Airplane 
Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the 
FAA, Los Angeles Aircraft Certification Office, Transport Airplane 
Directorate, 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 October 10, 1996.

    Issued in Renton, Washington, on August 26, 1996.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 96-22262 Filed 9-4-96; 8:45 am]
BILLING CODE 4910-13-U