{"id":"F2006B06753","name":"AD/SAAB/3 Amdt 1 - Main Spar Carry Through (U Profile) Corrosion","slug":"ad-saab-3-amdt-1-main-spar-carry-through-u-profile-corrosion","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":114580,"registerId":"commonwealth-F2006B06753-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/SAAB/3 Amdt 1 - Main Spar Carry Through (U Profile) Corrosion","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)  \nSAAB Safir Series Aeroplanes\n\nAD/SAAB/3\n\nAmdt 1\n\n  \nMain Spar Carry Through (U Profile) Corrosion 12/96\n\nApplicability: Safir models 91A, 91B, 91B2, 91C and 91D.\n\nRequirement: Action in accordance with SAAB 91 Safir SB 91.1.006 Rev1.\n\nNote: Swedish AD No. 1-100 refers.\n\nCompliance: At the next inspection due in accordance with the previous issue of this Directive or before 30 March 1997, whichever occurs first; thereafter at intervals not exceeding 12 months.\n\nThis amendment is effective from 7 November 1996.\n\nBackground: Corrosion damage has been reported in the lower U-profile of the fuselage main spar.\n\nThe U-profile is a highly loaded member and corrosion damage will degrade the structural capability.\n\nAmendment 1 revises the Requirement Document and re-references the Swedish AD. The initial issue of this Directive had effect from 10 November 1994.","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"Amendment 1 updates the referenced requirement document (service bulletin) and re-references the Swedish AD but does not alter the directive’s stated applicability (the same Safir models) or the compliance timing framework (initial deadline and subsequent 12‑month interval). The mechanical obligations—inspect per the SAAB service bulletin and repeat no more than every 12 months—remain present in this amendment. (Applicability; Requirement; Compliance; Amendment 1)"},"complexity_factors":["Requires following an external manufacturer document (SAAB 91 Safir SB 91.1.006 Rev1) rather than detailing inspection/repair steps in the directive itself (Requirement)","Specifies a one-off deadline (next inspection or before 30 March 1997) plus recurring maximum interval (annual), creating two timing rules to track (Compliance)","Applies to multiple aircraft models (91A, 91B, 91B2, 91C, 91D), requiring operators to confirm applicability to individual airframes (Applicability)","Amendment revises the requirement document and re-references an overseas AD, so operators must ensure they consult the correct, updated documents (Amendment 1; Note)","Technical judgement required to assess corrosion severity and decide appropriate corrective action under the service bulletin, creating operational discretion at the maintenance level (Background; Requirement)"],"plain_english_summary":"What this directive does mechanically\n\n- Requires owners/operators of certain SAAB Safir aeroplanes (models 91A, 91B, 91B2, 91C and 91D) to carry out inspections and any resulting work specified in the manufacturer service bulletin SAAB 91 Safir SB 91.1.006 Rev1 (Requirement). (Applicability; Requirement)\n- Sets the timing: the inspection must be done at the next inspection due under the previous version of this directive or before 30 March 1997, whichever is earlier; after that, inspections must be repeated at intervals not exceeding 12 months. (Compliance)\n- Records the directive became effective on 7 November 1996 and that Amendment 1 updates the reference document and the cross-reference to the Swedish airworthiness directive. (effective date; Amendment 1)\n\nWhy the rule exists (stated rationale)\n\n- The directive is prompted by reported corrosion in the lower U-profile of the fuselage main spar, a heavily loaded structural member; the stated safety concern is that corrosion will reduce structural capability. (Background)\n\nWho pays, who decides, and what changes in behaviour\n\n- Who pays: aircraft owners/operators pay for the inspection work and for any repairs or part replacements that the service bulletin requires. Maintenance organisations contracted by owners will incur labour/material costs to carry out the work. (Requirement; Compliance)\n- Who decides: the Civil Aviation Safety Authority issued the directive; the technical content of required actions is specified by SAAB in the referenced service bulletin (SAAB 91 Safir SB 91.1.006 Rev1). Operators must follow the service bulletin as the means of compliance. (Requirement; Amendment 1)\n- Behaviour change required: affected operators must schedule and perform the inspection within the stated deadline, then ensure recurring inspections no more than 12 months apart; they must follow the service bulletin’s procedures for inspection and any corrective action. (Compliance; Requirement)\n\nPractical costs, incentives, trade-offs and implementation points to note\n\n- Direct costs: inspections and any corrective work (cleaning, corrosion treatment, part repair/replacement) are borne by owners/operators on a recurring (annual) basis. The directive does not itself state repair costs or grounding time; those depend on inspection findings and the service bulletin’s remedies. (Requirement; Compliance)\n- Incentives and opportunity cost: owners must allocate maintenance time and budget to meet the directive’s schedule; that time cannot be used for other flying or maintenance needs. More frequent inspections raise ongoing operating costs but reduce the risk of undetected structural degradation. (Compliance; Background)\n- Effect on private businesses: independent maintenance organisations and parts suppliers are the likely service providers for the inspections/repairs, so the directive increases demand for their services among the affected fleet. It constrains no specific choice of provider beyond requiring compliance with the service bulletin. (Requirement)\n- Compliance burden and discretion: the directive prescribes the inspection interval and requires adherence to a specified SAAB service bulletin, limiting operator discretion about what constitutes compliance. Inspectors and maintenance personnel retain technical judgement in assessing corrosion severity and deciding what corrective work the service bulletin requires. (Requirement; Compliance)\n- Implementation risk and operational impact: detecting corrosion may trigger repair actions that take aircraft out of service; the text does not specify mandatory grounding thresholds, so implementation will follow the service bulletin and maintenance judgement. The directive updates the reference documents (Amendment 1), so operators must ensure they use the revised service bulletin version cited. (Background; Amendment 1)\n\nCross-references and administrative detail\n\n- The directive refers to Swedish AD No. 1-100 as a related document and states that Amendment 1 revises the requirement document and re-references that Swedish AD. Operators should consult the referenced service bulletin and may review the Swedish AD for related detail. (Note; Amendment 1)\n\nSource citations: Applicability; Requirement; Compliance; Background; Amendment 1; Note."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This amendment maintains the original scope — corrosion inspection of the main spar U-profile on SAAB Safir aircraft. The amendment merely updates technical references (revised Service Bulletin and Swedish AD citation) without expanding the aircraft models affected, the nature of the inspection, or the structural components covered."},"complexity_factors":["Single, specific applicability (5 aircraft models)","Single requirement referencing one external technical document (Service Bulletin)","Simple compliance timeline with clear deadline and recurring interval","No defined terms section","No nested exceptions or conditional logic","Minimal cross-referencing (only to Swedish AD and previous issue)"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA). It applies to specific models of **SAAB Safir aeroplanes** (models 91A, 91B, 91B2, 91C, and 91D).\n\n**What it does:**\n- Requires owners/operators to inspect the **main spar carry-through** — a critical structural component that runs through the fuselage and carries wing loads — for **corrosion damage** in a specific U-shaped section (the \"U-profile\").\n- Mandates compliance with a specific **Service Bulletin** (SB 91.1.006 Rev1) issued by the manufacturer, SAAB.\n\n**Why it matters:**\n- Corrosion in this highly stressed structural member can **weaken the airframe** and potentially lead to structural failure. This is a **safety-critical issue**.\n\n**When action is required:**\n- **First inspection:** By the earlier of either the next scheduled inspection under the previous version of this directive, or **30 March 1997**.\n- **Ongoing:** Repeat inspections at least **every 12 months** thereafter.\n\n**What changed in this amendment:**\n- Updates the reference document to a revised Service Bulletin and updates the reference to the corresponding Swedish aviation safety directive."}},"importantCases":[],"_links":{"self":"/api/acts/ad-saab-3-amdt-1-main-spar-carry-through-u-profile-corrosion","history":"/api/acts/ad-saab-3-amdt-1-main-spar-carry-through-u-profile-corrosion/history","analysis":"/api/acts/ad-saab-3-amdt-1-main-spar-carry-through-u-profile-corrosion/analysis","conflicts":"/api/acts/ad-saab-3-amdt-1-main-spar-carry-through-u-profile-corrosion/conflicts","importantCases":"/api/acts/ad-saab-3-amdt-1-main-spar-carry-through-u-profile-corrosion/important-cases","documents":"/api/acts/ad-saab-3-amdt-1-main-spar-carry-through-u-profile-corrosion/documents"}}