AD/RAD/85 Amdt 1 - Sandel ST3400 Terrain Awareness Warning System/Radio Magnetic Indicator

The directive operates through several core regulatory concepts typical of airworthiness regulation.

Airworthiness Directive (AD): This is a legally enforceable instrument issued by CASA to mandate corrective action on aircraft, engines, propellers, or components when an unsafe condition exists. ADs are part of the continuing airworthiness framework. Non-compliance renders the aircraft unairworthy and illegal to operate in Australian airspace. The instrument cites FAA AD 2006-16-18 R1 as its counterpart, demonstrating the practice of regulatory harmonisation: CASA often adopts or adapts FAA directives given the global nature of aircraft manufacturing and operation. However, it remains a separate Australian legal requirement, not merely a reference. Note 2 makes clear the FAA AD is the accepted alternate method of compliance (AMOC) reference.

Applicability: The directive applies to a specific population of units: Sandel ST3400 TAWS/RMI units approved under FAA TSO C113, C151a, or C151b, as identified in Sandel Service Bulletin SB3400-01 Rev B. It does not apply to all ST3400 units or all aircraft types. The note lists many potential aeroplane models, but it is not exhaustive. The legal effect is that any operator of an aircraft with a unit that falls within the applicability must comply, even if their specific model is not listed. This is a common source of confusion; operators must determine applicability based on the unit’s TSO and service bulletin status, not just aircraft type.

Requirements: Four numbered requirements:

1. Placard installation: A placard stating "NOT FOR PRIMARY VOR NAVIGATION" must be affixed to the TAWS/RMI, following the manufacturer’s service bulletin.
2. AFM revision: The Limitations section of the applicable Aircraft Flight Manual must be revised to include a statement prohibiting use of the ST3400 for primary VOR navigation unless the indicator has software 3.07 or A3.06 or later. This may be done by inserting a copy of the directive itself into the AFM - a pragmatic compliance shortcut.
3. Software upgrade: Field-load updated software (revision 3.07 for S/N under 2000, A3.06 for S/N 2000 and subsequent) within 90 days. Later revisions are acceptable. After upgrade, requirements 1 and 2 placard/AFM revisions may be removed.
4. Installation ban: As of the original effective date (25 December 2006), unmodified units may not be installed as new or replacement spares.

Compliance timeframes:

• Requirements 1 and 2: within 14 days after 31 July 2008 (the amendment’s effective date).
• Requirement 3: within 90 days after 31 July 2008.
• Requirement 4: unchanged, meaning it has been in effect since 25 December 2006. This retrospective effect may catch operators who were unaware of the original directive.

Background: The directive’s justification is a single FAA report of an in-flight bearing error. The original AD was issued to prevent a bearing error that could cause deviation from flight path, reducing separation from other aircraft or terrain, and potentially leading to collision. This is a classic risk-based regulatory trigger: one incident (or one reported error) precipitates mandatory action across an entire fleet. The cost-benefit analysis is not published. The directive does not disclose how many units are affected in Australia, the probability of the error occurring, or the expected accident reduction. The implicit assumption is that the cost of compliance is outweighed by the risk of a catastrophic event. That assumption is not tested in the instrument.

The primary duty-holders are aircraft operators and aircraft owners who use the Sandel ST3400 TAWS/RMI in Australian registered aircraft. This includes airlines (Airbus, Boeing, Bombardier, etc.), charter operators, corporate flight departments, and private owners of the listed aeroplane models. In practice, the affected aircraft are largely corporate jets, regional turboprops, and some older airliners, reflecting the ST3400’s typical installation. The directive also affects maintenance organisations (including approved Part 145 repair stations) that perform installation, removal, or software loading on these units. They must have access to the service bulletin and the correct software load and must ensure placarding and AFM revision are completed to the required standard.

Original equipment manufacturers (OEMs) and suppliers: Sandel Avionics is directly affected because its service bulletin is the compliance method authorised. The directive effectively mandates that Sandel produce and distribute the updated software (or authorise later revisions). If Sandel goes out of business or stops supporting the ST3400, compliance becomes problematic. Similarly, third-party distributors of ST3400 units are prohibited from selling unmodified units for installation on Australian aircraft as spares, which may disrupt their inventory.

Dealers and lessors: Aircraft lessors may have contractual obligations to maintain the aircraft in an airworthy condition. The directive imposes costs that may fall on lessees or lessors depending on lease terms. The ban on installation of unmodified spares affects lessors that own multiple units.

CASA itself is the regulator. The directive demonstrates CASA’s resource commitment to monitor foreign ADs and issue domestic equivalents. The compliance burden on CASA includes receiving reports, possibly auditing compliance, and processing any applications for alternative methods of compliance (AMOC). Note that the directive explicitly accepts later revisions of the Sandel SB approved by the FAA as an AMOC to the FAA AD, which streamlines Australian compliance but delegates some authority to the FAA.

Indirect effects fall on passengers and insurers. Passengers benefit from reduced risk of bearing error, though that risk was already very low. Insurers may adjust premiums for operators that comply versus those that do not, but the directive makes compliance mandatory, so non-compliance itself is a legal risk.

The directive does not affect the general public directly. It is a narrow, technical instrument aimed at a specific part population. However, the economic incidence is concentrated: the costs fall on a small number of operators who must individually bear the modification cost. There is no fund or cross-subsidy from other aviation participants.

The directive creates a clear set of duties, with corresponding rights.

Duty to comply with timeframes: The operator must complete placard and AFM revision within 14 days of 31 July 2008. Failure to do so means the aircraft is not compliant and cannot lawfully be operated. The software upgrade must be completed within 90 days. The operator has no discretion to extend these deadlines unless CASA issues a specific extension (which is not mentioned in the directive). The 14-day window is short; operators with multiple aircraft may find it challenging to schedule labour and procure placards in that period.

Duty to follow the approved method: The directive explicitly prescribes compliance in accordance with Sandel ST3400 Service Bulletin SB3400-01 Rev B. It also accepts later revisions approved by the FAA as an AMOC to FAA AD 2006-16-18. However, the operator must ensure that the revision used is indeed approved. If a later revision is not yet an FAA-approved AMOC, the operator cannot rely on it. This imposes a monitoring duty: the operator must track FAA AMOC approvals. The directive does not give CASA the exclusive right to approve AMOC; it defers to FAA approvals for later SB revisions. This is efficient but creates a potential gap if the FAA approves something the FAA deems equivalent but CASA has not separately assessed.

Right to remove placard and AFM revision after upgrade: Once the software upgrade is completed (Requirement 3), the operator may remove the placard and revert the AFM limitations. This is a significant right: it restores full functionality of the ST3400 for VOR navigation. The operator must ensure the upgrade is properly logged and evidenced, as a future maintenance release or audit may require proof.

Right to use later software revisions: The directive states that revisions later than 3.07 or A3.06, as applicable, are considered acceptable for compliance. This is important because it allows operators to install the latest software without needing a separate CASA approval, as long as the newer revision is covered by the same service bulletin family. However, the ambiguities: does “later revisions” include those not yet released? Yes, but the operator must still verify the installation procedure is documented and approved. If the manufacturer issues a later revision that changes hardware requirements, it may not be covered.

Right to install modified units: After the software upgrade has been accomplished on a unit, it can be installed as a spare or as initial installation. The directive only prohibits installation of unmodified units. So an operator may install a modified unit on a different aircraft type without additional AMOC if the unit is already compliant. However, the applicability is based on the unit itself, not the aircraft model. So if a modified ST3400 is installed on a model not listed, it might still be affected if the unit is of the type described in the applicability. This is a subtle point: the directive applies to the unit, not just the listed aircraft. Operators should assume any aircraft with an ST3400 falling under the TSO and SB scope must comply regardless of listing.

Right to maintain the unit unmodified if the aircraft is never operated: The directive does not require removal of unmodified units from aircraft that are never flown (e.g., stored or grounded). The ban on installation only applies to active installation. However, if the aircraft is later returned to service, the unit must comply by the effective dates. An owner could keep a stock of unmodified units for non-flying purposes, but that is of limited practical use.

The directive itself does not set out specific penalties; as a legislative instrument, it is enforceable under the general enforcement provisions of the Civil Aviation Act 1988 and the Civil Aviation Safety Regulations 1998. The main penalty for operating an aircraft that does not comply with an applicable airworthiness directive is that the aircraft is deemed not airworthy. Operating a non-airworthy aircraft is an offence. Under the Civil Aviation Act, the maximum penalty for a contravention involving safety can be substantial (for corporations, up to 2,000 penalty units; for individuals, up to 500 penalty units or imprisonment, or both). As of the time of writing, one penalty unit is $313 (subject to indexation), so a corporation could face up to $626,000 per offence. Directors and officers may also be personally liable if they authorised or were reckless as to the contravention.

CASA can also take administrative action: it can suspend or cancel an aircraft’s certificate of airworthiness, issue directions, or ground the aircraft immediately if there is an imminent safety risk. In practice, CASA may issue a “safety confirmation” requiring the operator to demonstrate compliance before further flight.

The enforcement burden falls on the operator to prove compliance, usually through maintenance records. If an operator fails to upgrade the software within 90 days, any flight after that date would be illegal. The 14-day placard/AFM requirement is similarly absolute.

The directive provides no defence of ignorance or limitation of liability. An operator who purchased an aircraft with an uncleared AD still must comply.

CASA’s enforcement discretion is broad. In practice, CASA may issue a warning letter or infringement notice for minor or first-time non-compliance, but repeat or flagrant breaches can lead to prosecution. The directive does not create a private right of action; only CASA can enforce.

One gotcha: the directive’s requirement 4 is stated as “Remains unchanged as ‘As of 25 December 2006 (the effective date of the original issue of this Directive)’.” This means that any installation of an unmodified unit after that date (which is now almost 18 years ago if we are reading this in 2024) has already been illegal. An operator who replaced a unit in 2007 with an unmodified unit was in breach even if they were unaware of the original directive. The limitation period for prosecution under Australian federal law is generally 2 years for summary offences but 10 years for indictable offences. Depending on the offence classification, past breaches may still be prosecutable. This creates potential retrospective liability.

The directive is explicitly part of a cascade of regulatory interactions.

Interaction with FAA regulations: The directive is based on FAA AD 2006-16-18 R1. It harmonises Australian requirements with US requirements for the same equipment. For an Australian operator that also operates aircraft under US registration (e.g., an Australian charter company operating a US-registered aircraft), they must comply with both ADs. Since the Australian directive accepts later SB revisions approved by the FAA as an AMOC, the compliance paths are aligned. However, the Australian timeframes differ from the original FAA AD. Operators must check whether the FAA AD has different compliance dates (the original FAA AD is referenced but not reproduced). This can cause confusion: an operator who complied with the FAA AD later may have missed the Australian dates.

Interaction with other CASA airworthiness directives: This is one AD among many. An aircraft may be subject to multiple ADs simultaneously. Compliance with AD/RAD/85 does not relieve the operator from complying with other ADs that might apply to other components. There is no provision for prioritisation or extension due to conflicts. The operator must schedule compliance for each AD individually.

Interaction with the Aircraft Flight Manual (AFM): Requirement 2 mandates a revision to the AFM Limitations section. The AFM is an approved document; its revision must be accomplished in accordance with the aircraft type certification basis and may require CASA approval if it is not inserted as a temporary copy of the directive. The directive permits insertion of a copy of the directive itself, which is a practical means of temporary revision. However, once the software upgrade is completed, the operator must ensure the AFM is reverted to its original state (or a new approved version). Failure to remove the limitation could create operational confusion or unnecessary restrictions.

Interaction with Parts Manuals and Maintenance Manuals: The placard installation and software upgrade must be recorded in the aircraft’s continuing airworthiness records. If the aircraft’s maintenance program references the service bulletin, compliance is straightforward. If not, the operator must amend the program.

Interaction with leasing and contract law: Leases often require the lessee to maintain airworthiness and comply with all mandatory ADs. The cost of compliance falls on the lessee unless the lease provides otherwise. The ban on installation of unmodified spares may affect spares pooling agreements.

Interaction with export/import laws: If an Australian operator exports the ST3400 unit (e.g., as a spare), the directive does not directly apply outside Australia. But the unit may be subject to the FAA AD in the destination country. Exporting a non-compliant unit could be lawful in Australia, but the buyer may refuse it.

Interaction with state and territory law: The directive is binding on all aircraft in Australian territory but does not create rights or duties under state tort law. However, compliance could be evidence of due diligence in a negligence claim after an incident.

Interaction with international treaty obligations: Australia is a signatory to the Chicago Convention, and CASA’s adoption of FAA standards promotes the goal of international harmonisation. There is no conflict with ICAO standards here.

The document labelled “AD/RAD/85 Amdt 1” indicates it is an amendment to a previous directive. The background states: “The original issue of this Directive became effective on 25 September 2006.” The original issue would have been AD/RAD/85 (no amendment number). That original directive contained the same four requirements but without the flexibility for later software revisions. The amendment (Amdt 1) was signed on 20 June 2008 and becomes effective on 31 July 2008.

The amendment changes specifically: (a) it allows later software revisions than those originally specified (revision 3.07 or A3.06) to be acceptable for compliance; (b) it clarifies that the placard and AFM revisions may be removed after the software upgrade is accomplished; (c) it updates reference to Sandel Service Bulletin SB3400-01 Revision B (presumably the original issue referred to an earlier revision, though that is not stated); (d) it changes compliance dates: the original dates would have been from 25 September 2006; now new deadlines run from 31 July 2008 for those who have not already accomplished the earlier requirements.

The amendment also adds Note 2 citing FAA AD 2006-16-18 R1. The original issue may have cited the base FAA AD without the revision. The amendment also clarifies that later SB revisions approved by the FAA as AMOC to the FAA AD are acceptable for the Australian AD.

No further amendments are shown in the source. The directive appears final. No revocation date is given. The AD remains in force until the unsafe condition is resolved through design changes that render the unit not susceptible to the fault, or until CASA rescinds the AD. The software upgrade requirement may be considered a terminating action; once the upgrade is done, the AD is largely spent for that aircraft, but the AD itself remains on the books for the unit population.

From a procedural perspective, the amendment was signed by a Delegate of CASA (James Coyne) on 20 June 2008. It appears to be an ex parte administrative action; there is no indication of public consultation or comment period. ADs are typically issued without prior notice due to safety urgency, but this amendment came nearly two years after the original, suggesting it was not an emergency.

The amendment history is limited. For a full picture, one would need to consult CASA’s AD register to see if AD/RAD/85 has been further amended or replaced. The source does not provide that information. As of writing this deep dive, that information is not in the source, so it cannot be extrapolated.

The source document does not refer to any litigation. There is no mention of court cases, appeals, or administrative review. This is typical for routine ADs. Airworthiness directives are often not litigated because the compliance cost is low relative to litigation cost and because the safety imperative makes challenges risky. However, there are broader contexts worth noting.

In Australia, ADs are legislative instruments subject to disallowance by Parliament under the Legislation Act 2003. They can also be challenged on judicial review grounds (e.g., lack of procedural fairness, unreasonableness, error of law). The source does not indicate any such challenge for AD/RAD/85 or its amendment. It is likely that no judicial review occurred.

At common law, an operator who suffered loss from a defective AD (e.g., if the directive turned out to be based on erroneous data) could potentially seek damages from CASA for misfeasance in public office, but that would be an uphill battle. There is no record of such a claim here.

In the United States, the underlying FAA AD may have been subject to challenge, but that is not relevant for Australian law.

The aviation industry generally accepts ADs as cost of doing business. Non-compliance may lead to CASA enforcement action, which could result in civil penalty proceedings or even criminal prosecutions in the Federal Court. Again, no such case is referenced.

Thus the litigation history for this instrument is essentially none. This does not mean it is unimportant; it means the instrument has not been tested in court. That may be because the requirements are straightforward, the compliance costs are manageable, and the industry is law-abiding. It may also be because the alternative (legal challenge) is more expensive than just fitting the placard and loading software.

Several subtle traps await an unwary operator.

Trap 1: The 14-day compliance window for placard and AFM revision counts from the amendment’s effective date (31 July 2008) even if the aircraft is overseas or in maintenance shutdown. There is no provision for extension. If the aircraft is in heavy maintenance with no access to the flight deck, the operator must still have the placard fitted and AFM revised within 14 days, even if that means delaying other work. Ignoring the DFW (duty to comply) during downtime is still non-compliance if the aircraft later flies without the changes.

Trap 2: The placard must state “NOT FOR PRIMARY VOR NAVIGATION”. The service bulletin specifies the exact wording, size, colour, placement. Using a generic placard or a computer-printed label may not comply. The operator must follow the SB exactly. Using a hand-written label taped to the unit is unlikely to be acceptable. Also, if the placard is removed after software upgrade, the operator must physically remove it; leaving it in place could cause operational confusion.

Trap 3: The AFM revision method - inserting a copy of the directive - is only a temporary revision. The operator must ensure that after the software upgrade is done, the AFM is restored to its approved state. If the operator leaves the temporary revision in place, the AFM would contain a limitation that is no longer applicable. That might be considered a non-compliance with the AFM regulations (which require the AFM to be current and accurate). Also, if the aircraft is sold or leased during the period between compliance and removal, the new operator may not know to remove the limitation.

Trap 4: Requirement 4 retroactively bans installations since 25 December 2006. If an operator installed a modified unit after that date but before the amendment (e.g., in 2007) they need to check if the unit had been upgraded to the required software. If not, that installation was also non-compliant. This could create a chain of non-compliance: the initial installation was illegal, and any subsequent flight in that configuration was illegal. The operator may need to ground the aircraft and rectify, even if the unit has since been upgraded.

Trap 5: Later software revisions - “are considered acceptable for compliance” - but only if they are incorporated via a version of the service bulletin that is an FAA-approved AMOC. If Sandel releases revision 4.00 but the FAA has not specifically approved it as an AMOC to the AD, the operator cannot rely on that revision. The operator must ensure the revision they load is covered by the service bulletin chain referenced. The directive uses past tense: “later revisions of the above SB, approved by the FAA as an AMOC to FAA AD 2006-16-18, are considered acceptable.” This implies that each later revision requires FAA approval. A revision that is not yet approved is not acceptable. Operators must monitor FAA AMOC status.

Trap 6: The ban on installation of unmodified units also applies to installations performed by the operator themselves. An operator cannot buy a used ST3400 unit from an aircraft salvage yard and install it without verifying it has been upgraded. The operator must ask for proof of compliance.

Trap 7: The directive does not specify record-keeping requirements, but the operator must maintain evidence of compliance. A typical CASA audit would ask for the maintenance entry showing the placard installation, the AFM revision, the software load log, and the removal of placard/AFM revision. If these records are incomplete, the operator may be deemed non-compliant even if the work was done.

Trap 8: The reference to FAA AD 2006-16-18 R1 means the operator must obtain a copy and understand its requirements. The Australian directive does not reproduce the FAA AD; it just references it. The FAA AD may contain additional details, such as specific compliance timeframes for the original FAA AD or alternative methods that are not automatically accepted in Australia. Relying solely on the Australian directive could lead to gaps.

**Trap 9: The directive was issued in 2008. If an aircraft has been imported into Australia after that date with a ST3400 that was never modified, the new operator must immediately comply. The 14-day and 90-day clocks start from the date the aircraft becomes subject to the Australian regulatory system. However, the original compliance dates have long passed. CASA may have issued a later compliance bulletin or could consider the operator in breach from the moment of import. The operator must verify compliance prior to import.

Compliance requires a systematic approach. The operator should take the following steps, assuming they are affected as per the applicability.

Step 1: Determine applicability. Check if the aircraft is fitted with a Sandel ST3400 TAWS/RMI that is identified in Sandel ST3400 Service Bulletin SB3400-01 Rev B. Check the unit’s TSO approval (must be C113, C151a, or C151b). If the unit is not from that population, the directive does not apply. If it does, proceed.

Step 2: Check current compliance status. Determine if the unit has ever been upgraded. Check the maintenance records for evidence of placard, AFM revision, and software load. If the software is revision 3.07 (S/N <2000) or A3.06 (S/N >=2000) or later, the software requirement is met. If it is earlier, the unit is non-compliant.

Step 3: For units that have never been upgraded, accomplish within 90 days of 31 July 2008 (or immediately if the dates have passed). However, since this is a historical AD, new operators must comply immediately. The procedure is:

• Obtain Sandel ST3400 Service Bulletin SB3400-01 Rev B and a copy of the new software (revision 3.07 or A3.06 or later approved revision). If the later revision is used, confirm it is an approved AMOC to FAA AD 2006-16-18.
• Perform the field-load per the SB. This may require access to the aircraft, a maintenance technician with appropriate avionics training, and a protected work area.
• After loading, verify the software version using the unit’s self-test or maintenance mode.
• Record the software load in the aircraft maintenance log.

Step 4: For all affected units (whether upgraded or not), accomplish placard installation (Requirement 1):

• Procure a placard with the exact text “NOT FOR PRIMARY VOR NAVIGATION”. Ensure it is durable and legible.
• Install it on the TAWS/RMI unit in accordance with the SB. The SB likely specifies a location on the bezel or near the display.
• Record the placard installation.

Step 5: Revise the AFM limitations (Requirement 2):

• Insert a copy of the AD/RAD/85 Amdt 1 into the AFM, or otherwise incorporate the required statement. The statement must say: “Use of ST3400 TAWS/RMI for primary VOR navigation is prohibited unless the indicator has 3.07 or A3.06 software or later.”
• If the AFM is an electronic document, the insert method may be impractical. The operator may need a formal amendment. Check with the manufacturer or CASA. For paper AFMs, insertion is accepted.
• Record the revision.

Step 6: For units that are upgraded later, after the software load is done, you may remove the placard and remove or delete the AFM limitation. Do not remove the placard before the software upgrade, even if you have it on order.

Step 7: If the unit has never been upgraded and you are installing it as a new or replacement spare, you must upgrade it before installation. Requirement 4 bans installation of unmodified units as of 25 December 2006. So any spare unit held in inventory must be upgraded before it is installed.

Step 8: Maintain records. Keep copies of the service bulletin, software load evidence, placard installation record, AFM revision record, and any subsequent removal. These records should be easily retrievable for CASA audit.

**Step 9: If the aircraft is sold or leased, provide the new operator with a record of compliance. The removal of placard/AFM limitation may not be obvious to subsequent operators if not documented.

Step 10: Monitor for later SB revisions. If a newer revision than 3.07/A3.06 is released and approved by FAA as AMOC, you may install it. But you do not have to upgrade beyond the original requirement unless the software fix changes the hardware compatibility.

**Step 11: If you have difficulty obtaining the software or service bulletin, contact Sandel Avionics or its authorised representatives. Do not perform a non-approved modification. If time compliance cannot be met, apply to CASA for an extension or AMOC. But note the original 14-day and 90-day dates were in 2008; any current non-compliance is already a breach.

**Step 12: If the aircraft is being exported and the unit is not upgraded, consider doing so to satisfy the destination country’s AD. But the Australian AD does not expire upon export.

In summary, compliance is a one-time exercise per unit, involving a specific set of steps. The most onerous part is the software load and ensuring the service bulletin and software are obtained. Given the age of the directive, most units in service would already be compliant. New owners of affected aircraft should verify compliance as part of the pre-purchase inspection. Non-compliance exposes the operator to serious legal penalties, potential grounding, and liability.