[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