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[Federal Register Volume 62, Number 188 (Monday, September 29, 1997)]
[Rules and Regulations]
[Pages 50861-50862]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-25416]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-NM-63-AD; Amendment 39-10147; AD 97-20-10]
RIN 2120-AA64

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

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD), 
applicable to certain de Havilland Model DHC-8-100, -200, and -300 
series airplanes, that requires modification of the attitude and 
heading reference systems (AHRS). This amendment is 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 actions specified by this AD are intended to prevent simultaneous 
power loss to both AHRS's, which could result in reduced 
controllability of the airplane.

DATES: Effective November 3, 1997.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of November 3, 1997.

ADDRESSES: The service information referenced in this AD may be 
obtained from Bombardier, Inc., Bombardier Regional Aircraft Division, 
Garratt Boulevard, Downsview, Ontario M3K 1Y5, Canada. 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, New York Aircraft Certification Office, 
Engine and Propeller Directorate, 10 Fifth Street, Third Floor, Valley 
Stream, New York; or at the Office of the Federal Register, 800 North 
Capitol Street, NW., suite 700, Washington, DC.

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: A proposal to amend part 39 of the Federal 
Aviation Regulations (14 CFR part 39) to

[[Page 50862]]

include an airworthiness directive (AD) that is applicable to de 
Havilland Model DHC-8-100, -200, and -300 series airplanes was 
published in the Federal Register on July 22, 1997 (62 FR 39194). That 
action proposed to require modification of the attitude and heading 
reference systems (AHRS).
    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. No comments were submitted in response 
to the proposal or the FAA's determination of the cost to the public.

Conclusion

    The FAA has determined that air safety and the public interest 
require the adoption of the rule as proposed.

Cost Impact

    The FAA estimates that 173 de Havilland Model DHC-8-100, -200, and 
-300 series airplanes of U.S. registry will be affected by this AD, 
that it will take approximately 4 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 $10 per airplane. Based on 
these figures, the cost impact of the AD on U.S. operators is estimated 
to be $43,250, or $250 per airplane.
    The 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.

Regulatory Impact

    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.

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. 106(g), 40113, 44701.

Sec. 39.13  [Amended]

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

97-20-10  De Havilland, Inc.: Amendment 39-10147. Docket 97-NM-63-
AD.

    Applicability: Model DHC-8-100, -200, and -300 series airplanes, 
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 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 the effective date of 
this AD, 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.
    (d) The modification shall be done in accordance with Bombardier 
Alert Service Bulletin S.B. A8-34-117, Revision `C', dated February 
14, 1997. 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 Bombardier, Inc., 
Bombardier Regional Aircraft Division, Garratt Boulevard, Downsview, 
Ontario M3K 1Y5, Canada. Copies may be inspected at the FAA, 
Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, 
Washington; or at the FAA, New York Aircraft Certification Office, 
Engine and Propeller Directorate, 10 Fifth Street, Third Floor, 
Valley Stream, New York; or at the Office of the Federal Register, 
800 North Capitol Street, NW., suite 700, Washington, DC.
    (e) This amendment becomes effective on November 3, 1997.

    Note 3: The subject of this AD is addressed in Canadian 
airworthiness directive CF-97-01R1, dated February 3, 1997.

    Issued in Renton, Washington, on September 19, 1997.
Vi L. Lipski,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 97-25416 Filed 9-26-97; 8:45 am]
BILLING CODE 4910-13-U
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