[Federal Register Volume 64, Number 207 (Wednesday, October 27, 1999)]
[Proposed Rules]
[Pages 57789-57790]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-28079]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 99-NM-209-AD]
RIN 2120-AA64
Airworthiness Directives; McDonnell Douglas Model MD-90 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 certain McDonnell Douglas Model
MD-90 series airplanes. This proposal would require a one-time detailed
visual inspection to detect fatigue cracking of certain longerons and
the attaching frames of the lower left nose; and repair, if necessary.
The proposal also would require installation of a preventive
modification. This proposal is prompted by several reports of fatigue
cracking of certain longerons and the attaching frames. The actions
specified by the proposed 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: Comments must be received by December 13, 1999.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-114,
Attention: Rules Docket No. 99-NM-209-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 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 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.
FOR FURTHER INFORMATION CONTACT: Carl Fountain, Aerospace Engineer,
Airframe Branch, ANM-120L; FAA, Los Angeles Aircraft Certification
Office, 3960 Paramount Boulevard, Lakewood, California 90712; telephone
(562) 627-5222; fax (562) 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 99-NM-209-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-114, Attention: Rules
Docket No. 99-NM-209-AD, 1601 Lind Avenue, SW., Renton, Washington
98055-4056.
Discussion
The FAA has received reports indicating that cracking of the
fuselage longerons-to-frame attachment holes occurred on three
McDonnell Douglas Model DC-9 series airplanes. The fatigue cracking was
found between longerons 22 though 26 on the left side at stations
Y=160.000 and Y=200.000. These airplanes had accumulated between 59,110
and 74,445 total flight cycles. The cracking of the longeron segments
has been attributed to fatigue. Such fatigue cracking, if not
corrected, could result in reduced structural integrity of the
fuselage, and consequent loss of pressurization of the airplane.
The fuselage longerons-to-frame attachments of McDonnell Douglas
Model MD-90 series airplanes are similar to those of the affected
McDonnell Douglas Model DC-9 series airplanes. Therefore, the Model MD-
90 may be subject to the same unsafe condition.
Other Relevant Rulemaking
On November 20, 1998, the FAA issued AD 98-24-33, amendment 39-
10919 (63 FR 66739, December 3, 1998), applicable to certain McDonnell
Douglas DC-9 and MD-88 series airplanes, to require a one-time visual
inspection to detect fatigue cracks between longerons 22 through 26 and
the attaching frames, and corrective action, if necessary. However,
this proposed AD would not affect the current requirements of that
previously issued AD.
Explanation of Relevant Service Information
The FAA has reviewed and approved McDonnell Douglas Service
Bulletin MD90-53-004, dated August 20, 1998, which describes procedures
for a one-time detailed visual inspection to detect cracking of
longerons 22 through 26 and the attaching frames at stations Y=160.000
and Y=200.000 of the lower left nose, and repair, if necessary. The
service bulletin also provides procedures for a preventive modification
(i.e., installation of clips and doublers under longeron flanges and
shims longeron) to relieve preloads.
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 accomplishment of the actions specified in
the service bulletin described previously.
Cost Impact
There are approximately 7 airplanes of the affected design in the
worldwide fleet. The FAA estimates that 6 airplanes of U.S. registry
would be affected by this proposed AD.
[[Page 57790]]
It would take approximately 1 work hour per airplane to accomplish
the proposed inspection, at an average labor rate of $60 per work hour.
Based on these figures, the cost impact of the inspection proposed by
this AD on U.S. operators is estimated to be $360, or $60 per airplane.
It would take approximately 6 work hours per airplane to accomplish
the proposed modification, at an average labor rate of $60 per work
hour. Parts would cost approximately $312 per airplane. Based on these
figures, the cost impact of the modification proposed by this AD on
U.S. operators is estimated to be $4,032, or $672 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 99-NM-209-AD.
Applicability: Model MD-90 series airplanes, as listed in
McDonnell Douglas Service Bulletin MD90-53-004, dated August 20,
1998; 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 (b) 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:
Inspection and Modification
(a) Prior to the accumulation of 40,000 total landings, or
within 24 months after the effective date of this AD, whichever
occurs later: Perform a detailed visual inspection to detect
cracking of longerons 22 through 26 (inclusive) and the respective
attaching frames at station frames Y=160.000 and Y=200.000 of the
left lower nose, in accordance with McDonnell Douglas Service
Bulletin MD90-53-004, dated August 20, 1998.
Note 2: For the purposes of this AD, a detailed visual
inspection is defined as: ``An intensive visual examination of a
specific structural area, system, installation, or assembly to
detect damage, failure, or irregularity. Available lighting is
normally supplemented with a direct source of good lighting at
intensity deemed appropriate by the inspector. Inspection aids such
as mirror, magnifying lenses, etc., may be used. Surface cleaning
and elaborate access procedures may be required.''
(1) If no cracking is detected: Prior to further flight, install
clips and doublers under the longeron flanges and shim the longerons
in accordance with the service bulletin.
(2) If any cracking is detected: Prior to further flight, repair
the cracks and install clips and doublers under the longeron flanges
and shim the longerons in accordance with the service bulletin.
Alternative Methods of Compliance
(b) 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 Manager, Los Angeles ACO.
Special Flight Permits
(c) 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.
Issued in Renton, Washington, on October 21, 1999.
D.L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 99-28079 Filed 10-26-99; 8:45 am]
BILLING CODE 4910-13-U