{"id":"F2009L00690","name":"AD/DHC-8/133 Amdt 2 - Main Landing Gear System","slug":"ad-dhc-8-133-amdt-2-main-landing-gear-system","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":77623,"registerId":"commonwealth-F2009L00690-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Bombardier (Boeing Canada/De Havilland) ","sectionType":"division","heading":"Bombardier (Boeing Canada/De Havilland) DHC-8 Series Aeroplanes","content":"### Bombardier (Boeing Canada/De Havilland) DHC-8 Series Aeroplanes\n\n| AD/DHC-8/133 Amdt 2 | Main Landing Gear System | 4/2009 DM |\n| ------------------- | ------------------------ | --------- |\n\n| Applicability: | Bombardier Inc. DHC-8 aircraft, Models 400, 401 and 402, serial numbers 4001, 4003, 4004, 4006, and 4008 through 4208.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           |\n| -------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | 1. General Visual Inspection of the Main Landing Gear System - Applicable to DHC-8 Aircraft, Models 400, 401, and 402, Serial Numbers 4001, 4003, 4004, 4006, 4008 through 4182.Perform a general visual inspection of the left hand and right hand main landing gear system in accordance with Bombardier DHC-8 Series 400 Maintenance Requirements Manual (PSM 1-84-7), Part 1 (Maintenance Review Board Report), tasks Z700-03E (left hand) and Z700-04E (right hand) and rectify any discrepancy found.2. General Visual Inspection of the Main Landing Gear Retract Actuator Jam Nut - Applicable to DHC-8 Aircraft, Models 400, 401, and 402, Serial Numbers 4001, 4003, 4004, 4006, 4008 through 4208.a. Perform a general visual inspection of the left hand and right hand main landing gear retract actuator jam nut to ensure the wire lock is in place and the nut is secured. If the wire lock is not in place or the jam nut is not secured, accomplish Bombardier Repair Drawing (RD) 8/4-32-059 Issue 5 or later approved revision.b. Repeat the actions detailed in Requirement 2.a. of this AD.3. Detailed Visual Inspection of the Main Landing Gear Retract Actuator - Applicable to DHC-8 Aircraft, Models 400, 401, and 402, Serial Numbers 4001, 4003, 4004, 4006, 4008 through 4182.a. Perform a detailed visual inspection and any required action(s) in accordance with Bombardier RD 8/4-32-059 Issue 5 or later approved revision.b. Repeat the actions detailed in Requirement 3.a. of this AD.Respective inspections performed in accordance with earlier issues of RD 8/4-32-059 satisfy the actions detailed in Requirements 2 and 3 of this AD. |\n\n|     | If the visual inspection of the piston (p/n 46570-1/-3) threads and thread relief area for evidence of corrosion in accordance with RD 8/4-32-059 Rev. NC was performed without using borescope or 10X magnification mirror, a one time deferral for up to 500 landings is permissible to complete the inspection of the piston using borescope or 10X magnification mirror.4. Reporting Requirement - Applicable to DHC Models 400, 401 and 402, serial numbers 4001, 4003, 4004, 4006, and 4008 through 4208.Report any discrepancies found during any of the above inspections to the Bombardier Technical Help Desk.5. Modification of Main Landing Gear Retract Actuator - Applicable to DHC-8 Aircraft, Models 400, 401, and 402, Serial Numbers 4001, 4003, 4004, 4006, 4008 through 4182.Incorporate Bombardier Modsum 4-901603 to replace the affected retract actuator with a new design retract actuator, p/n 46550-13. Bombardier Service Bulletin (SB) 84-32-55, Revision A, dated 10 March 2008, or later revisions approved by the Chief, Continuing Airworthiness, Transport Canada provides approved instructions for incorporating Modsum 4-901603.Terminating Action 1.Incorporation of Modsum 4-901603 provides terminating action to the visual inspections detailed in Requirement 3 of this AD.Note 1: Incorporation of Modsum 4-901603 in accordance with Revision NC of Bombardier SB 84-32-55, dated 14 January 2008, meets Requirement 5 of this AD.Note 2: Incorporation of Modsum 4-901610 to replace the affected retract actuator with a new design retract actuator, p/n 46550-15, also satisfies Requirement 5 of this AD.6. Maintenance Requirement - Applicable to DHC-8 Aircraft, Models 400, 401, and 402, Serial Numbers 4001, 4003, 4004, 4006, 4008 through 4208.Amend the Transport Canada approved maintenance schedule by incorporating task numbers 320100-211 (Detailed Inspection of the Retraction Actuator Rod End Jam Nut, Gland Nut and Actuator Attachment Pins for Condition, Security of Installation and Corrosion) and 320100-212 (Restoration of the Retraction Actuator for Complete Overhaul) as introduced by the Temporary Revision (TR) MRB–35 of the DHC-8 Series 400 Maintenance Requirements Manual, PSM1-84-7. |\n| --- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n\n|             | Terminating Action 2.Incorporation of maintenance task numbers 320100-211 and 320100-212 provides terminating action to the general visual inspections detailed in Requirement 2 of this AD.Ferry Flight: Applicable to DHC-8 Aircraft, Models 400, 401, and 402, Serial Numbers 4001, 4003, 4004, 4006, 4008 through 4208.To permit the ferry of an aircraft to a location where the inspection requirements of this directive can be accomplished, adhere to the following procedures and limitations:Flight Crew Limitations and Procedures:A. Ferry Flight with gear extended and pinned.B. Landing to be conducted at a minimum descent rate.C. Minimize braking on landing.D. Flight to be conducted per Aircraft Operating Manual (AOM) Section 4.8.E. Essential crew only on board.F. Flight in known or forecast icing condition is prohibited.Maintenance Procedures:(i) Inspect the left hand and right hand main landing gear retract actuator jam nut to ensure the wire lock is in place and the nut is secure.(ii) Perform the general visual inspections as defined in accordance with Bombardier All Operators Message No. 236 Rev A or later revisions.(iii) If items 1 and 2 results are satisfactory, insert main landing gear ground lock pins and lockwire in place.(iv) Ensure the nose landing gear ground lock is engaged.Note 3: Transport Canada AD CF-2007-20 R2 dated 6 February 2009 refers. |\n| ----------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Compliance: | For Requirement 1 - Remains unchanged as detailed in the original issue of this AD as:Before further flight after 14 September 2007 (the effective date of the original issue of this AD), unless previously accomplished.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |\n\n|     | For Requirement 2a - Remains unchanged as detailed in the original issue of this AD as:Before further flight after 14 September 2007, unless previously accomplished.For Requirement 2b - At intervals not to exceed 250 landings or one month from the previous inspection, whichever occurs first.For Requirement 3a - Remains unchanged as detailed in the original issue of this AD as:For aircraft main landing gear retract actuator (p/n 46550-7 or 46550-9) that have accumulated 8,000 or more landings or in service for more than 4 years since new, whichever occurs first at 14 September 2007 - before further flight after14 September 2007.For aircraft main landing gear retract actuator (p/n 46550-7 or 46550-9) that have accumulated between 4,000 to 7,999 landings or in service between 2 to 4 years since new at 14 September 2007 - Within 500 flight hours or 3 months after the effective date of this AD, whichever occurs first.For aircraft main landing gear retract actuator (p/n 46550-7 or 46550-9) that have accumulated less than 4,000 landings or less than 2 years service in service since new, at 14 September 2007 - Prior to reaching 4,500 landings or 27 months in service new, whichever occurs first.For aircraft main landing gear retract actuator (p/n 46550-11) - Prior to reaching 4,500 landings or 27 months in service new, whichever occurs first.For Requirement 3b - At intervals not to exceed 2,000 landings or one calendar year from the previous inspection, whichever occurs first.For Requirement 4 - Within 7 days after each inspection.For Requirement 5For aircraft main landing gear retract actuators (p/n 46550-7 or 46550-9 or 46550-11) that have accumulated 7,500 or more landings or more than 4 years in service since new at the effective date of this AD - Within 500 landings or 3 months from the effective date of this AD, whichever occurs first.For aircraft main landing gear retract actuators (p/n 46550-7 or 46550-9 or 46550-11) that have accumulated less than 7,500 landings, and 4 years or less in service since new at the effective date of this directive - Prior to reaching 8,000 landings or 51 months in service since new, whichever occurs first. |\n| --- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |\n\n|             | For Requirement 6 - Within 30 days after the effective date of this AD.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |\n| ----------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n|             | This Amendment becomes effective on 9 March 2009.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              |\n| Background: | The original issue of this AD was in response to two reported cases of main landing gear collapse. Main landing gear collapse may result in an unsafe landing of the aircraft.Amendment 1 changed the compliance time by introducing calendar periods and repetitive inspections until such time that a terminating action becomes available.Amendment 2 amends the detailed visual inspection requirement and adds a requirement to mandate the incorporation of main landing gear actuator part number 46550-13 and adds additional maintenance requirements.The original issue of this AD became effective on 14 September 2007.Amendment 1 of this AD became effective on 2 November 2007. |\n\n![](image.001.png)  \nJames Coyne  \nDelegate of the Civil Aviation Safety Authority\n\n19 February 2009","sortOrder":0},{"sectionNumber":"AD/DHC-8/133 Amdt 2","sectionType":"part","heading":"AD/DHC-8/133 Amdt 2","content":"## AD/DHC-8/133 Amdt 2","sortOrder":1},{"sectionNumber":"Main Landing Gear System","sectionType":"part","heading":"Main Landing Gear System","content":"## Main Landing Gear System","sortOrder":2},{"sectionNumber":"4/2009 DM","sectionType":"part","heading":"4/2009 DM","content":"## 4/2009 DM","sortOrder":3}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":7,"scope_assessment":{"changed":true,"description":"The original AD was a straightforward emergency directive requiring inspections after two landing gear collapses. Amendment 1 expanded it to include repetitive inspections with calendar-based deadlines. Amendment 2 (this version) significantly broadened the scope by: (1) mandating physical modification/replacement of parts (new actuator design), (2) adding permanent maintenance schedule changes, (3) introducing alternative compliance paths (different part numbers satisfying the same requirement), and (4) creating a complex system of terminating actions. What began as an urgent safety inspection has evolved into a comprehensive lifecycle management program for the landing gear system."},"complexity_factors":["Multiple overlapping applicability criteria based on aircraft model, serial number ranges, and specific part numbers (p/n 46550-7, -9, -11, -13, -15)","Six distinct requirements with different compliance deadlines and repetitive intervals (250 landings/1 month vs 2,000 landings/1 year)","Nested conditional logic: compliance deadlines vary based on accumulated landings (4,000/7,500/8,000 thresholds) AND service time in years (2/4/27/51 months) AND part number","Cross-references to external documents: Bombardier Maintenance Requirements Manual (PSM 1-84-7), Repair Drawing RD 8/4-32-059, Service Bulletin SB 84-32-55, Modsum 4-901603, All Operators Message No. 236","Two separate \"terminating actions\" that end different inspection requirements (Modsum 4-901603 ends Requirement 3; maintenance tasks 320100-211/212 end Requirement 2)","Exception within exception: Allowance for 500-landing deferral if earlier inspection was done without borescope/10X magnification","Amendment structure requires reading across three versions (original, Amendment 1, Amendment 2) to understand full compliance history","Ferry flight provisions with 6 flight crew limitations and 4 maintenance procedures"],"plain_english_summary":"CASA requires operators of specific Bombardier DHC‑8‑400 (Q400) aircraft to inspect and, if needed, repair the main landing‑gear system after two gear‑collapse incidents. The AD mandates visual and detailed checks (including the retract actuator jam nut), reporting to Bombardier, updates to maintenance schedules, and eventual replacement with improved actuators.\n\nCompliance intervals vary by landings and part age, and ferry flights to a repair facility are allowed with the gear secured under prescribed precautions."},"flash_summary":{"complexity_score":7,"scope_assessment":{"changed":true,"description":"Amendment 2 expands the original AD by revising the detailed visual-inspection requirement, mandating incorporation of a redesigned retract actuator (Modsum 4-901603 / p/n 46550-13, or Modsum 4-901610 / p/n 46550-15) as terminating action, and adding maintenance tasks 320100-211 and 320100-212 to the approved schedule. It also adds reporting, ferry-flight limits and inspection-deferral detail. See Background and Requirements 3, 5 and 6 (and related Notes)."},"complexity_factors":["Multiple, distinct mandatory actions: general visual inspections, detailed inspections, reporting, modification, and maintenance-schedule changes (Requirements 1–6).","Varied compliance timing tied to part numbers, accumulated landings, and calendar age with multiple bands and different deadlines (Compliance section for Requirements 1–5).","Terminating actions depend on incorporation of Modsum 4-901603 or 4-901610 (p/n 46550-13 or 46550-15) and reference specific Bombardier SB revisions (Requirement 5; Notes 1–2).","Inspections and corrective actions must follow external Bombardier documents (RD 8/4-32-059, SB 84-32-55, TR MRB–35) and only later approved revisions are acceptable (Requirements 1–3, 5–6).","Deferral allowance and inspection technique specificity: one-time deferral up to 500 landings if earlier inspection lacked borescope/10X mirror; detailed borescope/magnification required thereafter (deferral paragraph).","Ferry-flight procedures impose operational constraints (gear pinned, minimal braking, crew limits, no flight in icing) and maintenance checks before ferrying (Ferry Flight section).","Serial-number specific applicability and overlapping ranges increase tracking and recordkeeping burdens for operators (Applicability).","Mandatory reporting to Bombardier Technical Help Desk within 7 days after inspections creates a recurring administrative requirement (Requirement 4; Compliance).","Interplay with earlier amendments and Transport Canada/CASA approvals creates layered regulatory references and potential interpretation issues (Background; Note 3)."],"plain_english_summary":"This Airworthiness Directive requires operators of Bombardier DHC‑8 Models 400–402 (specified serial numbers) to inspect the main landing gear and retract actuator, report any defects, update maintenance schedules, and install a redesigned retract actuator (p/n 46550‑13 or 46550‑15) as a terminating action for some inspections. It prescribes specific compliance times, repetitive inspection intervals, ferry‑flight limits and maintenance tasks. Operators pay for inspections, repairs and modifications; work must follow Bombardier and Transport Canada/CASA approved documents."},"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"}},"importantCases":[],"_links":{"self":"/api/acts/ad-dhc-8-133-amdt-2-main-landing-gear-system","history":"/api/acts/ad-dhc-8-133-amdt-2-main-landing-gear-system/history","analysis":"/api/acts/ad-dhc-8-133-amdt-2-main-landing-gear-system/analysis","conflicts":"/api/acts/ad-dhc-8-133-amdt-2-main-landing-gear-system/conflicts","importantCases":"/api/acts/ad-dhc-8-133-amdt-2-main-landing-gear-system/important-cases","documents":"/api/acts/ad-dhc-8-133-amdt-2-main-landing-gear-system/documents"}}