[Federal Register Volume 63, Number 122 (Thursday, June 25, 1998)]
[Rules and Regulations]
[Pages 34585-34587]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-16695]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 96-NM-203-AD; Amendment 39-10626; AD 98-13-35]
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 repetitive high frequency eddy current inspections of 
certain areas of the fuselage to detect cracks of the skin and/or 
longeron, and various follow-on actions. This amendment also requires 
installation of a preventative modification, which terminates the 
repetitive inspections. This amendment is prompted by reports 
indicating that, due to material fatigue caused by installation preload 
and cabin pressurization cycles, fatigue cracks were found in the skin 
and longerons of the fuselage. The actions specified by this AD are 
intended to prevent such fatigue cracks, which could result in loss of 
the structural integrity of the fuselage and, consequently, lead to 
rapid depressurization of the airplane.

DATES: Effective July 30, 1998.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of July 30, 1998.

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 7, 1997 (62 FR 10492). That action proposed to require repetitive 
high frequency eddy current (HFEC) inspections of the external areas of 
the fuselage skin to detect cracks of the skin and/or longeron between 
stations Y=160.000 and Y=218.000, and various follow-on actions. That 
action also proposed to require the installation of a preventative 
modification, which would constitute terminating action for the 
repetitive inspection requirements.

Explanation of Changes Made to Proposed AD

    Since issuance of the NPRM, the FAA has received a report 
indicating that, during inspection of a McDonnell Douglas Model DC-9-32 
series airplane, fatigue cracking was found in additional structure 
that is within the subject area of the proposed AD (i.e., between 
stations Y=160.000 and Y=218.000). The additional area is approximately 
10 inches by 6 inches and is directly between areas subject to the 
proposed inspection required by this AD. Because

[[Page 34586]]

of the small size of the additional area and its location, the FAA 
finds that adding this area to the existing requirements of the final 
rule will not increase significantly the inspection burden on 
operators. Therefore, in addition to the area between stations 
Y=160.000 and Y=218.000 (as specified in McDonnell Douglas DC-9 Service 
Bulletin 53-235, which was referenced in the proposed AD as the 
appropriate source of service information), the FAA has determined that 
the repetitive HFEC inspections also must be conducted in the entire 
area between stations Y=160.000 and Y=180.000, longeron 4 left and 
longeron 5 left. The FAA has revised paragraph (a) of the final rule 
accordingly, and has added one work hour to the cost impact information 
below, to account for the additional time necessary to accomplish the 
required inspection. In addition, McDonnell Douglas is planning on 
revising the referenced service bulletin to coincide with the 
requirements of this final rule.

Comments

    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received.
    Several commenters support the proposed rule.

Request to Allow Credit for Inspections Performed Previously

    One commenter requests that the compliance time for paragraph (a) 
of the proposed AD be revised to allow credit for internal visual 
inspections performed previously in accordance with Task C46-53300 of 
the Corrosion Prevention and Control Program (CPCP) [required by AD 92-
22-08 R1, amendment 39-8591 (58 FR 32281, June 9, 1993)]. The commenter 
states that, since the primary failure mode is a cracked longeron or 
shear clip, the internal visual inspection will have a crack detection 
threshold lower than that of the initial external eddy current 
inspection specified in paragraph (a) of the proposed AD. The FAA 
concurs. The FAA finds that the structure and area specified in this AD 
are identical to the structure and area being inspected in accordance 
with the CPCP AD 92-22-08 R1. The FAA has determined that, for 
airplanes that have been inspected previously in accordance with Task 
C46-53300 of the CPCP (required by AD 92-22-08 R1) within 6,000 
landings prior to the effective date of this AD, the initial HFEC 
inspection required by this AD shall be accomplished within 12,000 
landings. The FAA finds that a 12,000-landing compliance time 
represents an appropriate interval of time allowable for these affected 
airplanes to continue to operate without compromising safety. The FAA 
has revised paragraph (a) of the final rule accordingly.

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 1,728 McDonnell Douglas Model DC-9 and DC-
9-80 series airplanes, Model MD-88 airplanes, and C-9 (military) series 
airplanes of the affected design in the worldwide fleet. The FAA 
estimates that 1,152 airplanes of U.S. registry will be affected by 
this AD.
    It will take approximately 17 work hours per airplane to accomplish 
the required HFEC inspection, at an average labor rate of $60 per work 
hour. Based on these figures, the cost impact of the HFEC inspection 
required by this AD on U.S. operators is estimated to be $1,175,040, or 
$1,020 per airplane, per inspection cycle.
    It will take approximately 89 work hours per airplane to accomplish 
the required modification, at an average labor rate of $60 per work 
hour. The cost of required parts will range from $13,771 to $15,292 per 
airplane. Based on these figures, the cost impact of the modification 
required by this AD on U.S. operators is estimated to be between 
$22,015,872 ($19,111 per airplane) and $23,768,064 ($20,632 per 
airplane).
    The cost impact figures discussed above are 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:

98-13-35  McDonnell Douglas: Amendment 39-10626. Docket 96-NM-203-
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), and -87 
(MD-87) series airplanes; Model MD-88 airplanes; and C-9 (military) 
series airplanes; as listed in McDonnell Douglas DC-9 Service 
Bulletin 53-235, dated September 15, 1993; 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 (f) 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.


[[Page 34587]]


    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent fatigue cracks in the skin and longerons of the 
fuselage, which could result in loss of the structural integrity of 
the fuselage and, consequently, lead to rapid depressurization of 
the airplane, accomplish the following:
    (a) Perform a high frequency eddy current (HFEC) inspection of 
the external areas of the fuselage to detect cracks of the skin and/
or longeron between stations Y=160.000 and Y=218.000, in accordance 
with McDonnell Douglas DC-9 Service Bulletin 53-235, dated September 
15, 1993; and of the entire area between stations Y=160.000 and 
Y=180.000, longeron 4 left and longeron 5 left. Perform the 
inspection at the time specified in paragraph (a)(1) or (a)(2) of 
this AD, as applicable.

    Note 2: Where there are differences between this AD and the 
referenced service bulletin, the AD prevails.

    (1) For airplanes other than those identified in paragraph 
(a)(2) of this AD: Inspect prior to the accumulation of 30,000 total 
landings, or within 8,000 landings after the effective date of this 
AD, whichever occurs later.
    (2) For airplanes that have been inspected previously in 
accordance with Task C46-53300 of the Corrosion Prevention and 
Control Program (CPCP), as required by AD 92-22-8-R1, amendment 39-
8591, within 6,000 flight cycles prior to the effective date of this 
AD: Inspect within 12,000 landings after the effective date of this 
AD.
    (b) Condition 1 (No Cracks). If no crack is detected during any 
inspection required by this AD, accomplish either paragraph (b)(1) 
or (b)(2) of this AD, in accordance with McDonnell Douglas DC-9 
Service Bulletin 53-235, dated September 15, 1993.
    (1) Condition 1, Option I (Repetitive Inspection). Repeat the 
HFEC inspection required by paragraph (a) of this AD, and the aided 
visual inspection specified in paragraph 2.E. of the Accomplishment 
Instructions of the service bulletin, at intervals not to exceed 
10,000 landings.
    (2) Condition 1, Option II (Terminating Action Modification). 
Accomplish the preventative modification installation of clips and 
doublers between stations Y=160.000 and Y=218.000, in accordance 
with the service bulletin. Accomplishment of the modification 
constitutes terminating action for the repetitive inspection 
requirements of this AD.
    (c) Condition 2 (Skin Cracks). If any skin crack is detected 
during any inspection required by this AD, prior to further flight, 
repair it in accordance with McDonnell Douglas DC-9 Service Bulletin 
53-235, dated September 15, 1993. After repair, accomplish either 
paragraph (b)(1) or (b)(2) of this AD.
    (d) Condition 3 (Longeron Cracks). If any longeron crack is 
detected during any inspection required by this AD, prior to further 
flight, repair it in accordance with McDonnell Douglas DC-9 Service 
Bulletin 53-235, dated September 15, 1993. After repair, accomplish 
either paragraph (b)(1) or (b)(2) of this AD.
    (e) Prior to the accumulation of 100,000 total landings, or 
within 4 years after the effective date of this AD, whichever occurs 
later, accomplish the preventative modification specified in 
paragraph 2.J. of the Accomplishment Instructions of McDonnell 
Douglas DC-9 Service Bulletin 53-235, dated September 15, 1993. 
Accomplishment of the modification constitutes terminating action 
for the requirements of this AD.
    (f) 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 3: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Los Angeles ACO.

    (g) 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.
    (h) The actions shall be done in accordance with McDonnell 
Douglas DC-9 Service Bulletin 53-235, dated September 15, 1993. 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 
Capitol Street, NW., suite 700, Washington, DC.
    (i) This amendment becomes effective on July 30, 1998.

    Issued in Renton, Washington, on June 17, 1998.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 98-16695 Filed 6-24-98; 8:45 am]
BILLING CODE 4910-13-U