AD Amdt-39-11086

[Federal Register Volume 64, Number 55 (Tuesday, March 23, 1999)]
[Rules and Regulations]
[Pages 13890-13892]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 99-6980]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 96-NM-203-AD; Amendment 39-11086; AD 98-13-35 R1]
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; correction.

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SUMMARY: This amendment corrects information in an existing 
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 currently 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. That AD also requires installation of a preventative 
modification, which terminates the repetitive inspections. The actions 
specified in that AD are intended to prevent fatigue cracks, which 
could result in loss of the structural integrity of the fuselage and, 
consequently, lead to rapid depressurization of the airplane. This 
amendment corrects the requirements of the current AD by indicating the 
specific area in which the subject inspection must be conducted. This 
amendment is prompted by communication received from the manufacturer 
that the current requirements of the AD are different than the service 
information referenced as the appropriate service information in the 
current AD.

EFFECTIVE DATE: July 30, 1998.

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: On June 17, 1998, the FAA issued AD 98-13-
35, amendment 39-10626 (63 FR 34585, June 25, 1998), which 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. 
That AD requires repetitive high frequency eddy current inspections of 
certain areas of the

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fuselage to detect cracks of the skin and/or longeron, and various 
follow-on actions. That AD also requires installation of a preventative 
modification, which terminates the repetitive inspections. That action 
was 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 
required by that 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.

Actions Since Issuance of Previous Rule

    Since the issuance of AD 98-13-35, the FAA has received information 
from the manufacturer that the specified area of the initial inspection 
requirements of paragraph (a) of that AD differs from the service 
information provided in McDonnell Douglas DC-9 Service Bulletin 53-235, 
dated September 15, 1993 (cited in the AD as the appropriate source of 
service information for accomplishment of the required actions).
    The FAA's intent in AD 98-13-35 was to require the actions 
described in McDonnell Douglas DC-9 Service Bulletin 53-235. In order 
to prevent operators from misinterpreting the specific area of the 
initial inspection, the FAA finds that the inspection requirements of 
paragraph (a) must be revised to specify inspection only of the 
fuselage, in lieu of the fuselage skin and/or longeron. Accordingly, 
this action revises paragraph (a) of the existing AD to remove 
reference to inspection of the longeron and to limit the area that is 
subject to the inspection (skin between stations Y=160.000 and 
Y=218.000; skin at the longeron attachments).
    Action is taken herein to clarify and correct these requirements of 
AD 98-13-35 and to correctly add the AD as an amendment to section 
39.13 of the Federal Aviation Regulations (14 CFR 39.13).
    The final rule is being reprinted in its entirety for the 
convenience of affected operators. The effective date remains July 30, 
1998.
    Since this action only clarifies and corrects a current 
requirement, it has no adverse economic impact and imposes no 
additional burden on any person. Therefore, notice and public 
procedures hereon are unnecessary.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

Adoption of the Correction

    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 removing amendment 39-10626 (63 FR 
34585, June 25, 1998), and by adding a new airworthiness directive 
(AD), amendment 39-11086, to read as follows:

98-13-35 R1  McDonnell Douglas: Amendment 39-11086. Docket 96-NM-
203-AD. Revises AD 98-13-35, Amendment 39-10626.

    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.

    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 between 
stations Y=160.000 and Y=218.000, and of the skin at the longeron 
attachments between stations Y=160.000 and Y=180.000, longeron 4 left 
and longeron 5 left, in accordance with McDonnell Douglas DC-9 Service 
Bulletin 53-235 dated September 15, 1993. 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.

Alternative Methods of Compliance

    (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

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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.

Special Flight Permits

    (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 effective date of this amendment remains July 30, 1998.

    Issued in Renton, Washington, on March 16, 1999.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 99-6980 Filed 3-22-99; 8:45 am]
BILLING CODE 4910-13-U