{"id":"F2006B10760","name":"AD/HU 369/96 Amdt 1 - Engine Control and Warning Systems","slug":"ad-hu-369-96-amdt-1-engine-control-and-warning-systems","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":56209,"registerId":"commonwealth-F2006B10760-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/HU 369/96 Amdt 1 - Engine Control and Warning Systems","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \nMcDonnell Douglas (Hughes) and Kawasaki 369 Series Helicopters\n\nAD/HU 369/96\n\nAmdt 1\n\n  \nEngine Control and Warning Systems 6/99\n\nDM\n\nApplicability: Model 369E (serial numbers (S/N) 384E and subsequent), Model 369FF (S/N 076FF and subsequent), Model 500N and Model 600N series helicopters.\n\nRequirement: 1. If not previously accomplished, carry out the following:\n\n    (a) Access relays K1, K2, K3, K5, K104, and K200 (relay part number (P/N) HS4240).\n\n    (b) Remove each relay specified in sub-paragraph (a) from its receptacle (P/N HS4256-1).\n\n    (c) Using a No. 60 drill bit or a 0.40 inch diameter wire as a gauge, attempt to insert the gauge into every contact socket of each relay receptacle, see Figure\n\n    (To prevent damage to the receptacle and contact socket, ensure the gauge is inserted perpendicular to the face of the receptacle.) If the gauge can be inserted into the contact socket, the socket must be replaced with a new socket P/N 019-0075-002.\n\n![](image.002.png)  \n\n    2. Inspect any replacement relay, P/N HS4240, in accordance with paragraph (c) of this Directive.\n\nNote 1: FAA Priority Letter AD 99-08-07 refers.\n\nCOMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\nNote 2: Boeing McDonnell Douglas Helicopter Systems (MDHS) Service Bulletin SB369E-090, SB369F-077, SB500N-017, SB600N-014 dated 6 July 1998 pertains to\n\nthis directive.\n\nCompliance: 1. Prior to 17 May 1999.\n\n2. Prior to fitting to an aircraft.\n\nThis Amendment becomes effective on 12 May 1999.\n\nBackground: The FAA has received a report of an incident involving a MDHS 600N helicopter where the engine control unit (ECU) fail light illuminated, even though the ECU continued to automatically control the engine. The helicopter manufacturer has also reported two additional similar incidents on other model 600N helicopters. The cause of the ECU malfunction indication was determined to be contact sockets of a relay receptacle that did not correctly fit the corresponding pins of a relay. This directive requires the inspection of the contact sockets of each affected relay receptacle to ensure that the sockets are the correct size.\n\nAmendment 1 revises the list of affected aircraft and adds an initial inspection of the relays.\n\nThe original issue of this Airworthiness Directive became effective on 21 August 1998.","sortOrder":0}],"analysis":{"flash_summary_failed":{"failed":true,"reason":"Unauthenticated. Configure AI_GATEWAY_API_KEY or use a provider module. Learn more: https://ai-sdk.dev/unauthenticated-ai-gateway","source":"analysis-cron"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is Amendment 1 to an existing Airworthiness Directive. The amendment slightly expands the list of affected aircraft and adds an initial inspection requirement, but remains tightly focused on the original safety issue (faulty relay sockets in engine control systems). The scope has not grown beyond the original safety purpose."},"complexity_factors":["Single discrete maintenance task with clear sequential steps","Only 6 specific relay part numbers to identify","One simple pass/fail test (gauge insertion)","Single replacement part number specified","No nested conditions or cross-references to other legislation sections","Limited applicability (4 specific helicopter models with serial number cutoffs)"],"plain_english_summary":"This FAA safety order requires owners/operators of certain McDonnell Douglas (Hughes) and Kawasaki helicopters (369E/369FF/500N/600N series) to inspect six engine‑control relay sockets for excessive clearance and replace any that accept the specified 0.40‑in gauge. Loose contacts have caused false engine‑control warnings and could mask or lead to control failures. The directive mandates testing each socket with the gauge and fitting approved replacement sockets when the gauge fits."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"Amendment 1 broadened and clarified the original directive’s scope by revising the list of affected aircraft (specific serial-number thresholds for Model 369E and 369FF are included and Model 500N/600N series are named) and by adding an initial inspection requirement for relays. Concretely, the amendment adds the explicit step to inspect replacement relays (paragraph 2) and updates applicability; therefore the directive moved from a single corrective-action requirement to include an upfront inspection of replacement parts, increasing the number of in-practice checks operators must perform before fitting parts."},"complexity_factors":["Short, focused directive limited to a small set of parts and relays (six relays listed).","Few defined technical elements (three part numbers: HS4240 relay, HS4256-1 receptacle, 019-0075-002 replacement socket).","Simple binary test (gauge insertion using No. 60 drill bit / 0.40 inch wire) with one replacement action if the test fails.","Two compliance conditions (in‑service aircraft by a date; replacement relays inspected prior to fitting).","Cross-references to an FAA Priority Letter AD and a manufacturer service bulletin (adds some external documents to consult).","A single implementation precaution (insert gauge perpendicular to avoid damage)."],"plain_english_summary":"**What this directive does (mechanical effect)\n\n- It requires operators and maintenance organisations to inspect specific relays and their receptacles on certain McDonnell Douglas (Hughes) and Kawasaki 369/500N/600N helicopters.  The inspection uses a No. 60 drill bit or a 0.40 inch diameter wire as a gauge to check each contact socket in the relay receptacle.  If the gauge can be inserted into a socket the socket must be replaced with a specified new socket (P/N 019-0075-002).\n- The directive names six relays to be checked (K1, K2, K3, K5, K104 and K200), the relay part number to be removed and inspected (P/N HS4240) and the receptacle part number (P/N HS4256-1).\n- Any replacement relays (P/N HS4240) must also be inspected the same way before being fitted to an aircraft.\n\n**Who this affects\n\n- Owners/operators and maintenance organisations responsible for Model 369E (S/N 384E and subsequent), Model 369FF (S/N 076FF and subsequent), Model 500N and Model 600N helicopters.\n- Maintenance technicians who will perform the physical inspection and any socket replacements.\n\n**Why it matters (stated reason and how the rule addresses it)\n\n- The stated reason: there were incidents in which the engine control unit (ECU) \"fail\" warning light illuminated even though the ECU continued to control the engine. The manufacturer traced the false warning to relay contact sockets that did not properly fit relay pins, producing an incorrect ECU-fail indication.\n- How the directive addresses it: by ensuring contact sockets are the correct size so relays make reliable contact and do not produce spurious ECU-fail warnings.\n\n**Key compliance facts (how it works in practice)\n\n- Action: remove each listed relay from its receptacle, then try to insert the gauge into every contact socket of the receptacle perpendicular to the face. Replace any socket that admits the gauge.\n- Parts cited: relay P/N HS4240, receptacle P/N HS4256-1, replacement socket P/N 019-0075-002.\n- Timing: the inspection must be done by the stated compliance date in the directive for in-service aircraft; replacement relays must be inspected before they are fitted to aircraft.\n- Cross-references: the directive notes an FAA Priority AD and a manufacturer service bulletin that provide related instructions.\n\n**Costs, incentives and practical trade-offs\n\n- Who pays: aircraft owners/operators pay for labour, technician time, and any replacement sockets or relays required.\n- Time and downtime: the inspection is a short mechanical check (gauge insertion) per receptacle, but aircraft may be grounded until work is completed; replacement of sockets or relays increases maintenance time.\n- Parts and supply risk: mandatory replacement uses a specific socket part number; delayed availability would lengthen downtime or force sourcing actions.\n- Risk of improper inspection: the directive warns to insert the gauge perpendicular to avoid damaging the receptacle; incorrect technique could damage parts and increase costs.\n- Enforcement and decision-making: the Civil Aviation Safety Authority issues the directive (makes it mandatory); maintenance personnel decide pass/fail and carry out replacements in accordance with the directive and the manufacturer service bulletin.\n\n**Implementation risk and compliance burden\n\n- Low technical complexity of the test (gauge insertion) but requires careful handling to avoid damaging receptacles.\n- Potential for repeat inspection of replacement relays if replacements are not checked before installation (the directive requires inspecting replacements).\n- The measure is narrowly targeted (specific relays and part numbers), so compliance burden is concentrated on the affected fleet rather than diffuse across many types.\n\n**Relation of the stated purpose to costs and incentives (analytical note)\n\n- The directive's intervention is narrowly tailored to reduce false engine-control warnings caused by misfitting relay sockets (stated benefit). The direct cost is the maintenance time and parts paid by operators. Because the problem produces a warning light rather than loss of engine control, the directive trades modest inspection and replacement costs against reduced false warnings and the operational consequences of responding to them. The manufacturer’s service bulletin and the FAA AD reduce information costs for operators by providing matching technical instructions.\n\n(References in the directive: Requirement paragraphs 1(a)–(c) and 2; Compliance dates; Applicability; Background; Notes referring to FAA AD and MDHS service bulletin.)"}},"importantCases":[],"_links":{"self":"/api/acts/ad-hu-369-96-amdt-1-engine-control-and-warning-systems","history":"/api/acts/ad-hu-369-96-amdt-1-engine-control-and-warning-systems/history","analysis":"/api/acts/ad-hu-369-96-amdt-1-engine-control-and-warning-systems/analysis","conflicts":"/api/acts/ad-hu-369-96-amdt-1-engine-control-and-warning-systems/conflicts","importantCases":"/api/acts/ad-hu-369-96-amdt-1-engine-control-and-warning-systems/important-cases","documents":"/api/acts/ad-hu-369-96-amdt-1-engine-control-and-warning-systems/documents"}}