[Federal Register Volume 62, Number 45 (Friday, March 7, 1997)]
[Proposed Rules]
[Pages 10492-10494]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-5572]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 96-NM-203-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
directive (AD) that is applicable to 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 repetitive high frequency
eddy current inspections of the external areas of the fuselage to
detect cracks of the skin and/or longeron, and various follow-on
actions. The proposal also would require the installation of a
preventative modification, which would terminate the repetitive
inspections. This proposal 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 the proposed 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: Comments must be received by April 16, 1997.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-103,
Attention: Rules Docket No.96-NM-203-AD, 1601 Lind Avenue, SW., Renton,
Washington 98055-4056. Comments may be inspected at this
[[Page 10493]]
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 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-203-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-203-AD, 1601 Lind Avenue, SW., Renton, Washington
98055-4056.
Discussion
The FAA has received several reports indicating that, on certain
McDonnell Douglas Model DC-9 series airplanes, cracks were found in the
skin and longerons of the fuselage. The cracked fuselage skin was found
on airplanes that had accumulated 61,345 or more total landings. The
cracked fuselage longerons were found on airplanes that had accumulated
45,850 or more total landings. The cracking occurred between longeron 5
left and longeron 8 right, between stations Y=160.000 and Y=218.000.
Investigation revealed that the apparent cause of such cracking has
been attributed to material fatigue, as a result of installation
preload and cabin pressurization cycles. This condition, if not
detected and corrected in a timely manner, could result in loss of the
structural integrity of the fuselage and, consequently, lead to rapid
depressurization of the airplane.
The subject area on certain McDonnell Douglas Model DC-9-80 series
airplanes, Model MD-88 airplanes, and C-9 (military) series airplanes
is identical to that on the affected Model DC-9 series airplanes.
Therefore, all of these airplanes may be subject to the same unsafe
condition.
Explanation of Relevant Service Information
The FAA has reviewed and approved McDonnell Douglas Service
Bulletin 53-235, dated September 15, 1993. The service bulletin
describes procedures for performing 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. (These follow-on actions
include repetitive inspections or installation of a preventative
modification, and repair of cracked skin or longerons.) The service
bulletin also describes procedures for installation of a preventative
modification, which would eliminate the need for repetitive
inspections. The preventative modification involves installation of
clips and doublers between certain stations. Accomplishment of the
preventative modification will minimize the possibility of further
crack development.
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 repetitive 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. The proposed AD also would require the installation of a
preventative modification, which would constitute terminating action
for the repetitive inspection requirements. The actions would be
required to be accomplished in accordance with the service bulletin
described previously.
Differences Between the Proposal and the Referenced Service
Information
This proposed AD would differ from the referenced service bulletin
in that it would mandate the accomplishment of the terminating
preventative modification for the repetitive inspections. The service
bulletin provides that action only as optional procedure.
Mandating the terminating action is based on the FAA's
determination that long term continued operational safety will be
better assured by modifications or design changes to remove the source
of the problem, rather than by repetitive inspections. Long term
inspections may not be providing the degree of safety assurance
necessary for the transport airplane fleet. This, coupled with a better
understanding of the human factors associated with numerous repetitive
inspections, has led the FAA to consider placing less emphasis on
special procedures and more emphasis on design improvements. The
proposed modification requirement is in consonance with these
considerations.
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 would be affected by
this proposed AD.
It would take approximately 16 work hours per airplane to
accomplish the proposed HFEC inspection, at an average labor rate of
$60 per work hour. Based on these figures, the cost impact of the HFEC
inspection proposed by this AD on U.S. operators is estimated to be
$1,105,920, or $960 per airplane, per inspection cycle.
It would take approximately 89 work hours per airplane to
accomplish the proposed modification, at an average labor rate of $60
per work hour. The cost of required parts would range from $13,771 to
$15,292 per airplane. Based on these figures, the cost impact of the
proposed AD on U.S. operators is estimated to be between $22,015,872
[[Page 10494]]
($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 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-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
otherwise 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) Prior to the accumulation of 30,000 total landings, or
within 8,000 landings after the effective date of this AD, whichever
occurs later, 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.
(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 2: 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.
Issued in Renton, Washington, on February 28, 1997.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 97-5572 Filed 3-6-97; 8:45 am]
BILLING CODE 4910-13-U
