[Federal Register Volume 67, Number 95 (Thursday, May 16, 2002)]
[Rules and Regulations]
[Pages 34823-34826]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 02-12064]



[[Page 34823]]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2001-NM-197-AD; Amendment 39-12749; AD 2002-10-03]
RIN 2120-AA64


Airworthiness Directives; McDonnell Douglas Model DC-9-81 (MD-
81), DC-9-82 (MD-82), DC-9-83 (MD-83), DC-9-87 (MD-87), MD-88, and MD-
90-30 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-9-81 (MD-81), DC-9-82 
(MD-82), DC-9-83 (MD-83), DC-9-87 (MD-87), MD-88, and MD-90-30 
airplanes. This AD requires replacement of certain main landing gear 
(MLG) shock strut piston assemblies with new or serviceable, improved 
assemblies, which constitutes terminating action for the requirements 
of certain other ADs. This action is necessary to prevent fatigue 
cracking of the MLG shock strut pistons, which could result in failure 
of the MLG shock strut pistons during landing or jacking of the 
airplane, and consequent damage to the airplane structure and injury to 
the passengers, flightcrew, or ground personnel. This action is 
intended to address the identified unsafe condition.

DATES: Effective June 20, 2002. The incorporation by reference of 
certain publications listed in the regulations is approved by the 
Director of the Federal Register as of June 20, 2002.

ADDRESSES: The service information referenced in this AD may be 
obtained from Boeing Commercial Aircraft Group, Long Beach Division, 
3855 Lakewood Boulevard, Long Beach, California 90846, Attention: Data 
and Service Management, Dept. C1-L5A (D800-0024). This information may 
be examined at the Federal Aviation Administration (FAA), Transport 
Airplane Directorate, Rules Docket, 1601 Lind Avenue, SW., Renton, 
Washington; at the FAA, 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: David Y. J. Hsu, Aerospace Engineer, 
Airframe Branch, ANM-120L, FAA, Los Angeles Aircraft Certification 
Office, 3960 Paramount Boulevard, Lakewood, California 90712-4137; 
telephone (562) 627-5323; 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-9-81, -82, -83, and -87 series airplanes; Model MD-88 airplanes; and 
Model MD-90-30 series airplanes; was published in the Federal Register 
on August 29, 2001 (66 FR 45657). That action proposed to require 
replacement of certain main landing gear (MLG) shock strut piston 
assemblies with new or serviceable, improved assemblies, which would 
constitute terminating action for the requirements of certain other 
ADs.

Comments

    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received.

Request To Clarify Compliance Threshold

    One commenter requests that the FAA clarify the compliance 
threshold stated in paragraph (a) of the proposed AD. The commenter 
states that the compliance time stated in the proposed AD, ``Before the 
accumulation of 30,000 total landings, or within 5,000 landings after 
the effective date of this AD, whichever occurs later,'' should be 
revised to ``(Before) the accumulation of 30,000 total landings . . . 
on an MLG shock strut piston, or within 5,000 landings after the 
effective date of this AD, whichever occurs later.'' The commenter 
states that it has airplanes in its fleet with more than 40,000 total 
landings that are equipped with affected MLG shock strut pistons that 
have accumulated fewer than 1,000 landings. The commenter points out 
that, as written, the proposed AD would require discarding a piston 
with significantly fewer than 30,000 landings (i.e., the compliance 
threshold for the proposed replacement) because the piston is installed 
on an airplane with more than 30,000 total landings. The commenter 
requests that the compliance threshold be stated in terms of total 
landings on the MLG shock strut piston.
    The FAA concurs that the compliance time stated in paragraph (a) of 
this AD needs to be clarified. As the commenter notes, the compliance 
threshold should be stated in terms of total accumulated landings on 
the MLG shock strut piston assembly, not in terms of total landings of 
the airplane. Paragraph (a) of this AD has been revised accordingly. 
Also, as a result of this change, we find it necessary to clarify what 
compliance time must be used if an operator cannot determine the number 
of landings on an MLG shock strut piston assembly. Thus, we have added 
the following statement to paragraph (a) of this AD: ``If the MLG shock 
strut piston is not serialized or the number of landings on the piston 
cannot be conclusively determined, consider the total number of 
landings on the piston assembly to be equal to the total number of 
landings accumulated by the airplane with the highest total number of 
landings in the operator's fleet.''

Request To Make Proposed AD Consistent With Other Related 
Rulemaking

    Three commenters request that we revise the proposed AD to make the 
AD consistent with AD 2001-09-18, amendment 39-12225 (66 FR 23840, May 
10, 2001), which is one of the related rulemaking actions identified in 
the proposed AD. The commenters note that the compliance time in the 
proposed AD, the later of 30,000 total landings or 5,000 landings after 
the effective date, conflicts with a provision in AD 2001-09-18 that 
allows a 60,000-total-landing threshold for replacement of the MLG 
shock strut pistons, as long as repetitive inspections are performed. 
The commenters ask us to add the same provisions for continuing 
repetitive inspections into the proposed AD. One commenter suggests 
this could be accomplished by making the proposed AD a supersedure of 
AD 2001-09-18. Two commenters remark that AD 2001-09-18 gives operators 
more flexibility, in that it allows deferral of the replacement of the 
MLG shock strut piston assembly. One of these commenters also notes 
that allowing repetitive inspections to continue for a longer time 
reduces the cost impact on operators by allowing them to use spares 
already in their inventory. Also with regard to the cost impact, two 
commenters stress that the compliance times in the proposed AD would be 
economically burdensome for operators. The commenters state that the 
requirements of AD 2001-09-18 provide a level of safety that is equal 
to the level that would be provided by the proposed AD.
    We do not concur. We note that AD 2001-09-18 addresses fatigue 
cracking only in the area of the torque link lugs of the MLG pistons. 
This AD addresses fatigue cracking not only in the area of the torque 
link lugs but also in the small radius on the base of the jackball of 
the MLG shock strut piston assembly. Therefore, we find that the 
requirements

[[Page 34824]]

of AD 2001-09-18 are not equivalent to those of this AD. No change to 
the final rule is necessary in this regard.

Request To Reduce Grace Period for Compliance Time

    One commenter, the airplane manufacturer, requests that we revise 
the proposed AD to reduce the compliance time from the later of 30,000 
total landings or 5,000 landings after the effective date of this AD, 
to the later of 30,000 total landings or 2,500 landings after the 
effective date of this AD. The commenter states that it did not 
anticipate that operators would have the option to continue using 
affected MLG pistons beyond the compliance time recommended in the 
service bulletins referenced in the proposed AD, 30,000 total landings 
or 5,000 landings after January 31, 2000 (the date of the original 
issue of the service bulletin), whichever is later. The commenter notes 
that the proposed grace period of 5,000 landings after the effective 
date of this AD will apply to many airplanes, because operators with 
insufficient tracking information must assume that all MLG pistons in 
the affected fleet have accumulated landings equivalent to the airplane 
in their fleet with the most landings, and many of these ``fleet 
leader'' airplanes have already accumulated more than 30,000 total 
landings. The commenter asserts that its analysis suggests that the 
probability of cracking of the jackball of the piston increases with 
continued usage of the piston beyond 30,000 total landings. Consistent 
with this analysis, the commenter notes that certain relevant service 
bulletins that describe procedures for inspections of the jackball of 
the MLG piston currently specify reduced inspection intervals for MLG 
pistons with more than 35,000 total landings. The commenter states that 
the FAA's proposed compliance time for the replacement that would be 
required by the proposed AD will make it necessary for the airplane 
manufacturer to revise these relevant inspection service bulletins to 
specify significantly shorter repetitive inspection intervals for 
pistons with even more than 35,000 total landings, to ensure the 
continued safety of these airplanes until the replacement in this AD is 
accomplished.
    We do not concur with the commenter's request to reduce the grace 
period for the replacement required by this AD. In developing an 
appropriate compliance time for the replacement required by this AD, we 
considered not only the degree of urgency associated with addressing 
the subject unsafe condition, but also the average utilization of the 
affected fleet and the availability of required parts. At the average 
usage rate for the affected airplanes, the grace period of 2,500 
landings recommended by the commenter would allow about 500 days for 
the airplane to be modified according to the requirements of this AD. 
We find that this may not allow operators sufficient time to get 
required parts and accomplish this AD on all affected airplanes in 
their fleets. We have determined that the grace period of 5,000 
landings, as proposed, represents an appropriate interval of time 
wherein an ample number of required parts will be available and 
affected operators may comply with this AD. Considering the nature of 
the MLG piston failures at the jackball that have been reported, the 
FAA finds that such a compliance time will not adversely affect the 
safety of the affected airplanes. No change to the final rule is 
necessary in this regard.

Request To Specify Affected Part Numbers in Applicability Statement

    One commenter requests that we revise the applicability statement 
of the proposed AD to identify the specific part numbers for the MLG 
shock strut piston assemblies affected by this AD. While the commenter 
provides no specific reason for its request, we infer that the 
commenter is requesting this change for clarity. We do not concur that 
such a change is necessary. The applicability statement of this AD 
refers to the McDonnell Douglas Model DC-9-81 (MD-81), DC-9-82 (MD-82), 
DC-9-83 (MD-83), DC-9-87 (MD-87), MD-88, and MD-90-30 airplanes listed 
in the two service bulletins referenced in this AD. Because no more 
affected airplanes will be produced, these service bulletins clearly 
identify all affected airplanes and all affected part numbers for the 
MLG shock strut piston assembly. No change to the final rule is 
necessary in this regard.

Comments on Cost Impact

    Three commenters request that we revise the Cost Impact section of 
the proposed AD to more accurately state the costs associated with the 
proposed AD. The Cost Impact section of the proposed AD states, ``The 
manufacturer has committed previously to its customers that it will 
bear the cost of replacement parts, subject to the conditions in the 
warranty. As a result, the cost of those parts is not attributable to 
this proposed AD.'' All three commenters disagree with this statement 
and ask the FAA to revise the proposed AD to include the potential cost 
of replacement parts. The commenters point out that, while Model MD-90-
30 airplanes are covered for the cost of replacement parts associated 
with Boeing Service Bulletin MD-90-32-031, Revision 01, dated April 25, 
2001, the other airplane models subject to the proposed AD will be 
covered for the full cost of replacement parts associated with Boeing 
Service Bulletin MD-80-32-309, Revision 01, dated April 25, 2001, only 
if the airplane was in warranty as of June 1991. The commenters explain 
that, for airplanes not covered by the warranty provisions, the cost of 
the replacement MLG pistons will be up to $255,438, plus, according to 
one commenter, $8,000 for necessary replacement bearings, seals, etc., 
for a total cost of up to $263,438. One of the commenters states that a 
review of the records of U.S.-registered airplanes subject to the 
proposed AD shows that approximately 320 airplanes are not covered by 
warranty, and the operators of these airplanes will have to purchase 
the replacement parts at this price.
    We partially concur with the request to include the cost of 
replacement parts. As we stated in the proposed AD, the provision of 
required parts is ``subject to the conditions in the warranty.'' We do 
not have access to, and it is not feasible to consider, the individual 
warranty contracts between the airplane manufacturer and the operators 
of affected airplanes.
    For the benefit of affected operators, however, we will acknowledge 
the cost of replacement parts for airplanes that are not fully covered 
by warranty provisions in this AD. Also, based on the current price of 
replacement parts, we have also revised our cost impact estimate for 
the approximately 320 U.S.-registered airplanes not covered by warranty 
provisions.
    In addition to the comments on the cost of parts, one of the 
commenters also contends that its experience shows that the proposed 
replacement will take 56 work hours, rather than the 28 estimated in 
the proposed AD. The commenter provides no data to substantiate its 
estimate. We are not revising the work-hour estimate in this AD. The 
estimate that 28 work hours will be needed for the required replacement 
is based on the best information currently available from the airplane 
manufacturer. We note that this figure is consistent with the estimate 
provided in the service bulletin. No change to the final rule is 
necessary in this regard.
    Also, another commenter takes issue with the boilerplate statement, 
``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

[[Page 34825]]

actions in the future if this AD were not adopted.'' The commenter 
asserts that this statement ``has the potential to mislead operators to 
the true cost of the proposed rule.'' The commenter states that it has 
already done the intent of the proposed AD on many airplanes in its 
fleet.
    We infer that the commenter is requesting that we remove this 
statement from the AD. We do not concur. The statement to which the 
commenter refers is included in nearly all ADs and declares what 
assumptions we have made in estimating the cost of the requirements of 
the AD on the U.S.-registered fleet of airplanes. We use these 
assumptions because it is not feasible for the FAA to determine how 
many airplanes are already in compliance with a particular service 
bulletin, or whether an operator would accomplish a particular service 
bulletin if we didn't issue an AD to require it. Therefore, we 
calculate the cost impact estimate based on the assumption that the 
action has not been done on any U.S.-registered airplanes before the 
effective date of the AD, and that no operator would do the action if 
the FAA did not issue an AD to require it. We recognize that, in nearly 
all cases, some operators will have already done the AD requirements 
before the effective date of the AD, so the future economic impact of 
that AD on U.S. operators may be less than the estimated cost stated in 
the AD. No change to the final rule is necessary in this regard.

Explanation of Change to Applicability

    The FAA has revised the applicability statement in this final rule 
to identify model designations as published in the most recent type 
certificate data sheet for the affected models. We have also revised 
related model designations in the preamble.

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 1,380 Model DC-9-81 (MD-81), DC-9-82 (MD-
82), DC-9-83 (MD-83), DC-9-87 (MD-87), MD-88, and MD-90-30 airplanes of 
the affected design in the worldwide fleet. The FAA estimates that 820 
airplanes of U.S. registry will be affected by this AD, that it will 
take approximately 28 work hours per airplane to accomplish the 
required actions, and that the average labor rate is $60 per work hour.
    The manufacturer has committed previously to its customers that it 
may bear the cost of replacement parts, subject to the conditions in 
the warranty. For the approximately 500 U.S.-registered airplanes 
covered by the manufacturer's warranty provisions, the cost of required 
parts is not attributable to this AD. Therefore, based on the figures 
stated above, the cost impact of the AD on U.S. operators of these 
airplanes is estimated to be $840,000, or $1,680 per airplane.
    Based on information received from the airplane manufacturer, up to 
320 U.S.-registered airplanes subject to this AD may NOT be covered by 
the manufacturer's warranty provisions. For these airplanes, required 
parts will cost approximately $263,438 per airplane. Based on these 
figures, the cost impact of the AD on U.S. operators of these airplanes 
is estimated to be $84,837,760, or $265,118 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. The cost impact figures discussed 
in AD rulemaking actions represent only the time necessary to perform 
the specific actions actually required by the AD. These figures 
typically do not include incidental costs, such as the time required to 
gain access and close up, planning time, or time necessitated by other 
administrative actions.

Regulatory Impact

    The regulations adopted herein will not have a substantial direct 
effect 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, it 
is determined that this final rule does not have federalism 
implications under Executive Order 13132.
    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:

2002-10-03   Mcdonnell Douglas: Amendment 39-12749. Docket 2001-NM-
197-AD.

    Applicability: Model DC-9-81 (MD-81), DC-9-82 (MD-82), DC-9-83 
(MD-83), DC-9-87 (MD-87), and MD-88 airplanes, as listed in Boeing 
Service Bulletin MD80-32-309, Revision 01, dated April 25, 2001; and 
Model MD-90-30 airplanes, as listed in Boeing Service Bulletin MD90-
32-031, Revision 01, dated April 25, 2001; 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 main landing gear (MLG) shock 
strut pistons, which could result in failure of the MLG shock strut 
pistons during landing or jacking of the airplane, and consequent 
damage to the airplane structure and injury to the passengers, 
flightcrew, or ground personnel, accomplish the following:

Replacement

    (a) Before the accumulation of 30,000 total landings on the MLG 
shock strut piston

[[Page 34826]]

assemblies, or within 5,000 landings after the effective date of 
this AD, whichever occurs later: Replace the MLG shock strut piston 
assemblies, left and right-hand sides, with new or serviceable, 
improved assemblies, per the Accomplishment Instructions of Boeing 
Service Bulletin MD80-32-309, Revision 01, dated April 25, 2001 (for 
Model DC-9-81 (MD-81), DC-9-82 (MD-82), DC-9-83 (MD-83), DC-9-87 
(MD-87), and MD-88 airplanes); or Boeing Service Bulletin MD90-32-
031, Revision 01, dated April 25, 2001 (for Model MD-90-30 
airplanes); as applicable. If the MLG shock strut piston is not 
serialized or the number of landings on the piston cannot be 
conclusively determined, consider the total number of landings on 
the piston assembly to be equal to the total number of landings 
accumulated by the airplane with the highest total number of 
landings in the operator's fleet.

    Note 2: Accomplishment of the replacement specified in Boeing 
Service Bulletin MD80-32-309, dated January 31, 2000 (for Model DC-
9-81 (MD-81), DC-9-82 (MD-82), DC-9-83 (MD-83), DC-9-87 (MD-87), and 
MD-88 airplanes); or Boeing Service Bulletin MD90-32-031, dated 
January 31, 2000 (for Model MD-90-30 airplanes); as applicable; 
before the effective date of this AD, is considered acceptable for 
compliance with the requirement of paragraph (a) of this AD.

Compliance With Requirements of Other ADs

    (b) Accomplishment of the replacement required by paragraph (a) 
of this AD constitutes terminating action for the requirements of AD 
99-13-07, amendment 39-11201, AD 2000-03-08, amendment 39-11567, and 
AD 2001-09-18, amendment 39-12225.

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. 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 Boeing Service 
Bulletin MD80-32-309, Revision 01, dated April 25, 2001; or Boeing 
Service Bulletin MD90-32-031, Revision 01, dated April 25, 2001; as 
applicable. 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 Boeing Commercial 
Aircraft Group, Long Beach Division, 3855 Lakewood Boulevard, Long 
Beach, California 90846, Attention: Data and Service Management, 
Dept. C1-L5A (D800-0024). Copies may be inspected at the FAA, 
Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, 
Washington; at the FAA, 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.

Effective Date

    (f) This amendment becomes effective on June 20, 2002.

    Issued in Renton, Washington, on May 8, 2002.
Kalene C. Yanamura,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 02-12064 Filed 5-15-02; 8:45 am]
BILLING CODE 4910-13-P