AD/ML-M4/19 - Elevator Controls

Airworthiness Directive: An AD is a legally enforceable safety notice issued under the Civil Aviation Act 1988 (Cth) and associated regulations. It mandates inspection, repair, modification or operational restrictions on aircraft, engines or components to correct an unsafe condition. Non-compliance renders the aircraft unairworthy and can result in enforcement action by CASA. This AD, numbered AD/ML-M4/19, applies specifically to the Maule M-4 series.

Elevator control rigging: The elevator is the primary pitch control surface on the tailplane. Rigging refers to the mechanical adjustment of cables, pulleys, bellcranks and control horns so that forward or aft stick movement produces the correct elevator deflection. Reversed rigging occurs when the control cables are attached to the wrong side of the control horn, causing the elevator to move up when the pilot pushes forward, or down when the pilot pulls back. Such a reversal is catastrophic at low altitude. The AD targets four specific attachment points: the top and bottom of the forward and rear elevator control horns and their respective cable ends. The colour coding acts as a visual cue to prevent this misconnection during reassembly.

Colour coding: The directive specifies yellow enamel paint applied to discrete parts. Yellow is a high-visibility colour that contrasts with typical metal or grey components. The intention is that a mechanic reassembling the control system will see the paint and check that cable ends are attached to the correctly coloured horn surfaces. The directive does not specify the shade or brand of enamel; it only says “yellow enamel paint”. The practical effect is that owners must acquire a suitable paint and apply it carefully to avoid overspray or obscuring part identification. The durability of the paint matters because a faded paint mark may lose its warning function over time, though the AD does not mandate repainting intervals.

Caution text insertion: The text must be added to the FAA-approved maintenance program, which for Australian aircraft is normally the CASA-approved maintenance data (e.g., the approved maintenance manual or an accepted alternative). The caution explicitly requires a pre-flight check of elevator direction after any cable reconnection. This supplements any existing rigging checks in the manufacturer’s procedures. The AD allows insertion of a copy of the AD itself or the text from page 3 of Maule Service Bulletin No. 30. This is a permanent record that future maintainers must follow.

Compliance trigger: The wording “before the next time the elevator control cable is disconnected for any reason or within the next 12 calendar months” is a common AD drafting technique. It avoids forcing an immediate grounding while ensuring eventual compliance. However, it introduces uncertainty: if a cable disconnect occurs earlier than 12 months, the operator must have complied already or must to temporarily ground the aircraft until the work is done. The operator bears the cost of monitoring whether a disconnect event has occurred.

The AD applies directly to the registered owners and operators of the specific aeroplane models and serial numbers listed in Table 1 of the directive. The models covered are: Bee Dee M-4, M-4, M-4-180C, M-4-180V, M-4-210, M-4-210C, M-4-210S, M-4-220C, M-4-220S, M-4C, M-4S and M-4T. All serial numbers are affected except for the M-4-180V, which is limited to serial numbers 47001T through 47014T. The aircraft are mostly light utility or bush aircraft used in agricultural, survey, training and private operations. The fleet in Australia is likely small, but these are often operated by small businesses or private owners who are directly burdened by the compliance cost.

Maintenance organisations: Licensed Aircraft Maintenance Engineers (LAMEs) and approved maintenance organisations (AMOs) that work on these types must be familiar with the AD and possess a copy of Mandatory Service Bulletin No. 30. The colour coding and manual update require labour hours and consumables, which the owner or operator pays for. The maintenance entity also assumes liability if it fails to comply while performing other work. The Note about CAR 42G imposes additional requirements on any maintenance on flight controls, including a requirement for a dual inspection or test after assembly. That note means the AD is not the only regulation that affects the work; it sits alongside the existing regulatory framework for flight control systems.

Regulators: CASA is the enforcing authority. The AD was signed by a delegate on 22 December 2008 and became effective 12 February 2009. CASA will expect to see evidence of compliance during an airworthiness review or ramp inspection. The FAA is also indirectly affected because the AD mirrors FAA AD 2008-24-02; any aircraft imported from the United States may have already complied with the FAA version, but Australian operators still need to ensure compliance with the CASA AD as a separate legal requirement.

Third parties: Insurers may require proof of AD compliance before underwriting hull or liability cover. Purchasers of used aircraft will check for AD compliance as part of the pre-purchase inspection. Flying schools and charter operators using Maule aircraft must manage the risk of a mechanic disconnecting the elevator cable during routine maintenance before the AD has been complied with, which could delay the return to service.

Duty to comply: The primary duty is on the owner or operator to ensure the aircraft meets the requirements of the AD before the specified time. This duty is absolute; ignorance of the AD or the existence of a pending maintenance schedule does not excuse non-compliance. The aircraft may not be flown unless the AD has been complied with. If the aircraft has had the elevator cable disconnected before the 12-month deadline, compliance must have occurred before that disconnect. If the owner discovers a cable disconnect has happened before compliance, the aircraft is unairworthy until the colour coding and manual update are complete.

Duty to follow Maule Service Bulletin No. 30: The directive mandates that the colour coding be performed “Follow[ing] Maule Aerospace Technology, Inc. Mandatory Service Bulletin No. 30 dated 4 March 2008.” This imposes a duty to obtain a copy of that bulletin and adhere to its instructions. The bulletin itself contains the detailed procedure, possibly including specific paint application locations, masking requirements, and any special materials. Operators must pay for this bulletin from Maule unless a copy is otherwise available. The AD does not incorporate the bulletin by reference in the sense of full republication; instead it relies on the separate commercial document.

Duty to insert caution into maintenance program: The operator or maintainer must modify the approved maintenance data. This may require a revision to the maintenance manual that is acceptable to CASA, though the AD provides two simple insertion methods: a copy of the AD itself or the text from page 3 of the service bulletin. The effect is that the caution becomes part of the mandatory maintenance instructions for that aircraft.

Rights: The operator has a right to use alternative means of compliance, although this AD does not explicitly mention a CASA alternative means of compliance (AMOC) process. Under the general CASR framework, a person may apply to CASA for an approval of a different method of correcting the unsafe condition, but that would be an administrative process not detailed in this AD. The operator also has the right to perform the work themselves if they are a suitably qualified person under the regulations, or to contract a licensed maintainer.

Additional duties under CAR 42G: Note 1 of the AD reminds operators of regulation 42G of the Civil Aviation Regulations 1988. That regulation imposes additional requirements when any part of the flight control system is assembled, adjusted, repaired, modified or replaced. It typically requires a functional test and certification by a licensed engineer. That obligation is separate from the AD and must be satisfied during any maintenance on the elevator system.

Non-compliance with an airworthiness directive is a serious breach of Australian aviation law. The Civil Aviation Act 1988 provides for penalties of up to 50 penalty units (per offence) for an individual who operates an aircraft in a condition that endangers safety, and higher penalties for a body corporate. A penalty unit is currently $313, so the maximum fine for an individual is around $15,650 per offence. More significantly, the aircraft may be grounded by CASA, and the operator may face suspension or cancellation of their air operator’s certificate or maintenance approval. Criminal prosecution is possible if the breach causes or risks serious harm.

The language of this AD itself does not prescribe a specific penalty; it merely states the requirement. Enforcement is through the general enforcement mechanisms of the Civil Aviation Act and regulations. If an operator is found flying a Maule M-4 after the compliance deadline without having performed the colour coding and manual update, CASA can issue a show-cause notice, impose a fine, or in extreme cases seek injunctions. The person who performed the maintenance may also be liable if they failed to bring the AD to the owner’s attention or if they reconnected cables without performing the AD work.

From a practical enforcement perspective, CASA inspectors often check for AD compliance during routine audits or airworthiness reviews. The penalties are a deterrent, but the real consequence for most operators is the disruption of having the aircraft taken out of service for an unscheduled compliance action. The AD’s prospective compliance trigger reduces the chance of accidental non-compliance, but it also places the burden on the operator to maintain awareness of the condition of their elevator control cables.

FAA AD 2008-24-02: The CASA AD explicitly references the US FAA directive. That FAA AD is also mandatory for US-registered Maule M-4 aircraft. For a dual-registered aircraft or an aircraft that is imported from the US, compliance with the US AD does not automatically satisfy the Australian requirement. The CASA AD stands independently. However, the content is essentially identical, so compliance with one likely means compliance with the other in terms of physical actions. The difference is the legal enforcement body and the effective date.

Maule Mandatory Service Bulletin No. 30: This is a manufacturer’s data document. It is incorporated by reference into the directive. The service bulletin itself may contain information about additional inspections or rigging checks. The AD does not modify the bulletin; it simply mandates that the colour coding and caution insertion be done according to it.

Civil Aviation Regulation 42G (1988): This regulation imposes supplementary requirements for flight control system assembly, adjustment, repair, modification or replacement. It typically requires a positive check of the control system for correct direction and freedom of movement before the aircraft is released for service. The Note in the AD reminds operators that the same maintenance event that triggers the AD (disconnecting cables) also engages CAR 42G. This means that the electrician or mechanic performing the cable work must not only do the colour coding but also comply with the separate rigorous testing requirements of 42G. The interaction adds administrative overhead and potential duplication of checks.

Continuing airworthiness management (CASR Part 42): Under Part 42, the registered operator is responsible for maintaining the aircraft in an airworthy condition, which includes compliance with all applicable ADs. This AD must be incorporated into the operator’s continuing airworthiness management system, typically as a task in the approved maintenance schedule. The AD becomes part of the aircraft’s permanent records.

International recognition: Australia generally recognises foreign ADs if the aircraft is imported, but the CASA AD takes precedence for Australian-registered aircraft. The fact that the FAA had already issued its AD suggests a coordinated international safety response.

The source document does not contain any amendment history. The AD number AD/ML-M4/19 suggests that it is the 19th airworthiness directive issued in the Maule M-4 series series, but whether it superseded or amended an earlier directive is not stated. The document itself appears to be the original issue, signed by a delegate of CASA on 22 December 2008 with an effective date of 12 February 2009. There is no reference to a previous version, a compliance date extension, or a later revision. The AD may have been superseded by a later directive or withdrawn, but that information is not within the supplied text. Practitioners should always check the current CASA database to see if AD/ML-M4/19 remains active or has been replaced. The date of the document (2008/2009) suggests it is relatively old, and the aircraft in question may have since been subject to other elevator control ADs. The lack of amendment history in the given material does not mean no changes ever occurred; it simply means the presented text is a single-point-in-time snapshot.

There is no litigation history provided in the source. The AD itself does not mention any court cases or appeals. Airworthiness directives rarely give rise to reported litigation unless a manufacturer challenges the directive’s validity or an accident leads to a negligence claim based on non-compliance. In this case, no such cases are referenced. Given the specificity of the AD (elevator controls on a niche model of light aircraft), it is likely that any disputes were handled administratively by CASA or through internal review rather than in open court. The lack of litigation history suggests the AD was implemented without significant legal challenge. However, operators should be aware that if they contest a CASA enforcement action for non-compliance, they could be involved in proceedings before the Administrative Appeals Tribunal or a state court, but that would be an adversarial response to an enforcement step, not a pre-existing case.

Compliance trigger ambiguity: The requirement to comply “before the next time the elevator control cable is disconnected for any reason or within the next 12 calendar months, whichever occurs first” creates a high risk of inadvertent non-compliance. If an owner has the aircraft in a hangar for unrelated work and a mechanic disconnects the elevator cable (e.g., to remove the tailplane), the owner must have already complied with the AD. If they have not, the aircraft cannot be returned to service until the colour coding and manual update are done. This can cause unexpected delays and costs. The safest approach is to comply early, well before any cable disconnect is likely, to avoid being caught.

Service bulletin not provided: The AD obliges the operator to follow Mandatory Service Bulletin No. 30 but does not reproduce it. The operator must locate and purchase that document from Maule Aerospace Technology. If the bulletin is unavailable or the operator does not realise it is required, the colour coding may be done incorrectly. The AD does not allow a substitute procedure unless an alternative means of compliance is approved. Failure to obtain and follow the bulletin could be considered non-compliance.

Yellow paint durability: The AD requires “yellow enamel paint”. It does not specify a particular product, application thickness, or inspection interval. Yellow enamel can chip, fade or be obscured by dirt or grease. If the paint becomes unreadable, the visual cue is lost. The AD does not require periodic repainting, so a maintainer may not know that the original paint has degraded. An inspector or later owner might consider the faded paint as non-compliance if it is no longer visible. A prudent operator would document the paint application and consider periodic inspection of the marks.

Manual insertion approval: The caution text must be inserted into the FAA-approved maintenance program. For an Australian aircraft, that program is CASA-approved. If the operator simply adds a loose page or inserts a copy of the AD without formal acceptance by CASA (or the delegated continuing airworthiness management organization), the maintenance program might be considered non-approved. The AD provides two allowed insertion methods, but the operator should confirm with their Part 42 or Part 145 organisation that the insertion process meets the required standards.

CAR 42G interactions: The Note about CAR 42G is easy to overlook. That regulation imposes separate requirements when any part of the flight control system is worked on, which may include a dual inspection and a functional test. An operator who complies only with the colour coding and manual update but overlooks 42G could be in breach of another regulation. The interaction also means that if a cable disconnect triggers both the AD and 42G, the maintenance entry must reflect compliance with both.

A step-by-step compliance path is as follows.

1. Locate and obtain the applicable service bulletin. The AD requires compliance with Maule Aerospace Technology, Inc. Mandatory Service Bulletin No. 30 dated 4 March 2008. Contact Maule or an authorised distributor to purchase a copy. US-based resources may have it available for download. Without the bulletin, the precise paint locations and any specific precautions cannot be confirmed.

2. Schedule the compliance action. The deadline is the earlier of the next elevator cable disconnect or 12 months from the effective date (12 February 2009). Given the potential for an unexpected disconnect, the operator should plan to complete the work at the next scheduled maintenance that already involves disconnecting the elevator cable, but no later than 12 February 2010. An even better approach is to complete it as soon as possible, even if no disconnect is planned, to eliminate the risk of being caught later.

3. Perform colour coding. Using yellow enamel paint, colour the four specified parts:

   • (a) the top of the rear elevator control horn,
   • (b) the elevator control cable end attached to the top of the rear control horn,
   • (c) the bottom of the forward elevator control horn,
   • (d) the elevator control cable end attached to the bottom of the forward control horn. Follow the details in the service bulletin for exact application, possibly including surface preparation, masking, and curing time. Ensure the paint is visible and durable. Document the application with photographs or a logbook entry.

4. Insert the caution text into the maintenance program. Choose one of the two methods:

   • Insert a copy of this AD into the FAA-approved maintenance program (e.g., the maintenance manual), or
   • Insert the text found on the bottom of page 3 of Maule Service Bulletin No. 30 into the program. The text to be inserted is: “CAUTION - BEFORE FLIGHT WHENEVER ELEVATOR CABLES ARE RECONNECTED OR NEW CABLES INSTALLED: Always check operation of elevators after a cable reconnect by pulling back on the control and ascertain that the elevators are in the UP position.” The insertion must be done in a way that it becomes part of the approved maintenance data. If the manual is paper, add a page; if electronic, update the file. Keep a record of the insertion date and method.

5. Record compliance in the aircraft logbook. Enter the AD number (AD/ML-M4/19), the date of compliance, a reference to the service bulletin, and a statement that the colour coding and caution insertion have been completed. Include the signature and licence number of the certifying engineer.

6. Consider CAR 42G requirements. If the compliance action is done during a cable disconnect (or any work on the flight control system), ensure that the additional requirements of CAR 42G are also met. This may include a dual inspection or a functional test of the elevator controls for correct direction. Even if no disconnection occurs (e.g., painting done without disassembly), the operator should note that future cable work will trigger 42G.

7. Maintain records for future maintenance. The colour coding should be preserved. The inserted caution text will continue to be part of the manual. Inform any future maintainer that the coding is in place. If the paint deteriorates, arrange for repainting even though the AD does not mandate an interval.

8. Consider alternative means of compliance (AMOC). If complying with the exact steps in the service bulletin is impractical (e.g., the bulletin is unobtainable or the paint is not available), the operator may apply to CASA for an approved alternative. This is not described in the AD itself, but the general provision for AMOCs under the CASR allows a person to propose equivalent or better safety measures. The application should be made before the compliance deadline, as CASA approval can take weeks. Without an AMOC, the strict terms of the AD must be followed.