[Federal Register Volume 63, Number 115 (Tuesday, June 16, 1998)]
[Proposed Rules]
[Pages 32771-32772]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-15885]



[[Page 32771]]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-NM-70-AD]
RIN 2120-AA64


Airworthiness Directives; de Havilland Model DHC-8-100, -200, and 
-300 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes to revise an existing airworthiness 
directive (AD), applicable to certain de Havilland Model DHC-8-100, -
200, and -300 series airplanes, that currently requires modification of 
the attitude and heading reference systems (AHRS). That AD was prompted 
by a report of loss of power to both AHRS's during flight due to a 
faulty terminal block to which the signal ground for the AHRS's is 
connected. The actions specified by that AD are intended to prevent 
simultaneous power loss to both AHRS's, which could result in reduced 
controllability of the airplane. This action would reduce the 
applicability of the existing AD.

DATES: Comments must be received by July 16, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 98-NM-70-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: Luciano Castracane, Aerospace 
Engineer, Systems and Equipment Branch, ANE-172, FAA, New York Aircraft 
Certification Office, Engine and Propeller Directorate, 10 Fifth 
Street, Third Floor, Valley Stream, New York 11581; telephone (516) 
256-7535; 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 98-NM-70-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-114, Attention: Rules 
Docket No. 98-NM-70-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    On September 19, 1997, the FAA issued AD 97-20-10, amendment 39-
10147 (62 FR 50861, September 29, 1997), applicable to certain de 
Havilland Model DHC-8-100, -200, and -300 series airplanes, to require 
modification of the attitude and heading reference systems (AHRS). That 
action was prompted by a report of loss of power to both AHRS's during 
flight due to a faulty terminal block to which the signal ground for 
the AHRS's are connected. The requirements of that AD are intended to 
prevent simultaneous power loss to both AHRS's, which could result in 
reduced controllability of the airplane.

Actions Since Issuance of Previous Rule

    Since issuance of that AD, the Transport Canada Aviation (TCA), 
which is the airworthiness authority for Canada, has issued Canadian 
airworthiness directive CF-97-01R2, dated August 13, 1997. This 
revision supersedes Canadian airworthiness directive CF-97-01R1, dated 
February 3, 1997, which was referenced in AD 97-20-10 as the parallel 
Canadian airworthiness directive for AD 97-20-10. The only change 
effected by CF-97-01R2 is to reduce the list of affected airplanes to 
serial numbers 3 through 472 inclusive. The effectivity listing of CF-
97-01R2 limits accomplishment of the modification of the AHRS to those 
airplanes on which the modification was not accomplished in production.

FAA's Conclusions

    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, TCA has kept the FAA informed of the 
situation described above. The FAA has examined the findings of the 
TCA, 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.

Explanation of Requirements of Proposed Rule

    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 revise AD 97-20-10 to 
continue to require modification of the AHRS. The proposed AD also 
would reduce the applicability of that AD to airplanes having serial 
numbers 3 through 472 inclusive.

Cost Impact

    The FAA estimates that 167 de Havilland Model DHC-8-100, -200, and 
-300 series airplanes of U.S. registry would be affected by this 
proposed AD, that it would take approximately 4 work hours per airplane 
to accomplish the proposed actions, and that the average labor rate is 
$60 per work hour. Required parts would cost approximately $10 per 
airplane. Based on these figures, the cost impact of the proposed AD on 
U.S. operators is estimated to be $41,750, or $250 per airplane.

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    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.

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 39-10147 (62 FR 
50861, September 29, 1997), and by adding a new airworthiness directive 
(AD), to read as follows:

De Havilland, Inc.: Docket 98-NM-70-AD. Revises AD 97-20-10, 
Amendment 39-10147.

    Applicability: Model DHC-8-100, -200, and -300 series airplanes, 
serial numbers 3 through 472 inclusive, 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 (b) 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 simultaneous power loss to both attitude and heading 
reference systems (AHRS), which could result in reduced 
controllability of the airplane, accomplish the following:
    (a) Within 400 hours time-in-service after November 3, 1997 (the 
effective date of AD 97-20-10, amendment 39-10147), modify the 
AHRS's, in accordance with Bombardier Alert Service Bulletin S.B. 
A8-34-117, Revision `C', dated February 14, 1997.
    (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, New York Aircraft Certification 
Office (ACO), FAA, Engine and Propeller Directorate. Operators shall 
submit their requests through an appropriate FAA Principal 
Maintenance Inspector, who may add comments and then send it to the 
Manager, New York ACO.

    Note 2: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the New York 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.

    Note 3: The subject of this AD is addressed in Canadian 
airworthiness directive CF-97-01R2, dated August 13, 1997.

    Issued in Renton, Washington, on June 9, 1998.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 98-15885 Filed 6-15-98; 8:45 am]
BILLING CODE 4910-13-U