AD Amdt-39-10697

[Federal Register Volume 63, Number 152 (Friday, August 7, 1998)]
[Rules and Regulations]
[Pages 42219-42220]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 98-21097]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-NM-70-AD; Amendment 39-10697; AD 97-20-10 R1]
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 revises 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 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 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 amendment reduces the 
applicability of the existing AD.

DATES: Effective September 11, 1998.
    The incorporation by reference of Bombardier Alert Service Bulletin 
S.B. A8-34-117, Revision `C', dated February 14, 1997, as listed in the 
regulations, was approved previously by the Director of the Federal 
Register as of November 3, 1997 (62 FR 50861, September 29, 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, Engine and Propeller Directorate, New York 
Aircraft Certification Office, 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) by revising AD 97-20-10, 
amendment 39-10147 (62 FR 50861, September 29, 1997), which is 
applicable to certain de Havilland Model DHC-8-100, -200, and -300 
series airplanes, was published in the Federal Register on June 16, 
1998 (63 FR 32771). The action proposed to reduce the applicability of 
the existing AD.

Comments

    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.

[[Page 42220]]

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 167 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 $41,750, 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 removing amendment 39-10147 (62 FR 
50861, September 29, 1997), and by adding a new airworthiness directive 
(AD), amendment 39-10697, to read as follows:

97-20-10  R1 De Havilland, Inc.: Amendment 39-10697. 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.
    (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 previously by 
the Director of the Federal Register as of November 3, 1997 (62 FR 
50861, September 29, 1997). 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, Engine and Propeller Directorate, New 
York Aircraft Certification Office, 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.

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

    (e) This amendment becomes effective on September 11, 1998.

    Issued in Renton, Washington, on July 31, 1998.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 98-21097 Filed 8-6-98; 8:45 am]
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