Civil Aviation Order 20.6 - Continuation of flight with 1 or more engines inoperative

Three legal and operational concepts structure the Order.

1. Licence condition status. Section 2 makes the Order a condition on the flight crew licence of the pilot in command of an Australian aircraft. The form of the instrument is not a general duty applying to all persons; it is a condition attaching to the pilot’s licence. The Order therefore functions within the licensing regime as a prescriptive obligation placed on the licence-holder.

2. Immediate notification duty. Section 3.1 creates an immediate, affirmative communication duty when an engine fails or its rotation is intentionally stopped in flight. The pilot must notify the nearest Air Traffic Services Unit “immediately”, supply “all relevant information” and set out the intended conduct of the flight. “Immediately” is unqualified in the Order, so the temporal requirement is strict within the text; the content requirement is similarly broad through the phrase “all relevant information”.

3. Discretion subject to mandatory factors. Section 3.2 confers discretion to select an aerodrome other than the “nearest suitable aerodrome” but makes that discretion conditional. The pilot may proceed to another aerodrome only if, after consideration of “all relevant factors”, the pilot deems that proceeding both “safe and operationally acceptable.” The Order then prescribes a list of factors that “must” be included in that consideration. The list is extensive and mixes technical performance factors (altitude, weight, usable fuel, distance, risk of another engine failing), environmental factors (weather, terrain, populous areas), operational factors (air traffic congestion, relative characteristics of aerodromes), equipment condition (availability of the inoperative engine to be used) and human factors (pilot familiarity with the aerodrome). The drafting imposes a duty to consider these items, but it does not provide a formula for balancing them; the assessment remains an operational judgement by the pilot.

Other drafting features to note. The Order distinguishes “multi‑engine aircraft” for the permissive discretion in s 3.2, while the immediate notification in s 3.1 applies to any aircraft where an engine fails or rotation is stopped. The Order is silent on definitions (for example, “nearest suitable aerodrome”, “availability of the inoperative engine to be used”, and “operationally acceptable” are not defined inside the text). Finally, the Order records amendment history in the Notes and specifies it was made under identified subregulations of the Civil Aviation Regulations 1988.

The primary legal subject is the pilot in command of an Australian aircraft: the Order is explicitly applied as a condition on the pilot’s flight crew licence (s 2). That means the obligations and discretions in the instrument are owed by licence‑holding pilots for Australian aircraft.

Secondary or consequentially affected parties include:

• Air Traffic Services Units, which are the recipients of the mandatory immediate notifications and intended-action statements (s 3.1). The Order imposes an information obligation flowing to those units when an engine fails or rotation is stopped.

• Aerodrome operators and personnel at whichever aerodrome the pilot selects or to which the pilot diverts. The pilot’s exercise of the s 3.2 discretion may produce traffic, landing requests or emergency arrivals at aerodromes other than the nearest suitable one.

• Aircraft operators and owners. Although the Order addresses the pilot in command directly, decisions taken under the Order (choice of aerodrome, continuation of flight) have operational and financial consequences for operators and owners, including aircraft damage risk, maintenance planning, scheduling, diversion costs and potential interruption to services.

• Passengers and cargo interests. The choice whether to proceed to a selected aerodrome rather than the nearest suitable aerodrome affects arrival times, rerouting logistics, and perceived risk to persons and property.

The Order also affects regulatory administrators indirectly because it is expressed as a licence condition (s 2). The instrument does not itself set out enforcement modalities or penalties, but having the Order as a licence condition means regulators responsible for licences will treat non‑compliance as relevant to regulatory oversight. The Order binds “the pilot in command” where an engine fails or rotation is stopped in flight (s 3.1-3.2), and it differentiates multi‑engine aircraft for the discretionary provision in s 3.2; single‑engine aircraft are not afforded the s 3.2 discretion because the text confines that paragraph to multi‑engine aircraft.

Geographic scope: the Order applies to “an Australian aircraft” (s 2). The text does not limit application by flight phase, airspace or domestic/overseas flights; its application is expressed broadly across Australian aircraft and pilots holding Australian flight crew licences.

The Order sets out a small number of clear duties and a single conditional right.

Mandatory duties

• Notification duty (s 3.1). When an engine fails or rotation is stopped in flight, the pilot in command must notify the nearest Air Traffic Services Unit immediately, provide all relevant information and state the action the pilot intends to take with respect to the conduct of the flight. This is an affirmative and immediate duty to communicate,both the event (engine failure/stop) and the intended course of action must be disclosed to ATS.

• Consideration duty (s 3.2). For multi‑engine aircraft, if the pilot intends to proceed to an aerodrome other than the nearest suitable one, the pilot must consider “all relevant factors” before deciding. The Order expressly states what those relevant factors “must include” (s 3.2(a)-(i), (aa)). The drafting thus imposes a duty to take into account each listed factor in the pilot’s decision‑making process.

Conditional right

• Choice of aerodrome (s 3.2). The pilot in command of a multi‑engine aircraft has the right to proceed to an aerodrome of the pilot’s selection instead of the “nearest suitable aerodrome” provided that, upon consideration of the prescribed factors, the pilot deems such an action “safe and operationally acceptable.” That is a qualified discretion: the right to select a non‑nearest aerodrome exists only where the pilot can justify the decision under the listed considerations.

Prescriptive factor list

• The Order lists mandatory matters to be considered: (a) nature of the malfunctioning and possible mechanical difficulties; (aa) nature and extent of any city, town or populous area likely to be overflown; (b) availability of the inoperative engine to be used; (c) altitude, aircraft weight and usable fuel at time of stoppage; (d) distance to be flown and performance availability should another engine fail; (e) relative characteristics of aerodromes available; (f) weather en route and at landing points; (g) air traffic congestion; (h) type of terrain, including whether flight will be over water; and (i) pilot’s familiarity with the aerodrome to be used (s 3.2).

Content and boundaries

• The Order requires that the pilot “state the action he or she intends to take” when notifying ATS (s 3.1), establishing an expectation of proactive planning rather than mere reporting.

• The Order does not define a hierarchy among the listed factors; nor does it contain objective thresholds (for example, numerical fuel reserves or distance limits). The assessment whether proceeding to a selected aerodrome is “safe and operationally acceptable” is left to pilot judgement informed by the mandatory factor list.

• The Order applies to a pilot in command as a licence condition (s 2), which embeds these duties in the regulatory status of the pilot’s licence.

The Order itself does not specify penalties, sanctions or an enforcement procedure in its text. It is expressed to apply “as a condition on the flight crew licence of the pilot in command of an Australian aircraft” (s 2), which identifies its legal effect but does not enumerate the consequences that flow from a breach.

What the Order does state and what it does not

• Stated: the Order imposes express duties (notification (s 3.1) and consideration of specified factors when choosing an aerodrome for multi‑engine aircraft (s 3.2)) and describes the instrument’s application as a licence condition (s 2).

• Not stated: there are no penalty clauses, infringement notices, specified fines, suspension procedures or explicit enforcement pathways in the Order’s text. The Order’s compilation and Notes record its making under identified subregulations of the Civil Aviation Regulations 1988, but the Order does not reproduce or restate those subregulations’ sanctioning provisions.

Implications for enforcement (source‑grounded limits)

• Because the Order is a condition on the flight crew licence (s 2), regulatory authorities exercising licence oversight will regard compliance with the Order as part of the conditions that the licence-holder must satisfy. The Order does not set out which administrative or disciplinary steps will follow a breach; that detail would be found elsewhere in the regulatory framework under which the licence is issued and enforced, but those instruments are not reproduced in this Order.

• The Order creates evidential touchpoints for enforcement: the immediate notification requirement (s 3.1) generates contemporaneous communications that can be documented; the required consideration of specified factors (s 3.2) creates a standard against which a pilot’s decision can be assessed. The Order does not state how a pilot must document that consideration, or what standard of proof will be applied if the pilot’s decision is questioned.

Practical enforcement considerations visible from the Order

• The Order’s lack of in‑text penalties means enforcement will rely on its status as a licence condition. Regulators will need to show non‑compliance with the duties in s 3.1 or failures in the consideration required by s 3.2 to pursue licence‑related action. The Order provides the substantive description of what compliance requires but not the procedural mechanism for enforcement.

• Cases of disputed compliance will turn on demonstrable facts: whether the pilot notified ATS immediately (s 3.1), and whether the pilot considered the mandatory factors before electing to proceed to a selected aerodrome (s 3.2). The Order supplies the checklist of factors but does not describe how a regulator will weigh them.

The Order is an instrument made under the Civil Aviation Regulations framework; its preamble notes it was made under subregulations 5.11(2) and 303(1) of the Civil Aviation Regulations 1988. The Order’s text does not reproduce or restate those subregulations, but the citation in the preamble establishes the Order’s statutory provenance within the regulatory regime.

Interaction points apparent from the Order

• Licence regime interface. Section 2 makes the Order a condition on the flight crew licence. That situates the Order within the broader licensing and regulatory regime for pilots. Enforcement, sanctioning or licence variation powers that operate in relation to licence conditions are therefore relevant to the Order’s practical effect, but those powers are not set out in the Order itself.

• Operational interface with Air Traffic Services. Section 3.1 requires immediate notification to the nearest Air Traffic Services Unit and an intention statement. That creates a direct operational interface with ATC procedures and ATS units’ responsibilities to manage traffic and emergency handling. The Order does not purport to override any ATC instruction or to define how ATC must respond; it simply creates an information flow from pilot to ATS.

• Interaction with aerodrome operational rules. Section 3.2 contemplates a pilot electing to proceed to an aerodrome of selection rather than the nearest suitable aerodrome. That decision will necessarily intersect with aerodrome operating rules, availability of landing services, and tower or aerodrome acceptance procedures. The Order does not cover aerodrome consent mechanics or whether aerodrome operators may refuse or impose conditions.

• Relationship to aircraft and operator responsibilities. The Order focuses on the pilot in command; it does not address operator obligations (such as maintenance reporting, technical investigation or post‑flight mandatory reporting) that may exist elsewhere. Where those obligations intersect with a pilot’s decision to continue to a selected aerodrome, operators will be affected operationally, but the Order does not itself allocate duties to operators.

Limits and gaps in expressed interactions

• The Order does not define key terms used in interaction contexts,“nearest suitable aerodrome”, “availability of the inoperative engine to be used”, and what exactly constitutes “operationally acceptable”. Those definitions, if needed for cross‑instrument consistency, must be located in other legislative or regulatory texts or in operational guidance; the Order itself does not provide them.

• The Order does not specify whether an ATS instruction can lawfully require a pilot to divert to a particular aerodrome contrary to the pilot’s exercise of the s 3.2 discretion. The Order requires notification and a statement of intended action but does not address conflicts between pilot judgement under s 3.2 and directives that may be issued by ATS under other rules.

• The Order is silent about documentation standards for the required consideration under s 3.2. This leaves open how evidence of compliance is to be produced when the Order’s interaction with other regulatory processes (investigations, licensing reviews) is triggered.

The compilation supplied records the creation and amendment history up to 2010. Key entries and their mechanical effects are recorded in the Notes and the tabular “Table of Orders” and “Table of Amendments”.

Chronology and instruments

• CAO 2004 No. R4: Notified 8 December 2004 and commenced 8 December 2004 (see s 2 of that instrument). The Table of Orders lists CAO 2004 No. R4 as the earlier instrument in the compilation.

• CAO 20.6 2010 No. 1: Registered on FRLI 6 August 2010 and commenced 7 August 2010 (see s 2 of that instrument). The compilation was prepared on 9 August 2010 taking into account amendments up to CAO 20.6 2010 No. 1.

Table of Amendments (provision‑level changes)

• The Notes include a “Table of Amendments” that identifies how s 20.6 was affected by the instruments. The entry for “s. 20.6” shows that the 2004 instrument (2004 No. R4) was the provision affected and that CAO 20.6 2010 No. 1 later amended the CAO title.

• The Table of Amendments records specific shorthand actions against subparagraphs of the provision: “subs. 1” is recorded as added (ad.) by CAO 20.6 2010 No. 1; “subs. 2” is recorded as repealed and substituted (rs.) by CAO 20.6 2010 No. 1; and “subs. 3” is recorded as amended (am.) by CAO 20.6 2010 No. 1. Those notations indicate the structure of s 20.6 was modified by the 2010 instrument, with insertion, substitution and amendment of subparagraphs.

Compilation metadata

• The compilation states it was prepared by the Legislative Drafting Branch, Legal Services Division, Civil Aviation Safety Authority, Canberra, and was current to amendments up to the 2010 instrument (Notes). The Notes explicitly list the two CAO instruments and their commencement dates.

What the amendment history shows functionally

• The Order’s current wording in the compilation reflects the structure and content after the 2010 amendments. The amendment table confirms changes to the subparagraphs and the CAO title, but the compilation does not supply the pre‑amendment text for direct comparison. The Notes provide the formal record of instruments and dates rather than a narrative history of policy intent.

• Practically, any legal or operational analysis of compliance or obligations must rely on the version in the compilation, which incorporates the 2010 amendments. The compilation’s metadata identifies the instruments that produced those changes and their commencement dates.

The compilation of Civil Aviation Order 20.6 provided contains no litigation history, judicial determinations, citations of cases or references to proceedings. It includes the Order text, the Notes on amendments, and the tables recording instruments and amendments; it does not provide or reference decisions that interpret or apply the Order.

What is and is not present in the source

• Present: the Order’s operative text (ss 1-3), the declaration that it applies as a condition on the pilot’s flight crew licence (s 2), the prescribed duties and factor list (s 3.1-3.2), and the compilation Notes recording amendment instruments and dates.

• Not present: any judicial or tribunal decisions, administrative determinations, or appeals that test the Order’s application, including any matters considering what constitutes compliance with “immediately” in s 3.1 or how to weigh the mandatory factors in s 3.2. The Notes and Tables do not list cases.

Implication for legal research and practice

• Absent any litigation recorded in the compilation, advisers and practitioners must treat the Order on its textual terms and, if interpretive guidance is required (for example, defining “nearest suitable aerodrome” or establishing evidential standards for “consideration”), seek interpretation from regulatory guidance, operational manuals, or seek declaratory guidance from relevant administrative bodies. Such sources are outside the compilation provided and are not reproduced in this document.

• Where a dispute may arise about compliance with the Order (for example, if a regulator alleges the pilot did not adequately consider the factors in s 3.2), practitioners should be prepared to address the evidential question of what contemporaneous communications with Air Traffic Services Units (required under s 3.1) and what decision documentation exists to demonstrate consideration of the mandatory factors. The Order itself identifies the points regulators will look to,notification and factor consideration,but does not supply case law or adjudicative interpretations.

The Order is short but contains several drafting features and silences that produce practical and legal risks for pilots, operators and regulators. These are concrete points drawn from the text.

Immediate timing obligation (s 3.1)

• The pilot must notify the nearest Air Traffic Services Unit “immediately” on engine failure or stoppage in flight. “Immediately” is unqualified, which imposes a strict temporal expectation. In practice, this can create tension between immediate safety actions (fly the aircraft) and the requirement to communicate. The Order does not specify how to reconcile competing immediate actions or what minimal written or verbal content satisfies the “all relevant information” requirement in chaotic situations.

Unspecified content scope (s 3.1)

• The duty to provide “all relevant information” and “state the action he or she intends to take” is broad. The Order does not specify examples or a minimum set of data to disclose. That vagueness can expose pilots to second‑guessing about whether sufficient information was provided to ATS.

Undefined terms and thresholds

• The Order uses terms that are not defined within the instrument: “nearest suitable aerodrome”; “availability of the inoperative engine to be used”; “safe and operationally acceptable”. These are material concepts for the pilot’s exercise of discretion under s 3.2 but carry no definitional guidance inside the Order.

• “Availability of the inoperative engine to be used” is a particularly awkward phrase. Its plain text could be read as requiring the pilot to consider whether the inoperative engine can be restored to service during flight, or whether it could be used after landing. The Order does not clarify whether temporary in‑flight restart capability is required, or how to assess that availability.

Mandatory factor list but discretionary balancing (s 3.2)

• The Order mandates that particular factors “must” be included in the pilot’s consideration, but it leaves the overall balancing of those factors to the pilot’s judgement. There is no prescribed weighting or objective yardstick. This combination means pilots carry a duty to consider a long checklist under time pressure and then justify a discretionary call without clear standards in the Order itself.

Geographic/populous area emphasis (s 3.2(aa))

• The inclusion of the “nature and extent of any city, town or populous area over which the aircraft is likely to fly” as a mandatory factor (item (aa)) imposes an express duty to take public safety geography into account. Pilots may face heightened scrutiny if their chosen route or destination implies flight over populated areas, and the Order places that factor within the mandated checklist.

Applicability limited to multi‑engine aircraft for the discretionary provision

• Only the pilot in command of a multi‑engine aircraft is allowed the s 3.2 discretion to proceed to an aerodrome of selection. The Order does not offer corresponding discretion for single‑engine aircraft; the absence is explicit in the text but may produce operational confusion in mixed‑fleet operations where company procedures might be more permissive.

Evidential burden not specified

• The Order does not prescribe how pilots should record their consideration of the mandatory factors. In post‑incident regulatory review, the lack of contemporaneous documentation could make it difficult for pilots to demonstrate that they satisfied the s 3.2 consideration duty.

Silence on post‑decision obligations

• The Order addresses the decision to proceed to a selected aerodrome, but does not specify subsequent reporting, maintenance or operational steps once the flight lands at the selected aerodrome. The Order therefore leaves open how decisions under the instrument integrate with operators’ reporting systems and technical investigation requirements.

Amendment notation without historical text

• The Notes and Table of Amendments record additions, substitutions and amendments (for example, subs. 1 added; subs. 2 repealed and substituted; subs. 3 amended by CAO 20.6 2010 No. 1) but the compilation does not present earlier text for side‑by‑side comparison. Users seeking to understand the policy change introduced by the 2010 amendments will need to consult the earlier instruments directly.

Compliance under the Order requires pilots and operators to translate the immediate notification requirement and the mandatory factor consideration into practicable procedures. The Order itself provides the legal baseline (ss 2-3); below are concrete, source‑grounded steps to satisfy the Order’s textual requirements.

1. Train pilots on the immediate notification duty (s 3.1)

• Establish a standard phraseology and minimum content checklist for the emergency radio call to the nearest Air Traffic Services Unit that satisfies “all relevant information” and states the intended action. Include items such as nature of engine failure, number of engines affected, current position/altitude, fuel onboard (usable fuel), estimated time/distance to nearest aerodromes, intended aerodrome selection and landing intent.

• Reinforce that the duty to notify is immediate; train to ensure that basic pilot‑ flying actions (aviate, navigate, communicate) are sequenced to permit an immediate brief notification as soon as it is safe to transmit.

2. Adopt a decision checklist mapping the mandatory factors (s 3.2)

• Create a short, standard decision checklist that maps directly to the Order’s factors (s 3.2(a)-(i), (aa)). For multi‑engine operations, the checklist should require pilots to expressly consider: the malfunction’s nature and likely mechanical sequelae; whether the inoperative engine can be made available for use; altitude/weight/fuel state; distance and engine‑out performance margin; characteristics of candidate aerodromes; weather at route and aerodrome; air traffic congestion; terrain and water overflight implications; and pilot familiarity with candidate aerodromes.

• Include a rapid tick‑box or electronic capture on the flight deck log or company occurrence reporting system to record the consideration of each factor and the pilot’s rationale for selecting a non‑nearest aerodrome, to create contemporaneous evidence of compliance.

3. Communication with Air Traffic Services (s 3.1 linkage)

• When notifying ATS immediately, include confirmation that the pilot has considered the mandatory factors and state the chosen aerodrome plus the primary reasons for selection (for example, better runway length given current weight, weather conditions, lower traffic, availability of services). This aligns the notification requirement with the decision standard the Order imposes.

4. Operator procedures and SOPs

• Operators should update Standard Operating Procedures (SOPs) and emergency checklists to incorporate the Order’s mandatory factor list and the immediate notification requirement. Make it explicit which cockpit crewmember is responsible for the ATS notification and for documenting the factor consideration.

• Provide training scenarios, simulator exercises and quick reference cards that replicate engine failure-in-flight situations and require pilots to use the checklist and make selection decisions under time pressure.

5. Documentation and recordkeeping

• Maintain an after‑flight report entry that records the occurrence, the ATS communications (time stamped), the factors considered per s 3.2, the aerodrome selected, and the reasons. This will be the primary record demonstrating compliance with the Order’s duties.

• Ensure the occurrence is logged in the aircraft technical log and in the operator’s safety management system records, cross‑referencing the immediate ATS notification entry.

6. Risk allocation and company notification

• Operators should define the protocol for immediate internal notification and escalation when an engine fails or is stopped in flight,so that maintenance, operations control and relevant safety managers are informed sufficiently early to prepare for diversion, passenger handling and technical investigation.

7. Familiarity and aerodrome selection planning

• Where possible, ensure that company routes and crew rostering match pilot familiarity with diversion aerodromes. The Order lists pilot familiarity with the aerodrome as a mandatory consideration (s 3.2(i)); structured training and route exposure reduce the judgemental burden in an emergency.

8. Practical guidance on the “availability” factor

• Because the Order requires consideration of the “availability of the inoperative engine to be used” (s 3.2(b)), operators should incorporate into their engine‑failure procedures guidance on assessing restart probability and in‑flight useability, and require pilots to document that assessment briefly when electing to continue.

9. Integrate with ATC liaison and aerodrome capacity

• Given the duty to notify the nearest ATS unit immediately (s 3.1), operators should have standing agreements or liaison protocols with ATC and preferred diversion aerodromes to streamline landing acceptance and emergency handling.

10. Legal and evidential readiness

• Recognise that the Order imposes duties as a licence condition (s 2). Maintain records that demonstrate compliance with s 3.1 and the factor consideration in s 3.2 to support licence‑based enquiries. Where the operator’s internal procedures require additional steps, ensure those steps do not conflict with the pilot’s immediate duties under the Order.

These measures map directly to the Order’s textual requirements (s 3.1-3.2). The Order does not prescribe documentation formats, specific performance thresholds or penalties; compliance therefore turns on demonstrable exercise of the notification duty and the consideration of the listed factors in the pilot’s decision to proceed to a selected aerodrome.