{"id":"F2006L01091","name":"AD/CONVAIR/14 - Main Landing Gear Beam Webs","slug":"ad-convair-14-main-landing-gear-beam-webs","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":58431,"registerId":"commonwealth-F2006L01091-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Kelowna Flightcraft (General Dynamics/Co","sectionType":"division","heading":"Kelowna Flightcraft (General Dynamics/Convair) Series Aeroplanes","content":"### Kelowna Flightcraft (General Dynamics/Convair) Series Aeroplanes\n\n| AD/CONVAIR/14 | Main Landing Gear Beam Webs | 5/2006 |\n| ------------- | --------------------------- | ------ |\n\n| Applicability: | Model 340 and 440 aircraft, and all such model aircraft converted to turbopropeller power.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            |\n| -------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | 1. Inspect main landing gear (MLG) beam webs part number (P/N) 340-1650551-7, -8, -53, and -54 for crack indications in the upper flange radius area by dye penetrant inspection procedures, in accordance with General Dynamics 640 (340D) Service Bulletin No. 57-3, dated 17 April 1970.2. If no cracks are detected, repeat the Requirement 1 inspection.3. If cracks are detected during any Requirement 1 inspection, accomplish one of the following:a. If MLG beam web cracking exceeds 7-inches total length and/or extends more than 2-inches forward or aft of the P/N 340-8510109 MLG trunnion fitting, replace the beam web before further flight.b. If MLG beam web cracking is less than 2.75-inches long and orientated in a wing chordwise direction along the web flange bend radius, either:(i) Stop-drill the crack in accordance with Section 2.(B)(3) of SB No. 57-3, and reinspect for further crack propagation at intervals not to exceed 50 hours time in service until the beam is reinforced in accordance with Requirement 4 or replaced in accordance with Requirement 3.a.; or,(ii) Replace the beam web.4. If cracks are between 2.75-inches and 7-inches in length and do not extend more than 2-inches forward or aft of the P/N 340-8510109 MLG trunnion fitting, either replace the beam web or stop-drill and reinforce the beam web in accordance with Section 2.(B)(4) of SB No. 57-3. If the beam web is stop-drilled and reinforced, it must be reinspected for further crack propagation, until the beam web is replaced.Cracks propagating beyond a stop-drill hole may be stop-drilled again providing the crack length remains within the above stated limits.Note: FAA AD 70-12-01 Amdt 39-1000 refers. |\n\n| Compliance: | 1. Unless the initial inspection is already accomplished, within 50 hours time in service after 11 May 2006 unless accomplished within the last 450 hours time in service.2. At intervals not to exceed 500 hours time in service.3. Before further flight.3.b. (i) Reinspect at intervals not to exceed 50 hours time in service, until reinforcement or replacement.4. Reinspect at intervals not to exceed 500 hours time in service, until beam web is replaced. |\n| ----------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n|             | This Airworthiness Directive becomes effective on 11 May 2006.                                                                                                                                                                                                                                                                                                                                                                                                       |\n| Background: | The FAA requires inspection for cracks, and if necessary, replacement of the main landing gear beam webs.                                                                                                                                                                                                                                                                                                                                                            |\n\n![](image.001.png)  \nDavid Villiers  \nDelegate of the Civil Aviation Safety Authority\n\n29 March 2006","sortOrder":0},{"sectionNumber":"AD/CONVAIR/14","sectionType":"part","heading":"AD/CONVAIR/14","content":"## AD/CONVAIR/14","sortOrder":1},{"sectionNumber":"Main Landing Gear Beam Webs","sectionType":"part","heading":"Main Landing Gear Beam Webs","content":"## Main Landing Gear Beam Webs","sortOrder":2},{"sectionNumber":"5/2006","sectionType":"part","heading":"5/2006","content":"## 5/2006","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"},"kimi_summary":{"content_quality":"ok","complexity_score":4,"scope_assessment":{"changed":false,"description":"This is a standard Airworthiness Directive with focused scope — it addresses a specific structural defect in specific aircraft models. The scope remains tightly constrained to the identified safety issue without expansion into broader operational or maintenance requirements."},"complexity_factors":["Multiple conditional pathways based on crack measurements (3 distinct size categories with different actions)","Cross-reference to external technical document (General Dynamics Service Bulletin No. 57-3) for inspection procedures","Nested sub-requirements (3.b.(i) with its own reinspection interval)","Specific part numbers referenced (P/N 340-1650551-7, -8, -53, -54 and P/N 340-8510109)","Multiple compliance timeframes (50 hours, 450 hours, 500 hours, 'before further flight')","Technical aviation terminology requiring domain knowledge (dye penetrant inspection, stop-drilling, trunnion fitting, wing chordwise direction)"],"plain_english_summary":"This AD mandates inspections of main landing gear beam webs on certain Convair 340/440 (including turboprop conversions) to detect cracks in the upper flange radius. Operators must do an initial inspection soon after the effective date and repeat periodically; corrective actions depend on crack severity, ranging from stop‑drilling and increased inspections to immediate replacement and grounding. It’s intended to prevent catastrophic landing‑gear failure and aligns with an FAA directive."},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"This AD confines itself to inspection and repair/replacement requirements for specific main landing gear beam webs on Convair Model 340/440 aircraft. The Background notes it follows the FAA requirement; the AD does not expand the subject matter beyond detection and remediation of cracks in the specified beam webs. It therefore appears consistent with the original safety‑focused intent and does not broaden the regulatory scope to unrelated systems or additional aircraft types."},"complexity_factors":["Four specific part numbers (MLG beam webs) identified: P/N 340-1650551-7, -8, -53, -54","Multiple conditional branches based on crack length and location: <2.75 inches, 2.75–7 inches, >7 inches, and forward/aft extension more than 2 inches of trunnion fitting","Orientation requirement for one branch (wing chordwise along web flange bend radius)","Several distinct required actions: dye‑penetrant inspection, stop‑drilling, reinforcement per Service Bulletin, replacement","Multiple inspection intervals with exceptions: initial 50 hours (unless done within last 450 hours), recurring 500 hours, 50‑hour reinspection after stop‑drilling","Allowance to stop‑drill again if propagation stays within limits (nested exception)","Cross‑references to an external Service Bulletin (General Dynamics SB No. 57‑3) and to FAA AD 70‑12‑01, adding external procedural and historical dependencies","Requirement to act 'before further flight' in some cases (immediate operational effect)"],"plain_english_summary":"**What this instrument does (mechanics)\n\n- Requires operators of Convair Model 340 and 440 aeroplanes (including those converted to turboprops) to inspect specific main landing gear (MLG) beam webs (part numbers 340-1650551-7, -8, -53 and -54) for cracks using dye‑penetrant inspection techniques in accordance with General Dynamics Service Bulletin No. 57‑3 (17 April 1970).  \n\n- Sets different mandatory responses depending on the size, orientation and location of any crack found:  \n  - Cracks > 7 inches in total length or extending more than 2 inches forward or aft of the MLG trunnion fitting (P/N 340‑8510109): replace the beam web before further flight (Requirement 3.a).  \n  - Cracks < 2.75 inches and oriented chordwise along the flange bend radius: either stop‑drill and reinspect at short intervals (≤ 50 hours time in service) until the beam is reinforced or replaced, or replace the beam web (Requirement 3.b.(i) and (ii)).  \n  - Cracks between 2.75 and 7 inches that do not extend more than 2 inches forward/aft of the trunnion fitting: either replace the beam web or stop‑drill and reinforce the beam per the service bulletin, with continuing inspections until replacement (Requirement 4).  \n  - If a crack that has been stop‑drilled grows beyond the stop‑drill hole but remains within the stated length/location limits it may be stop‑drilled again; otherwise the replacement requirement applies.  \n\n- Specifies inspection timing: initial inspection within 50 hours time in service after 11 May 2006 unless the inspection was already done within the last 450 hours; recurring inspections at intervals not to exceed 500 hours, except where stop‑drilling requires 50‑hour reinspections (Compliance section).  \n\n**Who this affects\n\n- Aircraft owners/operators of Convair Model 340 and 440 types (including turboprop conversions).  \n- Maintenance organisations and technicians who will carry out dye‑penetrant inspections, stop‑drilling, reinforcements and beam replacements.  \n- Parts suppliers who provide the specified beam webs or reinforcement kits.  \n\n**Why it matters (stated purpose and practical test)\n\n- Stated purpose: to detect and remediate cracks in the MLG beam webs to maintain airworthiness (the Background notes this follows a corresponding FAA requirement).  \n\n- Practical trade‑offs and implementation considerations:  \n  - Who pays: aircraft operators pay for inspections, repetitive monitoring, stop‑drilling repairs, reinforcement work or beam replacements, plus associated aircraft downtime.  \n  - Who decides: certifying maintenance organisations/engineers must follow the Service Bulletin procedures; CASA delegates enforce compliance with the AD. Any deviations or alternative methods typically require regulatory approval.  \n  - Behaviour change: operators must add scheduled inspections to maintenance programmes, carry out shorter interval inspections where cracks are managed by stop‑drilling, and replace or reinforce parts when thresholds are reached.  \n  - Costs vs benefits: the measure imposes recurring inspection and possible replacement costs on a relatively small, identifiable fleet (concentrated cost). The stated benefit is reduced risk of MLG failure from undetected cracking.  \n  - Market effects: creates demand for specific spare parts and reinforcement kits and potentially benefits specialist MROs (maintenance, repair and overhaul providers) able to perform the work. If replacement parts are scarce (likely for older Convair types), that scarcity could raise costs or extend downtime.  \n  - Compliance and operational risk: inspection relies on dye‑penetrant methods and adherence to the older service bulletin; correct application and interpretation require trained technicians. Frequent 50‑hour reinspections (when stop‑drilling is used) increase operational and logistical burden.  \n\n**Cross‑references and enforcement mechanics\n\n- The AD cross‑references General Dynamics (Convair) Service Bulletin No. 57‑3 (17 April 1970) for the inspection and repair procedures and notes FAA AD 70‑12‑01. These cross‑references mean operators must follow the SB procedures or obtain an approved equivalent.  \n\n**Net effect in plain terms\n\nOperators of Convair 340/440 aircraft must inspect specified MLG beam webs on a regular schedule, take immediate action (replacement) for large/poorly located cracks, and may use stop‑drilling and reinforcement as temporary or permanent remedies depending on crack size and location. The rule shifts inspection and repair costs onto operators, imposes recurring maintenance commitments, and creates demand for specific parts and specialist maintenance services.**"}},"importantCases":[],"_links":{"self":"/api/acts/ad-convair-14-main-landing-gear-beam-webs","history":"/api/acts/ad-convair-14-main-landing-gear-beam-webs/history","analysis":"/api/acts/ad-convair-14-main-landing-gear-beam-webs/analysis","conflicts":"/api/acts/ad-convair-14-main-landing-gear-beam-webs/conflicts","importantCases":"/api/acts/ad-convair-14-main-landing-gear-beam-webs/important-cases","documents":"/api/acts/ad-convair-14-main-landing-gear-beam-webs/documents"}}