[Federal Register Volume 63, Number 232 (Thursday, December 3, 1998)]
[Rules and Regulations]
[Pages 66739-66741]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-31698]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-NM-21-AD; Amendment 39-10919; AD 98-24-33]
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: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD), 
applicable to certain McDonnell Douglas Model DC-9 and DC-9-80 series 
airplanes, Model MD-88 airplanes, and C-9 (military) series airplanes, 
that requires 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. 
This amendment is prompted by several reports of fatigue cracking of 
certain longerons and the attaching frames. The actions specified by 
this 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: Effective January 7, 1999.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of January 7, 1999.

ADDRESSES: The service information referenced in this AD 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 Federal Aviation Administration 
(FAA), Transport Airplane Directorate, Rules Docket, 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, Los Angeles Aircraft Certification 
Office, 3960 Paramount Boulevard, Lakewood, California 90712; telephone 
(562) 627-5237; fax (562) 627-5210.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal 
Aviation Regulations (14 CFR part 39) to include an airworthiness 
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 was published in the Federal Register on 
March 24, 1998 (63 FR 14047). That action proposed to 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.
    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received.

Support for the Proposal

    Two commenters support the proposed rule.

Request To Provide Option for Other Inspection Techniques

    One commenter requests that the FAA revise the proposal to provide 
the option of using a dye check or a non-destructive testing (NDT) 
inspection method instead of (or in conjunction with) the required 
visual inspection. The FAA does not concur with this request. An 
inspection procedure was established several years ago to address 
inspections of the affected longerons. The FAA finds that introducing a 
new inspection procedure at this point would not be feasible. However, 
the FAA would consider a request for approval of a different inspection 
technique, in accordance with the provision of paragraph (d) of this 
AD, provided that adequate justification accompanies the request.

Requests To Extend Compliance Time

    One commenter states that the proposed grace period of 6,000 flight 
cycles is logistically impractical due to the heavy access required in 
the electrical/electric (E/E) equipment compartment to accomplish the 
inspection/modification. The commenter suggests that the compliance 
time for the modification be revised to coincide with the next 
scheduled inspection interval per Corrosion Task No. 45-53301 in the 
DC9/MD80 Corrosion Prevention and Control Document MDC-K4606, which is 
required by AD 92-22-08, amendment 39-8394 (57 FR 57895, December 8, 
1992).
    Another commenter also requests that, for airplanes that have 
accumulated 40,000 or more total landings, the FAA require an external 
eddy current inspection within 6,000 landings, and repetitive 
inspections every 2,500 landings until the terminating modification is 
accomplished. The commenter proposes that if a cracked longeron is 
found, only a repair per the SRM should be required prior to further 
flight--not the modification. The commenter suggests that the 
modification should be required at the next scheduled ``D'' check, but 
no later than 12,000 landings.
    The commenter indicates that it inspects the subject longerons at 
an interval of approximately 11,000 landings. Based on this inspection 
experience and the damage tolerance characteristics (i.e., crack 
detectability, crack growth rate, and residual strength) of the 
fuselage skin and longerons, the commenter states that the proposed 
grace period of 6,000 landings for airplanes that have accumulated 
40,000 or more total landings is too restrictive and not justified. The 
commenter believes that an equivalent level of safety can be maintained 
with a repetitive inspection that is based on damage tolerance 
principles, while minimizing the operational impact to operators.
    Another commenter requests that, if no cracking is detected, the 
FAA allow the option of continuing repetitive inspections in lieu of 
accomplishing the modification prior to further flight, as specified in 
the proposal.
    The FAA concurs partially. The FAA does not consider that 
repetitive inspections are warranted in this case since continual 
access to repetitively inspect the affected longerons is difficult. 
However, the FAA agrees that the proposed grace period can be extended. 
The FAA considers that an extension of that grace period to 12,000 
landings will provide time for operators of large fleets to access, 
inspect, and modify. The FAA finds that such an extension of the grace 
period will not compromise the safety of the affected fleet. Paragraph 
(a)(2) of this AD has been revised accordingly.

[[Page 66740]]

    Additionally, for airplanes that have been inspected prior to the 
effective date of this AD in accordance with Corrosion Task No. 45-
53301 of DC9/MD80 Corrosion Prevention and Control Document MDC-K4606, 
the FAA has added a new paragraph (a)(1) to this final rule to require 
that the actions be accomplished at the next scheduled repetitive 
corrosion task inspection.

Requests To Revise Cost Impact Information

    One commenter does not object to the proposed rule, but requests 
that the cost impact information be revised to agree with the estimates 
presented in the referenced service bulletin (33.3 and 41.8 work hours) 
to provide industry with a more consistent cost estimate. Another 
commenter indicates that, based on the access requirements and actual 
work hours expended for similar actions, the proposed actions would 
take approximately 80 work hours per airplane with an elapsed time of 
40 hours. The commenter believes that it is important to reflect 
accurate cost impact figures in the final rule since it will have a 
significant economic impact on operators.
    The FAA does not concur. The number of work hours necessary to 
accomplish the required actions, specified as 25 in the cost impact 
information, was provided to the FAA by the manufacturer based on the 
best data available to date. No change to the cost impact information 
has been made.

Conclusion

    After careful review of the available data, including the comments 
noted above, the FAA has determined that air safety and the public 
interest require the adoption of the rule with the changes previously 
described. The FAA has determined that these changes will neither 
increase the economic burden on any operator nor increase the scope of 
the AD.

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 will be affected by this AD, that it will take 
approximately 25 work hours per airplane (excluding work hours 
necessary to gain access and close up) to accomplish the required 
actions, and that the average labor rate is $60 per work hour. Based on 
these figures, the cost impact of the 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 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 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.
    For the reasons discussed above, I certify that this action (1) is 
not a ``significant regulatory action'' under Executive Order 12866; 
(2) is not a ``significant rule'' under DOT Regulatory Policies and 
Procedures (44 FR 11034, February 26, 1979); and (3) 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 final evaluation has been prepared for this action 
and it is contained in the Rules Docket. A copy of it 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:

    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:

98-24-33  McDonnell Douglas: Amendment 39-10919. 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 (d) 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) 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. Perform the 
inspection at the time specified in paragraph (a)(1) or (a)(2) of 
this AD, as applicable.
    (1) For airplanes that have been inspected prior to the 
effective date of this AD in accordance with Corrosion Prevention 
and Control Program Document MDC-K4606, Corrosion Task No. 45-53301: 
Perform the inspection at the next scheduled repetitive corrosion 
task inspection.
    (2) For airplanes other than those identified in paragraph 
(a)(1) of this AD: Perform the inspection prior to the accumulation 
of 40,000 total landings, or within 12,000 landings after the 
effective date of this AD, whichever occurs later:
    (b) If no cracking is detected: Prior to further flight, install 
clips and doublers under the longeron flanges and shim the longerons 
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.
    (c) If any cracking is detected: Prior to further flight, repair 
the cracks and install clips and doublers under the longeron

[[Page 66741]]

flanges and shim the longerons 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.
    (d) 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.

    (e) Special flight permits may be issued in accordance with 
Secs. 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.
    (f) The actions shall be done in accordance with McDonnell 
Douglas DC-9 Service Bulletin 53-256, dated August 12, 1993; 
McDonnell Douglas DC-9 Service Bulletin 53-256, Revision 1, dated 
November 29, 1994; or McDonnell Douglas MD-80 Service Bulletin 53-
265, dated June 13, 1994; as applicable. 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 The Boeing Company, Douglas Products Division, 3855 
Lakewood Boulevard, Long Beach, California 90846, Attention: 
Technical Publications Business Administration, Dept. 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 Captiol Street, NW., suite 700, 
Washington, DC.
    (g) This amendment becomes effective on January 7, 1999.

    Issued in Renton, Washington, on November 20, 1998.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 98-31698 Filed 12-2-98; 8:45 am]
BILLING CODE 4910-13-U