[Federal Register Volume 60, Number 105 (Thursday, June 1, 1995)]
[Rules and Regulations]
[Pages 28525-28527]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-12951]



-----------------------------------------------------------------------


DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 94-NM-194-AD; Amendment 39-9245; AD 95-11-12]


Airworthiness Directives; McDonnell Douglas Model DC-9, DC-9-80, 
and C-9 (Military) Series Airplanes, and Model MD-88 Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

-----------------------------------------------------------------------

SUMMARY: This amendment adopts a new airworthiness directive (AD), 
applicable to certain McDonnell Douglas Model DC-9, DC-9-80, and C-9 
(military) series airplanes, and Model MD-88 airplanes, that requires 
repetitive replacement of the emergency power switch in the overhead 
switch panel with a new switch. This amendment is prompted by a report 
of heavy smoke in the cockpit coming from the overhead switch panel on 
a Model DC-9-81 series airplane. The actions specified by this AD are 
intended to ensure replacement of the emergency power switch when it 
has reached its maximum life limit; an emergency power switch that is 
not replaced could fail and lead to a short in the electrical circuit, 
which could result in a fire in the overhead switch panel and smoke in 
the cockpit.

DATES: Effective July 3, 1995.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of July 3, 1995.

ADDRESSES: The service information referenced in this AD 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 Federal Aviation Administration (FAA), Transport 
Airplane Directorate, Rules Docket, 1601 Lind Avenue, SW., Renton, 
Washington; or at the FAA, Los Angeles Aircraft Certification Office, 
Transport Airplane Directorate, 3960 Paramount Boulevard, Lakewood, 
California; or at the Office of the Federal Register, 800 North Capitol 
Street, NW., suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT: Elvin Wheeler, Aerospace Engineer, 
[[Page 28526]] Systems and Equipment Branch, ANM-130L, FAA, Transport 
Airplane Directorate, Los Angeles Aircraft Certification Office, 3960 
Paramount Boulevard, Lakewood, California 90712; telephone (310) 627-
5344; fax (310) 627-5210.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal 
Aviation Regulations (14 CFR part 39) to include an airworthiness 
directive (AD) that is applicable to certain McDonnell Douglas Model 
DC-9, DC-9-80, and C-9 (military) series airplanes, and Model MD-88 
airplanes was published in the Federal Register on December 20, 1994 
(59 FR 65518). That action proposed to require repetitively replacing 
the emergency power switch in the overhead switch panel with a new 
switch at regular intervals.
    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received.
    One commenter supports the proposed rule.
    Two commenters request that the compliance time for accomplishment 
of the replacement be extended from the proposed 12 months to 18 
months. One of these commenters states that such an extension will 
allow the replacement to be accomplished during a regularly scheduled 
maintenance check. The FAA does not concur. In developing an 
appropriate compliance time for this action, the FAA considered not 
only the degree of urgency associated with addressing the subject 
unsafe condition, but the availability of required parts and the 
practical aspect of installing the required replacement with a maximum 
interval of time allowable for all affected airplanes to continue to 
operate without compromising safety. Since maintenance schedules vary 
from operator to operator, there would be no assurance that the 
replacement will be accomplished during that time. The manufacturer has 
advised that an ample number of required parts will be available for 
replacement of the emergency power switch on the U.S. fleet within the 
proposed compliance period. However, under the provisions of paragraph 
(b) of the final rule, the FAA may approve requests for adjustments to 
the compliance time if data are presented to justify such an 
adjustment.
    Several commenters request that the compliance time for 
accomplishing the proposed replacement be based on switch cycle usage, 
rather than calendar time. Two commenters note that a compliance time 
based on a calendar time would impose a severe penalty on operators 
that cycle the switch only once a day and would also impose a somewhat 
lesser penalty on operators who cycle the switch on the first flight of 
the day and at crew changes. One commenter states that, due to the fact 
that the switches do not have counters to record actual switch cycles, 
it is critical that operators have the flexibility to establish an 
equivalent calendar time or airplane cycle limit based on their 
individual procedures for exercising these switches.
    The FAA does not concur with the commenters' request to base the 
compliance time on switch cycles. Compliance times for AD's are 
normally based on a parameter related to failure of a particular 
component. In this case, the failure of the emergency power switch is 
undoubtedly related to the number of switch cycles. However, because 
switch cycles are not recorded, referencing switch cycles in the 
compliance time would make it impossible to verify compliance at the 
required time. Therefore, the FAA has selected a compliance time that 
equates to the approximate number of switch cycles specified in 
McDonnell Douglas DC-9 Service Bulletin 24-150, assuming that the 
switch is cycled once for each flight cycle. Under provisions of 
paragraph (b) of the final rule, however, operators may apply for the 
approval of an extension of the compliance time if sufficient 
justification is presented to the FAA. For example, such justification 
may consist of data demonstrating that the operator only cycles the 
switch once a day, or at each crew change, rather than once per flight 
cycle.
    Since issuance of the proposal, the FAA has reviewed and approved 
McDonnell Douglas DC-9 Service Bulletin 24-150, Revision 1, dated April 
7, 1995, which describes the appropriate procedures for repetitively 
replacing the emergency power switch in the overhead switch panel with 
a new switch at regular intervals. Therefore, the final rule has been 
revised to reference this revision of the service bulletin as an 
additional source of service information.
    The FAA points out that it inadvertently used the phrase ``time-in-
service'' after the term ``3 years'' in paragraph (a) of the proposal 
when referring to the compliance threshold for installation of the 
emergency power switch. Since that phrase is inappropriate, the FAA has 
removed it from the final rule. Likewise, the FAA has removed that 
phrase from the reference to the repetitive replacement interval.
    After careful review of the available data, including the comments 
noted above, the FAA has determined that air safety and the public 
interest require the adoption of the rule with the changes previously 
described. The FAA has determined that these changes will neither 
increase the economic burden on any operator nor increase the scope of 
the AD.
    There are approximately 1,990 Model DC-9, DC-9-80, and C-9 
(military) series airplanes and Model MD-88 airplanes of the affected 
design in the worldwide fleet. The FAA estimates that 992 airplanes of 
U.S. registry will be affected by this AD, that it will take 
approximately 2 work hours per airplane to accomplish the required 
actions, and that the average labor rate is $60 per work hour. Required 
parts will cost approximately $1,434 per airplane. Based on these 
figures, the total cost impact of the AD on U.S. operators is estimated 
to be $1,541,568, or $1,554 per airplane, per replacement cycle.
    The total cost impact figure discussed above is based on 
assumptions that no operator has yet accomplished any of the 
requirements of this AD action, and that no operator would accomplish 
those actions in the future if this AD were not adopted.
    The regulations adopted herein will 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 final 
rule does not have sufficient federalism implications to warrant the 
preparation of a Federalism Assessment.
    For the reasons discussed above, I certify that this action (1) is 
not a ``significant regulatory action'' under Executive Order 12866; 
(2) is not a ``significant rule'' under DOT Regulatory Policies and 
Procedures (44 FR 11034, February 26, 1979); and (3) 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 final evaluation has been prepared for this action 
and it is contained in the Rules Docket. A copy of it may be obtained 
from the Rules Docket at the location provided under the caption 
ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety. [[Page 28527]] 

Adoption of the Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration amends 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. App. 1354(a), 1421 and 1423; 49 U.S.C. 
106(g); and 14 CFR 11.89.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by adding the following new 
airworthiness directive:

95-11-12 McDonnell Douglas: Amendment 39-9245. Docket 94-NM-194-AD.

    Applicability: Model DC-9-10, -20, -30, -40, and -50 series 
airplanes; Model DC-9-81 (MD-81), DC-9-82 (MD-82), DC-9-83 (MD-83), 
and DC-9-87 (MD-87) series airplanes; Model MD-88 airplanes; and C-9 
(military) series airplanes; as listed in McDonnell Douglas DC-9 
Service Bulletin 24-150, dated March 28, 1994; 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 (b) 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 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.
    To ensure replacement of the emergency power switch that have 
reached the maximum life limit, accomplish the following:
    (a) Prior to the accumulation of 3 years since installation of 
the emergency power switch in the overhead switch panel, or within 
12 months after the effective date of this AD, whichever occurs 
later, replace the emergency power switch with a new switch in 
accordance with the procedures specified in McDonnell Douglas DC-9 
Service Bulletin 24-150, dated March 28, 1994, or Revision 1, dated 
April 7, 1995. Thereafter, replace the emergency power switch at 
intervals not to exceed 3 years.
    (b) 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 2: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Los Angeles ACO.

    (c) 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.
    (d) The replacement shall be done in accordance with McDonnell 
Douglas DC-9 Service Bulletin 24-150, dated March 28, 1994; or 
McDonnell Douglas DC-9 Service Bulletin 24-150, Revision 1, dated 
April 7, 1995. This incorporation by reference was approved by the 
Director of the Federal Register in accordance with 5 U.S.C. 552(a) 
and 1 CFR part 51. Copies may be obtained from McDonnell Douglas 
Corporation, 3855 Lakewood Boulevard, Long Beach, California 90846, 
Attention: Technical Publications Business Administration, 
Department C1-L51 (2-60). Copies may be inspected at the FAA, 
Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, 
Washington; or at the FAA, Los Angeles Aircraft Certification 
Office, Transport Airplane Directorate, 3960 Paramount Boulevard, 
Lakewood, California; or at the Office of the Federal Register, 800 
North Capitol Street, NW., suite 700, Washington, DC.
    (e) This amendment becomes effective on July 3, 1995.

    Issued in Renton, Washington, on May 22, 1995.
S.R. Miller,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 95-12951 Filed 5-31-95; 8:45 am]
BILLING CODE 4910-13-U