DHC-3 (Otter) Series Aeroplanes
DHC-3 (Otter) Series Aeroplanes
DHC-3 (Otter) Series Aeroplanes
| AD/DHC-3/40 Amdt 1 | Elevator Servo-Tab Assembly | 8/2008 |
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| Applicability: | All Model DHC-3 aircraft with any of the following Supplemental Type Certificates (STC) installed: SA01-111; SA89-32; or SA02-15 for turbine engines or STCSA83-18 for the PZL ASZ-621R-M18 engine. |
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| Requirement: | Install one of the following elevator flutter prevention kits:a. Viking Air Ltd. Retro Kit No. V3MK1148 Issue 3, or later Transport Canada approved revision; in accordance with Viking Air Ltd. STC SA99-219 Issue 3, or later Transport Canada approved revision;b. American Automotives Inc STC No. SA03-99 (FAA STC No. SA01059SE) with new elevator servo-tab and redundant control linkage; orc. Other modifications, approved by Transport Canada, designed to prevent the elevator servo-tab flutter.Note: Transport Canada AD CF-2006-02R1 refers. |
| Compliance: | Unless already accomplished, within 300 flight hours or 6 months after 31 July 2008, whichever occurs first. |
| This Amendment becomes effective on 31 July 2008. | |
| Background: | Transport Canada received several reports of incidents on turbine-powered DHC-3 aircraft whereby the control rod of the elevator servo-tab system detached from the servo-tab. This failure can cause severe flutter of the elevator servo-tab and could lead to loss of control of the aircraft.Turbine engines are more powerful, allow for a higher cruise speed, and therefore may reduce the elevator servo-tab flutter margins. This Directive requires installation of a kit to reduce the probability of elevator servo-tab failure due to flutter. |
| Amendment 1 is issued in response to a revision of the related Transport Canada AD which was prompted, following a review of the service history of all Model DHC-3 aircraft, that those aircraft with the higher powered PZL ASZ-621R-M18 reciprocating radial engine installed (STC SA83-18) could reach cruise speeds similar to the turbine powered aircraft. |
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David Villiers
Delegate of the Civil Aviation Safety Authority
12 June 2008