{"id":"F2006B04237","name":"AD/BEECH 90/48 Amdt 2 - Wing Spar Fitting Fatigue - Inspection","slug":"ad-beech-90-48-amdt-2-wing-spar-fitting-fatigue-inspection","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":44001,"registerId":"commonwealth-F2006B04237-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/BEECH 90/48 Amdt 2 - Wing Spar Fitting Fatigue - Inspection","content":"![](image.001.png)  \n![](image.002.png)  \nBeechcraft 90 and 65-90 (King Air) Series Aeroplanes\n\nAIRWORTHINESS DIRECTIVE\n\n![](image.002.png)\n\n![](image.002.png)  \nFor the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/BEECH 90/48 Amdt 1 and issues the following AD under subregulation 39.1 (1) of CAR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.\n\nAD/BEECH 90/48\n\nAmdt 2\n\n  \nWing Spar Fitting Fatigue \\- Inspection 11/2000\n\nApplicability: All model 65-90, 65-A90, B90, C90, and E90 aircraft, except serial nos. LJ-1085, and LJ 1088 and subsequent. All model F90 aircraft except serial nos. LA-226 and subsequent.\n\nRequirement: 1. Remove the wing main spar lower attachment bolts in accordance with the manufacturer’s instructions. Strip all paint from the “bathtub” portion of the four outer wing to centre section main spar lower attachment fittings.\n\n    2. For all except F90: Perform a fluorescent liquid penetrant inspection of all four fittings in accordance with the Beechcraft Structural Inspection and Repair Manual (SIRM) P/N 98-39006B3 as revised May 28 1999, Chapter 57-13-01 Chart 201 Index Nos. 1 and 10, or 57-13-02 Chart 201 Index Nos. 1 and 5, as applicable to individual aeroplanes. When inspecting the “bathtub” portion of the fittings, pay particular attention to the bolt counterbore and fillet radius. As an alternative, this inspection may be performed using an eddy current (pencil probe) procedure as detailed in Chapter 20-00-00 of the SIRM in which case paint strip is not required.\n\n    3. For model F90 aircraft only: Perform a fluorescent liquid penetrant inspection of all four fittings in accordance with the Beechcraft Structural Inspection and Repair Manual (SIRM) P/N 98-39006B3 as revised May 28 1999, Chapter 57-14-01 Chart 201 Index No. 1. Pay particular attention to the bolt counterbore and fillet radius in the “bathtub” portion of the centre wing fitting, and the radius at the end of the barrel nut recess in the outer wing fitting. As an alternative, this inspection may be performed using the eddy current procedure specified in 4 below.\n\n    4. For model F90 aircraft only: Perform an eddy current inspection of all four fittings in accordance with the Beechcraft Structural Inspection and Repair Manual (SIRM) P/N 98-39006B3 as revised May 28 1999, Chapter 57-14-01 Chart 201 Index No. 2. Paint strip is not required for eddy current inspection.\n\nIn accordance with the SIRM, should a fatigue crack be found in the outer wing fitting, the complete outer wing main spar lower cap must be replaced before further flight. A crack in a centre section fitting requires replacement of the affected component only.\n\nCOMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\nNote 1: The SIRM Chapter 20-00-00 “Warning” regarding not removing paint for penetrant inspections should be disregarded. To prevent corrosion, some form of protective treatment, such as a standard zinc chromate primer, should be applied between inspections, to surfaces from which the paint has been removed.\n\nNote 2: Solvent removers should be used wherever possible. If the use of other paint strippers is unavoidable, the complete removal of residue must be ensured before inspection. In either case, the use of mechanical or abrasive means of paint removal must be avoided.\n\nNote 3: It is recommended that the penetrant be applied to the counterbore and recess radii using a fine artist’s paint brush. This will simplify penetrant removal and minimise false indications. Care should be taken to ensure full coverage of the fillet radius and a similar distance (at least 5 mm) into the cylindrical portion of the counterbore, in particular on the side of the hole adjacent to the “bottom of the bathtub”.\n\nNote 4: No attempt should be made to polish out suspect indications, as this has led in the past to the obscuring of large cracks. Where suspect indications need to be confirmed, seek specialist NDT advice.\n\nNote 5: Inspection of the bolts and nuts is detailed in the current issue of AD/BEECH 90/69.\n\nCompliance: For Models 65-90, 65-A90, B90, and C90 and E90 aircraft, Requirements 1 and 2: Prior to exceeding 3000 hours component time in service, and thereafter at intervals not exceeding 200 hours component time in service. Where the eddy current procedure is used, the recurring inspection interval may be doubled.\n\nFor Model F90 aircraft only:\n\nRequirement 3: At intervals not exceeding 5 calendar years.\n\nRequirement 4: Prior to exceeding 20 000 hours component time in service, and thereafter at intervals not exceeding 1200 hours component time in service.\n\nNote 6: Inspections carried out in accordance with previous issues of this or related ADs, satisfy the initial inspection requirements of this amendment.\n\nThis Amendment becomes effective on 2 November 2000.\n\nBackground: The original issue of this Airworthiness Directive became effective on 30 June 1977, and was based on the known fatigue history of the “bathtub” fittings.\n\nAmdt 1 was issued by Telex on 24 May 1979, and reduced the inspection threshold and interval for most models following an in-flight failure of an outer wing fitting on a King Air 65-90 aeroplane in Canada, and issue of Canadian emergency AD\n\nCF 79-06.\n\nThis Amendment results from a review of the AD which confirmed the need for the requirement and the appropriateness of the inspection intervals. It consolidates AD/BEECH 90/47 and AD/BEECH 90/48 Amdt 1 into a single AD. The applicability has been curtailed to exclude later production aircraft which have clevis fittings in lieu of the “bathtub” type fittings. The requirements have been aligned with the Beechcraft SIRM to the extent possible; and the use of eddy current inspection of the “bathtub” is allowed as an optional alternative to fluorescent dye penetrant, with a corresponding increase in the repetitive inspection interval. Since the E90 shares the same fittings as the earlier models, the same inspection intervals also apply; this was overlooked when Amendment 1 was issued. The model F90 has also been added, it uses different fittings for which the SIRM inspection procedures and intervals have been adopted.\n\n![](image.003.png)  \n\nDavid Alan Villiers\n\nDelegate of the Civil Aviation Safety Authority 22 September 2000\n\n![](image.002.png)  \n\nThe above AD is notified in the Commonwealth of Australia Gazette on 4 October 2000.","sortOrder":0}],"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":true,"description":"This Amendment 2 significantly expanded and refined the original 1977 directive. It consolidated two separate ADs (90/47 and 90/48 Amdt 1) into one, added the E90 model which was overlooked in Amendment 1, added the F90 model with its own distinct procedures, introduced eddy current testing as an alternative to dye penetrant, and refined applicability to exclude newer aircraft with improved clevis fittings. The scope evolved from a simple fatigue inspection for early models to a comprehensive, model-differentiated safety regime."},"complexity_factors":["Multiple aircraft variants with different inspection procedures (F90 vs all others)","Two alternative inspection methods (fluorescent penetrant vs eddy current) with different preparation requirements and recurring intervals","Specific technical references to manufacturer manual chapters, part numbers, and revision dates (SIRM P/N 98-39006B3, specific chapter/section numbers)","Conditional logic: different compliance intervals depending on aircraft model and inspection method chosen","Serial number-based exclusions creating applicability boundaries","Cross-reference to related AD (AD/BEECH 90/69) for bolt inspection requirements","Five detailed technical notes regarding paint removal methods, corrosion protection, and inspection techniques"],"plain_english_summary":"This AD orders owners/operators of certain Beechcraft King Air 90 series (65-90, 65-A90, B90, C90, E90, F90) to inspect the wing “bathtub” spar fittings for fatigue cracks and replace any cracked parts before flight. Inspections require bolt removal, paint stripping and NDT (fluorescent dye penetrant or eddy‑current); F90s follow different procedures.\n\nIt responds to a past in‑flight fitting failure and mandates initial and recurring inspections (e.g. initial before 3,000 fh for most, then 200–400 fh intervals or specified alternate intervals for F90s)."},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":true,"description":"This amendment both narrows and expands the AD's scope compared with earlier issues. It consolidates two prior ADs into one and narrows applicability by excluding later-production aircraft that use clevis fittings instead of the bathtub fittings (reducing scope for those later aircraft). At the same time it expands scope by formally adding the F90 and correcting omission to include the E90, and by aligning the inspection requirements with the Beechcraft SIRM and allowing an eddy-current alternative (which changes inspection practice and intervals). The net effect is a re-scoped and modernised directive: fewer aircraft are covered because of fitting-type exclusions, but additional models are included and inspection options/intervals were adjusted — so the content and operational impact were materially changed from the original AD."},"complexity_factors":["Multiple aircraft-model distinctions (65-90, 65-A90, B90, C90, E90, and F90) with differing requirements and exceptions","Serial-number carve-outs that exclude later-production aircraft from applicability","Two alternate inspection methods (fluorescent liquid penetrant and eddy current) with different preparatory actions (paint strip required for penetrant, not for eddy current)","Different compliance intervals depending on model and inspection method (hours-based intervals, calendar years for one method, and a doubled interval option when eddy current is used)","Cross-references to specific SIRM chapters and charts for procedural detail rather than embedding full procedures in the AD","Several advisory notes that modify practical implementation (e.g. overriding a SIRM \"warning\", corrosion-protection advice, paint-stripping cautions, NDT handling of suspect indications)","Replacement rules differ by location of crack (outer wing fitting requires full outer wing main spar lower cap replacement; centre section only the affected component)","References to other ADs (for bolt/nut inspection) and prior inspections counting toward compliance, creating cross-document compliance paths"],"plain_english_summary":"**What this instrument does (in plain English)**\n\n- This is an airworthiness directive (a mandatory safety requirement from the aviation regulator) that tells operators of certain Beechcraft 90/65-90 (King Air) series aeroplanes to inspect specific wing spar attachment fittings for fatigue cracks and to replace parts if cracks are found. (An airworthiness directive requires action to correct an identified unsafe condition.)\n\n- Which aeroplanes are affected: All Beechcraft model 65-90, 65-A90, B90, C90 and E90 aircraft except serial nos. LJ-1085 and LJ-1088 and subsequent; and all F90 aircraft except serial nos. LA-226 and subsequent. (See the “Applicability” paragraph.)\n\n**What inspectors or operators must do (mechanics and maintenance organisations)**\n\n- Requirement 1 (practical step): Remove the wing main spar lower attachment bolts and strip paint from the \"bathtub\" area of the four outer wing-to-centre section main spar lower attachment fittings. This prepares the fittings for inspection.\n\n- Requirement 2 (for all models except F90): Perform a fluorescent liquid penetrant inspection of all four fittings following the Beechcraft Structural Inspection and Repair Manual (SIRM) procedures referenced, paying particular attention to the bolt counterbore and fillet radius in the bathtub area. As an allowed alternative to penetrant testing, an eddy-current (pencil probe) inspection from the SIRM may be used; if eddy current is used, paint does not need to be removed.\n\n- Requirement 3 (for F90 only): Perform a penetrant inspection of all four fittings following the F90-specific SIRM chart; pay attention to specified radii and recesses. An eddy-current alternative for F90s is allowed (see requirement 4).\n\n- Requirement 4 (for F90 only): If using eddy current on F90s, follow the SIRM eddy-current procedure; paint strip is not required.\n\n- If a fatigue crack is found in an outer wing fitting, the whole outer wing main spar lower cap must be replaced before the aeroplane flies again. If a crack is found in a centre section fitting, replace just the affected component. (Requirement section.)\n\n**When inspections must be done (compliance timing)**\n\n- For models 65-90, 65-A90, B90, C90 and E90: the initial inspection must be done before the component exceeds 3,000 hours in service, then repeatedly at intervals no greater than 200 hours component time-in-service. If the eddy-current method is used, the recurring interval may be doubled (i.e. inspections can be done less frequently). (See Compliance paragraph.)\n\n- For F90 aircraft: if using the penetrant inspection (Requirement 3), do so at intervals not exceeding 5 calendar years. If using the eddy-current procedure (Requirement 4), do the initial eddy-current inspection before the component exceeds 20,000 hours in service and then at intervals not exceeding 1,200 hours component time-in-service.\n\n- Inspections already done under prior related ADs count toward the initial inspection requirement. (Note 6.)\n\n**Practical implementation details and cautions**\n\n- The SIRM (Beechcraft manual) charts and chapters cited provide the technical method. The AD aligns the requirements to that manual and permits eddy-current testing as an alternative to penetrant testing in particular cases.\n\n- The AD warns not to follow a conflicting SIRM \"warning\" about not removing paint for penetrant inspections: where penetrant is used the paint must be removed for inspection and, to prevent corrosion, some protective treatment (for example zinc chromate primer) should be applied between inspections. (Note 1.)\n\n- Use solvent removers where possible for paint stripping; avoid mechanical/abrasive removal. Apply penetrant carefully (recommendation to use a fine artist's brush) and do not attempt to polish or grind away suspicious indications—seek specialist non-destructive testing (NDT) advice if needed. (Notes 2–4.)\n\n**Who pays and who decides**\n\n- Operators of the affected aircraft (owners / operators) pay for the inspections, any paint removal and protective treatment, labour, downtime, and replacement parts if cracks are found.\n\n- The Civil Aviation Safety Authority (CASA) delegate made the directive; within the AD, operators and their maintenance organisations decide which permitted inspection method to use (penetrant or eddy current) consistent with the SIRM and the AD.\n\n**Costs, incentives, trade-offs and likely effects on behaviour**\n\n- Direct costs: recurring maintenance labour and possible part replacements. If an outer wing fitting crack is found, replacing the complete outer wing main spar lower cap will be a significant parts-and-labour cost and will take the aircraft out of service until repaired.\n\n- Incentives: Operators can choose the inspection method where alternatives are permitted. Using eddy-current testing reduces the need to strip paint and allows longer intervals in some cases, which lowers recurring labour and corrosion exposure but requires access to eddy-current equipment and appropriately qualified NDT technicians.\n\n- Trade-offs and risks: Removing paint for penetrant inspections introduces a corrosion-prevention step (additional cost and work) and the AD warns about correct paint-stripping methods to reduce damage. There is also a risk that operators who try to \"polish out\" suspect indications may obscure real cracks; the AD instructs against that.\n\n- Effects on third parties: Maintenance organisations with NDT capability are likely to see increased work; operators without in-house capability may need to outsource inspections. Parts supply (spare spar lower caps) may become an intermittent constraint for operators who discover cracks.\n\n**Mechanisms that constrain behaviour**\n\n- Mandatory inspection intervals and the requirement to replace cracked fittings are direct constraints that force ongoing maintenance and potential capital expenditure.\n\n- The AD permits some operational flexibility (choice of inspection method where allowed and differing intervals tied to method and model) which reduces costs for operators able to use the eddy-current alternative.\n\n**Where the directive came from (stated rationale) and how that squares with the rules**\n\n- The AD says it responds to known fatigue history of the bathtub-type fittings and to at least one in-flight failure on a King Air 65-90. The amendment consolidates older ADs, narrows applicability to aircraft built with clevis rather than bathtub fittings, aligns procedures and intervals with the Beechcraft SIRM where possible, adds model F90 and corrects a prior omission in applying the same intervals to the E90. That explanation appears in the Background section and is reflected in the Requirement and Compliance sections.\n\n**Bottom line**\n\n- If you operate an affected Beechcraft 90/65-90-series aircraft, you must inspect specified wing spar attachment fittings on the schedule in the AD, using the SIRM procedures cited, and replace parts where cracks are found. The AD prescribes how inspections are done, allows an eddy-current alternative in specified cases (with longer intervals), and sets out corrosion-prevention and NDT cautions. This creates an ongoing maintenance cost and operational downtime risk for operators, while giving a choice of inspection techniques that can reduce recurring costs for those able to use them. (Requirements 1–4; Compliance paragraphs; Notes 1–6.)"}},"importantCases":[],"_links":{"self":"/api/acts/ad-beech-90-48-amdt-2-wing-spar-fitting-fatigue-inspection","history":"/api/acts/ad-beech-90-48-amdt-2-wing-spar-fitting-fatigue-inspection/history","analysis":"/api/acts/ad-beech-90-48-amdt-2-wing-spar-fitting-fatigue-inspection/analysis","conflicts":"/api/acts/ad-beech-90-48-amdt-2-wing-spar-fitting-fatigue-inspection/conflicts","importantCases":"/api/acts/ad-beech-90-48-amdt-2-wing-spar-fitting-fatigue-inspection/important-cases","documents":"/api/acts/ad-beech-90-48-amdt-2-wing-spar-fitting-fatigue-inspection/documents"}}