{"id":"F2008L02523","name":"AD/DHC-3/40 Amdt 1 - Elevator Servo-Tab Assembly","slug":"ad-dhc-3-40-amdt-1-elevator-servo-tab-assembly","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":74495,"registerId":"commonwealth-F2008L02523-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"DHC-3 (Otter) Series Aeroplanes","sectionType":"division","heading":"DHC-3 (Otter) Series Aeroplanes","content":"### DHC-3 (Otter) Series Aeroplanes\n\n| AD/DHC-3/40 Amdt 1 | Elevator Servo-Tab Assembly | 8/2008 |\n| ------------------ | --------------------------- | ------ |\n\n| 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.                                                                                                                                                                                                                                                                                                                                                         |\n| -------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| 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. |\n| Compliance:    | Unless already accomplished, within 300 flight hours or 6 months after 31 July 2008, whichever occurs first.                                                                                                                                                                                                                                                                                                                                                                                                                                                |\n|                | This Amendment becomes effective on 31 July 2008.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           |\n| 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. |\n\n|     | 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. |\n| --- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n\n![](image.001.png)  \nDavid Villiers  \nDelegate of the Civil Aviation Safety Authority\n\n12 June 2008","sortOrder":0},{"sectionNumber":"AD/DHC-3/40 Amdt 1","sectionType":"part","heading":"AD/DHC-3/40 Amdt 1","content":"## AD/DHC-3/40 Amdt 1","sortOrder":1},{"sectionNumber":"Elevator Servo-Tab Assembly","sectionType":"part","heading":"Elevator Servo-Tab Assembly","content":"## Elevator Servo-Tab Assembly","sortOrder":2},{"sectionNumber":"8/2008","sectionType":"part","heading":"8/2008","content":"## 8/2008","sortOrder":3}],"analysis":{"flash_summary_failed":{"failed":true,"reason":"A positive credit balance is required for all requests, including BYOK, so fallback providers remain available. Add credits at https://vercel.com/d?to=%2F%5Bteam%5D%2F%7E%2Fai%3Fmodal%3Dtop-up to continue.","source":"analysis-cron"},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":true,"description":"Amendment 1 expands the directive’s scope to include DHC‑3 aircraft fitted with the high‑powered PZL ASZ‑621R‑M18 reciprocating engine (STC SA83‑18), because such installations can achieve cruise speeds similar to turbine‑powered aircraft; previously the directive targeted turbine‑engined STC installations."},"complexity_factors":["Multiple specific STCs listed for applicability (SA01‑111; SA89‑32; SA02‑15; STCSA83‑18) increasing identification complexity for operators","Several approved compliance options: two named kits/STCs or any Transport Canada‑approved alternative, creating choice and approval uncertainty","Cross‑jurisdictional reference to Transport Canada AD and approvals (Transport Canada decisions determine acceptable modifications)","A fixed compliance window (300 flight hours or six months after 31 July 2008) that imposes operational scheduling and potential grounding costs","Technical installation work (servo‑tab and redundant linkage in one option) may require specialized parts and maintenance labour","Amendment expands applicability based on engine performance (PZL ASZ‑621R‑M18), so prior records and STC tracking must be rechecked","Enforcement relies on operators certifying or proving kit installation within a defined timeframe","Limited prescribed method for demonstrating equivalent safety (must be Transport Canada approved), which concentrates discretion with the regulator"],"plain_english_summary":"Mandates that owners/operators of DHC-3 (Otter) aircraft fitted with certain supplemental type certificates (turbine-engine STCs and the high‑powered PZL ASZ‑621R‑M18 STC) install an approved elevator flutter‑prevention kit. The rule names three compliance pathways (two specific kits or any Transport Canada‑approved modification) and sets a compliance window of 300 flight hours or six months after 31 July 2008. The stated purpose is to reduce the risk of servo‑tab detachment and severe elevator flutter; owners bear installation cost and scheduling burden."},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":true,"description":"The original AD (implied by 'Amendment 1') was issued for turbine-powered DHC-3 aircraft only. This amendment expands the scope to include aircraft with the PZL ASZ-621R-M18 reciprocating radial engine (STC SA83-18) after review showed these piston-engine aircraft could reach similar cruise speeds to turbine models, creating the same flutter risk."},"complexity_factors":["Short, single-purpose directive with one primary requirement","Only 4 defined STC (Supplemental Type Certificate) references to identify affected aircraft","Three alternative compliance paths (kit options a, b, or c) with cross-references to Transport Canada approvals","Simple time-based compliance formula (300 hours OR 6 months, whichever first)","No nested exceptions or conditional logic — straightforward applicability test","Background explanation included but not legally operative"],"plain_english_summary":"This AD mandates that owners/operators of certain De Havilland Canada DHC‑3 (Otter) aeroplanes fitted with specified turbine or Polish radial engine upgrades install an approved safety kit within 300 flight hours or 6 months (from 31 July 2008). The kit prevents dangerous elevator servo‑tab flutter caused by detached control rods on faster‑modified aircraft. It addresses reported failures that could lead to severe vibration and loss of control."}},"importantCases":[],"_links":{"self":"/api/acts/ad-dhc-3-40-amdt-1-elevator-servo-tab-assembly","history":"/api/acts/ad-dhc-3-40-amdt-1-elevator-servo-tab-assembly/history","analysis":"/api/acts/ad-dhc-3-40-amdt-1-elevator-servo-tab-assembly/analysis","conflicts":"/api/acts/ad-dhc-3-40-amdt-1-elevator-servo-tab-assembly/conflicts","importantCases":"/api/acts/ad-dhc-3-40-amdt-1-elevator-servo-tab-assembly/important-cases","documents":"/api/acts/ad-dhc-3-40-amdt-1-elevator-servo-tab-assembly/documents"}}