[Federal Register Volume 61, Number 21 (Wednesday, January 31, 1996)]
[Proposed Rules]
[Pages 3341-3343]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-1875]



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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 95-NM-185-AD]


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

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the adoption of a new airworthiness 
directive (AD) that is applicable to certain McDonnell Douglas Model 
DC-9 and Model DC-9-80 series airplanes, Model MD-88 airplanes, and 
Model C-9 (military) series airplanes. This proposal would require 
modification of the slant panel insulation blankets on the slant 
pressure panel of the main landing gear. The proposal would also 
require a visual inspection to detect discrepancies of the left and 
right seal assemblies of the overwing emergency exit door, and 
replacement of any discrepant door seal. This proposal is prompted by a 
report that the flaps and landing gear did not extend or retract 
properly due to water accumulation in the slant pressure panel area. 
The actions specified by the proposed AD are intended to prevent such 
water accumulation, which could result in the failure of the flaps or 
landing gear to properly extend or retract.

DATES: Comments must be received by March 26, 1996.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 

[[Page 3342]]
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 95-NM-185-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.
    The service information referenced in the proposed rule 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.

FOR FURTHER INFORMATION CONTACT: Brent Bandley, Aerospace Engineer, 
Airframe Branch, ANM-120L, FAA, Los Angeles Aircraft Certification 
Office, 3960 Paramount Boulevard, Lakewood, California 90712; telephone 
(310) 627-5237; fax (310) 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.
    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 notice must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 95-NM-185-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-103, Attention: Rules 
Docket No. 95-NM-185-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The FAA has received a report that the flaps and landing gear did 
not extend or retract properly in flight on a Model DC-9-31 series 
airplane. Investigation revealed that the potable water lines over the 
center section had frozen and ruptured. The potable water leaked from 
the water lines through the door seals of the overwing exit door and 
accumulated in the slant pressure panel area. The water then dripped 
and froze on various cables in the main wheel well area, which 
prevented the flaps and landing gear from operating properly. If not 
corrected, the possibility of water pooling in the slant pressure panel 
area could continue, and consequently could drip and freeze on the 
cables in the main wheel well area; this situation could then prevent 
the flaps and landing gear form operating properly.
    The potable water line installation, overwing exit door seals, and 
slant pressure panel area on certain Model DC-9-80 series airplanes, 
Model MD-88 airplanes, and C-9 (military) series airplanes are 
essentially identical in configuration to that of Model DC-9 series 
airplanes. Therefore, those airplanes may be subject to the same unsafe 
condition identified on the Model DC-9 series airplanes.
    The FAA has reviewed and approved McDonnell Douglas Service 
Bulletin DC9-53-268, dated August 11, 1995, which describes procedures 
for modification of the slant panel insulation blankets on the slant 
pressure panel of the main landing gear. The modification involves 
trimming the insulation blankets, sealing the trimmed area, and 
reidentifying the insulation blankets. Accomplishment of the 
modification will allow the water to drain out through the drain holes 
and minimize the possibility of water accumulating in the slant 
pressure panel area. The service bulletin also describes procedures for 
a visual inspection to detect discrepancies (i.e., defects and constant 
gap) of the left and right seal assemblies of the overwing emergency 
exit door, and replacement of any discrepant door seal.
    Since an unsafe condition has been identified that is likely to 
exist or develop on other products of this same type design, the 
proposed AD would require modification of the slant panel insulation 
blankets on the slant pressure panel of the main landing gear. The 
proposed AD would also require a visual inspection to detect 
discrepancies of the left and right seal assemblies of the overwing 
emergency exit door, and replacement of the discrepant door seal. The 
actions would be required to be accomplished in accordance with the 
service bulletin described previously.
    There are approximately 1,500 McDonnell Douglas Model DC-9 and 
Model DC-9-80 series airplanes, Model MD-88 airplanes, and Model C-9 
(military) series airplanes of the affected design in the worldwide 
fleet. The FAA estimates that 1,000 airplanes of U.S. registry would be 
affected by this proposed AD, that it would take approximately 8 work 
hours per airplane to accomplish the proposed actions, and that the 
average labor rate is $60 per work hour. Based on these figures, the 
cost impact of the proposed AD on U.S. operators is estimated to be 
$480,000, or $480 per airplane.
    The cost impact figure discussed above is 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 regulations proposed herein would 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 
proposal would not have sufficient federalism implications to warrant 
the preparation of a Federalism Assessment.
    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. 
    
[[Page 3343]]


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 USC 106(g), 40113, 44701.


Sec. 39.13  [Amended]

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

McDonnell Douglas: Docket 95-NM-185-AD.

    Applicability: Model DC-9-10, -20, -30, -40, and -50 series 
airplanes; Model DC-9-81 (MD-81), -82 (MD-82), -83 (MD-83), -87 (MD-
87) series airplanes; Model MD-88 airplanes; and Model C-9 
(military) series airplanes; as listed in McDonnell Douglas Service 
Bulletin DC9-53-268, dated August 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 
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 use the authority 
provided in paragraph (b) 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 water accumulation in the slant pressure panel area, 
which could result in the failure of the flaps or landing gear to 
properly extend or retract, accomplish the following:
    (a) Within 24 months after the effective date of this AD, 
accomplish paragraphs (a)(1) and (a)(2) of this AD, in accordance 
with McDonnell Douglas Service Bulletin DC9-53-268, dated August 11, 
1995.
    (1) Modify the slant panel insulation blankets on the slant 
pressure panel of the main landing gear.
    (2) Perform a visual inspection to detect discrepancies (i.e., 
defects and constant gap) of the left and right seal assemblies of 
the overwing emergency exit door. If any discrepancy is detected, 
prior to further flight, replace door seal in accordance with the 
service bulletin.
    (b) 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.

    (c) 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 January 26, 1996.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 96-1875 Filed 1-30-96; 8:45 am]
BILLING CODE 4910-13-U