AD 96-25-16

This amendment adopts a new airworthiness directive (AD), applicable to certain de Havilland Model DHC-7 series airplanes, that requires modification of the power control relay installation of the emergency lights. This amendment also requires revising the FAA-approved Airplane Flight Manual to include procedures for turning off and on the emergency lights switch in certain conditions. This amendment is prompted by a report that the emergency lights do not automatically illuminate when all generated electrical power on the airplane is lost and the power to the left essential bus is maintained from the aircraft batteries. The actions specified by this AD are intended to ensure that the emergency lights illuminate when needed in an emergency situation.

Final rule

96-25-16 DE HAVILLAND, INC.: Amendment 39-9859. Docket 95-NM-257-AD.
Applicability: Model DHC-7 series airplanes, serial numbers 003 through 113 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 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 (c) 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 ensure that the emergency lights illuminate when needed in an emergency situation, accomplish the following:

(a) Within 6 months after the effective date of this AD, modify the power control relay installation of the emergency lights, in accordance with de Havilland Service Bulletin S.B. 7-33-23, Revision 'A', dated October 20, 1995.

(b) Following accomplishment of paragraph (a) of this AD, revise the Limitations Section of the FAA-approved Airplane Flight Manual (AFM) by inserting a copy of de Havilland Dash 7 Flight Manual PSM 1-71A-1A, Revision 39, dated August 22, 1994, into the AFM.

(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, 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 commentsand 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.

(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.

(e) The modification shall be done in accordance with de Havilland Service Bulletin S.B. 7-33-23, Revision `A', dated October 20, 1995. The AFM revision shall be done in accordance with de Havilland Dash 7 Flight Manual PSM 1-71A-1A, Revision 39, dated August 22, 1994. 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.

(f) This amendment becomes effective on February 3, 1997.

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 de Havilland Model DHC-7 series airplanes was published in the Federal Register on September 11, 1996 (61 FR 47834). That action proposed to require modification of the power control relay installation of the emergency lights. Following accomplishment of the proposed modification, that action also proposed to require revising the Limitations Section of the FAA-approved Airplane Flight Manual to include procedures for turning off and on the emergency lights switch.

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 47 de Havilland Model DHC-7 series airplanes of U.S. registry will be affected by this AD.

It will take approximately 4 work hours per airplane to accomplish the required modification, at an average labor rate of $60 per work hour. Required parts will cost approximately $2,713 per airplane. Based on these figures, the cost impact of the modification required by this AD on U.S. operators is estimated to be $138,791, or $2,953 per airplane.

It will take approximately 1 work hour per airplane to accomplish the required AFM revision, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the AFM revision required by this AD on U.S. operators is estimated to be $2,820, or $60 per airplane.

The cost impact figures discussed above are 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 ADwere 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.

39.13 - [Amended]
2. Section 39.13 is amended by adding the following new airworthiness directive: