[Federal Register Volume 61, Number 167 (Tuesday, August 27, 1996)]
[Proposed Rules]
[Pages 44002-44004]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-21743]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 96-NM-53-AD]
RIN 2120-AA64


Airworthiness Directives; McDonnell Douglas Model DC-9-80 Series 
Airplanes and Model MD-88 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 certain McDonnell Douglas Model 
DC-9-80 series airplanes and Model MD-88 airplanes. This proposal would 
require visual/dye penetrant and ultrasonic inspections to detect 
cracks in the vertical leg of the rear spar lower cap of the wings, and 
various follow-on actions. This proposal is prompted by reports that, 
due to improper torque tightening of the attach studs of the flap hinge 
fitting, fatigue cracks were found in the vertical leg of the rear spar 
lower cap of the wing. The actions specified by the proposed AD are 
intended to prevent such fatigue cracking, which, if not detected and 
corrected in a timely manner, could result in loss of the spar cap, and 
consequent damage to the spar cap web and adjacent wing skin structure; 
this condition could lead to reduced structural integrity of the wing.

DATES: Comments must be received by October 7, 1996.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 96-NM-53-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.

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 
(310) 627-5237; 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

[[Page 44003]]

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 96-NM-53-
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. 96-NM-53-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The FAA has received reports of fatigue cracks found in the 
vertical leg of the rear spar lower cap of the wing on two McDonnell 
Douglas Model MD-81 airplanes. One of the airplanes had accumulated 
17,354 total landings, and the other airplane had accumulated 
approximately 24,000 total landings. These fatigue cracks ran out of 
the lower inboard attach stud hole for the inboard flap hinge fitting 
of the outboard flap at station Xrs=164.000 on the left or right wings. 
This fatigue cracking apparently is the result of applying less than 
the required torque on the attach studs of the flap hinge fitting, 
during production of these airplanes. Fatigue cracking in the vertical 
leg of the rear spar lower cap of the wings, if not detected and 
corrected in a timely manner, could result in loss of the spar cap, and 
consequent damage to the spar cap web and adjacent wing skin structure; 
this condition could lead to reduced structural integrity of the wing.

Explanation of Relevant Service Information

    The FAA has reviewed and approved McDonnell Douglas MD-80 Service 
Bulletin 57-184, Revision 1, dated December 22, 1994. The service 
bulletin describes procedures for performing visual/dye penetrant and 
ultrasonic inspections to detect cracks in the vertical leg of the rear 
spar lower cap of the wings below and in the adjacent area of the two 
lower attaching stud holes for the inboard hinge fitting of the 
outboard flap at station Xrs=164.000. For cases where no cracks are 
detected during inspection, the service bulletin describes procedures 
for either tightening the four mounting studs of the flap hinge fitting 
in the rear spar caps (two studs in the upper cap and two studs in the 
lower cap) to applicable torque value, or conducting repetitive visual/
dye penetrant and ultrasonic inspections. For cases where any crack is 
detected during the inspection, the service bulletin describes 
procedures for performing a high frequency eddy current inspection to 
confirm existence of cracking, and various follow-on actions. (These 
follow-on actions include, among other actions, replacement of the 
entire spar cap, permanent splice repair of the spar cap, temporary 
repair of the spar cap, and repetitive inspections.)

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 visual/dye penetrant and ultrasonic 
inspections to detect cracks in the vertical leg of the rear spar lower 
cap of the wings below and in the adjacent area of the two lower 
attaching stud holes for the inboard hinge fitting of the outboard flap 
at station Xrs=164.000, and various follow-on actions. The actions 
would be required to be accomplished in accordance with the service 
bulletin described previously. If any crack progression is found during 
any repetitive eddy current inspection, the repair/replacement would be 
required to be accomplished in accordance with a method approved by the 
FAA.

Cost Impact

    There are approximately 489 McDonnell Douglas Model DC-9-80 series 
airplanes and Model MD-88 airplanes of the affected design in the 
worldwide fleet. The FAA estimates that 306 airplanes of U.S. registry 
would be affected by this proposed AD, that it would take approximately 
26 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 
$477,360, or $1,560 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 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 96-NM-53-AD.

    Applicability: Model DC-9-81 (MD-81), DC-9-82 (MD-82), DC-9-83 
(MD-83), DC-9-87 (MD-87) series airplanes and Model MD-88 airplanes, 
as listed in McDonnell Douglas MD-80 Service Bulletin 57-184, 
Revision 1, dated December 22, 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

[[Page 44004]]

requirements of this AD is affected, the owner/operator must request 
approval for an alternative method of compliance in accordance with 
paragraph (e) 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 in the vertical leg of the rear spar 
lower cap of the wing, which could lead to reduced structural 
integrity of the wing, accomplish the following:
    (a) Perform visual/dye penetrant and ultrasonic inspections to 
detect cracks in the vertical leg of the rear spar lower cap of the 
wings below and in the adjacent area of the two lower attaching stud 
holes for the inboard hinge fitting of the outboard flap at station 
Xrs=164.000, in accordance with McDonnell Douglas MD-80 Service 
Bulletin 57-184, Revision 1, dated December 22, 1994; at the time 
specified in paragraph (a)(1), (a)(2), (a)(3), or (a)(4) of this AD, 
as applicable.
    (1) For airplanes that have accumulated less than 8,000 total 
landings as of the effective date of this AD: Perform the inspection 
prior to the accumulation of 10,000 landings or within 3,000 
landings after the effective date of this AD, whichever occurs 
later.
    (2) For airplanes that have accumulated 8,000 or more total 
landings but less than 10,000 total landings as of the effective 
date of this AD: Perform the inspection within 3,000 landings after 
the effective date of this AD.
    (3) For airplanes that have accumulated 10,000 or more total 
landings but less than 15,000 total landings as of the effective 
date of this AD: Perform the inspection within 2,400 landings after 
the effective date of this AD.
    (4) For airplanes that have accumulated 15,000 or more total 
landings as of the effective date of this AD: Perform the inspection 
within 1,800 landings after the effective date of this AD.
    (b) Condition 1. If no crack is detected during any inspection 
required by paragraph (a) of this AD, accomplish the requirements of 
either paragraph (b)(1) or (b)(2) of this AD, in accordance with 
McDonnell Douglas MD-80 Service Bulletin 57-184, Revision 1, dated 
December 22, 1994.
    (1) Condition 1, Option 1. Prior to further flight, tighten the 
four mounting studs of the flap hinge fitting in the rear spar caps 
(2 studs in the upper cap and 2 studs in the lower cap) to the 
applicable torque value, in accordance with the service bulletin. 
Accomplishment of this tightening of the mounting studs of the flap 
hinge fitting constitutes terminating action for the repetitive 
inspection requirements of paragraph (b)(2) of this AD.
    (2) Condition 1, Option 2. Repeat the visual/dye penetrant and 
ultrasonic inspections required by paragraph (a) of this AD 
thereafter at intervals not to exceed 3,000 landings until paragraph 
(b)(1) of this AD is accomplished.
    (c) Condition 2. If any crack is detected during any inspection 
required by paragraph (a) or (b)(2) of this AD, prior to further 
flight, perform a high frequency eddy current inspection to confirm 
the existence of cracking, in accordance with McDonnell Douglas MD-
80 Service Bulletin 57-184, Revision 1, dated December 22, 1994. 
After this inspection, accomplish the requirements of either 
paragraph (c)(1), (c)(2), or (c)(3) of this AD, as applicable.
    (1) If no cracking is confirmed, accomplish the requirements of 
either paragraph (b)(1) [``Condition 1, Option 1''] or (b)(2) 
[``Condition 1, Option 2''] of this AD.
    (2) Condition 2, Option 1. If any cracking is confirmed, prior 
to further flight, replace the entire spar cap or accomplish the 
permanent splice repair of the spar cap, and tighten the four 
mounting studs of the flap hinge fitting in the rear spar caps (2 
studs in the upper cap and 2 studs in the lower cap) to the 
applicable torque value, in accordance with the service bulletin. 
Accomplishment of this tightening of the mounting studs constitutes 
terminating action for the repetitive inspection requirements of 
paragraph (c)(3) of this AD.
    (3) Condition 2, Option 2. If cracking is confirmed and it does 
not extend beyond the location limits and does not exceed the 
maximum permissible crack length of 2 inches, prior to further 
flight, accomplish the temporary repair modification of the spar cap 
in accordance with the service bulletin. Thereafter, repeat the eddy 
current inspection at intervals not to exceed 3,000 landings until 
paragraph (c)(2) of this AD is accomplished.
    (i) If any crack progression is found during any repetitive eddy 
current inspection following accomplishment of the temporary repair, 
prior to further flight, contact the Manager, Los Angeles Aircraft 
Certification Office, FAA, Transport Airplane Directorate, telephone 
(310) 627-5237, fax (310) 627-5210, to establish the appropriate 
repair or replacement interval.

    Note 2: Operators should note that, unlike the recommended 
compliance time of ``within 3,000 landings after discovery of 
cracking,'' which is specified in the service bulletin as the time 
for accomplishing the permanent splice repair or replacement of the 
spar cap, this AD requires that operators contact the FAA prior to 
further flight. The FAA finds that the repair/replacement interval 
should be established based on the crack progression. Where there 
are differences between the AD and the service bulletin in this 
regard, the AD prevails.

    (ii) If any new crack is found during any repetitive eddy 
current inspection following accomplishment of the temporary repair, 
prior to further flight, accomplish the permanent repair in 
accordance with the service bulletin.
    (d) Within 10 days after accomplishing the initial visual/dye 
penetrant and ultrasonic inspections required by paragraph (a) of 
this AD, submit a report of the inspection results (both positive 
and negative findings) to the Manager, Los Angeles ACO, 3229 East 
Spring Street, Long Beach, California 90806-2425; telephone (310) 
627-5237; fax (310) 627-5210. Information collection requirements 
contained in this regulation have been approved by the Office of 
Management and Budget (OMB) under the provisions of the Paperwork 
Reduction Act of 1980 (44 U.S.C. 3501 et seq.) and have been 
assigned OMB Control Number 2120-0056.
    (e) 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.

    (f) 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 August 20, 1996.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 96-21743 Filed 8-26-96; 8:45 am]
BILLING CODE 4910-13-U