Airworthiness Directive · Amendment 39-11678 · Bombardier Model DHC-8-100 Series Airplanes
Bombardier Model DHC-8-100 Series Airplanes
Model DHC-8-100 series airplanes, serial numbers 003 through 020 inclusive; certificated in any category; except those on which Modification 8/0198 has been installed.
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.
This amendment adopts a new airworthiness directive (AD), applicable to certain Bombardier Model DHC-8-100 series airplanes, that requires changing the power supply for the thunderstorm lights from the left secondary bus to the left essential bus. This amendment is prompted by issuance of mandatory continuing airworthiness information by a foreign civil airworthiness authority. The actions specified by this AD are intended to prevent a failure of the thunderstorm lights in the cockpit after loss of all generated electrical power. This condition could result in the cockpit instruments not being visible to the flight crew during certain emergency procedures, and consequent reduced controllability of the airplane.
To prevent a failure of the thunderstorm lights in the cockpit after loss of all generated electrical power, which could result in the cockpit instruments not being visible to the flight crew during certain emergency procedures, and consequent reduced controllability of the airplane, accomplish the following:
(a) Within 6 months after the effective date of this AD, accomplish Bombardier Modification 8/0198 (including changing the power supply for the thunderstorm lights from the left secondary bus to the left essential bus) in accordance with Bombardier Service Bulletin S.B. 8-24-69, Revision ‘A', dated June 11, 1999.
