AD/B737/275 - P15 Refuel Panel Wire Chafing

The AD is built around a few central concepts that any operator or maintainer must understand.

Airworthiness Directive (AD). An AD is a legally enforceable notice issued by CASA under Part 39 of the Civil Aviation Regulations 1988 (now superseded by the Civil Aviation Safety Regulations 1998 but still relevant). It mandates an action necessary to maintain the airworthiness of an aircraft type. Failure to comply with an AD renders the aircraft unairworthy and exposes the operator or owner to enforcement action, including grounding, suspension of an Air Operator’s Certificate, or criminal prosecution. This AD is numbered AD/B737/275 and is also referred to by the CASA series number 2/2006. It was signed by a delegate of CASA on 16 December 2005 and takes effect 16 February 2006.

Detailed inspection. The AD explicitly defines a “detailed inspection” in Note 1. It is “an intensive visual examination of a specific structural area, system, installation, or assembly to detect damage, failure, or irregularity.” The inspector must use supplemented lighting at an intensity deemed appropriate, and may use aids such as mirrors or magnifying lenses. Surface cleaning and elaborate access procedures may be required. This is distinct from a general visual inspection or a more severe non‑destructive test. The definition matters because it sets the expected rigour: a cursory look will not suffice.

Discrepancy. The term “discrepancy” is not further defined, but in context it includes any damage, failure, irregularity, or condition that could lead to chafing, arcing, or fire. The AD requires corrective action for any discrepancy found. The corrective action must be done before further flight, and for the classic models it also requires “related investigative actions,” which suggests the need to determine root cause or extent of damage before simply repairing the immediate finding.

Group 1 and Group 2 aeroplanes (NG series). Within the Next Generation models the AD creates two sub‑groups. The source does not provide the criteria for grouping, but they are defined in the Boeing Service Bulletin. Typically Group 1 are earlier production aircraft, Group 2 later ones, but the exact definitions can only be ascertained by reading the service bulletin. Group 2 requires both the clamp/T‑bolt inspection and the wire bundle inspection; Group 1 requires only the clamp/T‑bolt inspection.

Alternate Method of Compliance (AMOC). The AD recognises that later revisions of the two Boeing Service Bulletins may be used if the FAA has approved them as an AMOC to FAA AD 2005‑23‑17. This provision reduces regulatory rigidity: if Boeing issues a revised service bulletin that, for example, changes the inspection technique or scope, and the FAA agrees it is equivalent, then CASA will accept it as compliant. This also means the operator must check for any FAA‑approved revisions after the AD’s effective date.

Effective date and compliance times. The AD operates on a single temporal trigger: the effective date of 16 February 2006. The one‑time inspections must be accomplished within 18 months after that date (i.e., by 16 August 2007). There is no recurrence requirement; the AD is described as a “one‑time” inspection. However, if the inspection results in corrective action, the corrective action must be performed before further flight, effectively making the grounding a possible immediate consequence.

Pre‑compliance credit. Actions accomplished before the effective date in accordance with the original (pre‑revision) service bulletins or with the Information Notices are “acceptable for compliance with the corresponding actions.” This avoids forcing operators who had already taken action under earlier advisory material to repeat the work needlessly. However, it means the operator must have documentary evidence that the earlier work was done to the precise specifications of those earlier bulletins.

The AD imposes mandatory duties on several classes of persons and organisations.

Aircraft operators and owners. The primary duty falls on the registered operator of each aeroplane that falls within the applicability. For a commercial airline, that is the Air Operator Certificate (AOC) holder; for a private owner, it is the individual or entity on the aircraft register. The operator must ensure the inspection is performed within 18 months of the effective date, and must ensure that any corrective action is performed before further flight. This imposes a direct compliance cost in labour, materials, and, in the event discrepancies are found, unscheduled maintenance that could ground the aircraft for some time.

Maintenance organisations. The AD requires that the inspection be carried out “in accordance with the Accomplishment Instructions” of the relevant Boeing service bulletin. This means a qualified maintenance organisation, typically one with a CASA‑approved maintenance organisation certificate, must perform the work. The maintenance organisation must have a current copy of the service bulletin and must train its personnel on the detailed inspection requirements. The cost of the inspection includes the technician’s time, access panels, lighting, and potential cleaning. While the AD is a one‑time event, it still creates a schedule pressure and a resource demand.

Aircraft importers and lessors. Aircraft imported into Australia after the effective date but still within the 18‑month compliance window must have the inspection done. Lessors may contractually require the lessee to comply, but the legal duty under the AD rests on the operator, not the owner. This can create contractual disputes if the lessor fails to provide the necessary service bulletins or historical records.

Regulator (CASA). CASA must enforce the AD, either through its own surveillance or in response to reports from the public. CASA has the power to ground aircraft that are not in compliance, and to impose civil penalties or prosecute for breaches of the Airworthiness Directive provisions in the Civil Aviation Regulations.

Manufacturer (Boeing). Boeing is indirectly affected. The AD mandates use of Boeing service bulletins, and Boeing can influence the compliance burden by issuing revised service bulletins or AMOCs. If Boeing’s service bulletins are incorrect or impractical, the AD forces operators to follow them nonetheless. Boeing also bears reputational risk from the underlying defect.

Applicable aircraft. The AD applies to a defined set of line numbers for each series. Classic series lines 1 through 3132; Next Generation lines 0001 through 1240. This means many older 737‑100 and ‑200 aircraft built before the line‑number cut‑off are included, but those above 3132 (i.e., later production) are not. Similarly, Next Generation aircraft after line 1240 are excluded. The cut‑off appears based on the point in production where Boeing incorporated a design change, probably a different clamp arrangement or wire routing. An operator must check the line number of each of its airframes against the AD’s table.

Refuelling personnel. The Background explicitly mentions “injury to refuelling personnel” as one risk. While the AD does not impose duties on ground crew directly, they are the beneficiaries of the safety improvement.

The AD creates specific duties and a few limited rights.

Duty to inspect. For each affected aeroplane, the operator must ensure that a one‑time detailed inspection is performed within 18 months after 16 February 2006. For classic models, that means inspecting wire bundle W0024 to connector D04578P. For NG Group 1, it means inspecting the clamp and T‑bolt assembly of the wing thermal anti‑ice duct. For NG Group 2, both inspections are required.

Duty to correct and investigate. If any discrepancy is found during the inspection, the operator must perform “any applicable corrective action” and, for classic models, also “related investigative actions.” The corrective action must be accomplished before further flight. The AD does not specify what constitutes acceptable corrective action; it defers to the Boeing service bulletin. That bulletin presumably describes approved repair procedures, such as replacing chafed wiring, installing insulation, or repositioning clamps.

Duty to document. While not explicit, the requirement to carry out actions “in accordance with” the service bulletin implies that the operator must document the inspection and any corrective actions, and preserve that documentation for the life of the aircraft. Typically that means a signed maintenance release and an entry in the aircraft’s technical log or maintenance records.

Right to use previously accomplished actions. An operator that had already performed the relevant inspection before 16 February 2006 using earlier versions of the service bulletins (original 2003 versions or their Information Notices) is deemed compliant with the corresponding actions. This saves the cost of re‑doing the inspection if it was done within the prior two and a half years. However, the operator must ensure it was done to those specific earlier bulletins. If a later revision added new steps, those steps may still need to be performed.

Right to use later FAA‑approved revisions. If after the AD’s effective date Boeing releases a revision of the service bulletin that addresses the same issue, and the FAA approves that revision as an AMOC to FAA AD 2005‑23‑17, then CASA accepts it as compliant. This gives operators flexibility to use improved or more efficient procedures. However, it also imposes a monitoring duty: the operator cannot simply set and forget the AD; it must check for FAA AD updates and AMOC approvals.

Right to operate aircraft until the compliance deadline (subject to conditions). The AD does not require immediate grounding. It gives 18 months for the inspection. During that period the aircraft may continue in service, assuming no other defect makes it unairworthy. But if a problem is discovered during the inspection, the aircraft must be grounded until corrective action is completed.

No right to alternative methods without CASA approval. The AD only accepts FAA‑approved AMOCs for later revisions of the two named service bulletins. If an operator wishes to use a different repair scheme or inspection method, it would need to seek a separate approval from CASA, likely under Civil Aviation Regulation 39.

The AD itself does not set out penalties, but it is a legislative instrument made under the Civil Aviation Act 1988 and the Civil Aviation Regulations. Non‑compliance with an Airworthiness Directive is separate from a breach of a regulation: it renders the aircraft unairworthy and exposes the operator to enforcement under the Act.

Criminal penalty. Under section 20A of the Civil Aviation Act 1988, an operator who operates an aircraft that is not airworthy (including by reason of non‑compliance with an AD) may be liable for a penalty of up to 200 penalty units (currently $31,300 per unit, but indexed; at the time of the AD it was lower). Each flight on a non‑compliant aircraft is a separate offence. The maximum fine for an individual can be substantial, and for a body corporate it can be up to five times that amount (s. 20A(3)). Additionally, a person who contravenes a regulation made under the Act may face a penalty of up to 50 penalty units (Civil Aviation Regulations 1988, reg. 300). Operating an aircraft in breach of an AD could lead to both a charge under the Act and a charge under the regulation.

Administrative enforcement. CASA can take immediate enforcement steps without going through the courts. Under Part 7 of the Act, CASA can issue a direction to the operator to ground the aircraft until the AD is complied with. It can suspend or vary the Air Operator’s Certificate if the operator is not maintaining its aircraft properly. CASA can also issue an infringement notice (a fine) for certain minor breaches, though failing to comply with an AD is unlikely to be treated as minor.

Civil liability. If a failure to comply with the AD contributed to an accident, the operator may face civil claims for damages from injured ground crew, passengers, or third parties. The AD is a mandatory standard; a breach of it would be strong evidence of negligence.

Enforcement history. The source does not provide any litigation or enforcement history specific to this AD. However, CASA has in the past grounded entire fleets over AD compliance, such as during the R44 main‑rotor blade ADs. An operator should expect that if a spot check reveals non‑compliance, CASA will act firmly, particularly given the stated risk of fire during refuelling.

Note of limitation. The AD is now nearly two decades old. It is likely that most or all affected airframes have been inspected. But if an aircraft has been stored, sold, or returned to service after a long storage period, the operator must still verify compliance before operation. The penalty clock would reset on the first flight without the inspection having been certified.

This AD sits within a web of domestic and international legal instruments.

Civil Aviation Act 1988 and Civil Aviation Regulations 1988 (now superseded). The AD is made under the authority of the Act. The regulations (particularly Part 39 - Airworthiness) give CASA the power to issue ADs. Non‑compliance is an offence under the Act. The AD is a “legislative instrument” under the Legislation Act 2003, meaning it must be registered on the Federal Register of Legislation and is publicly available.

Civil Aviation Safety Regulations 1998 (CASR). Although the AD refers to the old regulations, CASR Part 39 now governs airworthiness directives. The AD remains valid and is continued in force by transitional provisions. Operators must be aware that CASR Part 39 imposes additional obligations such as record‑keeping and reporting of defects. The AD’s requirement to perform corrective action before further flight aligns with CASR 42.080 (maintenance of airworthiness). A maintenance organisation performing the work must be approved under CASR Part 145 (Maintenance Organisations).

FAA AD 2005‑23‑17. The Australian AD is based on the FAA AD. The AD explicitly notes that later revisions of the Boeing service bulletins are acceptable if the FAA approves them as an AMOC. This creates a system of mutual recognition: CASA does not require a separate CASA approval; it relies on the FAA’s determination. However, the AD is an independent Australian legal instrument, not just an endorsement of the FAA AD. An operator cannot rely solely on compliance with the FAA AD if that compliance does not meet the specific wording of the CASA AD (for example, if the FAA AD has different compliance times or applicability). The CASA AD supersedes any inconsistent FAA AD for Australian‑registered aircraft.

Civil Aviation (Superseded) Regulations. For older aircraft, the AD may interact with the legacy regulations such as Air Navigation Orders that impose continuing airworthiness duties. The AD typically overrides any less stringent requirement.

Occupational health and safety laws. In each state and territory, work health and safety legislation imposes a duty on persons conducting a business or undertaking to ensure the health and safety of workers. If an operator fails to inspect or correct the wiring chafing, and a refueller is injured, the operator could face prosecution under WHS laws in addition to CASA enforcement.

Aircraft leasing and financing. Leases often require the lessee to maintain the aircraft in airworthy condition and comply with all ADs. The lessor may require evidence of compliance before delivery. Financing documents may give the lender the right to take possession if the aircraft is not airworthy.

Contractual warranties. An airline that has sold an aircraft may owe contractual obligations to the buyer regarding AD compliance. The AD’s acceptance of pre‑effective date actions (if done per earlier bulletins) can be important in disputes over whether the aircraft was correctly maintained before sale.

The source document is apparently the original AD, effective 16 February 2006. No amendments are recorded in the text itself. However, the AD refers to earlier service bulletins (2003 versions and Information Notices) and later revisions approved as AMOC. It is likely that subsequent revisions of the Boeing service bulletins have been issued and approved by the FAA, and those revisions are automatically accepted by CASA under the AD’s terms. Therefore, while the AD text has not been formally amended, the practical requirements have evolved as Boeing revised its service bulletins.

The standard CASA process for amending an AD is to issue a new AD number (e.g., AD/B737/275 Amendment 1) or to supersede the AD entirely. A search of the Federal Register of Legislation would reveal whether this has occurred. Given that the AD concerns a one‑time inspection for a defect identified in 2005‑2006, it is plausible that the AD is still in force but that all affected aircraft have completed its requirements. An operator re‑importing an old 737 into Australia would still need to verify compliance against the original AD or any superseding AD. No evidence of litigation over this specific AD.

The source document contains no references to litigation, and no readily identifiable reported cases exist that specifically cite AD/B737/275. This is typical for a routine airworthiness directive; most AD compliance occurs without courtroom disputes. However, several categories of potential litigation could arise.

Civil litigation after an accident would likely include pleadings on AD compliance. For example, if an undetected wire chafe caused a fire during refuelling and injured ground staff, the operator’s failure to perform the detailed inspection within 18 months would be strong evidence of negligence per se. The AD sets a clear standard; any deviation would be difficult to justify.

Administrative law challenges could occur if CASA grounds an aircraft and the operator seeks judicial review of CASA’s decision to issue the AD or to refuse an AMOC. However, CASA’s decisions are reviewable under the Administrative Appeals Tribunal Act 1975. There have been cases where operators challenged ADs on grounds that the regulator did not follow proper procedure (e.g., Raptor Helicopters Pty Ltd v CASA, though not specific to this AD). The delegate’s signature on 16 December 2005 appears proper.

Criminal enforcement actions are possible under section 20A of the Civil Aviation Act. Any prosecution decisions would be by the Commonwealth Director of Public Prosecutions. Case law on operating an unairworthy aircraft includes DPP v Qantas Airways (various), though not on point here.

Given the age of the AD, any direct litigation over non‑compliance in the 2006‑2007 period is now likely concluded or settled. The continuing relevance is for aircraft that might be returned to service after storage or imported.

Operators and advisers should watch for the following traps in AD/B737/275.

Line number verification. The AD applies only to specific line number ranges. Many operators may not have line numbers readily accessible; they need to consult the aircraft’s data plate or Boeing records. Using the wrong line number could lead to unnecessary work or, worse, missing a required inspection. For example, a 737‑300 with line number 2975 is included, but a 737‑300 with line number 3135 is not. The difference is literally a handful of airframes.

NG Group 2 additional inspection. The NG series classification into Group 1 and Group 2 is critical. Group 2 aeroplanes require both the clamp/T‑bolt inspection and the wire bundle inspection. If an operator only does the clamp inspection because it mistakenly believes all NGs are Group 1, it will be non‑compliant. The AD gives no explicit method to determine the group without referring to the Boeing service bulletin, which is incorporated by reference. The operator must obtain and read the bulletin.

Pre‑flight grounding for discrepancies. The AD states that corrective action must be done “before further flight after the Requirement 2.a. or 2.b. inspection.” This means if a discrepancy is found, the aircraft cannot be dispatched on its next flight until the correction is complete. There is no grace period. This can cause operational disruption and financial loss if the discrepancy is discovered at a remote location without the necessary parts or skills.

Acceptance of pre‑effective date work. The AD accepts actions done before the effective date under earlier bulletins only if those actions correspond to “the corresponding actions required by this Directive.” If an earlier inspection looked at a different part of the wiring or used a different definition of detailed inspection, it may not be considered equivalent. An operator claiming credit must have detailed records proving that the earlier work exactly matched what the AD now requires.

Later revisions of service bulletins. The AD automatically accepts later revisions of the service bulletins only if they have been approved by the FAA as an AMOC to FAA AD 2005‑23‑17. If Boeing issues a revision that the FAA has not yet approved, it does not automatically become acceptable under the Australian AD. The operator would need to obtain CASA’s approval separately, or wait for FAA approval. Monitoring this is burdensome.

Record‑keeping for imported aircraft. An aircraft imported into Australia after August 2007 (18 months after effective date) must have evidence that the inspection was completed before that deadline. If the previous overseas operator did not do the inspection because the aircraft was not subject to the FAA AD at that time, or because the line number was exempt under US rules, the Australian operator may need to arrange the inspection now, even though the AD’s compliance time has long passed. The AD does not expire; it remains a continuing obligation until complied with.

No repetitive requirement. Because the AD is a one‑time inspection, an operator might assume that after the initial check no further action is needed. However, if the corrective action involved replacing wires, the new wiring could still eventually chafe. The AD does not mandate a recurrence interval, but the operator’s continuing airworthiness management system under CASR Part 42 should still monitor the condition via routine maintenance. Simply stopping after the AD is not enough.

Relationship with FAA AD. An Australian operator that also holds a US FAA registration (e.g., for a wet‑leased or imported aircraft) must comply with both ADs. Although the CASA AD mirrors the FAA AD, the compliance times and applicability could differ if one AD is amended and the other is not. The operator cannot assume compliance with one equals compliance with the other.

Compliance with AD/B737/275 should be approached methodically.

Step 1: Determine applicability. For each 737 on the Australian register, identify the exact model (e.g., 737‑300, 737‑800) and obtain the line number from the aircraft data plate or Boeing technical records. Compare against the table in the AD: classic series lines 1‑3132, NG series lines 0001‑1240. If the aircraft falls outside these numbers, no action is required, but the operator should document that finding.

Step 2: Obtain the correct Boeing Service Bulletin. For classic models, obtain Boeing Special Attention Service Bulletin 737‑28‑1193, Revision 1 dated 28 July 2005. For NG models, obtain Boeing Special Attention Service Bulletin 737‑28‑1200, Revision 1 dated 28 July 2005. If later revisions exist and have been FAA‑approved as AMOC, the operator may use them. The operator must check the FAA website for the current AMOC status.

Step 3: Identify NG group. For NG models, the service bulletin defines Group 1 and Group 2. The operator must read the bulletin to determine which group applies to each airframe, based on line number or other criteria. This determines whether the wire bundle inspection is also required. Document the grouping.

Step 4: Schedule the inspection. The AD must be accomplished within 18 months after 16 February 2006. For aircraft that have not yet been inspected (e.g., recently imported), the AD must still be done before operation. There is no extension beyond the 18 months; the AD is a one‑time event, but if missed, the aircraft is unairworthy from the date the 18 months expired. The operator should incorporate the inspection into the scheduled heavy maintenance visit or as a standalone task.

Step 5: Perform the detailed inspection. A licensed aircraft maintenance engineer (LAME) or an approved maintenance organisation must carry out the inspection per the Accomplishment Instructions of the service bulletin. The inspection is visual but intensive; the worker must have adequate lighting, and may need to remove access panels and clean the area. A magnifying lens or mirror may be used. For NG models, the clamp/T‑bolt assembly on the wing thermal anti‑ice duct must be examined for discrepancies. Wire bundle W0024 must be examined for chafing, damage, or loose connections.

Step 6: Document findings. Record the inspection result in the aircraft maintenance records. The entry should state that the AD was complied with, reference the service bulletin used, and note any discrepancies found. If no discrepancies, the corrective action is not required, but the record should still state “no discrepancy” or equivalent.

Step 7: Correct any discrepancies. If a discrepancy is found, perform the corrective action described in the service bulletin (e.g., replace chafed wires, install insulation, adjust clamp position). For classic models, also perform “related investigative actions” - this likely means checking adjacent wiring for collateral damage. Complete the corrective action before the next flight. Document the repair.

Step 8: Verify pre‑compliance credit. If the aircraft had any prior inspection done before 16 February 2006 under the original 2003 service bulletin or the Information Notices, the operator must confirm that it was done to the precise specifications and that it matches the “corresponding actions.” If it does, no new inspection is needed for that portion. Obtain records from the previous owner if the aircraft was imported. If records are missing, repeat the inspection to be safe.

Step 9: Maintain records. Keep all maintenance entries and inspection checklists for the life of the aircraft. This includes the service bulletin reference, date of inspection, inspector’s certification, and any corrective action documentation. CASA may request these during a surveillance audit.

Step 10: Monitor for superseding ADs. The operator should subscribe to CASA’s AD notifications to determine if AD/B737/275 is superseded or if a new directive covering the same issue is issued. Given the age of the AD, it is unlikely to be superseded, but checking annually is prudent. For NG models, check the FAA’s website for further AMOCs to the Boeing service bulletins.

Practical tip. Many operators will have already completed this inspection years ago. The risk now is that an aircraft that was parked, stored, or imported without proper records may not have the inspection documented. Before any sale or lease‑return, the compliance status of this AD should be confirmed as part of the technical records review. The cost of repeating the inspection is less than the cost of an enforcement action.