[Federal Register Volume 64, Number 139 (Wednesday, July 21, 1999)]
[Proposed Rules]
[Pages 39097-39100]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-18626]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 98-NM-267-AD]
RIN 2120-AA64
Airworthiness Directives; McDonnell Douglas Model DC-9-81, -82, -
83, and -87 Series Airplanes (MD-81, -82, -83, and -87), 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 supersedure of an existing
airworthiness directive (AD), applicable to all McDonnell Douglas Model
DC-9-81, -82, -83, and -87 series airplanes (MD-81, -82, -83, and -87),
and Model MD-88 airplanes, that currently requires visual or eddy
current inspections to detect cracks of the actuator cylinder support
brackets of the slat drive mechanism assembly, and replacement of any
cracked brackets. This action would continue to require repetitive eddy
current inspections, would add an inspection requirement, and would
expand the area of inspection. This action also would provide
terminating action for the repetitive inspections. This proposal is
prompted by reports indicating that additional cracking was found
outside the original inspection area. The actions specified by the
proposed AD are intended to prevent inadvertent slat retraction in
flight.
DATES: Comments must be received by September 7, 1999.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-114,
Attention: Rules Docket No. 98-NM-267-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 Boeing Commercial Aircraft Group, Long Beach 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: Brent Bandley, Aerospace Engineer,
Airframe Branch, ANM-120L, FAA, Transport Airplane Directorate, Los
Angeles Aircraft Certification Office, 3960 Paramount Boulevard,
Lakewood, California 90712-4137; telephone (562) 627-5237; 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 98-NM-267-AD.'' The
[[Page 39098]]
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. 98-NM-267-AD, 1601 Lind Avenue, SW., Renton, Washington
98055-4056.
Discussion
On September 27, 1991, the FAA issued AD 91-21-11, amendment 39-
8058 (56 FR 51645, October 15, 1991), applicable to all McDonnell
Douglas Model DC-9-81, -82, -83, and -87 series airplanes (MD-81, -82,
-83, and -87), and Model MD-88 airplanes, to require visual or eddy
current inspections to detect cracks of the actuator cylinder support
brackets of the slat drive mechanism assembly, and replacement of any
cracked brackets. That action was prompted by reports of failures of
the slat drive mechanism. The requirements of that AD are intended to
prevent inadvertent slat retraction in flight.
Actions Since Issuance of Previous Rule
In the preamble to AD 91-21-11, the FAA specified that the actions
required by that AD were considered to be interim action. The FAA
indicated that it may consider further rulemaking action to require
only repetitive eddy current inspections for airplanes that have
accumulated 10,000 or more landings. The FAA has determined that
further rulemaking action is indeed necessary; this proposed AD follows
from that determination.
Since the issuance of AD 91-21-11, the FAA has received a report
indicating that additional cracking was found outside the original
inspection area. The cracking was found on a McDonnell Douglas Model
MD-83 series airplane that had accumulated 32,478 total flight hours.
The repetitive inspections in AD 91-21-11 were required to be performed
on the top of the clevis lug (a U-shaped fitting that has matching
holes in the arms of the U) of the actuator cylinder support brackets.
The additional cracking was found within the clevis lug in the
transition radius between the body of the actuator cylinder support
bracket and the clevis lug.
Explanation of Relevant Service Information
The FAA has reviewed and approved McDonnell Douglas Alert Service
Bulletin
MD80-27-A322, Revision 03, dated August 4, 1998, which, among other
things, describes procedures for a one-time, visual inspection and
repetitive eddy current inspections to detect cracks of the actuator
cylinder support brackets of the slat drive mechanism assembly. For
certain airplanes, this would involve a one-time, visual and eddy
current inspections, followed by repetitive eddy current inspections.
For certain other airplanes this would involve repetitive eddy current
inspections.
The FAA also has reviewed and approved McDonnell Douglas Service
Bulletin MD80-27-322, Revision 02, dated February 11, 1998, which,
among other things, describes procedures for modification of the
actuator cylinder support bracket of the slat drive mechanism assembly.
This modification involves replacing the actuator cylinder support
bracket with a new, improved bracket and installing new associated
components.
The specific modification of the actuator cylinder support bracket
is predicated on whether a previous modification has been installed in
accordance with a prior issue of McDonnell Douglas Service Bulletin
MD80-27-322. For those airplanes on which a previous modification has
been installed, operators would have the option of choosing one of the
following:
Option 1: Replacement and reidentification of the actuator
cylinder support bracket assemblies, hydraulic pipe assemblies, and
clamp assemblies with new components; or replacement of the hydraulic
pipe clamp assemblies with new clamp assemblies; or
Option 2: Removal and return of the slat drive mechanism
to the manufacturer for modification and reidentification; installation
of the modified and reidentified slat drive mechanism assembly,
replacement of the hydraulic pipe assemblies with new pipe assemblies;
or replacement of the hydraulic pipe clamp assemblies with new clamp
assemblies.
For those airplanes on which no previous modification has been
installed, operators would have the option of the choosing one of the
following:
Option 1: Replacement of the actuator cylinder support
bracket assemblies, and hydraulic pipe assemblies and clamp assemblies
with new components; and reidentification of the slat drive mechanism.
Option 2: Removal and return of the slat drive mechanism
to the manufacturer for modification and reidentification; installation
of the modified and reidentified slat drive mechanism, and replacement
of the hydraulic pipe clamp assemblies with new clamp assemblies.
Accomplishment of the modification for both actuator cylinder
support brackets would eliminate the need for the repetitive
inspections. Accomplishment of the action specified in the service
bulletins is intended to adequately address the identified unsafe
condition.
FAA's Determination
The FAA has examined the circumstances and reviewed all the
available information related to the additional cracking that was
reported. Additionally, the FAA reviewed the requirements of AD 91-21-
11, which required that either a visual or an eddy current inspection
be performed to detect cracking of the slat drive mechanism. In light
of the criticality of the unsafe condition (inadvertent retraction of
the slats during flight), the FAA has determined that visual inspection
methods may not be as effective in detecting the types of cracks
associated the slat drive mechanism. This proposed AD would require a
one-time visual inspection and an eddy current inspection be performed
on all airplanes on which no previous inspection has been performed in
accordance with AD 91-21-11. For airplanes on which the last inspection
performed in accordance with AD 91-21-11 was a visual inspection, this
proposed AD would require a visual inspection within 1,000 landings and
an eddy current inspection within 6 months. All airplanes would be
required to repeat the eddy current inspection at intervals not
exceeding 3,000 landings, or until the terminating modification is
accomplished, which would eliminate the need for the 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 supersede AD 91-21-11 to continue to require eddy
current inspections for cracks of the actuator cylinder support
brackets of the slat drive mechanism assembly, and replacement of any
cracked brackets. This action also would add an inspection requirement
and expand the area of inspection. This action also would provide
terminating action for the repetitive inspections. The actions would be
required to be accomplished in accordance with the service bulletins
described previously, except as discussed below.
[[Page 39099]]
Differences Between Proposed Rule and Service Information
Operators should note that, although McDonnell Douglas Service
Bulletin MD80-27-322, Revision 02, provides service information for
performing repetitive visual and eddy current inspections, this
proposed AD would require an initial visual inspection and repetitive
eddy current inspections be performed in accordance with Revision 03 of
the McDonnell Douglas Alert Service Bulletin MD80-27-A322. The FAA has
determined that Revision 03 of the McDonnell Douglas alert service
bulletin provides complete inspection instructions for the expanded
inspection area that would be required by this proposed AD.
Additionally, operators should note that, although the McDonnell
Douglas alert service bulletin (previously described), recommends that
the initial visual inspection be performed within 60 days and that the
eddy current inspection be performed within 6 months after receipt of
the service bulletin, this proposed AD would require that the initial
inspection be performed as described below, as applicable:
For airplanes on which no inspection has been performed in
accordance with AD 91-21-11: Perform visual and eddy current
inspections prior to the accumulation of 10,000 total landings or
within 30 days after the effective date of this AD, whichever occurs
later.
For airplanes on which the last inspection that was
performed in accordance with AD 91-21-11 was a visual inspection:
Perform visual inspection within 1,000 landings after the last visual
inspection, followed by an eddy current inspection within 6 months.
For airplanes on which the last inspection that was
performed in accordance with AD 91-21-11 was an eddy current
inspection: Perform eddy current inspection within 3,000 landings after
the last eddy current inspection.
In developing the appropriate compliance time, the FAA considered
the manufacturer's recommendation and the degree of urgency associated
with addressing the subject unsafe condition. In light of these
factors, the FAA finds that the compliance time specified by this
proposed AD to be appropriate.
Cost Impact
There are approximately 1,180 airplanes of the affected design in
the worldwide fleet. The FAA estimates that 787 airplanes of U.S.
registry would be affected by this proposed AD.
The inspections that are currently required by AD 91-21-11 take
approximately 3 work hours per airplane to accomplish, at an average
labor rate of $60 per work hour. Based on these figures, the cost
impact of the currently required actions on U.S. operators is estimated
to be $141,660, or $180 per airplane, per inspection cycle.
The one-time visual inspection that is proposed in this AD action
would take approximately 1 work hour per airplane to accomplish, at an
average labor rate of $60 per work hour. Based on these figures, the
cost impact of the proposed requirements of the AD on U.S. operators is
estimated to be $47,220, or $60 per airplane.
The inspections of the expanded area that are proposed in this AD
action would take approximately 2 work hours per airplane to
accomplish, at an average labor rate of $60 per work hour. Based on
these figures, the cost impact of the proposed requirements of this AD
on U.S. operators is estimated to be $94,440, or $120 per airplane, per
inspection cycle.
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.
Should an operator be required or elect to accomplish the
terminating modification that is provided by this AD action, it would
take between 130 and 162 work hours per airplane to accomplish, at an
average labor rate of $60 per work hour. Required parts would cost
$22,574 per airplane. Based on these figures, the cost impact of the
optional terminating modification, is estimated to be between $30,374
and $32,294 per airplane.
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 39-8058 (56 FR
51645, October 15, 1991), and by adding a new airworthiness directive
(AD), to read as follows:
McDonnell Douglas: Docket 98-NM-267-AD. Supersedes AD 91-21-11,
Amendment 39-8058.
Applicability: All Model DC-9-81, -82, -83, and -87 series
airplanes (MD-81, -82, -83, and -87); and Model MD-88 airplanes;
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 (h)(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 inadvertent slat retraction in flight, accomplish the
following:
Restatement of Certain Requirements of AD 91-21-11, Amendment 39-8058
(a) Prior to the accumulation of 10,000 total landings or within
30 days after October 30, 1991 (the effective date of AD 91-21-11),
whichever occurs later, perform a visual or eddy current inspection
to detect cracks of
[[Page 39100]]
the actuator cylinder support brackets of the slat drive mechanism
assembly, part numbers 5938886--(any configuration) and 5938887--
(any configuration), in accordance with the instructions in
McDonnell Douglas MD-80 Alert Service Bulletin A27-322, dated August
22, 1991 (hereinafter referred to as ``A27-322'').
(b) If no crack is found during the inspection required by
paragraph (a) of this AD, repeat the inspection at the following
intervals:
(1) If the immediately preceding inspection was accomplished
using visual means, conduct the next inspection within 1,000
landings.
(2) If the immediately preceding inspection was accomplished
using eddy current means, conduct the next inspection within 3,000
landings.
(c) If any crack is found during any inspection required by
paragraph (a) or (b) of this AD, prior to further flight, remove and
replace the slat drive mechanism with a new part, part numbers
5938887--(any configuration) and 5938886--(any configuration), in
accordance with A27-322.
New Requirements of This AD
Initial and Repetitive Inspections
(d) Perform visual and/or eddy current inspections, as
applicable, to detect cracks of the actuator cylinder support
brackets of the slat drive mechanism assembly, in accordance with
McDonnell Douglas Alert Service Bulletin MD80-27-A322, Revision 03,
dated August 4, 1998, at the time specified in paragraph (d)(1),
(d)(2), or (d)(3), as applicable, of this AD.
(1) For airplanes on which no inspection has been performed in
accordance with AD 91-21-11: Perform both visual and eddy current
inspections prior to the accumulation of 10,000 total landings or
within 30 days after the effective date of this AD, whichever occurs
later.
(2) For airplanes on which the immediately preceding inspection
was performed using visual means in accordance with AD 91-21-11,
accomplish the requirements of paragraphs (d)(2)(i) and (d)(2)(ii)
of this AD.
(i) Within 1,000 landings after the immediately preceding visual
inspection, perform a visual inspection; and
(ii) Within 6 months after the last visual inspection required
by paragraph (d)(2)(i) of this AD, perform an eddy current
inspection.
(3) For airplanes on which the immediately preceding inspection
was performed using eddy current means in accordance with AD 91-21-
11: Perform an eddy current inspection within 3,000 landings after
the last eddy current inspection.
(e) If no crack is found during any inspection required by
paragraph (d) of this AD, repeat the eddy current inspection
thereafter at intervals not to exceed 3,000 landings until the
actions specified in paragraph (g) of this AD are accomplished for
both actuator cylinder support brackets of the slat drive mechanism
assembly.
Corrective/Terminating Action
(f) If any cracking is found during any inspection required by
paragraph (d) or (e) of this AD, prior to further flight, modify the
actuator cylinder support bracket of the slat drive mechanism
assembly (Option 1 or 2 for Group 1 or 2 airplanes, as applicable)
in accordance with McDonnell Douglas Service Bulletin MD80-27-322,
Revision 02, dated February 11, 1998, as specified in paragraph
(f)(1) or (f)(2), as applicable, of this AD.
(1) For airplanes identified as Group 1 in the service bulletin:
Accomplish the actions as identified in the service bulletin as
Group 1 Option 1 or Group 1 Option 2.
(2) For airplanes identified as Group 2 in the service bulletin:
Accomplish the actions as identified in the service bulletin as
Group 2 Option 1 or Group 2 Option 2.
(g) Accomplishment of the modification of the actuator cylinder
support bracket specified in paragraph (f) of this AD constitutes
terminating action for the repetitive inspections required by this
AD, provided that both actuator cylinder support brackets are
modified.
Alternative Methods of Compliance
(h)(1) 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.
(2) Alternative methods of compliance, approved previously in
accordance with AD 91-21-11, amendment 39-8058, are approved as
alternative methods of compliance for this AD.
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.
Special Flight Permits
(i) 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 July 15, 1999.
D.L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 99-18626 Filed 7-20-99; 8:45 am]
BILLING CODE 4910-13-U
