[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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