[Federal Register Volume 60, Number 205 (Tuesday, October 24, 1995)]
[Rules and Regulations]
[Pages 54417-54419]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-25987]



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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 95-NM-183-AD; Amendment 39-9413; AD 95-22-06]


Airworthiness Directives; McDonnell Douglas Model DC-9-80 Series 
Airplanes and Model MD-88 Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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SUMMARY: This amendment adopts a new airworthiness directive (AD) that 
is applicable to certain McDonnell Douglas Model DC-9-80 series 
airplanes and Model MD-88 airplanes. This action requires repetitive 
inspections to detect fatigue cracking of the shock strut cylinder of 
the main landing gear (MLG), and replacement of any cracked shock strut 
cylinder with a serviceable part. This action also provides for 
installation of brake line hydraulic restrictors on the MLG brake 
systems, which, if accomplished, terminates the repetitive inspection 
requirement. This amendment is prompted by a report indicating that 
fatigue cracking and subsequent fracturing of the shock strut cylinder 
of the MLG occurred due to high stress loads on the cylinder as a 
result of braking induced vibration. The actions specified in this AD 
are intended to prevent such fracturing, which could result in collapse 
of the MLG and consequent reduced controllability of the airplane 
during landing.

DATES: Effective November 8, 1995.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of November 8, 1995.
    Comments for inclusion in the Rules Docket must be received on or 
before December 26, 1995.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 95-NM-183-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056.
    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 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.

FOR FURTHER INFORMATION CONTACT: Brent Bandley, Aerospace Engineer, 
Airframe Branch, ANM-120L, FAA, Transport Airplane Directorate, Los 
Angeles Aircraft Certification Office, 3960 Paramount Boulevard, 
Lakewood, California 90712; telephone (310) 627-5237; fax (310) 627-
5210.

SUPPLEMENTARY INFORMATION: The FAA received a report indicating that 
the shock strut cylinder of the left main landing gear (MLG) fractured 
on a McDonnell Douglas Model DC-9-80 series airplane. The fractured MLG 
collapsed during landing rollout. The affected shock strut cylinder had 
accumulated 6,386 total landings and 18,236 total hours time-in-
service. Investigation revealed that the fracturing was the result of 
fatigue cracking caused by high stress loads on the shock strut 
cylinder. These high stress loads were induced by vibration, which 
occurs during landing rollout when the aircraft is at speeds between 40 
and 50 knots, with the anti-skid system on during moderate to heavy 
braking. Fatigue cracking and subsequent fracturing of the shock strut 
cylinder, if not corrected, could result in collapse of the MLG; such a 
collapse could adversely affect the controllability of the airplane 
during landing.
    The FAA has reviewed and approved McDonnell Douglas Alert Service 
Bulletin MD80-32A286, dated September 11, 1995, which describes 
procedures for repetitive dye penetrant 

[[Page 54418]]
and magnetic particle inspections to detect cracking of the shock strut 
cylinder of the MLG, and replacement of any cracked shock strut 
cylinder with a serviceable part. The alert service bulletin also 
describes procedures for installation of brake line hydraulic 
restrictors on the left and right MLG brake systems, which eliminates 
the need for the repetitive inspections. Accomplishment of the 
installation will minimize stress loads induced by vibration and the 
possibility of fatigue cracking of the shock strut cylinder.
    Since an unsafe condition has been identified that is likely to 
exist or develop on other Model DC-9-80 series airplanes and Model MD-
88 airplanes of the same type design, this AD is being issued to 
prevent fracturing of the shock strut cylinder of the MLG, which could 
result in collapse of the MLG and consequent reduced controllability of 
the airplane during landing. This AD requires repetitive dye penetrant 
and magnetic particle inspections to detect cracking of the shock strut 
cylinder of the MLG, and replacement of any cracked shock strut 
cylinder with a crack-free serviceable part. This AD also provides for 
the installation of brake line hydraulic restrictors on the left and 
right MLG brake systems, which terminates the repetitive inspection 
requirement if it is accomplished prior to further flight after 
inspections are performed and no cracking is found. However, all 
airplanes, including those on which brake line hydraulic restrictors 
have been installed previously, are required to perform the inspections 
at least one time. The actions are required to be accomplished in 
accordance with the alert service bulletin described previously.
    Operators should note that, McDonnell Douglas Alert Service 
Bulletin MD80-32A286, dated September 11, 1995, recommends that the 
accomplishment of the inspections be completed within 6 months (from 
the issue date of the service bulletin). While the FAA agrees that 6 
months is an appropriate time interval in which the inspections can be 
accomplished and an adequate level of safety maintained, this AD 
specifies a compliance time of 90 days for the accomplishment of the 
inspections. This 90-day compliance time was developed by taking into 
account the manufacturer's recommended 6-month time interval from 
September 11, 1995 (the service bulletin issue date), as well as the 
number of days that are normally required for the rulemaking process to 
be completed (approximately 90 days). In consideration of both of these 
factors, the FAA finds that a compliance time of 90 days after the 
effective date of this final rule will fall approximately at the same 
time (calendar date) for compliance that has been recommended by the 
manufacturer. By adjusting the compliance time interval in this way:
    1. Operators will be provided, in effect, with a full 6 months in 
which to complete the inspections;
    2. The inspections can be accomplished within an interval of time 
that parallels normal scheduled maintenance for a majority of affected 
operators; and
    3. The inspections will be accomplished within an appropriate 
interval to prevent the initiation and propagation of fatigue cracking 
in the shock strut cylinder.
    In addition, the McDonnell Douglas service bulletin recommends that 
the installation of brake line hydraulic restrictors be accomplished 
within 12 months. However, this AD does not require such installation 
at a specified time; it is provided in this AD as an optional 
terminating action. The FAA may consider additional rulemaking to 
require accomplishment of the installation, but has determined that the 
repetitive inspections will maintain an adequate level of safety in the 
fleet in the meantime.
    Since a situation exists that requires the immediate adoption of 
this regulation, it is found that notice and opportunity for prior 
public comment hereon are impracticable, and that good cause exists for 
making this amendment effective in less than 30 days.

Comments Invited

    Although this action is in the form of a final rule that involves 
requirements affecting flight safety and, thus, was not preceded by 
notice and an opportunity for public comment, comments are invited on 
this rule. Interested persons are invited to comment on this 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 under the caption ADDRESSES. All 
communications received on or before the closing date for comments will 
be considered, and this rule may be amended in light of the comments 
received. Factual information that supports the commenter's ideas and 
suggestions is extremely helpful in evaluating the effectiveness of the 
AD action and determining whether additional rulemaking action would be 
needed.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the rule that might 
suggest a need to modify the 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 that 
summarizes each FAA-public contact concerned with the substance of this 
AD will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this rule must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 95-NM-183-AD.'' The postcard will be date stamped and 
returned to the commenter.
    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.
    The FAA has determined that this regulation is an emergency 
regulation that must be issued immediately to correct an unsafe 
condition in aircraft, and that it is not a ``significant regulatory 
action'' under Executive Order 12866. It has been determined further 
that this action involves an emergency regulation under DOT Regulatory 
Policies and Procedures (44 FR 11034, February 26, 1979). If it is 
determined that this emergency regulation otherwise would be 
significant under DOT Regulatory Policies and Procedures, a final 
regulatory evaluation will be prepared and placed in the Rules Docket. 
A copy of it, if filed, 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:


[[Page 54419]]

    Authority: 49 U.S.C. 106(g), 40101, 40113, 44701.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by adding the following new 
airworthiness directive:

95-22-06  McDonnell Douglas: Amendment 39-9413. Docket 95-NM-183-AD.

    Applicability: Model DC-9-81 (MD-81), DC-9-82 (MD-82), DC-9-83 
(MD-83), and DC-9-87 (MD-87) series airplanes, and Model MD-88 
airplanes; as listed in McDonnell Douglas Alert Service Bulletin 
MD80-32A286, dated September 11, 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 use the authority 
provided in paragraph (e) of this AD to request approval from the 
FAA. This approval may address either no action, if the current 
configuration eliminates the unsafe condition; or different actions 
necessary to address the unsafe condition described in this AD. Such 
a request should include an assessment of the effect of the changed 
configuration on the unsafe condition addressed by this AD. In no 
case does the presence of any modification, alteration, or repair 
remove any airplane from the applicability of this AD.

    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent collapse of the main landing gear (MLG) due to 
fracturing of the shock strut cylinder, accomplish the following:
    (a) For airplanes on which brake line hydraulic restrictors have 
not been installed on the left and right MLG brake systems in 
accordance with McDonnell Douglas Alert Service Bulletin MD80-
32A286, dated September 11, 1995, prior to the effective date of 
this AD: Within 90 days after the effective date of this AD, perform 
dye penetrant and magnetic particle inspections to detect cracking 
of the shock strut cylinder of the MLG, in accordance with McDonnell 
Douglas Alert Service Bulletin MD80-32A286, dated September 11, 
1995.
    (1) If no cracking is found, repeat the inspections thereafter 
at intervals not to exceed 1,200 landings.
    (2) If any cracking is found, prior to further flight, replace 
the shock strut cylinder with a crack-free serviceable part in 
accordance with the alert service bulletin. After replacement, 
repeat the inspections at intervals not to exceed 1,200 landings.
    (b) For airplanes on which brake line hydraulic restrictors have 
been installed on the left and right MLG brake systems in accordance 
with McDonnell Douglas Alert Service Bulletin MD80-32A286, dated 
September 11, 1995, prior to the effective date of this AD: Within 
90 days after the effective date of this AD, perform dye penetrant 
and magnetic particle inspections to detect cracking of the shock 
strut cylinder of the MLG, in accordance with McDonnell Douglas 
Alert Service Bulletin MD80-32A286, dated September 11, 1995.
    (1) If no cracking is found, no further action is required by 
this AD.
    (2) If any cracking is found, prior to further flight, replace 
the shock strut cylinder with a crack-free serviceable part in 
accordance with the alert service bulletin. After the cylinder is 
replaced and the brake line hydraulic restrictors are reinstalled, 
no further action is required by this AD.
    (c) Installation of brake line hydraulic restrictors on the left 
and right MLG brake systems, in accordance with McDonnell Douglas 
Alert Service Bulletin MD80-32A286, dated September 11, 1995, 
constitutes terminating action for the repetitive requirements of 
this AD only if it is accomplished prior to further flight after a 
dye penetrant and magnetic particle inspection is performed in 
accordance with this AD and no cracking is found during that 
inspection.
    (d) As of the effective date of this AD, no person shall install 
on any airplane a MLG shock strut cylinder or MLG assembly unless 
that part has been inspected and found to be crack free, in 
accordance with McDonnell Douglas Alert Service Bulletin MD80-
32A286, dated September 11, 1995.
    (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 initial inspection required by this AD can be accomplished. Such 
special flight permits may not be issued for airplanes on which 
cracking is found during an inspection required by this AD.
    (g) The actions shall be done in accordance with McDonnell 
Douglas Alert Service Bulletin MD80-32A286, dated September 11, 
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, 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.
    (h) This amendment becomes effective on November 8, 1995.

    Issued in Renton, Washington, on October 16, 1995.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 95-25987 Filed 10-23-95; 8:45 am]
BILLING CODE 4910-13-U