{"id":"F2006B06245","name":"AD/PITTS S-2/16 Amdt 2 - Upper Fuselage Longerons","slug":"ad-pitts-s-2-16-amdt-2-upper-fuselage-longerons","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":47208,"registerId":"commonwealth-F2006B06245-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/PITTS S-2/16 Amdt 2 - Upper Fuselage Longerons","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)  \nPitts S-1 and S-2 Series Aeroplanes\n\nAD/PITTS S-2/16\n\nAmdt 2\n\n  \nUpper Fuselage Longerons 4/98\n\nApplicability: Models S-2A, S-2S, S-2E and S-2SE, all serial numbers, and model S-2B serial numbers 5000 to 5350 inclusive.\n\nRequirement: 1. Inspect the fuselage longerons aft of the rear cabane strut attachments and forward of the instrument panel for cracks. Inspect, using a 10x magnifying glass, in accordance with paragraphs A.1 through A.4 and Figure 1 in the Accomplishment Instructions of Aviat Service Bulletin (SB) No. 24, revised November 22, 1996.\n\n    2. Either:\n\n    (a). Install an accelerometer and permanently mark the face with red marks (5 mm by 1.5 mm) at the +6g and -3g hash marks. Install a placard (Aviat part number 2-7604-47) stating the gravity (‘g’) force limitations within clear view of the pilot, in accordance with paragraph B.1 of the Accomplishment Instructions of Aviat SB No. 24, revised November 22, 1996; or,\n\n    (b). Install a placard within clear view of the pilot, using upper case letters at least\n\n3.2 mm in height, which incorporates the words ‘AEROBATIC MANOEUVRES PROHIBITED’.\n\n    3. Repair the aircraft by incorporating Aviat Kit Number S-2-513, in accordance with the Installation Instructions section in Aviat Kit No S-2-513, dated August 26, 1996, revised May 9, 1997.\n\nNote 1: Disregard the instructions in paragraph A.5 in the Accomplishment Instructions of Aviat SB No. 24, revised November 22, 1996. This AD takes precedence. Modification of the aircraft does not relieve the inspection requirement\n\nNote 2: FAA AD 97-26-20 refers.\n\nCompliance: 1. Inspect in accordance with Requirement 1 before further flight if unusual handling characteristics or airframe noises are noticed. Otherwise, inspect before 300 hours total time in service, or before 25 hours time in service after 26 March 1998, whichever occurs later. Thereafter inspect at intervals not to exceed 100 hours time in service.\n\n    2. Install either requirement 2(a) or 2(b) before 300 hours total time in service, or before 25 hours time in service after 26 March 1998, whichever occurs later. Compliance with requirement 2(a) at any later time cancels the aerobatic flight limitation of requirement 2(b).\n\n    3. Before further flight if damage is found as described by requirement 1\\. This amendment becomes effective on 26 March 1998.\n\nCOMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\nBackground: An unsafe condition may exist on certain Aviat (Pitts) aeroplanes. Four aircraft in the United States have reported cracking and failure of the longerons aft of the rear cabane strut attachments. In one incident, the cracked longeron made it very difficult to control the aeroplane. Investigation by the FAA has concluded that cracks are primarily caused by flight outside of the certificated ‘g’ limits of the aircraft.\n\nAccordingly the requirements of this AD have been revised to incorporate measures to assist the pilot to fly within the aircraft’s approved limits.\n\nAmendment 1 updated the FAA AD reference.\n\nAmendment 2 aligns the requirements with those of the FAA.\n\nAmendment 1 of this airworthiness directive became effective on 10 October 1996\\. The original issue of this airworthiness directive became effective on 31 May 1996.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This is Amendment 2 of an existing Airworthiness Directive. The amendments have remained focused on the original safety issue (longeron cracking due to excessive G-forces). Amendment 1 updated a reference number, and Amendment 2 aligned requirements with the US FAA. The scope has not expanded beyond addressing the specific structural defect and preventing G-limit exceedances."},"complexity_factors":["Multiple compliance pathways (Option 2(a) vs 2(b) with cancellation mechanism)","Tiered compliance deadlines based on flight hours and calendar dates","Cross-reference to external technical documents (Aviat Service Bulletin No. 24, Aviat Kit S-2-513)","Specific dimensional requirements (10x magnifying glass, 5mm x 1.5mm red marks, 3.2mm letter height)","Conditional logic for inspection timing (immediate vs. deferred based on symptoms)","Note 1 creates an explicit override of referenced external instructions (paragraph A.5)","Amendment history tracking (original, Amendment 1, Amendment 2) with different effective dates"],"plain_english_summary":"This AD for specific Pitts models (S‑2A, S‑2S, S‑2E, S‑2SE and certain S‑2B serials) addresses cracking and potential failure of upper fuselage longerons that can lead to loss of control. It requires regular inspections for cracks, repair with an Aviat kit if damage is found, and either installation of a G‑force meter with red‑limit warnings or a placard banning aerobatics. It targets owners/operators of affected aircraft to prevent G‑load–related structural failure."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The amendments refine and align the AD with the FAA's requirements (updating references and aligning operational controls), add the accelerometer/placard compliance options and clarify precedence over part of the Aviat Service Bulletin. These changes clarify compliance and enforcement but do not expand the AD's fundamental purpose beyond addressing longeron cracking and preventing flight beyond certificated g limits."},"complexity_factors":["Applicability covers multiple models plus a specific serial‑number range (S‑2B 5000–5350)","Three substantive requirements (inspection, placard/accelerometer choice, and repair kit installation)","Two alternative compliance options for Requirement 2 (accelerometer with markings and placard prohibiting aerobatics)","Time/interval rules with conditional earlier inspection (before further flight if unusual handling) and dual thresholds (before 300 hours TIS or before 25 hours after specified effective date)","Recurring inspection interval (every 100 hours TIS) after initial inspection","Cross‑references to external documents: Aviat Service Bulletin No. 24 (revised 22 Nov 1996) and Aviat Kit No. S‑2‑513 (with dates)","A direct precedence statement overruling a specific paragraph (A.5) in the service bulletin","Reference to an FAA Airworthiness Directive (FAA AD 97‑26‑20) for related context"],"plain_english_summary":"**What this directive does (mechanical changes first):**\n\n- It requires owners/operators of specified Aviat (Pitts) biplanes (Models S-2A, S-2S, S-2E, S-2SE — all serial numbers — and S-2B serial numbers 5000–5350) to inspect, placard or instrument, and repair the upper fuselage longerons (the long structural members running along the fuselage) to address cracking.\n\n- Specific actions required:\n  - Inspect the longerons located aft of the rear cabane strut attachments and forward of the instrument panel for cracks, using a 10× magnifying glass and following the steps A.1–A.4 and Figure 1 in Aviat Service Bulletin (SB) No. 24 (revised 22 Nov 1996) (Requirement 1).\n  - Either: (a) install an accelerometer, permanently mark the accelerometer face at the +6g and -3g hash marks with red marks (5 mm × 1.5 mm) and install an Aviat placard (part 2-7604-47) showing the g limits within clear view of the pilot (Requirement 2(a)); or (b) install a placard in clear view of the pilot, using upper‑case letters at least 3.2 mm high, stating “AEROBATIC MANOEUVRES PROHIBITED” (Requirement 2(b)). Installing the accelerometer later cancels the aerobatic prohibition if the accelerometer option is completed (Requirement 2).\n  - Repair the aircraft by fitting Aviat Kit No. S-2-513, following that kit's installation instructions (Requirement 3).\n\n- Timing / intervals (Compliance):\n  - Inspect immediately (before further flight) if unusual handling or airframe noises are noticed. Otherwise do the first inspection before 300 hours total time in service, or before 25 hours time in service after 26 March 1998 (whichever is later). After the initial inspection, repeat inspections at intervals not exceeding 100 hours time in service (Compliance—Requirement 1).\n  - Fit the accelerometer or placard before 300 hours TIS, or before 25 hours TIS after 26 March 1998 (whichever is later) (Compliance—Requirement 2).\n  - If damage/cracking is found, repair using the kit before further flight (Compliance—Requirement 3).\n\n- Notes and precedence:\n  - The directive says to disregard paragraph A.5 of Aviat SB No. 24 where it conflicts — the AD takes precedence. Modifying the aircraft (for example, installing the kit) does not remove the inspection requirement (Note 1).\n  - The AD cross‑references FAA AD 97‑26‑20 (Note 2).\n\n**Why it matters (official rationale and testing that claim):**\n\n- The stated safety problem is that four aircraft in the United States reported cracking and failure of the longerons aft of the rear cabane strut attachments; in one case the crack made the aeroplane hard to control. The FAA's investigation attributed the cracks primarily to flight beyond the aircraft's certificated g limits. The AD's stated purpose is to detect and repair cracking early and to reduce the chance of pilots operating outside the g limits by adding a placard or an accelerometer (Background).\n\n**Who pays, who decides, and what behaviour changes:**\n\n- Owners/operators pay for inspections, placards or accelerometer purchase/installation, and any kit repairs and labour. Maintenance providers perform the work and receive the business.\n- The Civil Aviation Safety Authority (CASA) requires compliance and can enforce the AD; pilots must operate the aircraft within the posted limits or, if they choose the placard option, must refrain from aerobatics.\n- Behavioural effect: either restrict aerobatic manoeuvres (placard option) or use an accelerometer to monitor g‑loads (accelerometer option). Repairing with the kit removes the structural deficiency but does not remove the inspection obligation.\n\n**Costs, incentives and trade‑offs (practical consequences):**\n\n- Direct costs: inspection time (repeating every 100 hours), cost of placard versus cost and installation of an accelerometer, and potential cost of installing Kit S‑2‑513 if cracks are found.\n- Incentives: operators who wish to continue aerobatic flying must install an accelerometer (option 2(a)) to avoid the prohibition; operators who do not need aerobatics can comply with the cheaper placard option (2(b)).\n- Opportunity costs: time aircraft are out of service for inspections, instrument or kit installation; potential need to remove aircraft from aerobatic commercial use unless accelerometer is fitted.\n- Implementation risks and practicalities: inspection relies on visual magnified inspection (10×) — that can produce false negatives or positives depending on inspector skill; kit availability and qualified mechanics affect how quickly repairs can be completed; enforcement depends on CASA oversight and maintenance records.\n- Effects on private enterprise and markets: minor redistributive effects — maintenance shops gain business; owners/operators of affected Pitts models bear the cost; no broad market or competition effects are expected beyond the small niche of aerobatic biplane operators.\n\n**Other mechanics and cross references to note:**\n\n- The AD requires following parts of Aviat SB No. 24 (A.1–A.4, Figure 1, and B.1) and the installation instructions for Aviat Kit No. S‑2‑513. Where the SB conflicts with this AD (paragraph A.5), the AD controls (Note 1).\n\n(See Requirement 1, Requirement 2(a)/(b), Requirement 3, Notes and Compliance sections of the AD.)"},"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"}},"importantCases":[],"_links":{"self":"/api/acts/ad-pitts-s-2-16-amdt-2-upper-fuselage-longerons","history":"/api/acts/ad-pitts-s-2-16-amdt-2-upper-fuselage-longerons/history","analysis":"/api/acts/ad-pitts-s-2-16-amdt-2-upper-fuselage-longerons/analysis","conflicts":"/api/acts/ad-pitts-s-2-16-amdt-2-upper-fuselage-longerons/conflicts","importantCases":"/api/acts/ad-pitts-s-2-16-amdt-2-upper-fuselage-longerons/important-cases","documents":"/api/acts/ad-pitts-s-2-16-amdt-2-upper-fuselage-longerons/documents"}}