[Federal Register Volume 60, Number 186 (Tuesday, September 26, 1995)]
[Proposed Rules]
[Pages 49525-49527]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-23809]
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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39
[Docket No. 95-NM-118-AD]
Airworthiness Directives; McDonnell Douglas Model DC-9-80 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 McDonnell Douglas
Model DC-9-80 series airplanes, that currently requires inspection and
replacement of certain suspect horizontal stabilizer primary trim
motors. That AD was prompted by an analysis which revealed that certain
incorrectly manufactured motor shafts could fail prematurely and, in
turn, cause the primary trim motor to fail. The actions specified in
that AD are intended to prevent such failures of the primary trim
motor, which could ultimately result in reduced controllability of the
airplane. This action would expand the applicability of the existing AD
to include additional airplanes.
DATES: Comments must be received by November 6, 1995.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-103,
Attention: Rules Docket No. 95-NM-118-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); or Sundstrand
Aerospace, 4747 Harrison Avenue, P.O. Box 7002, Rockford, Illinois
61125-7002. This information may be examined at the FAA, Transport
Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington.
FOR FURTHER INFORMATION CONTACT: Walter Eierman, Aerospace Engineer,
Systems and Equipment Branch, ANM-130L, FAA, Los Angeles Aircraft
Certification Office, 3960 Paramount Boulevard, Lakewood, California
90712; telephone (310) 627-5336; 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 95-NM-118-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. 95-NM-118-AD, 1601 Lind Avenue, SW., Renton, Washington
98055-4056.
Discussion -
On March 8, 1995, the FAA issued AD 95-06-04, amendment 39-9174 (60
FR 15034, March 22, 1995), applicable to certain McDonnell Douglas
Model DC-9-80 series airplanes, to require inspection and replacement
of certain suspect horizontal stabilizer primary trim motors. That
action was prompted by an analysis which revealed that certain
incorrectly manufactured motor shafts could fail prematurely and, in
turn, cause the primary trim motor to fail. The requirements of that AD
are intended to prevent such failures of the primary trim motor, which
could ultimately result in reduced controllability of the airplane. -
Since the issuance of that AD, the FAA received a report indicating
that an additional lot of motor output shafts was not subjected to a
hardening
[[Page 49526]]
process (heat treatment) during manufacture. Without this hardening
process, the defective output shafts may experience excessive wear,
which could lead to failure of the shaft and, consequently, failure of
the trim motor. A shaft failure in the primary trim motor could also
result in the inability of the trim gearbox to transmit the input from
the alternate trim motor. This condition, if not corrected, could
result in the loss of all stabilizer trim and subsequent reduced
controllability of the airplane. No failures have actually occurred in
service, however. -
The FAA has reviewed and approved McDonnell Douglas MD-80 Alert
Service Bulletin A27-342, Revision 1, dated May 15, 1995. The
inspection and replacement procedures described in this revision are
identical to those described in the original issue of the alert service
bulletin (which was referenced in AD 95-06-04). However, this revision
expands the effectivity listing to include additional airplanes that
are subject to the addressed unsafe condition. This revision also
contains minor editorial changes. -
The FAA also has reviewed and approved Sundstrand Service Bulletin
9590-27-012, dated August 8, 1995, which describes procedures for
modifying the brake motor. The modification involves replacing the
coupling in the brake motor with a coupling that has been heat-treated
and testing the brake motor. Accomplishment of this modification will
extend the service life of the brake motor. -
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 95-06-04 to continue to require
inspection and replacement of certain suspect horizontal stabilizer
primary trim motors. This action would expand the applicability of the
existing AD to include additional airplanes. The actions would be
required to be accomplished in accordance with the alert service
bulletin described previously. -
There are approximately 142 Model DC-9-80 series airplanes of the
affected design in the worldwide fleet. The FAA estimates that a total
of 73 airplanes of U.S. registry would be affected by this proposed AD.
-
The inspection of the horizontal stabilizer primary trim motor is
expected to take approximately 1 work hour per airplane to accomplish,
at an average labor rate of $60 per work hour. Based on these figures,
the total cost impact of this requirement is estimated to be $60 per
airplane. -
The actions specified in this proposed rule previously were
required by AD 95-06-04, which was applicable to approximately 13 U.S.-
registered airplanes. Based on the figures discussed above, the total
cost impact of the current requirements of that AD on U.S. operators is
estimated to be $390. In consideration of the compliance time and
effective date of AD 95-06-04, the FAA assumes that the operators of
the 13 airplanes subject to that AD have already initiated the required
actions. The proposed AD action would add no new costs associated with
those airplanes. -
This proposed action would be applicable to approximately 60
additional airplanes. Based on the figures discussed above, the total
new costs to U.S. operators that would be imposed by this new AD are
estimated to be $3,600. This figure is based on assumptions that no
operator of these additional airplanes 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. -
Replacement of suspect motors, if necessary, would require 5 work
hours to accomplish, at an average labor rate of $60 per work hour.
Required parts will be provided by Sundstrand Electric Power Systems
(the manufacturer of the horizontal stabilizer primary trim motors) at
no charge to operators. Based on these figures, the total cost impact
on U.S. operators for the replacement of suspect motors is estimated to
be $300 per airplane. -
Should an operator elect to modify a suspect motor, that action
would require 4 work hours to disassemble, modify, reassemble, and test
the motor (excluding removal and reinstallation of the motor from the
airplane). The average labor rate is $60 per work hour. Required parts
would be provided by Sundstrand at no charge to operators. Based on
these figures, the total cost impact on U.S. operators for modification
of a suspect motor is estimated to be $240 per airplane. -
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 USC 106(g), 40101, 40113, 44701.
Sec. 39.13 [Amended] -
2. Section 39.13 is amended by removing amendment 39-9174 (60 FR
15034, March 22, 1995), and by adding a new airworthiness directive
(AD), to read as follows:
McDonnell Douglas: Docket 95-NM-118-AD. Supersedes AD 95-06-04,
Amendment 39-9174.
-Applicability: Model DC-9-80 series airplanes; as listed in
McDonnell Douglas MD-80 Alert Service Bulletin A27-342, dated August
4, 1994, and in McDonnell Douglas MD-80 Alert Service Bulletin A27-
342, Revision 1, dated May 15, 1995; 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 use the authority
provided in paragraph (c) of this AD to request approval from the
FAA. This approval may address either no action, if the current
configuration eliminates the unsafe condition; or different actions
necessary to address the unsafe condition described in this AD. Such
a request should include an assessment of the effect of the changed
configuration on the unsafe condition
[[Page 49527]]
addressed by this AD. In no case does the presence of any modification,
alteration, or repair remove any airplane from the applicability of
this AD.
-Compliance: Required as indicated, unless accomplished
previously.
-Note 2: Paragraph (a) of this AD merely restates the
requirements of paragraph (a) of AD 95-06-04, amendment 39-9174. As
allowed by the phrase, ``unless accomplished previously,'' if those
requirements of AD 95-06-04 have already been accomplished, this AD
does not require that those actions be repeated.
-To prevent failure of the horizontal stabilizer primary trim
motor, accomplish the following: -
(a) For airplanes listed in McDonnell Douglas MD-80 Alert
Service Bulletin A27-342, dated August 4, 1994: Within 6 months
after April 21, 1995 (the effective date of AD 95-06-04, amendment
39-9174), conduct a visual inspection of the horizontal stabilizer
primary trim motor to determine if the motor is identified with one
of the suspect serial numbers listed in McDonnell Douglas MD-80
Alert Service Bulletin A27-342, dated August 4, 1994, or Revision 1,
dated May 15, 1995. Conduct this inspection in accordance with the
procedures specified in that service bulletin. -
(1) If the horizontal stabilizer primary trim motor is not
identified with a suspect serial number, no further action is
required by this AD. -
(2) If the horizontal stabilizer primary trim motor is
identified with a suspect serial number, prior to further flight,
accomplish either paragraph (a)(2)(i) or (a)(2)(ii) of this AD. -
(i) Replace the motor in accordance with the McDonnell Douglas
alert service bulletin. Or -
(ii) Modify the motor in accordance with Sundstrand Service
Bulletin 9590-27-012, dated August 8, 1995; and install the modified
motor in accordance with the McDonnell Douglas alert service
bulletin. -
(b) For airplanes listed in McDonnell Douglas MD-80 Alert
Service Bulletin A27-342, Revision 1, dated May 15, 1995, and not
subject to paragraph (a) of this AD: Within 6 months after the
effective date of this AD, conduct a visual inspection of the
horizontal stabilizer primary trim motor to determine if the motor
is identified with one of the suspect serial numbers listed in
McDonnell Douglas MD-80 Alert Service Bulletin A27-342, Revision 1,
dated May 15, 1995. Conduct this inspection in accordance with the
procedures specified in that service bulletin. -
(1) If the horizontal stabilizer primary trim motor is not
identified with a suspect serial number, no further action is
required by this AD. -
(2) If the horizontal stabilizer primary trim motor is
identified with a suspect serial number, prior to further flight,
accomplish either paragraph (b)(2)(i) or (b)(2)(ii) of this AD. -
(i) Replace the motor in accordance with the McDonnell Douglas
alert service bulletin. Or -
(ii) Modify the motor in accordance with Sundstrand Service
Bulletin 9590-27-012, dated August 8, 1995; and install the modified
motor in accordance with the McDonnell Douglas alert service
bulletin. -
(c) 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 Los Angeles ACO.
-(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 September 20, 1995.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 95-23809 Filed 9-25-95; 8:45 am]
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