[Federal Register Volume 61, Number 206 (Wednesday, October 23, 1996)]
[Proposed Rules]
[Pages 54969-54972]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-27238]
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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39
[Docket No. 96-NM-235-AD]
RIN 2120-AA64
Airworthiness Directives; McDonnell Douglas Model DC-9 Series
Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Notice of proposed rulemaking (NPRM).
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SUMMARY: This document proposes the supersedure of an existing
airworthiness directive (AD), applicable to certain
[[Page 54970]]
McDonnell Douglas DC-9 series airplanes, that currently requires
repetitive visual inspections to detect corrosion and cracking of the
fuselage upper skin and frames in the area of the loop antenna
assemblies of the automatic direction finder (ADF), and repair, if
necessary. This action would add a requirement to perform a visual and
an eddy current inspection of the fuselage forward upper skin under the
antennas, followed by the reinstallation of the ADF antennas using an
improved procedure. This proposal is prompted by the development of a
modification of the ADF antenna installation that would constitute
terminating action for the required repetitive visual inspections. The
actions specified by the proposed AD are intended to prevent rapid
decompression of the fuselage, significant structural damage, and
subsequent reduced structural integrity of the airplane, due to
problems associated with corrosion and fatigue cracking in the subject
area.
DATES: Comments must be received by December 3, 1996.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-103,
Attention: Rules Docket No. 96-NM-235-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: Wahib Mina, Aerospace Engineer,
Airframe Branch, ANM-120L, FAA, Los Angeles Aircraft Certification
Office, 3960 Paramount Boulevard, Lakewood, California 90712; telephone
(310) 627-5324; 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-235-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-235-AD, 1601 Lind Avenue, SW., Renton, Washington
98055-4056.
Discussion
On March 28, 1996, the FAA issued AD 96-07-51, amendment 39-9562
(61 FR 15882, April 10, 1996), applicable to certain McDonnell Douglas
DC-9 series airplanes, to require repetitive internal visual
inspections to detect corrosion and cracking of the fuselage forward
upper skin and to detect cracking of the fuselage frames in the subject
area. That AD also requires repair of any corrosion or cracking found.
That action was prompted by a report indicating that severe corrosion
and a 39-inch crack of the forward fuselage upper skin was found during
scheduled maintenance on a McDonnell Douglas Model DC-9-31 series
airplane. Additionally, subsequent inspection of the adjacent structure
revealed cracking of the fuselage frame at fuselage station 275. The
cracking found has been attributed to fatigue. Corrosion and fatigue
cracking in these areas, if not detected and corrected in a timely
manner, could result in rapid decompression of the fuselage,
significant damage to adjacent structure, and subsequent reduced
structural integrity of the airplane.
Actions Since Issuance of Previous Rule
Since the issuance of that AD, McDonnell Douglas has developed a
new procedure for the installation of the ADF antennas. Installation of
the antennas using the improved installation procedure will eliminate
the need for repetitive inspections to detect corrosion and cracking of
the fuselage upper skin for cracks and corrosion under the ADF loop
antenna.
Explanation of Relevant Service Information
The FAA has reviewed and approved McDonnell Douglas Service
Bulletin DC-9-53-284, dated August 20, 1996, which describes procedures
for a one-time visual and a one-time high frequency eddy current
inspection to detect corrosion and cracking of the fuselage forward
upper skin under the antennas. The service bulletin also describes
procedures for repair of certain corrosion or cracking that is within
the limits specified by the service bulletin. In addition, the service
bulletin describes procedures for modification of the ADF antennas
using an improved installation procedure. Accomplishment of the
inspections and installation procedure eliminates the need for
repetitive visual inspections of the area.
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 supersede AD 96-07-51 to continue to require
repetitive internal visual inspections to detect corrosion and cracking
of the fuselage forward upper skin and to detect cracking of the
fuselage frame in the area of the forward and aft loop antenna
assemblies of the automatic direction finder (ADF).
The proposed AD would add a requirement for removing the ADF
antennas and performing a one-time visual and a one-time high frequency
eddy current inspection to detect corrosion and cracking of the
fuselage forward upper skin under the antennas; reinstallation of the
ADF antennas using an improved installation procedure would constitute
terminating action for the previously required repetitive visual
inspections. The proposed AD also would require repair of any corrosion
or cracking detected that is within the limits specified by the service
bulletin. Those actions would be required to be accomplished in
accordance with the service bulletin described previously.
If any corrosion or cracking is detected that is beyond the limits
specified in the service bulletin, the repair would be required to be
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accomplished in acordance with a method approved by the FAA.
FAA's Determination Regarding Terminating Actions
The FAA has determined 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 569 McDonnell Douglas Model DC-9 series
airplanes of the affected design in the worldwide fleet. The FAA
estimates that 403 airplanes of U.S. registry would be affected by this
proposed AD.
The actions that are currently required by AD 96-07-51 take
approximately 5 work hours per airplane to accomplish, at an average
labor rate of $60 per work hour. Based on these figures, the cost
impact on U.S. operators of the actions currently required is estimated
to be $120,900, or $300 per airplane, per inspection.
The new actions that are proposed in this AD action would take
approximately 16 work hours per airplane to accomplish, at an average
labor rate of $60 per work hour. Based on these figures, the cost
impact on U.S. operators of the proposed requirements of this AD is
estimated to be $386,880, or $960 per airplane.
The cost impact figures discussed above are based on assumptions
that no operator has yet accomplished any of the current or 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 removing amendment 39-9562 (61 FR
15882, April 10, 1996), and by adding a new airworthiness directive
(AD), to read as follows:
McDonnell Douglas: Docket 96-NM-235-AD. Supersedes AD 96-07-51,
Amendment 39-9562.
Applicability: Model DC-9 series airplanes having fuselage
numbers 001 through 631 inclusive, 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 (c)(1)
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 rapid decompression of the fuselage, significant
structural damage, and subsequent reduced structural integrity of
the airplane, due to problems associated with corrosion and fatigue
cracking, accomplish the following:
(a) Within 15 days after April 15, 1996 (the effective date of
AD 96-07-51, amendment 39-9562): Perform an internal visual
inspection to detect corrosion and cracking of the fuselage forward
upper skin and to detect cracking of the fuselage frame in the area
of the forward and aft loop antenna assemblies of the automatic
direction finder (ADF), in accordance with McDonnell Douglas Alert
Service Bulletin DC9-53A282, dated March 20, 1996.
(1) If no corrosion or cracking is detected: Repeat the visual
inspection required by paragraph (a) of this AD thereafter at
intervals not to exceed six months.
(2) If any corrosion or cracking is detected that is within the
limits specified in Chapter 53-04, Figure 29, of the DC-9 Structural
Repair Manual (SRM): Prior to further flight, repair in accordance
with Chapter 53-04, Figure 29, of the SRM. Repeat the visual
inspection required by paragraph (a) of this AD thereafter at
intervals not to exceed six months.
(3) If any corrosion or cracking is detected in the fuselage
forward upper skin, or if any cracking is detected in the fuselage
frame, and that corrosion or cracking is outside the limits
specified in Chapter 53-04, Figure 29, of the SRM: Prior to further
flight, repair in accordance with a method approved by the Manager,
Los Angeles Aircraft Certification Office (ACO), FAA, Transport
Airplane Directorate.
(b) Within 24 months after the effective date of this AD: Remove
the ADF antennas and perform visual and high frequency eddy current
inspections to detect corrosion and cracking of the fuselage forward
upper skin under the antennas, in accordance with McDonnell Douglas
Service Bulletin DC9-53-284, dated August 20, 1996; and accomplish
the requirements of paragraph (b)(1), (b)(2), or (b)(3) of this AD,
as applicable, at the times specified. Accomplishment of the actions
specified in paragraph (b)(1) or (b)(2) of this AD constitute
terminating action for the requirements of paragraphs (a)(1) and
(a)(2) of this AD.
(1) If no cracking or corrosion is detected: Prior to further
flight, reinstall the ADF antennas using the improved installation
procedure in accordance with the service bulletin.
(2) If any cracking or corrosion is detected that is within the
limits specified in Chapter 53-04 of the DC-9 Structural Repair
Manual (SRM): Prior to further flight, repair in accordance with
Chapter 53-04 of the DC-9 SRM, and reinstall the ADF antennas using
the improved installation procedure in accordance with the service
bulletin.
(3) If any cracking or corrosion is detected that is outside the
limits specified in Chapter 53-04 of the SRM: Prior to further
flight, repair in accordance with a method approved by the Manager,
Los Angeles Certification Office (ACO), FAA, Transport Airport
Directorate.
(c)(1) An alternative method of compliance or adjustment of the
compliance time that
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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.
(2) Alternative methods of compliance, approved in accordance
with AD 96-07-71, amendment 39-9562, are approved as alternative
methods of compliance with this AD.
(d) 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 October 17, 1996.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 96-27238 Filed 10-22-96; 8:45 am]
BILLING CODE 4910-13-U
