{"id":"F2006B08790","name":"AD/DC3/13 - Flap Adjustment","slug":"ad-dc3-13-flap-adjustment","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":52133,"registerId":"commonwealth-F2006B08790-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/DC3/13 - Flap Adjustment","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)  \nDouglas DC3 Series Aeroplanes\n\nAD/DC3/13 Flap Adjustment NK\n\nApplicability: All models.\n\nRequirement: 1. Douglas SB No. 204 supplemented by Douglas Service for May 1947, page 18, leaves much to individual interpretation and consequently there is a possibility of maladjustment which may lead to flap push-pull tube failures. Flaps are to be adjusted in accordance with the procedure prescribed in para. 2 below.\n\n    2. Adjust the flaps in accordance with the following:\n\n    (a) Fully bottom jack in down position.\n\n    (b) Set the inboard rod adjustment to 7/8 inch between the tube end and the trunnion hexagon.\n\n    (c) Set the outboard adjustment to 1 1/2 inches between the tube ends.\n\n    (d) Place a 45 degree template between the underside of the flap and wing and set each turnbuckle (turnbuckles should be approximately 75 degree to push-pull tubes).\n\n    (e) Slowly raise flaps on handpump, checking the relative timing between the inboard and outboard flaps.\n\n    (f) Adjust the flaps to the same timing.\n\n    (g) With the actuating jack fully bottomed in the up position, adjust each turnbuckle to give a clearance of the flap from the felt pads of .05 inch. This clearance may be obtained by using a piece of 18 gauge metal sheet as a feeler gauge, first shaping the sheet to fit into position.\n\n    (h) Tighten each turnbuckle one turn (this raises the trailing edge of the flap .09 inch, giving a pad compression of 04 inch).\n\n    (i) Readjust with different setting of push-pull tubes if flap angle at full deflection is not 45 degrees + 2 degrees.\n\n    3. It should be noted that the flap operating linkage is such that with the flaps down slight slackness will be apparent at the trailing edge. This is normal and the turnbuckles must not be adjusted to eliminate this slackness.\n\n    4. Amend Maintenance Manuals to comply with this directive. OR ANO 105.1.6.1.5.14.","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":3,"scope_assessment":{"changed":false,"description":"This airworthiness directive maintains its original narrow scope — prescribing specific flap adjustment procedures for DC-3 aircraft to address a known safety risk from vague manufacturer instructions. It has not expanded beyond this technical maintenance requirement."},"complexity_factors":["Technical aviation terminology throughout (trunnion hexagon, turnbuckles, push-pull tubes, feeler gauge)","Precise mechanical measurements requiring specialised tools (45-degree template, 18-gauge metal sheet as feeler gauge)","Multi-step procedural sequence (9 steps) with interdependent adjustments","Reference to external technical documents (Douglas Service Bulletin 204, May 1947) without full reproduction","Nested conditional logic in step 2(i) requiring readjustment if angle tolerance not met","Exception to normal procedure in paragraph 3 (slackness is normal, do not correct)","Cross-reference to Civil Aviation Regulations Part 39 and maintenance manual amendment requirement"],"plain_english_summary":"This safety directive mandates precise flap adjustment procedures for Douglas DC‑3 aircraft in Australia, replacing vague manufacturer guidance. It requires licensed maintenance engineers and operators to follow specific measurement, angle and timing checks and to update manuals accordingly.\n\nIt matters because improper flap adjustment can break push‑pull tubes and disable landing control, posing a significant safety risk."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"The directive narrows and formalises prior guidance: it converts a previously interpretive service bulletin into mandatory, prescriptive adjustment measurements and requires maintenance‑manual amendments, making compliance obligatory across all DC‑3 models (see Requirement 1, Requirement 2, Requirement 4)."},"complexity_factors":["Applicability is broad: applies to all DC‑3 models (Applicability).","Technical tolerances are precise: flap angle 45° ±2° (Req 2i), pad clearance .05 inch and pad compression .04 inch (Req 2g–2h).","Specific component settings required: inboard rod 7/8 inch (Req 2b), outboard 1½ inches (Req 2c).","Manual, skill‑based procedure elements: use of handpump, timing checks and turnbuckle adjustments require trained technicians (Req 2d–2f).","Tools and gauges prescribed: 45° template, 18‑gauge sheet as feeler (Req 2d, 2g).","Some wording retains approximate guidance (e.g. 'turnbuckles should be approximately 75 degree'), leaving limited interpretive judgment (Req 2d).","Administrative burden: requires amendment of Maintenance Manuals to comply (Req 4).","Safety‑critical consequence motivating action: directive cites risk of flap push‑pull tube failures from maladjustment (Req 1).","Alternative compliance cross‑reference included (OR ANO 105.1.6.1.5.14), adding a compliance pathway choice."],"plain_english_summary":"This Airworthiness Directive requires all Douglas DC‑3 aeroplanes to have their flap push‑pull linkages adjusted to specific measurements and clearances and for maintenance manuals to be amended. It replaces an ambiguous service bulletin by prescribing exact rod lengths, turnbuckle settings, flap angle (45° ±2°) and pad clearances to reduce the risk of push‑pull tube failures. Operators and maintenance organisations must perform the hands‑on adjustments and bear the associated inspection, adjustment and documentation costs."}},"importantCases":[],"_links":{"self":"/api/acts/ad-dc3-13-flap-adjustment","history":"/api/acts/ad-dc3-13-flap-adjustment/history","analysis":"/api/acts/ad-dc3-13-flap-adjustment/analysis","conflicts":"/api/acts/ad-dc3-13-flap-adjustment/conflicts","importantCases":"/api/acts/ad-dc3-13-flap-adjustment/important-cases","documents":"/api/acts/ad-dc3-13-flap-adjustment/documents"}}