{"id":"F2007L03989","name":"AD/B717/25 - Power Conversion Distribution Unit","slug":"ad-b717-25-power-conversion-distribution-unit","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":160778,"registerId":"commonwealth-F2007L03989-current","compilationNumber":null,"startDate":"2026-04-04","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Boeing 717 Series Aeroplanes","sectionType":"division","heading":"Boeing 717 Series Aeroplanes","content":"### Boeing 717 Series Aeroplanes\n\n| AD/B717/25 | Power Coversion Distribution Unit | 11/2007 |\n| ---------- | --------------------------------- | ------- |\n\n| Applicability: | Model 717-200 aeroplanes. |\n| -------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement: | 1. Inspect the power conversion distribution units (PCDU) to determine its part number. A review of aeroplane maintenance records is acceptable in lieu of this inspection if the part number can be conclusively determined from that review. If the PCDU part number is 762904E or higher, no further work is required by this Directive. |\n| | 2. If, as a result of the Requirement 1 inspection, it is determined that the PCDU part number is below 762904E, carry out the following: |\n| | a. Modify the PCDU in accordance with Boeing Alert Service Bulletin (ASB) 717-24A0028, Revision 1, dated 20 December 2005. |\n| | Note 1: A modification accomplished before the effective date of this Directive in accordance with Boeing ASB 717-24A0028, dated 24 November 2004, is acceptable for compliance with Requirement 2.a. |\n| | Note 2: Boeing ASB 717-24A0028 refers to Hamilton Sundstrand Service Bulletin 40EGS22P-24-10, Revision 1, dated 11 May 2005, as an additional source of service information for the modification. |\n| | b. Accomplish the applicable actions specified in Table 1. |\n\n```html\n

Table 1

Do the following:

In accordance with Hamilton Sundstrand Service Bulletin (SB):

Rework the transformer rectifier unit assembly (TRU)

Rework the W3 wiring harness assembly to install direct lead wires to the TRU

Add a ground wire to the TRU transformer

Add an insulated spacer to the PCDU top cover

40EGS22P-24-3, dated 30 June 2000

Install new PCDU 186 firmware

40EGS22P-24-4, Revision 1, dated 2 January 2002

Install new PCDU 186 firmware

40EGS22P-24-6, dated 25 July 2002

Modify the top cover of the PCDU

40EGS22P-24-7, dated 3 September 2003

Modify printed wiring board (PWB) assemblies A4 and A5

Check and apply torque seal to fasteners on the TRU assembly and to PCDU internal fasteners, as applicable

40EGS22P-24-8, dated 4 September 2003

Modify PWB assembly A4

40EGS22P-24-9, dated 19 November 2003

Later revisions of the above SBs, approved by the United States Federal Aviation Administration (FAA) as an Alternate Method of Compliance (AMOC) to FAA AD 2007-19-03 are considered acceptable for compliance with the equivalent Requirements of this Directive.

Note 3: FAA AD 2007-19-03 Amdt 39-15193 refers.

Compliance:

For Requirements 1 and 2.a. - Within 20 months after the effective date of this Directive.

For Requirement 2.b. - Before or concurrently with the Requirement 2.a. modification.

\n```\n\n| | This Airworthiness Directive becomes effective on 25 October 2007. |\n| ----------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Background: | The United States Federal Aviation Administration (FAA) has advised that they have received reports of failed PCDUs, the loss of an electrical bus, together with the presence of a strong electrical burning odour in the flight deck and forward cabin. |\n| | This Directive requires the inspection of the PCDU to determine its part number and, if necessary, the modification of certain PCDUs. The Directive is issued to prevent the loss of an electrical bus due to PCDU failure which could result in the loss of all flight displays for an unacceptable time period together with a consequent emergency landing. |\n\n![](image.001.png) \nCharles Lenarcic \nDelegate of the Civil Aviation Safety Authority\n\n14 September 2007","sortOrder":0},{"sectionNumber":"AD/B717/25","sectionType":"part","heading":"AD/B717/25","content":"## AD/B717/25","sortOrder":1},{"sectionNumber":"Power Coversion Distribution Unit","sectionType":"part","heading":"Power Coversion Distribution Unit","content":"## Power Coversion Distribution Unit","sortOrder":2},{"sectionNumber":"11/2007","sectionType":"part","heading":"11/2007","content":"## 11/2007","sortOrder":3}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":4,"scope_assessment":{"changed":false,"description":"This is a standard Airworthiness Directive with a focused, single-purpose scope: addressing a specific known defect in a specific aircraft component. The structure follows the typical AD format (applicability, requirement, compliance, background) without scope creep. The reference to multiple service bulletins is necessary technical detail rather than expansion beyond original intent."},"complexity_factors":["Multiple conditional pathways: inspection outcome determines whether further action is required","Cross-references to 9 separate service bulletins (Boeing ASB 717-24A0028 and 8 Hamilton Sundstrand SBs)","Nested compliance structure: Requirement 1 → Requirement 2.a → Requirement 2.b with Table 1 actions","Alternative compliance methods allowed (maintenance records acceptable instead of physical inspection; earlier revision of Boeing ASB acceptable)","External regulatory references (FAA AD 2007-19-03 and AMOC provisions)","Specific part number threshold (762904E) as the critical decision point","Dual compliance timelines (20 months for main requirements, concurrent for secondary requirements)"],"plain_english_summary":"This CASA Airworthiness Directive requires operators of Boeing 717-200s to inspect the Power Conversion Distribution Unit (PCDU) part number and, if it’s lower than 762904E, perform mandated hardware and firmware modifications within 20 months. It addresses PCDU failures that can cause loss of electrical buses, prolonged blackout of flight displays, and burning smells — preventing forced/emergency landings and serious safety risks."},"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":false,"description":"The Directive’s scope is to inspect and, if necessary, modify PCDUs on Model 717-200 aeroplanes with part numbers below 762904E to prevent electrical bus loss. The text confines applicability to that model and to identified PCDU part numbers, prescribes specific service-bulletin methods, and sets compliance deadlines; it does not indicate an expansion or narrowing of that stated safety scope compared with the Directive’s expressed purpose."},"complexity_factors":["Part-number threshold rule: action depends on determining whether the PCDU part number is below 762904E (Requirement 1 & 2).","Multiple cross-referenced service bulletins for different discrete actions (Boeing ASB 717-24A0028 and several Hamilton Sundstrand SBs) and acceptable earlier revision notes (Requirement 2.a; Table 1; Notes 1–2).","Mixed hardware and software works: TRU rework, wiring harness changes, add ground/insulated spacer, PWB modifications, and firmware upgrade (Table 1).","Sequencing constraint: Table 1 actions (Requirement 2.b) must be done before or concurrently with the main modification (Requirement 2.a).","Compliance timing: explicit deadline (within 20 months for Requirements 1 and 2.a) and different timing for 2.b (Compliance).","Alternative methods approval: later SB revisions approved by FAA as AMOC are acceptable, creating conditional compliance routes (Table 1, Note 3).","Practical compliance burden: requirement allows records review instead of physical inspection only if part number can be conclusively determined (Requirement 1), shifting evidence and audit risk to operators.","Technical execution requires qualified maintenance/avionics facilities able to implement both firmware and physical rework (Table 1)."],"plain_english_summary":"This Directive tells operators of Boeing 717-200 aeroplanes to check the Power Conversion Distribution Unit (PCDU) part number and, if it is older than 762904E, to modify the PCDU using specified Boeing/Hamilton Sundstrand service bulletins (hardware and firmware changes). It affects aircraft operators and maintenance organisations because non‑compliant PCDUs must be reworked within the stated compliance period to reduce the risk of electrical bus loss and loss of flight displays."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b717-25-power-conversion-distribution-unit","history":"/api/acts/ad-b717-25-power-conversion-distribution-unit/history","analysis":"/api/acts/ad-b717-25-power-conversion-distribution-unit/analysis","conflicts":"/api/acts/ad-b717-25-power-conversion-distribution-unit/conflicts","importantCases":"/api/acts/ad-b717-25-power-conversion-distribution-unit/important-cases","documents":"/api/acts/ad-b717-25-power-conversion-distribution-unit/documents"}}