[Federal Register Volume 61, Number 6 (Tuesday, January 9, 1996)]
[Proposed Rules]
[Pages 636-637]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-261]



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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 95-NM-110-AD]


Airworthiness Directives; de Havilland Model DHC-7 Series 
Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the adoption of a new airworthiness 
directive (AD) that is applicable to certain de Havilland Model DHC-7 
series airplanes. This proposal would require modification of the 
emergency lights circuitry. This proposal is prompted by reports of the 
emergency lights turning on inadvertently due to voltage spikes from 
other equipment, and reports that the existing emergency light switch 
arrangement allows the flight compartment and flight attendant's panel 
switches to override each other. The actions specified by the proposed 
AD are intended to prevent such failures of the emergency light 
systems, which could prevent the use of the emergency lights in the 
event of an emergency.

DATES: Comments must be received by February 13, 1996.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 95-NM-110-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 Bombardier, Inc., Bombardier Regional Aircraft Division, 
Garratt Boulevard, Downsview, Ontario M3K 1Y5, Canada. This information 
may be examined at the FAA, Transport Airplane Directorate, 1601 Lind 
Avenue, SW., Renton, Washington; or at the FAA, Engine and Propeller 
Directorate, New York Aircraft Certification Office, 10 Fifth Street, 
Third Floor, Valley Stream, New York.

FOR FURTHER INFORMATION CONTACT: Wing Chan, Aerospace Engineer, Systems 
and Flight Test Branch, ANE-172, FAA, Engine and Propeller Directorate, 
New York Aircraft Certification Office, 10 Fifth Street, Third Floor, 
Valley Stream, New York 11581; telephone (516) 256-7511; fax (516) 568-
2716.

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-110-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-110-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    Transport Canada Aviation, which is the airworthiness authority for 
Canada, recently notified the FAA that an unsafe condition may exist on 
certain de Havilland Model DHC-7 series airplanes. Transport Canada 
Aviation advises that it has received reports indicating that the 
emergency lights on these airplanes have inadvertently turned on due to 
voltage spikes from other equipment when the main battery power is 
switched off. Transport Canada Aviation also advises that the existing 
emergency light switch arrangement can allow the flight compartment 
panel switch and the flight attendant's panel switch to override each 
other. Such failures of the emergency lighting system, if not 
corrected, could prevent the use of the emergency lights in the event 
of an emergency.
    De Havilland has issued Service Bulletin 7-33-7, dated October 17, 
1980, which describes procedures for modification of the emergency 
lights circuitry. The modification (Modification No. 7/1697) involves 
revising the switching logic of the emergency lights. This modification 
also entails reworking the wiring in the relay panel of the electrical 
equipment bay, and replacing the current emergency light switch (part 
number MS24659-21A) located on the passenger warning panel on the 
flight attendant's panel with a new type of switch. Accomplishment of 
this modification will ensure that the emergency lights can be turned 
on when necessary, that the emergency lights will not turn on 
inadvertently, and that the flight compartment and flight attendant's 
panel switches do not override each other. Transport Canada Aviation 
classified this service bulletin as mandatory and issued Canadian 
airworthiness directive CF-95-04, dated March 9, 1995, in order to 
assure the continued airworthiness of these airplanes in Canada.
    This airplane model is manufactured in Canada and is type 
certificated for operation in the United States under the provisions of 
section 21.29 of the Federal Aviation Regulations (14 CFR 21.29) and 
the applicable bilateral airworthiness agreement. Pursuant to this 
bilateral airworthiness agreement, Transport Canada Aviation has kept 
the FAA informed of the situation described above. The FAA has examined 
the findings of Transport Canada Aviation, reviewed all available 
information, and determined that AD action is necessary for products of 
this type design that are certificated for operation in the United 
States.
    Since an unsafe condition has been identified that is likely to 
exist or develop on other airplanes of the same type design registered 
in the United States, the proposed AD would require modification of the 
emergency lights circuitry. The actions would be required to be 
accomplished in accordance with the service bulletin described 
previously. 

[[Page 637]]

    The FAA estimates that 14 airplanes of U.S. registry would be 
affected by this proposed AD, that it would take approximately 8 work 
hours per airplane to accomplish the proposed actions, and that the 
average labor rate is $60 per work hour. Required parts would be 
provided by the manufacturer at no cost to operators. Based on these 
figures, the cost impact of the proposed AD on U.S. operators is 
estimated to be $6,720, or $480 per airplane.
    The cost impact figure discussed above is based on assumptions that 
no operator 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.
    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), 40101, 40113, 44701.


Sec. 39.13  [Amended]

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

De Havilland, Inc.: Docket 95-NM-110-AD.

    Applicability: Model DHC-7 series airplanes, serial numbers 3 
through 27 inclusive, on which de Havilland Modification No. 7/1697 
has not been installed; certificated in any category.

    Note 1: This AD applies to each airplane identified in the 
preceding applicability provision, regardless of whether it has been 
otherwise 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) 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 prevent failure of the emergency lighting system due to 
voltage spikes from other equipment or due to inadvertent override 
of the emergency lighting switches, accomplish the following:
    (a) Within 6 months after the effective date of this AD, modify 
the emergency lights circuitry by accomplishing de Havilland 
Modification No. 7/1697 (Emergency Lights--Revised Switching Logic), 
in accordance with the Accomplishment Instructions of de Havilland 
Service Bulletin No. 7-33-7, dated October 17, 1980.
    (b) As of the effective date of this AD, no person shall install 
an emergency light switch, part number MS24659-21A, on any airplane 
subject to this AD.
    (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, Standardization Branch, ANM-113, 
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, 
Standardization Branch, ANM-113.

    Note 2: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Standardization Branch, ANM-113.

    (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 January 3, 1996.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 96-261 Filed 1-9-96; 8:45 am]
BILLING CODE 4910-13-U