[Federal Register Volume 61, Number 132 (Tuesday, July 9, 1996)]
[Rules and Regulations]
[Pages 35944-35946]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-16951]


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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 95-NM-254-AD; Amendment 39-9686; AD 96-14-04]
RIN 2120-AA64


Airworthiness Directives; McDonnell Douglas Model DC-10 and MD-11 
Series Airplanes, and KC-10A (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 and MD-11 series 
airplanes, and KC-10A (military) airplanes, that requires identifying 
and replacing certain lock link bolts in the nose landing gear (NLG). 
This amendment is prompted by a report indicating that certain bolts 
were improperly heat-treated during manufacturing, which makes them 
prone to failure. The actions specified by this AD are intended to 
prevent failure of the lock link bolts in the NLG, which could result 
in the collapse of the NLG.

DATES: Effective August 13, 1996.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of August 13, 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: Wahib Mina, Aerospace Engineer, 
Airframe Branch, ANM-120L, FAA, Los Angeles Aircraft Certification 
Office, 3960 Paramount Boulevard, Lakewood, California 90712; telephone 
(310) 627-5324; 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 and MD-11 series airplanes, and KC-10A (military) airplanes was 
published in the Federal Register on March 18, 1996 (61 FR 10907). That 
action proposed to require a one-time visual inspection to identify 
suspect lock link bolts, and the replacement of those bolts with new 
serviceable bolts.
    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

    Four commenters support the proposal.

Request To Allow Records Search in Lieu of Inspection

    One commenter requests that the proposed rule be revised to allow 
operators to conduct a records search to determine if airplanes are 
equipped with the suspect bolt, rather than conduct an inspection of 
every airplane in order to determine if the bolt is installed. This 
commenter states that, for some operators, the NLG lock link bolts are 
required to have a tracking history (i.e., records track the bolt by 
serial number). For these operators, it would be more economically 
feasible, and just as productive, to conduct a records search in lieu 
of an inspection.
    The FAA concurs. Paragraph (a) of the final rule has been revised 
to provide for the option of conducting a records search.

Request To Extend the Compliance Time for Replacement

    Several commenters request that the proposed rule be revised to 
allow operators to replace suspect bolts at a later time. These 
commenters request that, instead of requiring that a suspect bolt be 
replaced prior to further flight after the inspection is accomplished, 
the proposed rule should permit operators to replace the bolt at any 
time after the inspection, but prior to the end of the 24-month 
compliance time. These commenters consider that this extension of the 
replacement time will obtain the same result as intended by the FAA, 
and will have a less disruptive impact on operators' schedules.
    The FAA concurs that the bolts need not be replaced prior to 
further flight after the inspection (or records search) is 
accomplished. The FAA makes this finding based on the following data 
pertinent to the configuration of the suspect bolts themselves:
    1. None of the suspect bolts were manufactured prior the initial 
production of the Model MD-11 series airplanes (in 1991). In light of 
this, the FAA is confident that none of the suspect bolts was installed 
as original equipment on any of the affected Model DC-10 series 
airplanes. (Model DC-10's have been produced since 1971.)
    2. The suspect bolts were manufactured using a process that did not 
affect their static strength requirement, but did reduce their fatigue 
life. These bolts should have a fatigue life in the range of 58,281 
landings; due to the manufacturing process used, however, the fatigue 
life

[[Page 35945]]

of the suspect bolts has been reduced to approximately 24,638 landings.
    3. A review of the utilization rates of the current worldwide fleet 
indicates that the highest number of landings accumulated on any Model 
MD-11 series airplane is approximately 5,000 landings.
    4. The average annual utilization rate of the airplanes affected by 
this AD is between 1,000 and 1,200 landings.
    These data indicate that, if any suspect bolt had been installed as 
original equipment on a Model MD-11 (even those airplanes with the 
highest number of landings accumulated so far), or installed as a 
replacement component on a Model DC-10, the fatigue life ``remaining'' 
on any suspect bolt is long enough to permit continued use of that bolt 
for a 24-month period.
    Based on these factors, the FAA has determined that a large enough 
margin of safety exists so that replacement of the suspect bolts may be 
accomplished within 24 months after the effective date of this AD, 
regardless of when the inspection (or records search) is performed. 
Paragraph (c) of the final rule has been revised to specify this.

Request To Permit Replacement With Other Than New Bolts

    One commenter, the airframe manufacturer, requests that the 
proposed rule be revised to delete the requirement that a ``new'' bolt 
be used as a replacement bolt. This commenter states that the use of 
the term ``new'' excludes the use of refurbished or serviceable bolts 
that do not have one of the suspect serial numbers.
    The FAA concurs. Serviceable (non-suspect) bolts are acceptable as 
replacement parts. Accordingly, paragraph (c) of the final rule has 
been revised to delete the word ``new'' from the description of 
required replacement bolts.

Request To Ensure Availability of Replacement Parts

    One commenter expresses concerns that the replacement bolts will 
not be available in a timely manner. This commenter states that several 
service bulletins recently have been released by McDonnell Douglas that 
recommend inspections and replacement of high-strength landing gear 
parts that were improperly heat-treated. This commenter is concerned 
that the bolt suppliers may not be able to meet the concurrent demand 
for the large quantity of parts needed for the entire affected fleet.
    The FAA acknowledges this commenters concerns, and just recently 
contacted the manufacturer on this very subject. The manufacturer has 
assured the FAA that its suppliers stand ready to meet the demand for 
parts for the total fleet.

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 565 Model DC-10 and MD-11 series airplanes 
and KC-10A (military airplanes) of the affected design in the worldwide 
fleet. The FAA estimates that 334 airplanes of U.S. registry will be 
affected by this proposed AD.
    It will take approximately .5 work hour per airplane to accomplish 
either a one-time inspection or a commensurate records search, at an 
average labor rate of $60 per work hour. Based on these figures, the 
cost impact of the AD on U.S. operators is estimated to be $10,020, or 
$30 per airplane.
    If a suspect lock link bolt is found to be installed on an 
airplane, its removal and replacement will take approximately 3 work 
hours to accomplish, at an average labor rate of $60 per work hour. 
(For operators of Model MD-11 series airplanes, the manufacturer has 
indicated that it will reimburse operators for certain of these labor 
costs as a labor credit allowance.) Replacement parts will be supplied 
by the manufacture at no charge to operators. Based on these figures, 
the cost impact of the replacement action on U.S. operators is 
estimated to be $180 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:

96-14-04 McDonnell Douglas: Amendment 39-9686. Docket 95-NM-254-AD.

    Applicability: Model DC-10-10, -15, -30, and -40 series 
airplanes, and KC-10A airplanes, as listed in McDonnell Douglas 
Service Bulletin DC10-32-242, dated November 1, 1995; and Model MD-
11 series airplanes as listed in McDonnell Douglas Service Bulletin 
MD11-32-060, dated November 6, 1995; 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 (e) 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.


[[Page 35946]]


    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent collapse of the nose landing gear as a result of 
failure of the lock link bolt, accomplish the following:
    (a) Within 24 months after the effective date of this AD, 
perform either a visual inspection or a records search to determine 
the serial number of the lock link bolt, part number (P/N) ACG7079-
1, installed in the nose landing gear (NLG). If the visual 
inspection is accomplished, it must be conducted in accordance with 
procedures specified in McDonnell Douglas Service Bulletin DC10-32-
242, dated November 1, 1995, for Model DC-10 series airplanes; or 
McDonnell Douglas Service Bulletin MD11-32-060, dated November 6, 
1995, for Model MD-11 series airplanes.
    (b) If the serial number of the lock link bolt is not AP001 
through AP036 inclusive, or AP200 through AP344 inclusive: No 
further action is required by this AD.
    (c) If the serial number of the lock link bolt is AP001 through 
AP036 inclusive, or AP200 through AP344 inclusive: Within 24 months 
after the effective date of this AD, replace the lock link bolt with 
a bolt, P/N ACG7079-1, that does not have one of those serial 
numbers.
    (d) As of the effective date of this AD, no person shall install 
a lock link bolt, part number (P/N) ACG7079-1, having a serial 
number of AP001 through AP036 inclusive, or AP200 through AP344 
inclusive, on any airplane.
    (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 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.

    (f) 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.
    (g) The inspection shall be done in accordance with McDonnell 
Douglas Service Bulletin DC10-32-242, dated November 1, 1995, for 
Model DC-10 series airplanes; and McDonnell Douglas Service Bulletin 
MD11-32-060, dated November 6, 1995, for Model MD-11 series 
airplanes. 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.
    (h) This amendment becomes effective on August 13, 1996.

    Issued in Renton, Washington, on June 27, 1996.
S.R. Miller,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 96-16951 Filed 7-8-96; 8:45 am]
BILLING CODE 4910-13-P