[Federal Register Volume 60, Number 100 (Wednesday, May 24, 1995)]
[Proposed Rules]
[Pages 27449-27451]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-12712]



[[Page 27449]]

DEPARTMENT OF TRANSPORTATION

14 CFR Part 39

[Docket No. 95-NM-16-AD]


Airworthiness Directives; McDonnell Douglas Model DC-9 and 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 all McDonnell Douglas Model DC-9 
and C-9 (military) series airplanes. This proposal would require 
replacement, inspection, and modification of the attach fittings of the 
main landing gear (MLG). This proposal is prompted by reports of severe 
structural damage and rupture of the integral fuel tank due to overload 
of the MLG caused by adverse landing conditions. The actions specified 
by the proposed AD are intended to minimize the possibility of primary 
structural damage and rupture of the integral fuel tank due to overload 
of the MLG; these conditions could lead to fuel spillage and a 
resultant fire.

DATES: Comments must be received by July 19, 1995.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 95-NM-16-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; or at the FAA, Transport Airplane 
Directorate, Los Angeles Aircraft Certification Office, 3960 Paramount 
Boulevard, Lakewood, California.

FOR FURTHER INFORMATION CONTACT: David Y. J. Hsu, Aerospace Engineer, 
Airframe Branch, ANM-120L, FAA, Transport Airplane Directorate, Los 
Angeles Aircraft Certification Office, 3960 Paramount Boulevard, 
Lakewood, California 90712; telephone (310) 627-5323; 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-16-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-16-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    Since October 28, 1971, the FAA has received 11 reports of severe 
structural damage and rupture of the wing integral fuel tank on 
McDonnell Douglas Model DC-9 series airplanes. These occurrences 
resulted from unpredictable overload of the main landing gear (MLG) 
caused by adverse landing conditions. Model DC-9 series airplanes 
having certain MLG fittings attached to the airframe in a particular 
manner can sustain damage of the primary structure and rupture of the 
integral fuel tank during certain abnormal landing conditions. Such 
conditions include overrunning the runway, going off the runway, 
skidding off the runway, taxiing into holes on a runway under repair, 
landing off the runway, or a hard landing. Structural damage of this 
type could compromise the integrity of the integral fuel tank. Should 
the integral fuel tank subsequently rupture, it could result in fuel 
spillage and a resultant fire.
    The FAA has reviewed and approved McDonnell Douglas DC-9 Service 
Bulletin 57-207, dated May 24, 1994, which references two other 
McDonnell Douglas DC-9 service bulletins that contain procedures which, 
when accomplished, will improve the capability of the MLG to break away 
during abnormal landing operations. These service bulletins contain 
procedures for replacement, inspection, and modification of the 
attachments of the MLG attach fittings, as follows:
    1. McDonnell Douglas DC-9 Service Bulletin 57-125, Revision 5, 
dated November 5, 1990, describes procedures for replacement of MLG 
attach fittings fabricated from 7079-T6 with fittings fabricated from 
7075-T73 aluminum alloy forgings. These procedures are specified in the 
service bulletin as Option 1.
    2. McDonnell Douglas DC-9 Service Bulletin 57-148, Revision 5, 
dated November 23, 1992. This service bulletin describes procedures for 
the following:

--Enlarging the counterbores in the MLG attach fitting at the inboard 
and outboard lower attachment holes, and performing a high frequency 
eddy current inspection of the counterbore areas to detect cracks;
--Shotpeening selected areas of the MLG attach fitting;
--Replacing the lower attachment bolts of the inboard and outboard MLG 
attach fittings with bolts having a different part number; and
--Replacing the fasteners through the lower flange of the MLG attach 
fitting with interference fit fasteners.

These procedures are identified in the service bulletin as Phase 2.
    Accomplishment of the actions described above will minimize the 
possibility of primary structural damage, fuel tank rupture, and 
possible fuel spillage due to unpredictable overload of the MLG caused 
by abnormal landing operations.
    Accomplishment of the procedures described in Revision 4 of 
McDonnell Douglas DC-9 Service Bulletin 57-125 is required currently by 
AD 90-18-03, amendment 39-6701 (55 FR 34704, August 24, 1990) to 
address an unsafe condition identified as cracking due to stress 
corrosion and subsequent degradation of the structural capability of 
the affected airplanes. Revisions 3, 4, and 5 of that service bulletin 
also specify procedures which, when accomplished, will improve the 
[[Page 27450]] capability of the MLG to break away during abnormal 
landing operations. Therefore, the FAA has determined that the unsafe 
condition related to structural damage of the integral fuel tank, as 
addressed by this proposed AD, also has been addressed adequately for 
those airplanes on which Option 1 of Revision 3, 4, or 5 of the service 
bulletin has been accomplished. However, the original version through 
Revision 2 of McDonnell Douglas DC-9 Service Bulletin 57-125 do not 
contain procedures that will improve the breakaway capability of the 
MLG. The FAA has previously approved accomplishment of Option 1 in 
accordance with the original version through Revision 2 of the service 
bulletin, in lieu of Revision 4, as an acceptable alternative method of 
compliance with AD 90-18-03. Therefore, for airplanes on which the 
procedures described in the original version, Revision 1, or Revision 2 
of McDonnell Douglas DC-9 Service Bulletin 57-125 have been 
accomplished, the FAA finds that Phase 2, as specified in McDonnell 
Douglas DC-9 Service Bulletin 57-148, also must be accomplished to 
ensure that the unsafe condition specified in this proposed AD is 
corrected.
    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 one of the actions specified below, as 
applicable. The actions would be required to be accomplished in 
accordance with the service bulletins described previously.
    1. Replacement of the attach fittings of both the right and left 
MLG's would be required for airplanes on which Option 1 (or production 
equivalent) of McDonnell Douglas DC-9 Service Bulletin 57-125 (original 
version through Revision 5) has not been accomplished.
    2. Inspection and modification of the attach fittings of both the 
right and left MLG's would be required for airplanes on which Option 1 
of McDonnell Douglas DC-9 Service Bulletin 57-125 (original version 
through Revision 2) has been accomplished, but on which Phase 2 of 
McDonnell Douglas DC-9 Service Bulletin 57-148 (original version 
through Revision 5) has not been accomplished.
    There are approximately 906 Model DC-9 and C-9 (military) series 
airplanes of the affected design in the worldwide fleet. The FAA 
estimates that 549 airplanes of U.S. registry would be affected by this 
proposed AD.
    The FAA estimates that the replacement specified as Option 1 in 
McDonnell Douglas DC-9 Service Bulletin 57-125 has been accomplished on 
all 549 airplanes of U.S. registry that would be affected by this 
proposed AD. (As discussed previously, accomplishment of Option 1 was 
required by AD 90-18-03.) Accordingly, the FAA finds that the proposed 
replacement required by this AD would impose no additional economic 
burden on any U.S. operator.
    However, should an affected airplane be imported and placed on the 
U.S. Register in the future, it would require approximately 425 work 
hours to accomplish Option 1, at an average labor charge of $60 per 
work hour. The cost of required parts would be $58,853 per airplane. 
Based on these figures, the total cost impact for accomplishing Option 
1 would be $84,353 per airplane.
    The FAA estimates that all 549 airplanes of U.S. registry would be 
required to accomplish the inspection and modification specified as 
Phase 2 in McDonnell Douglas DC-9 Service Bulletin 57-148. It would 
take approximately 36 work hours per airplane to accomplish Phase 2, at 
an average labor rate of $60 per work hour. Required parts would cost 
approximately $4,338 per airplane. Based on these figures, the total 
cost impact on U.S. operators for accomplishing Phase 2 is estimated to 
be $3,567,402, or $6,498 per airplane.
    The total cost impact figure discussed above is based on 
assumptions that no operator has yet accomplished this proposed 
requirement (Phase 2) of this AD action, and that no operator would 
accomplish that action in the future if this AD were not adopted.
    As a result of recent communications with the Air Transport 
Association (ATA) of America, the FAA has learned that, in general, 
some operators may misunderstand the legal effect of AD's on airplanes 
that are identified in the applicability provision of the AD, but that 
have been altered or repaired in the area addressed by the AD. The FAA 
points out that all airplanes identified in the applicability provision 
of an AD are legally subject to the AD. If an airplane has been altered 
or repaired in the affected area in such a way as to affect compliance 
with the AD, the owner or operator is required to obtain FAA approval 
for an alternative method of compliance with the AD, in accordance with 
the paragraph of each AD that provides for such approvals. A note has 
been included in this notice to clarify this long-standing requirement.
    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.

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. App. 1354(a), 1421 and 1423; 49 U.S.C. 
106(g); and 14 CFR 11.89.


Sec. 39.13  [Amended]

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

McDonnell Douglas: Docket 95-NM-16-AD.

    Applicability: All Model DC-9 and C-9 (military) series 
airplanes, 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 (c) 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 
[[Page 27451]] 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 minimize the possibility of primary structural damage and 
rupture of the integral fuel tank due to overload of the main 
landing gear (MLG) caused by adverse landing conditions, and 
subsequent fuel spillage and a resultant fire, accomplish the 
following:
    (a) For airplanes on which Option 1 (or production equivalent) 
has not been accomplished as specified in McDonnell Douglas DC-9 
Service Bulletin 57-125 (original issue through Revision 5): Within 
12 months after the effective date of this AD, replace the attach 
fittings of both the right and left MLG's in accordance with Option 
1 of the Accomplishment Instructions of McDonnell Douglas DC-9 
Service Bulletins 57-125, Revision 5, dated November 5, 1990.

    Note 2: Airplanes on which Option 1 has been accomplished as 
specified in any of the following revisions of McDonnell Douglas DC-
9 Service Bulletin 57-125, are considered to be in compliance with 
this AD and no further action is required by this AD:

------------------------------------------------------------------------
     Service bulletin No.       Revision level             Date         
------------------------------------------------------------------------
57-125.......................  Revision 3......  October 28, 1982; or   
                               Revision 4......  June 21, 1983; or      
                               Revision 5......  November 5, 1990.      
------------------------------------------------------------------------

    (b) For airplanes on which Option 1 has been accomplished as 
specified in McDonnell Douglas DC-9 Service Bulletin 57-125 
(original version through Revision 2); but on which Phase 2 has not 
been accomplished as specified in McDonnell Douglas DC-9 Service 
Bulletin 57-148 (original version through Revision 5): Within 12 
months after the effective date of this AD, inspect and modify the 
attach fittings of both the right and left MLG's in accordance with 
Phase 2 of McDonnell Douglas DC-9 Service Bulletin 57-148, Revision 
5, dated November 23, 1992.

    Note 3: Airplanes on which both Option 1 (or a production 
equivalent) has been accomplished as specified in any of the 
following revisions of McDonnell Douglas DC-9 Service Bulletin 57-
125; and Phase 2 (or a production equivalent) has been accomplished 
as specified in any of the following revisions of McDonnell Douglas 
DC-9 Service Bulletin 57-148; are considered to be in compliance 
with this AD and no further action is required by this AD:

------------------------------------------------------------------------
     Service bulletin No.       Revision level             Date         
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57-125.......................  (original)......  January 26, 1979; or   
                               Revision 1......  February 16, 1979; or  
                               Revision 2......  August 24, 1979;       
    and                                                                 
                                                                        
57-148.......................  (original)......  October 1, 1982; or    
                               Revision 1......  June 8, 1983; or       
                               Revision 2......  August 9, 1989; or     
                               Revision 3......  September 11, 1990; or 
                               Revision 4......  February 25, 1991; or  
                               Revision 5......  November 23, 1992.     
------------------------------------------------------------------------

    (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, 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 4: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Los Angeles ACO.

    (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.

    Issued in Renton, Washington, on May 18, 1995.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 95-12712 Filed 5-23-95; 8:45 am]
BILLING CODE 4910-13-U