[Federal Register Volume 66, Number 31 (Wednesday, February 14, 2001)]
[Proposed Rules]
[Pages 10243-10247]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 01-3700]


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

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-NM-298-AD]
RIN 2120-AA64


Airworthiness Directives; McDonnell Douglas Model DC-9, DC-9-80, 
and C-9 (Military) Series Airplanes; Model MD-88 Airplanes; and Model 
MD-90 Airplanes

AGENCY: Federal Aviation Administration, DOT.

[[Page 10244]]


ACTION: Supplemental notice of proposed rulemaking; reopening of 
comment period.

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

SUMMARY: This document revises an earlier proposed airworthiness 
directive (AD), applicable to certain McDonnell Douglas Model DC-9, DC-
9-80, and C-9 (military) series airplanes; Model MD-88 airplanes; and 
Model MD-90 airplanes that would have required, among other actions, a 
visual check to determine the part and serial numbers of the upper lock 
link assembly of the nose landing gear (NLG); repetitive inspections of 
certain upper lock link assemblies to detect fatigue cracking; and 
replacement of the upper lock link assembly with an assembly made from 
aluminum forging material, if necessary. Such replacement would 
constitute terminating action for the requirements of this AD. That 
proposal was prompted by a report indicating that an NLG upper lock 
link fractured prior to landing and jammed against the NLG shock strut, 
restricting the NLG from fully extending. This new action revises, 
among other actions, a list of suspect parts; delays accomplishment of 
a certain replacement; and revises the initial compliance time. The 
actions specified by this new proposed AD are intended to address the 
identified unsafe condition.

DATES: Comments must be received by March 12, 2001.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 97-NM-298-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056. Comments may be inspected at this 
location between 9:00 a.m. and 3:00 p.m., Monday through Friday, except 
Federal holidays. Comments may be submitted via fax to (425) 227-1232. 
Comments may also be sent via the Internet using the following address: 
[email protected]. Comments sent via fax or the Internet must 
contain ``Docket No. 97-NM-298-AD'' in the subject line and need not be 
submitted in triplicate. Comments sent via the Internet as attached 
electronic files must be formatted in Microsoft Word 97 for Windows or 
ASCII text.
    The service information referenced in the proposed rule may be 
obtained from Boeing Commercial Aircraft Group, Long Beach 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 FAA, Transport Airplane 
Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the FAA, 
Los Angeles Aircraft Certification Office, 3960 Paramount Boulevard, 
Lakewood, California.

FOR FURTHER INFORMATION CONTACT: Brent Bandley, Aerospace Engineer, 
Airframe Branch, ANM-120L, FAA, Los Angeles Aircraft Certification 
Office, 3960 Paramount Boulevard, Lakewood, California 90712-4137; 
telephone (562) 627-5237; fax (562) 627-5210.

SUPPLEMENTARY INFORMATION:

Comments Invited

    Interested persons are invited to participate in the making of the 
proposed rule by submitting such written data, views, or arguments as 
they may desire. Communications shall identify the Rules Docket number 
and be submitted in triplicate to the address specified above. All 
communications received on or before the closing date for comments, 
specified above, will be considered before taking action on the 
proposed rule.
    The proposals contained in this notice may be changed in light of 
the comments received.
    Submit comments using the following format:
     Organize comments issue-by-issue. For example, discuss a 
request to change the compliance time and a request to change the 
service bulletin reference as two separate issues.
     For each issue, state what specific change to the proposed 
AD is being requested.
     Include justification (e.g., reasons or data) for each 
request.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the proposed rule. All 
comments submitted will be available, both before and after the closing 
date for comments, in the Rules Docket for examination by interested 
persons. A report summarizing each FAA-public contact concerned with 
the substance of this proposal will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this action must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 97-NM-98-AD.'' The postcard will be date stamped and 
returned to the commenter.

Availability of NPRMs

    Any person may obtain a copy of this NPRM by submitting a request 
to the FAA, Transport Airplane Directorate, ANM-114, Attention: Rules 
Docket No. 97-NM-298-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    A proposal to amend part 39 of the Federal Aviation Regulations (14 
CFR part 39) to add an airworthiness directive (AD), applicable to 
certain McDonnell Douglas Model DC-9, DC-9-80, and C-9 (military) 
series airplanes, Model MD-88 airplanes, and Model MD-90 airplanes, was 
published as a notice of proposed rulemaking (NPRM) in the Federal 
Register on October 14, 1999 (64 FR 55644). That NPRM would have 
required, among other actions, a visual check to determine the part and 
serial numbers of the upper lock link assembly of the nose landing gear 
(NLG); repetitive inspections of certain upper lock link assemblies to 
detect fatigue cracking; and replacement of the upper lock link 
assembly with an assembly made from aluminum forging material, if 
necessary. Such replacement would have constituted terminating action 
for the requirements of this AD. That NPRM was prompted by a report 
indicating that, due to fatigue cracking, a NLG upper lock link 
fractured prior to landing and jammed against the NLG shock strut, 
restricting the NLG from fully extending. That condition, if not 
corrected, could result in injury to passengers and flight crew, and 
damage to the airplane.

Actions Since Issuance of Previous Proposal

    Due consideration has been given to the comments received in 
response to the NPRM.

Support for Proposed AD

    One commenter supports the proposed AD.

Requests To Revise Compliance Time

    Two commenters request that the compliance time of paragraph (a) of 
the proposed AD be revised to eliminate the words ``5,000 landings 
since the last inspection in accordance with paragraph (a) of AD 97-02-
10, [amendment 39-9895 (62 FR 3781, January 27, 1997)] whichever occurs 
first.'' The commenters state that paragraph (a) of AD 97-02-10 
requires classification of the subject links as exempt or non-exempt. 
According to AD 97-02-10, no further action is required if an airplane 
has an exempt link. One commenter also states that the proposed AD 
would require re-inspection of all NLG links regardless of 
classification findings in AD 97-02-10. As the compliance time is 
currently written in the proposed AD, the commenters state that their 
airplanes could exceed the

[[Page 10245]]

5,000-landing requirement for previously classified ``exempt'' links. 
The commenters also state that the proposed compliance time could 
severely limit the timeframe to inspect non-exempt links approaching 
the 5,000-landing repetitive inspection interval required by paragraph 
(c)(1) of AD 97-02-10.
    Based on the commenters' statements and after reviewing the wording 
of the compliance time of paragraph (a) of the proposed AD, the FAA 
finds that clarification is necessary. As indicated in the preamble of 
the proposed AD, unlike in Boeing Alert Service Bulletins MD90-32A019 
and DC9-32A298, there are no lock link assemblies specified as 
``exempt'' or ``non-exempt'' in this proposed AD. Instead, a one-time 
inspection is required to determine whether the upper lock link 
assembly is from an ``affected lot,'' as specified in Boeing Service 
Bulletin MD90-32-033 or DC9-32-315.
    In addition, we find that operators that are currently 
accomplishing the 5,000-landing repetitive inspection required by 
paragraph (c)(1) of AD 97-02-10 may have already exceeded or be near 
the threshold specified in paragraph (a) of the proposed AD [i.e., 
5,000 landings since the last inspection accomplished in accordance 
with paragraph (c)(1) of AD 97-02-10]. Therefore, we have determined 
that a 90-day grace period is necessary to preclude those airplanes 
from being grounded unnecessarily. In developing an appropriate 
compliance time for this action for the subject airplanes, we 
considered not only the manufacturer's recommendation, but the degree 
of urgency associated with addressing the subject unsafe condition, the 
average utilization of the affected fleet, and the time necessary to 
perform the inspections (one hour). In light of all of these factors, 
we find a 90-day grace period for initiating the proposed actions to be 
warranted, in that it represents an appropriate interval of time 
allowable for affected airplanes to continue to operate without 
compromising safety.
    Therefore, for airplanes on which the inspection required by 
paragraph (c)(1) of AD 97-02-10 has been accomplished, the proposed 
actions required by paragraph (a) of this AD must be accomplished prior 
to accumulation of 5,000 landings since the last inspection 
accomplished in accordance with paragraph (c)(1) of AD 97-02-10, or 
within 90 days after the effective date of this AD, whichever occurs 
later. For airplanes on which the inspection required by paragraph 
(c)(1) of AD 97-02-10 has NOT been accomplished, the proposed actions 
required by paragraph (a) of the AD must be accomplished within 2,500 
landings on the NLG after the effective date of this AD. We have 
revised paragraph (a) of the supplemental NPRM accordingly.

Request to Clarify the Requirements of Paragraph (c)(2)(iii) of the 
Proposed AD

    One commenter questions whether the FAA's intent in paragraph 
(c)(2)(iii) of the proposed AD was to require both a high frequency 
eddy current (HFEC) inspection ``and'' Type 1 fluorescent penetrant 
inspection or to require either one of those inspections. The commenter 
notes that the service bulletins referenced in the proposed AD 
recommend performing either an HFEC ``or'' a Type 1 fluorescent 
inspection, and that AD 97-02-10 requires accomplishment of either 
inspection.
    The FAA's intent was that paragraph (c)(2)(iii) of the proposed AD 
require either a HFEC inspection OR a Type 1 fluorescent penetrant 
inspection. We have revised paragraph (c)(2)(iii) of the supplemental 
NPRM accordingly.

Request to Delay Accomplishment of the Replacement

    One commenter, the airplane manufacturer, requests that the FAA 
revise paragraph (c)(2)(iii)(A) of the proposed AD to require a second 
inspection and, within 2,500 landings following accomplishment of the 
second inspection, replacement of the lock link specified in that 
paragraph. The commenter states that this second inspection and 
eventual replacement were identified in the referenced service 
bulletins. The commenter also states that the 5,000-landing delay of 
the replacement is necessary because there may be a parts-availability 
problem.
    The FAA agrees. Our intent was to follow the procedures recommended 
in the referenced service bulletins for these actions. We have revised 
paragraph (d) of the supplemental NPRM [paragraph (c)(2)(iii)(A) of the 
original NPRM] accordingly.

Explanation of New Service Information

    Since issuance of the NPRM, the FAA has reviewed and approved 
Revision 01 of Boeing (McDonnell Douglas) Service Bulletins DC9-32-315 
and MD90-32-033, both dated October 24, 2000. The effectivity listing 
of Revision 01 of the services bulletins has been revised to remove 
certain manufacturer's fuselage numbers from the effectivity listing 
and to add certain others. Revision 01 of these service bulletins also 
has been revised to:
    1. Update the list of affected serial numbers of the NLG upper lock 
link that are identifed as hand forging material;
    2. Redefine the type of etching method to be used when marking 
certain parts; and
    3. Clarify that, under a certain condition, the upper lock link 
must be reidentified with a ``black'' paint stripe.
    In addition, the revised service bulletins clarify the wording 
``aluminum forging'' as die forged aluminum to differentiate from hand 
forged aluminum and provide a method to identify materials made from a 
specific process. We have revised the supplemental NPRM accordingly to 
reference Revision 01 of the subject service bulletins as an 
appropriate source of service information.
    Operators should note that Revision 01 of Boeing Service Bulletin 
DC9-32-315 misidentifies the date of the original issue as June 21, 
1999. The correct date is March 11, 1999. Boeing is planning to correct 
this error in the next revision of the service bulletin.

Explanation of Change to the Applicability

    Because the effectivity listing in these revised service bulletins 
described above reflects the most current composition of operators and 
airplanes affected by this AD, the FAA has revised the applicability 
statement of the supplemental NPRM to reference these revised service 
bulletins.

Explanation of Change of Type of Inspection

    The FAA finds that it is not necessary to perform a ``detailed 
visual'' inspection to to determine a certain serial number of the lock 
link in paragraph (b) of the proposed AD.
    We have deleted the reference to ``detailed visual'' throughout the 
supplemental NPRM and deleted NOTE 2 (definition of a detailed visual 
inspection).

Conclusion

    Since these changes expand the scope of the originally proposed 
rule, the FAA has determined that it is necessary to reopen the comment 
period to provide additional opportunity for public comment.

Cost Impact

    There are approximately 2,100 Model DC-9, DC-9-80, and C-9 
(military) series airplanes; Model MD-88 airplanes; and Model MD-90 
airplanes of the affected design in the worldwide fleet. The FAA 
estimates that 1,400 airplanes of U.S. registry would be affected by 
this proposed AD.

[[Page 10246]]

    It would take approximately 1 work hour per airplane to accomplish 
the proposed inspections of the NLG upper lock link, at an average 
labor rate of $60 per work hour. Based on these figures, the cost 
impact of this inspection proposed by this AD on U.S. operators is 
estimated to be $84,000, or $60 per airplane.
    It would take approximately 4 work hours per airplane to accomplish 
each proposed replacement of the NLG upper lock link, at an average 
labor rate of $60 per work hour. Required parts would cost 
approximately $5,803 per airplane. Based on these figures, the cost 
impact of each replacement proposed by this AD on U.S. operators is 
estimated to be $8,460,200, or $6,043 per airplane.
    The cost impact figures discussed above are based on assumptions 
that no operator has yet accomplished any of the proposed 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 proposed herein would 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 proposal would not have federalism implications 
under Executive Order 13132.
    For the reasons discussed above, I certify that this proposed 
regulation (1) is not a ``significant regulatory action'' under 
Executive Order 12866; (2) is not a ``significant rule'' under the DOT 
Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); 
and (3) if promulgated, 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 copy of the draft 
regulatory evaluation prepared for this action is contained in the 
Rules Docket. A copy of it may be obtained by contacting the Rules 
Docket at the location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

The Proposed Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration proposes to amend 
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 removing amendment 39-9895 (62 FR 
3781, January 27, 1997), and by adding a new airworthiness directive 
(AD), to read as follows:

McDonnell Douglas: Docket 97-NM-298-AD. Supersedes AD 97-02-10, 
Amendment 39-9895.

    Applicability: Model DC-9, DC-9-80, and C-9 (military) series 
airplanes; Model MD-88 airplanes; and Model MD-90 airplanes; as 
listed in Boeing Service Bulletins DC9-32-315, and MD90-32-033, both 
Revision 01, dated October 24, 2000; 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 (f)(1) 
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 the upper lock link assembly of the nose landing gear 
(NLG) from fracturing due to fatigue cracking, and the NLG 
consequently failing to extend fully, which could result in injury 
to passengers and flight crew, and damage to the airplane, 
accomplish the following:

Removing and Retaining Upper Lock Link

    (a) Remove and retain the upper lock link, part number (P/N) 
3914464, and attaching parts; and do the inspections required by 
paragraphs (b) and (c) of this AD, per the applicable Boeing 
(McDonnell Douglas) service bulletin listed in Table 1 of this AD. 
The actions required by this paragraph shall be done at the 
applicable time specified in paragraph (a)(1) or (a)(2) of this AD. 
Table 1 is as follows:

                                                    Table 1.
----------------------------------------------------------------------------------------------------------------
           Service bulletin                 Revision level                Date                    Model
----------------------------------------------------------------------------------------------------------------
DC9-32-315...........................  Original or Revision 01  March 11, 1999.........  DC-9, DC-9-80, and C-9
                                                                October 24, 2000.......   (military) series
                                                                                          airplanes; and MD-88
                                                                                          airplanes.
MD90-32-033..........................  Original or Revision 01  March 11, 1999.........  MD-90 airplanes.
                                                                October 24, 2000.......
----------------------------------------------------------------------------------------------------------------

    (1) For airplanes on which the inspection required by paragraph 
(c)(1) of AD 97-02-10 has been done: Do the actions before 5,000 
landings since the last inspection done per paragraph (c)(1) of AD 
97-02-10, or within 90 days after the effective date of this AD, 
whichever occurs later.
    (2) For airplanes on which the inspection required by paragraph 
(c)(1) of AD 97-02-10 has NOT been done: Do the actions within 2,500 
landings on the NLG after the effective date of this AD.

Inspection

    (b) Do a one-time inspection of the NLG upper lock link assembly 
per Revision 01 of the applicable service bulletin listed in Table 1 
of this AD to determine whether the serial number of the lock link 
is identified in the affected lot specified in Condition 1 of the 
Accomplishment Instructions of Revision 01 of the applicable Boeing 
(McDonnell Douglas) service bulletin listed in Table 1 of this AD.

Condition 1 (Hand Forging Serial Number)

    (1) If the serial number of the upper lock link is not from the 
affected lot specified in Revision 01 of the applicable service 
bulletin (Condition 1), before further flight, do the etch 
inspection required by paragraph (c) of this AD.
    (2) If the serial number of the upper lock link is from the 
affected lot specified in the Revision 01 of the applicable service 
bulletin (Condition 1), before further flight, replace the lock link 
with a new upper lock link, P/N 3914464-507; a reidentified upper 
lock

[[Page 10247]]

link by adding an ``F'' to the part number, using an electro 
chemical deep etch method; or a new upper lock link assembly, P/N 
5965065-507; all made from die forged aluminum material; per the 
applicable service bulletin. Accomplishment of the replacement 
constitutes terminating action for the requirements of this AD.

Etch Inspection

    (c) Perform a one-time etch inspection of the NLG upper lock 
link to determine whether the lock link is made from die forged 
aluminum material (Condition 2), or from plate or bar material 
(Condition 3); per the applicable Boeing (McDonnell Douglas) service 
bulletin listed in Table 1 of this AD.

Condition 2 (Die Forged Aluminum Material)

    (1) If the upper lock link is made from die forged aluminum 
material, before further flight, restore the finish and reidentify 
the lock link by adding an ``F'' to the part number, using an 
electro chemical deep etch method, per the applicable service 
bulletin. Identification of the lock link as being made from die 
forged aluminum material constitutes terminating action for the 
requirements of this AD.

Condition 3 (Plate or Bar Material)

    (2) If the NLG upper lock link is made from plate or bar 
material, before further flight, do either Condition 3, Option 1, as 
specified by paragraph (c)(2)(i) of this AD, or Condition 3, Option 
2, as specified by paragraphs (c)(2)(ii) and (c)(2)(iii) of this AD.

Condition 3, Option 1

    (i) Permanently remove any discrepant upper lock link and 
replace with a new upper lock link, P/N 3914464-507; a reidentified 
upper lock link by adding an ``F'' to the part number, using an 
electro chemical deep etch method; or a new upper lock link 
assembly, P/N 5965065-507; all made from die forged aluminum 
material; per the applicable service bulletin. Accomplishment of the 
replacement constitutes terminating action for the requirements of 
this AD.

Condition 3, Option 2

    (ii) Restore the link finish and reidentify the upper lock link 
by adding a black paint stripe adjacent to the part number, 
indicating that the part is not made from die forged aluminum 
material, per the applicable service bulletin.
    (iii) Do a high frequency eddy current (HFEC) or Type I 
fluorescent penetrant inspection of the upper lock link assembly, P/
N 3914464--(any configuration), to detect cracking of the assembly; 
per McDonnell Douglas Alert Service Bulletin DC9-32A298, Revision 02 
[for Model DC-9, DC-9-80, and C-9 (military) series airplanes; and 
Model MD-88 airplanes], or Alert Service Bulletin MD90-32A019, 
Revision 02 (for Model MD-90 airplanes), both dated October 29, 
1997; as applicable.

Actions Following the Inspection Required by Paragraph (c)(2)(iii)

    (d) If no crack is detected during the HFEC or Type I 
fluorescent penetrant inspection required by paragraph (c)(2)(iii) 
of this AD, within 2,500 landings on the NLG since accomplishment of 
the inspection performed per paragraph (c)(2)(iii) of this AD, as 
applicable, do that inspection a second time. If no crack is 
detected during this second inspection, within 2,500 landings after 
accomplishment of the second inspection, replace the upper lock link 
with a new upper lock link, P/N 3914464-507; a reidentified upper 
lock link by adding an ``F'' to the part number, using an electro 
chemical deep etch method; or a new upper lock link assembly, P/N 
5965065-507; all made from die forged aluminum material; per the 
applicable Boeing (McDonnell Douglas) service bulletin listed in 
Table 1 of this AD. Accomplishment of the replacement action 
constitutes terminating action for the requirements of this AD.
    (e) If any crack is detected during the HFEC or Type I 
fluorescent penetrant inspection required by paragraph (c)(2)(iii) 
or (d) of this AD, before further flight, replace the discrepant NLG 
upper lock link with a new upper lock link, P/N 3914464-507; a 
reidentified upper lock link by adding an ``F'' to the part number, 
using an electro chemical deep etch method; or a new upper lock link 
assembly, P/N 5965065-507; all made from die forged aluminum 
material; per the applicable Boeing (McDonnell Douglas) service 
bulletin listed in Table 1 of this AD. Accomplishment of the 
replacement constitutes terminating action for the requirements of 
this AD.

Alternative Methods of Compliance

    (f)(1) 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 2: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Los Angeles ACO.
    (2) Alternative methods of compliance, approved previously in 
accordance with AD 97-02-10, amendment 39-9895, are approved as 
alternative methods of compliance with paragraph (f)(1) of this AD.

Special Flight Permits

    (g) 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.


    Issued in Renton, Washington, on February 8, 2001.
Donald L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 01-3700 Filed 2-13-01; 8:45 am]
BILLING CODE 4910-13-P