{"id":"F2007L04233","name":"AD/B717/26 - Versatile Integrated Avionics Digital Computer","slug":"ad-b717-26-versatile-integrated-avionics-digital-computer","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":70445,"registerId":"commonwealth-F2007L04233-current","compilationNumber":null,"startDate":"2026-04-02","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/B717/26 | Versatile Integrated Avionics Digital Computer | 12/2007 |\n| ---------- | ---------------------------------------------- | ------- |\n\n| Applicability: | Model 717-200 aeroplanes, as identified in Boeing Service Bulletin (SB)717-31-0013, dated 25 March 2005.                                                                                                                                                                                                                                                                                                                              |\n| -------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | 1. If not previously accomplished, upgrade the versatile integrated avionics (VIA) digital computer with new system software part number (P/N) PS4081970-909 and in-service data acquisition system (ISDAS) database software P/N PS4081642-909, in accordance with the Accomplishment Instructions of SB717-31-0013.                                                                                                                 |\n|                | Accomplishing this upgrade or the installation of VIA P/N 4081570-909 or subsequent terminates the requirements of AD/B717/15 for that aeroplane only.                                                                                                                                                                                                                                                                                |\n|                | Note 1: SB 717-31-0013 refers to Honeywell Alert SB 4081570-31-A6007, dated 9 March 2005, as an additional source of service information for doing the actions specified in Requirement 1 of this Directive.                                                                                                                                                                                                                          |\n|                | 2. VIA digital computer, P/N 4081570-904, -905, -906 or -907, may not be installed on any aeroplane as a replacement spare.                                                                                                                                                                                                                                                                                                           |\n|                | Later revisions of SB 717-31-0013, approved by the United States Federal Aviation Administration (FAA) as an Alternate Method of Compliance (AMOC) to FAA AD 2007-19-15, are considered acceptable for compliance with the equivalent Requirements of this Directive.                                                                                                                                                                 |\n|                | Note 2: FAA AD 2007-19-15 Amdt 39-15206 refers.                                                                                                                                                                                                                                                                                                                                                                                       |\n| Compliance:    | For Requirement 1 - Within 18 months after the effective date of this Directive.                                                                                                                                                                                                                                                                                                                                                      |\n|                | For Requirement 2 - As of the effective date of this Directive.                                                                                                                                                                                                                                                                                                                                                                       |\n|                | This Airworthiness Directive becomes effective on 22 November 2007.                                                                                                                                                                                                                                                                                                                                                                   |\n| Background:    | This Directive provides terminating action for AD/B717/15. AD/B717/15 currently requires a revision to the Limitations Section of the aircraft flight manual (AFM) to prohibit use of the flight management system (FMS) profile (PROF) mode for descent and/or approach operations unless certain conditions are met. AD/B717/15 will be cancelled in May 2009 when all affected aircraft will be in compliance with this Directive. |\n\n|     | This Directive requires upgrading the versatile integrated avionics (VIA) digital computer with new system software, which would end the need for the AFM revision. This Directive results from a report of two violations of the selected flight control panel (FCP) altitude during FMS PROF descents. The Directive is issued to prevent, under certain conditions during the FMS PROF descent, the un-commanded descent of an aeroplane below the selected level-off altitude, which could result in an unacceptable reduction in the separation between the aeroplane and nearby air traffic or terrain. |\n| --- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n\n![](image.001.png)  \nDavid Punshon  \nDelegate of the Civil Aviation Safety Authority\n\n2 October 2007","sortOrder":0},{"sectionNumber":"AD/B717/26","sectionType":"part","heading":"AD/B717/26","content":"## AD/B717/26","sortOrder":1},{"sectionNumber":"Versatile Integrated Avionics Digital Co","sectionType":"part","heading":"Versatile Integrated Avionics Digital Computer","content":"## Versatile Integrated Avionics Digital Computer","sortOrder":2},{"sectionNumber":"12/2007","sectionType":"part","heading":"12/2007","content":"## 12/2007","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":3,"scope_assessment":{"changed":false,"description":"This AD maintains its original narrow scope — addressing a specific software issue in the VIA digital computer on Boeing 717-200 aircraft. It does not expand beyond the original safety purpose of preventing uncommanded descents."},"complexity_factors":["Multiple cross-references to other documents (Boeing Service Bulletin 717-31-0013, Honeywell Alert SB, FAA AD 2007-19-15)","Specific part numbers (P/N) referenced throughout (PS4081970-909, PS4081642-909, 4081570-904 through -907)","Conditional logic: 'If not previously accomplished' and termination of previous AD requirements upon compliance","Dual compliance timelines (18 months for upgrade, immediate for installation ban)","Technical aviation terminology requiring domain knowledge (VIA, ISDAS, FMS PROF mode, AMOC)"],"plain_english_summary":"This AD mandates a software upgrade to the VIA digital computer on affected Boeing 717-200s, prohibits installing certain older VIA units, and rescinds the prior AD once the upgrade is done. It targets operators identified in Boeing’s service bulletin because reports showed automated descents could go below selected altitudes, creating collision/CFIT risk. Compliance required within 18 months of November 2007."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive remains focused on the original safety issue (preventing uncommanded descent during FMS PROF descents) and provides a technical fix that replaces the temporary operational limitation from the earlier AD (AD/B717/15). It adds a prohibition on installing certain older VIA spare part numbers and accepts FAA-approved SB revisions as an AMOC, but these are implementation details rather than a material expansion beyond the original safety-focused purpose."},"complexity_factors":["Single aircraft type applicability (Model 717-200) — limits scope","Two substantive requirements (software upgrade; prohibition on specific spare P/Ns)","One clear compliance timetable (18 months for upgrade; immediate for spare prohibition)","Cross-references to external documents: Boeing SB717-31-0013 and Honeywell Alert SB","Acceptance of FAA-approved later revisions as AMOC (external regulatory linkage)","Terminating action for a prior AD (AD/B717/15) — one conditional relationship","No extensive defined-terms section or layered exceptions"],"plain_english_summary":"**What this directive does (mechanically)**\n\n- Requires operators of certain Boeing 717-200 aircraft to upgrade the Versatile Integrated Avionics (VIA) digital computer with specified new system software (P/N PS4081970-909) and a specified in‑service data acquisition system (ISDAS) database software (P/N PS4081642-909), following the Boeing Service Bulletin SB717-31-0013 (Requirement 1). (Applicability; Requirement 1)\n- Prohibits the use of certain older VIA units (P/N 4081570-904, -905, -906 or -907) as replacement spares on any aircraft from the effective date. (Requirement 2)\n- Allows later revisions of the Boeing service bulletin that are accepted by the FAA as an Alternate Method of Compliance (AMOC) to be used instead of the exact bulletin referenced. (Requirement text)\n- Sets the compliance deadline for the software upgrade at within 18 months of the directive’s effective date; the spare‑parts prohibition is effective immediately. (Compliance)\n\n**Who is affected**\n\n- Airlines and operators that own or operate Boeing 717-200 aeroplanes identified in Boeing SB717-31-0013. (Applicability)\n- Maintenance organisations and engineers who perform avionics upgrades or manage spare inventories for those aeroplanes. (Requirement 1 & 2)\n- Parts suppliers and inventory managers who supply or stock VIA units for Boeing 717-200 fleets. (Requirement 2)\n\n**Why it matters (claimed purpose and mechanism)**\n\n- The directive’s stated purpose is to prevent possible uncommanded descent below the selected level‑off altitude during flight management system profile (FMS PROF) descents. The requirement is triggered by reports of two incidents where the selected flight control panel altitude was violated during FMS PROF descents. The software upgrade is intended to remove the need for the temporary flight manual limitation required by the earlier AD/B717/15. (Background; Requirement 1)\n\n**Who pays, who decides, and what behaviour changes**\n\n- Operators pay for the software upgrade, installation labour, and any associated aircraft downtime. The directive sets the standard; operators and approved maintenance organisations must carry out the upgrade within the 18‑month window. (Requirement 1; Compliance)\n- Maintenance providers decide how to schedule and perform the upgrade in accordance with the Boeing SB and any accepted FAA AMOC. (Requirement text)\n- Parts managers must stop installing the specified older VIA units as replacement spares from the effective date; they must either install the upgraded unit or ensure spares are not the prohibited P/Ns. (Requirement 2)\n\n**Trade-offs, costs and implementation risks**\n\n- Direct costs: purchase or software licensing costs of the VIA software and ISDAS database, labour for installation, and aircraft out‑of‑service time. (Requirement 1; Compliance)\n- Timing trade‑off: 18 months gives operators a finite compliance window to plan upgrades and minimise operational disruption, but it may concentrate work and parts demand. (Compliance)\n- Spare parts constraint: the immediate prohibition on certain P/Ns (Requirement 2) may force operators to use other spares or ground aircraft awaiting compliant parts, creating near‑term logistical costs for parts management.\n- Implementation risk: correct application of the Boeing Service Bulletin is required; the directive accepts FAA‑approved AMOCs, which provides some flexibility but places reliance on FAA acceptance processes. (Requirement text)\n\n**Effects on private enterprise and markets**\n\n- Maintenance and avionics providers have new work (upgrades) but face scheduling and resource constraints; parts suppliers who stock the prohibited P/Ns may see reduced demand for those items for affected aircraft. (Requirement 1 & 2)\n- The directive reduces operational freedom that was temporarily allowed under the previous AD (AFM limitation) by replacing that temporary operational restriction with a mandated hardware/software change. This shifts the compliance cost from operational restrictions (pilot procedures) to capital/maintenance action (software upgrade). (Background; Requirement 1)\n\n**Relation to prior regulatory action**\n\n- This AD is issued as terminating action for AD/B717/15 (which required an AFM revision limiting use of FMS PROF for descent/approach unless conditions were met). Once an individual aircraft has the upgrade installed (or VIA P/N 4081570‑909 or later), that aircraft no longer needs the AFM limitation required by AD/B717/15. (Requirement 1; Background)\n\n**Notes and cross‑references**\n\n- Boeing SB717-31-0013 cites Honeywell Alert SB 4081570-31-A6007 as additional guidance. (Note 1)\n- The directive references FAA AD 2007-19-15; later FAA‑approved revisions of the Boeing SB may serve as acceptable AMOCs. (Note 2; Requirement text)\n\n**Bottom line**\n\n- Operators of identified Boeing 717-200 aircraft must install specified VIA software and ISDAS database updates within 18 months, and they must not install certain older VIA units as spares from the effective date. The measure replaces an earlier operational restriction with a technical fix intended to prevent potential uncommanded descents during FMS PROF descents, shifting the cost to maintenance and parts management while allowing an FAA‑approved alternative compliance path. (Requirement 1 & 2; Background)"}},"importantCases":[],"_links":{"self":"/api/acts/ad-b717-26-versatile-integrated-avionics-digital-computer","history":"/api/acts/ad-b717-26-versatile-integrated-avionics-digital-computer/history","analysis":"/api/acts/ad-b717-26-versatile-integrated-avionics-digital-computer/analysis","conflicts":"/api/acts/ad-b717-26-versatile-integrated-avionics-digital-computer/conflicts","importantCases":"/api/acts/ad-b717-26-versatile-integrated-avionics-digital-computer/important-cases","documents":"/api/acts/ad-b717-26-versatile-integrated-avionics-digital-computer/documents"}}