[Federal Register: March 24, 1998 (Volume 63, Number 56)]
[Proposed Rules]               
[Page 14047-14049]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr24mr98-21]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-NM-21-AD]
RIN 2120-AA64

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

[[Page 14048]]

directive (AD) that is applicable to certain McDonnell Douglas Model 
DC-9 and DC-9-80 series airplanes, Model MD-88 airplanes, and C-9 
(military) series airplanes. This proposal would require a one-time 
visual inspection to detect fatigue cracking of the lower left nose of 
certain longerons and the attaching frames; repair, if necessary; and 
installation of a preventive modification. The proposal also would 
require installation of a preventive modification. This proposal is 
prompted by several reports of fatigue cracking of certain longerons 
and the attaching frames. The actions specified by the proposed AD are 
intended to prevent such fatigue cracking, which could result in 
reduced structural integrity of the fuselage, and consequent loss of 
pressurization of the airplane.

DATES: Comments must be received by May 8, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 97-NM-21-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 The Boeing Company, Douglas Products 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, Transport 
Airplane Directorate, 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; 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.
    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 97-NM-21-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-21-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The FAA has received reports indicating that cracking of the 
fuselage longerons-to-frame attachment holes occurred on three 
McDonnell Douglas Model DC-9 series airplanes. The cracking of the 
longeron segments has been attributed to fatigue. The fatigue cracking 
was found between longerons 22 though 26 on the left side at stations 
Y=160.000 and Y=200.000. These airplanes had accumulated between 59,110 
and 74,445 total flight cycles. Such fatigue cracking, if not 
corrected, could result in reduced structural integrity of the 
fuselage, and consequent loss of pressurization of the airplane.

Similar Airplanes

    The fuselage longerons-to-frame attachments of Model DC-9 series 
airplanes are similar to those of McDonnell Douglas Model DC-9-80 
series airplanes, Model MD-88 airplanes, and C-9 (military) series 
airplanes; therefore, these models also may be subject to this same 
unsafe condition.

Explanation of Relevant Service Information

    The FAA has reviewed and approved McDonnell Douglas DC-9 Service 
Bulletin 53-256, dated August 12, 1993, and Revision 1, dated November 
29, 1994 (for Model DC-9 series airplanes), and MD-80 Service Bulletin 
53-265, dated June 13, 1994 (for Model DC-9-80 series airplanes and MD-
88 airplanes). These service bulletins describe procedures for a one-
time visual inspection to detect cracking of the lower left nose of 
longerons 22 through 26 and the attaching frames at stations Y=160.000 
and Y=200.000. The service bulletins also provide procedures for a 
preventive modification (installation of clips and doublers under 
longeron flanges and shims longeron) to relieve preloads. Additionally, 
the service bulletins reference the applicable Structural Repair Manual 
for repairs, if necessary.

Explanation of Requirements of Proposed Rule

    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 a one-time visual inspection to detect 
cracking of the lower left nose of longerons 22 through 26 and the 
attaching frames at stations Y=160.000 and Y=200.000. The proposed rule 
also would require accomplishment of a preventive modification, and 
repair of any cracking detected. The actions would be required to be 
accomplished in accordance with the applicable service bulletin 
described previously.

Cost Impact

    There are approximately 2,000 Model DC-9, Model DC-9-80, and C-9 
(military) series airplanes, and Model MD-88 airplanes of the affected 
design in the worldwide fleet. The FAA estimates that 1,200 airplanes 
of U.S. registry would be affected by this proposed AD, that it would 
take approximately 25 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 $1,800,000, or $1,500 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.

Regulatory Impact

    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

[[Page 14049]]

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. 106(g), 40113, 44701.


Sec. 39.13  [Amended]

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

    McDonnell Douglas:   Docket 97-NM-21-AD.

    Applicability: Model DC-9-10, -20, -30, -40, -50 and C-9 
(military) series airplanes, as listed in McDonnell Douglas DC-9 
Service Bulletin 53-256, Revision 1, dated November 29, 1994; 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 MD-88 airplanes, as listed in McDonnell 
Douglas MD-80 Service Bulletin 53-265, dated June 13, 1994; 
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 (b) 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 longerons 22 through 26 and the 
attaching frames, which could result in reduced structural integrity 
of the fuselage, and consequent loss of pressurization of the 
airplane; accomplish the following:
    (a) Prior to the accumulation of 40,000 total landings, or 
within 6,000 landings after the effective date of this AD, whichever 
occurs later: Perform a visual inspection to detect cracking of the 
left lower nose of longerons 22 through 26 (inclusive) and the 
respective attaching frames at station frames Y=160.000 and 
Y=200.000; in accordance with McDonnell Douglas DC-9 Service 
Bulletin 53-256, dated August 12, 1993, or Revision 1, dated 
November 29, 1994 [for Models DC-9, -10, -20, -30, -40, -50, and C-9 
(military) series airplanes]; or McDonnell Douglas MD-80 Service 
Bulletin 53-265, dated June 13, 1994 (for Model DC-9-81, -82, -83, 
and -87 series airplanes, and MD-88 airplanes); as applicable.
    (1) If no cracking is detected: Prior to further flight, install 
clips and doublers under the longeron flanges and shim the longerons 
in accordance with the applicable service bulletin.
    (2) If any cracking is detected: Prior to further flight, repair 
the cracks and install clips and doublers under the longeron flanges 
and shim the longerons in accordance with the applicable 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 Manager, 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 March 17, 1998.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 98-7524 Filed 3-23-98; 8:45 am]
BILLING CODE 4910-13-U