{"id":"F2006B02873","name":"AD/B737/17 - Aft Lavatory Dispenser Cavity Liner","slug":"ad-b737-17-aft-lavatory-dispenser-cavity-liner","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":42215,"registerId":"commonwealth-F2006B02873-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/B737/17 - Aft Lavatory Dispenser Cavity Liner","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)  \nBoeing 737 Series Aeroplanes\n\nAD/B737/17 Aft Lavatory Dispenser Cavity Liner 12/88\n\nApplicability: All model 737 aeroplanes with line numbers 001 through 1425, equipped with non- modular aft lavatories.\n\nRequirement: 1. Inspect the area behind each aft lavatory towel and cup dispenser if the dispenser cavities are not enclosed by a liner, and remove any foreign material.\n\n2. Unless already accomplished, install a protective liner to enclose each aft lavatory towel and cup dispenser cavity in accordance with Boeing SB 737-25-1219.\n\nNote: FAA AD 88-14-07 Amdt 39-5966 refers.\n\nCompliance: 1. At intervals not exceeding 1000 hours time in service, until modified in accordance with Boeing SB 737-25-1219.\n\n2. Before 31 December 1989.\n\nBackground: The FAA has determined that the installation of a liner at each lavatory towel and cup dispenser cavity will prevent the accumulation of combustible material behind the aircraft sidewall, and alleviate a possible fire hazard.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, time-bound safety directive from 1988 addressing a specific fire hazard in early-model Boeing 737s. It has not expanded beyond its original narrow scope of requiring liner installation and interim inspections."},"complexity_factors":["Very short document (under 300 words)","Only 4 defined elements: applicability (line numbers), requirement (two numbered actions), compliance (two deadlines), and background","No cross-references to other legislation beyond a single note referencing the corresponding FAA directive","Simple conditional logic: 'if not already accomplished' and 'until modified'","Single technical reference to a Boeing Service Bulletin"],"plain_english_summary":"**What this is:** An Airworthiness Directive (AD) — essentially a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) for specific Boeing 737 aircraft.\n\n**Who it affects:** Owners and operators of Boeing 737 planes with serial numbers 001 through 1425 that have **non-modular aft lavatories** (older-style rear toilets where the towel and cup dispensers aren't in self-contained units).\n\n**What it requires:**\n- **Regular inspections:** Every 1,000 flight hours, check behind the towel and cup dispensers in the rear toilet. If there's no protective liner installed, clean out any rubbish or debris that has accumulated.\n- **Mandatory modification:** Install a protective liner around these dispenser cavities following Boeing's official instructions (Service Bulletin 737-25-1219) — and this must be done by 31 December 1989.\n\n**Why it matters:** The US Federal Aviation Administration (FAA) identified that debris could build up behind the aircraft's sidewall in these dispenser cavities, creating a **fire risk**. The liner acts as a barrier to stop combustible material accumulating in a hidden space where it could ignite.\n\n**Key point:** Once the liner is installed, the repetitive 1,000-hour inspections stop. Until then, keep checking and cleaning."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"No change in scope is evident from the instrument text. It applies specifically to the listed Boeing 737 line numbers with non-modular aft lavatories and prescribes inspection and modification to address combustible material accumulation as stated."},"complexity_factors":["Narrow applicability: limited to Boeing 737 line numbers 001–1425 and only where aft lavatories are non-modular (Applicability).","Dual obligations: recurring inspections (remove foreign material) plus a mandatory physical modification (install liner) (Requirement).","Timing constraints: 1,000‑hour inspection interval until modification; fixed deadline for modification (before 31 December 1989) (Compliance).","Dependence on an external engineering document: installation must follow Boeing SB 737-25-1219 (Requirement).","Operational work: physical access to dispenser cavities and removal/install tasks impose labour, downtime and parts costs on operators (Requirement).","Cross-reference to foreign regulator action: note refers to FAA AD 88-14-07, indicating coordinated technical basis (Note/Background).","Administrative enforcement: issued under CASA's Part 39 Schedule of Airworthiness Directives, creating a regulatory compliance obligation for operators."],"plain_english_summary":"This Airworthiness Directive requires operators of Boeing 737 aeroplanes (line numbers 001–1425) with non-modular aft lavatories to inspect behind each aft lavatory towel and cup dispenser for foreign material and, if not already done, to install a protective cavity liner per Boeing Service Bulletin SB 737-25-1219. Inspections must recur every 1,000 hours until the liner is fitted; liners must be installed by 31 December 1989. The stated aim is to prevent combustible build-up behind sidewalls and reduce a fire hazard (FAA finding)."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b737-17-aft-lavatory-dispenser-cavity-liner","history":"/api/acts/ad-b737-17-aft-lavatory-dispenser-cavity-liner/history","analysis":"/api/acts/ad-b737-17-aft-lavatory-dispenser-cavity-liner/analysis","conflicts":"/api/acts/ad-b737-17-aft-lavatory-dispenser-cavity-liner/conflicts","importantCases":"/api/acts/ad-b737-17-aft-lavatory-dispenser-cavity-liner/important-cases","documents":"/api/acts/ad-b737-17-aft-lavatory-dispenser-cavity-liner/documents"}}