Airworthiness Directive · Amendment 39-11525 · Bombardier Model DHC-8-100, -200, and -300 Series Airplanes
Bombardier Model DHC-8-100, -200, and -300 Series Airplanes
Model DHC-8-100, -200, and -300 series airplanes; serial numbers 003 through 538 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.
This amendment adopts a new airworthiness directive (AD) that is applicable to certain Bombardier Model DHC-8-100, -200, and -300 series airplanes. This action requires a one-time visual inspection to determine the part numbers of the beta back-up test switches of the propeller control system, and replacement of the switches, if necessary. This amendment is prompted by issuance of mandatory continuing airworthiness information by a foreign civil airworthiness authority. The actions specified in this AD are intended to prevent loss of the automatic overspeed protection of the propeller control system, which could result in a propeller overspeed condition and possible damage to the engine and propeller.
To prevent loss of the automatic overspeed protection of the propeller control system, which could result in a propeller overspeed condition and possible damage to the engine and propeller, accomplish the following:
(a) Within 50 flight hours after the effective date of this AD, perform a one-time visual inspection to determine the part numbers of the beta back-up test switches of the propeller control system, in accordance with de Havilland Alert Service Bulletin S.B. A8-61-30, Revision ‘B,’ dated December 6, 1999.
(1) If all switches have the correct part number (as specified by the alert service bulletin), no further action is required by this AD.
(2) If any switch does not have the correct part number (as specified by the alert service bulletin), prior to further flight, remove and replace the switch with a new switch having part number MS27407-6, in accordance with the alert service bulletin.
