Aviation safety issues and actions

Regulatory requirements and guidance for fuel planning of flights to remote islands and isolated aerodromes

Issue number: AO-2014-190-SI-10
Who it affects: All operators and flight crew who conduct flights to remote or isolated aerodromes
Issue owner: Civil Aviation Safety Authority
Transport function: Aviation: Air transport
Background: Investigation Report AO-2009-072
Issue release date: 23 November 2017
Current issue status: Safety action pending

Safety issue description

Although passenger-carrying charter flights to Australian remote islands were required to carry alternate fuel, there were no explicit fuel planning requirements for other types of other passenger-carrying flights to remote islands. There were also no explicit Australian regulatory requirements for fuel planning of flights to isolated aerodromes. In addition, Australia generally had less conservative requirements than other countries regarding when a flight could be conducted without an alternate aerodrome.

Proactive Action

Action number: AO-2014-190-NSA-035
Action organisation: Civil Aviation Safety Authority
Date: 23 November 2017
Action status: Closed

Following the 18 November 2009 accident involving VH-NGA, the Civil Aviation Safety Authority (CASA) conducted a special audit of the operator of VH‑NGA, which involved a detailed examination of the operator’s fuel policy and procedures.

In addition, during the reopened investigation, CASA advised the ATSB that, commencing in December 2009:

CASA conducted checks of all of the [Australian air ambulance] operators with aircraft capable of operating to a remote island aerodrome to ensure that they had a fuel policy that met the requirements for the carriage of "minimum safe fuel"…

CASA inspectors contacted operators or examined relevant operations manuals to ascertain whether there were any relevant issues or potential problems meriting further investigation and/or action by CASA. CASA has not been able to locate documentation recording the abovementioned checks but it is understood the checks did not reveal any issues…

During the original ATSB investigation into the 18 November 2009 accident, the ATSB and CASA had a number of meetings in respect of the general nature of the available fuel planning and fuel management guidance and its possible influence on the development of this accident.

Following these discussions, in July 2010, CASA issued the Notice of Proposed Rule Making (NPRM) 1003OS (Carriage of Fuel on Flights to a Remote Island). The purpose section of the NPRM stated:

3.1.1 The purpose of this NPRM is to consult on a proposed change to CAO 82.0 relating to the carriage of fuel for flights to remote islands. A ‘remote island’ is currently defined as Lord Howe Island; Norfolk Island; or Christmas Island.

3.1.2 Presently, CAO 82.0, subsection 3A requires all passenger-carrying charter flights in aeroplanes to a remote island to carry enough fuel for flight from the remote island to an alternate aerodrome, unless an operator’s operations manual states otherwise. There are no similar provisions for passenger-carrying aerial work, regular public transport (RPT), private or cargo-only charter flights.

3.1.3 The NPRM proposes an amendment to the Order which will require the carriage of enough fuel for flight from a remote island to an alternate aerodrome for all passenger-carrying aerial work, charter and RPT flights in aeroplanes, unless CASA approves otherwise.

3.1.4 The NPRM also proposes to re-designate Cocos (Keeling) Island as a remote island for the purposes of CAO 82.0.

The NPRM also stated:

3.7.4 In addition to changes to the relevant CAO, CASA also intends to review Civil Aviation Advisory Publication (CAAP) 234-1 relating to fuel requirements. This review is being undertaken in two phases: the first to enhance the guidance for fuel planning and in-flight fuel-related decision making on flights to remote destinations (including remote islands); and secondly a holistic review of guidelines for fuel and alternate planning.

3.7.5 The Standards and Recommended Practices (SARPs) promulgated by the International Civil Aviation Organization (ICAO) in relation to fuel and alternate requirements are currently being revised by ICAO, with amendments expected in the next 2 years. CASA is considering these changes and where considered appropriate, will propose to amend the relevant regulations in accordance with the revised ICAO SARPs.

In August 2012, CASA published a new version of CAAP 215-1(1) – Guide to preparation of operations manuals. The CAAP outlined suggested headings for an operations manual section on fuel policy. This included a sub-heading titled ‘conditions for flights to remote islands’.

In December 2014, CASA amended the fuel planning requirements in CAO 82.0 for operations to remote islands so that these requirements applied to RPT operations and aerial work operations involving air ambulance functions (regardless of whether a patient was carried) in addition to passenger-carrying charter flights. The list of remote islands was also amended to include the Cocos Islands.

Proactive Action

Action number: AO-2014-190-NSA-037
Action organisation: Civil Aviation Safety Authority
Date: 23 November 2017
Action status: Closed

In August 2009, CASA commenced a project to review the Australian requirements for fuel and alternates (Project OS 09/13 – Fuel and alternate requirements). The terms of reference noted that the ATSB database had provided evidence that fuel quantity issues were becoming problematic, and it was proposed to strengthen CAAP 234, and to change CAR 234 in order to encourage industry to follow the contents of the CAAP. It also noted proposed amendments to ICAO Annex 6 for fuel and alternate requirements for commercial air transport operations ‘require CASA to explore this issue and identify any potential issues the proposed ICAO amendments may have within the Australian aviation operating environment’.

In addition to changes to the requirements relating to Australian remote islands (see Safety action AO-2014-190-NSA-035), this project has involved various activities in relation to fuel planning.

On 25 June 2012, CASA advised the ATSB that amendment 36 to International Civil Aviation Organization (ICAO) Annex 6, State Letter AN 11/1.32-12/10 detailed a number of new Standards and Recommended Practices (SARP) in regard to fuel planning, in flight fuel management, the selection of alternates and extended diversion time operations (EDTO). In this respect, CASA provided the following update:

CASA intends to review Civil Aviation Advisory Publication (CAAP) 234-1 relating to fuel requirements. The ICAO fuel and alternate Standards and Recommended Practices (SARPs) are the basis of these changes and will be coordinated by CASA project OS09/13. While this project will focus specifically on passenger-carrying commercial flights the project will also be reviewing fuel requirements generally. The project will now be conducted in four phases. The first three phases will involve amendments to the relevant Civil Aviation Order (CAO) applicable Civil Aviation Advisory Publication (CAAP) 234-1 and Civil Aviation Regulation (CAR) 234. The project objectives are as follows:

– Phase 1 will involve amendments to the relevant CAOs and a review of CAAP 234-1 for flights to isolated aerodromes in light of the ICAO amendments. This phase will encompass fuel and operational requirements for flights to isolated aerodromes and will also consider the provision for flight to an alternate aerodrome from a destination that is a designated isolated aerodrome. The CAAP 234-1 will also be expanded to provide guidance and considerations necessary for flights to any isolated aerodrome, in particular when, and under what circumstances, a pilot should consider a diversion.

– Phase 2 will involve amendments to the relevant CAOs and further review of CAAP 234 in light of the ICAO amendments. This phase will encompass regulatory changes related to the implementation of general fuel planning, in-flight fuel management and the selection of alternate aerodromes. This review will include the methods by which pilots and operators calculate fuel required and fuel on-board.

– Phase 3 will involve amendment to CAR 234 to specify that the pilot in command, or the operator, must take reasonable steps to ensure sufficient fuel and oil shall be carried to undertake and continue the flight in safety. In addition, for flights conducted in accordance with Extended Diversion Time Operations (EDTO), CAO 82 and CAR 234 shall be amended to require consideration of a "critical fuel scenario" taking into account an aeroplane system failure or malfunction which could adversely affect safety of flight. It is anticipated that the methods chosen by the pilot-in-command and operator will therefore be sufficient to meet the requirements of CAR 234 to enable a flight to be undertaken and continue in safety.

– Phase 4 will involve the publication of internal and external educational material along with conducting briefings where necessary.

and that:

The amendment to the ICAO Annex 6 standards will be considered, and where appropriate, incorporated into the relevant legislation/advisory publication. In addition it is anticipated that there will be guidance material for operators who can demonstrate a particular level of performance-based compliance. The intent is to provide a bridge from the conventional approach to safety to the contemporary approach that uses process- based methods and Safety Risk Management (SRM) principles.

The ICAO Fuel and Flight Planning Manual are reflected in the SARP to Annex 6. Inclusion of the provisions of the Amendment 36 SARPs will be captured throughout this project. The ICAO SARP becomes effective from November 2012.

CASA will endeavour to make the changes as soon as possible - subject to third party arrangements such as drafting and resource availability. However the timing of the CAR changes will be subject to a timetable that is not necessarily able to be controlled by CASA.

In January 2016, as part of the project commenced in August 2009, CASA issued Consultation Draft (CD) 1508OS – Fuel and oil quantity requirements. The CD included proposed amendments to CAR 234 and CAAP 234. The explanation of the changes stated:

Regulation 234 of the Civil Aviation Regulations 1988 (CAR) requires the pilot-in-command of an aircraft to take reasonable steps to ensure that the aircraft carries sufficient quantities of fuel and oil for the proposed flight to be undertaken safely. The regulation also requires the operator of an aircraft to take reasonable steps to ensure that an aircraft does not begin a flight unless it is carrying sufficient fuel and oil to allow the flight to be conducted safely.

Australian Transport Safety Bureau (ATSB) reports have revealed incidents and accidents directly related to carriage of insufficient quantities of fuel. CASA proposes to address this safety issue by amending regulation 234 of CAR to provide updated fuel and oil requirements.

The current regulation 234 of CAR allows courts to consider any guidelines provided by CASA when determining whether sufficient fuel and oil were carried on a flight, which includes the guidelines provided in CAAP 234-1(1). While some of the information provided in the CAAP should be read as a requirement empowered by the current regulation 234, other information is advisory in nature. CASA intends to the make clearer the distinction between the regulatory requirements and the guidance material by transferring the requirements for determination of fuel and oil quantity from the CAAP to a proposed legislative instrument.

The CD proposed included fuel planning and fuel management requirements in an instrument, referenced by an amended CAR 234. The proposed instrument incorporated the definition of minimum safe fuel for a flight to a remote island from CAO 82.0. However, there were no other changes associated with remote islands or isolated aerodromes.

In March 2017, CASA advised the ATSB:

CASA is continuing, as part of the standards development process for the development of CASR Part 91 (General Operating and Flight Rules), to consider how to address the generalities of the ‘isolated aerodrome issue’. The specific operational parts for air transport (CASR 121/133/135) and aerial work (CASR 138) will subsequently consider whether additional constraints or conditions are needed, or if alleviation is available under certain conditions. These provisions, along with the fuel and alternate determination provisions will be subject to public consultation as part of the operational part suite…

The application of ‘isolated aerodrome’ SARPs is a vexatious issue because it relies on the interaction of the various ICAO SARPs that underpin it. It is very difficult to apply exactly the requirements of one ICAO SARP whilst not applying exactly the others that support it. In this case, the isolated aerodrome SARP relies on the fuel and alternate SARPs. These provisions require, inter-alia, that an alternate be nominated in almost all cases and that fuel quantities be determined on that basis. The isolated aerodrome SARP then allows alleviation from that requirement under certain conditions, most notably, when the nearest alternate is beyond approximately 90 minutes flight time.

Australian legislation has provisions that accommodate our unique infrastructure, particularly the absence of predominately independent runways at many aerodromes supporting air transport operations. The Australian rule set also allows for flights to be conducted without an alternate under certain operating conditions, such as weather above set criteria.

In August 2017 (after receiving the draft ATSB report for the reopened investigation), CASA advised the ATSB:

As mentioned in the report, prior to this accident CASA had already commenced Project OS 09/13 - Fuel and Alternate Requirements – to develop improvements to CASA regulations and orders relating to fuel carriage, fuel guidance and isolated aerodromes policy in light of proposed ICAO changes.

On 23 December 2014, CAO 82.0 was amended to require RPT passenger carrying operations and aerial work operations for ambulance functions or for functions substantially similar to ambulance functions to meet the same remote island requirements that had applied to charter passenger carrying operations at the time of this accident.

As part of this Project, CASA extensively examined the ICAO concept of isolated aerodromes, the historical context that led to the CASA remote island policy in place at the time of the accident and reviewed these in light of technological changes and the scope of Australian aviation operations to the identified remote islands. CASA determined that the implemented policy - that all passenger carrying charter, RPT and aerial work ambulance flights must nominate and plan for an alternate for all remote island operations and that a nominated alternate cannot itself be a remote island - was more conservative than the ICAO isolated aerodrome concept.

More generically, the policy regarding when a flight can be conducted without providing for an alternate aerodrome is being examined as part of Project OS 99/08 - CASR Part 91.

ATSB comment:

The ATSB acknowledges CASA’s safety action has reduced the risk associated with flights carrying passengers to Australian remote islands. The ATSB also notes that Australian major airlines which operate to isolated aerodromes (other than Australian remote islands) have risk controls in place that exceed the current minimum regulatory requirements.

Nevertheless, the ATSB is concerned other types of operators carry passengers on flights to isolated aerodromes both in Australia and internationally, and there are still limited Australian regulatory requirements that specifically address the hazards associated with such flights.

The ATSB acknowledges CASA is still considering changes to fuel planning requirements for isolated aerodromes as part of its project on fuel and alternates. The ATSB also acknowledges the complexity of specifying more detailed regulatory requirements in this area in line with ICAO requirements. Nevertheless, the ATSB is concerned that this matter still has not yet been addressed, and accordingly it issues the following recommendation.


Action number: AO-2014-190-SR-042
Action organisation: Civil Aviation Safety Authority
Date: 23 November 2017
Action status: Monitor

The Australian Transport Safety Bureau recommends that the Civil Aviation Safety Authority continue its work in reviewing fuel planning requirements and guidance and address the limitations associated with requirements and guidance for fuel planning of flights for all types of passenger operations to isolated aerodromes in Australia and internationally.

Additional correspondence

Response date: 21 February 2018
Response from: Civil Aviation Safety Authority (CASA)
Action status: Monitor
Response text:

CASA accepts this recommendation and notes that prior to the accident flight, CASA had already commenced work to address deficiencies in existing legislation and guidance material on fuel planning. In July 2009, four months prior to the accident flight, CASA had commenced the Fuel and Alternates Project (OS 09/13). CASA leveraged its involvement in the International Civil Aviation Organization (ICAO) Operations Panel - Fuel Use Sub-Group (FUSG) to incorporate the ICAO fuel SARP development work into legislation and guidance material, as appropriate.

In the period following the release of the initial investigation report in August 2012 CASA has taken proactive action to advance changes to fuel related legislation and guidance material. The ATSB AO-2009-072 (reopened) report comprehensively covers what CASA has already implemented, including action taken regarding inflight fuel management entries in the AIP ENR 1.1 (based on requirements in ICAO Annexe 6), along with entries in CAAP 215-1(1) and CAO 82.0. ICAO published the initial version of the Flight Planning and Fuel Management Manual (FPFM) in December 2015, which forms the basis of the international standard guidance material for fuel and alternate determination and importantly; in-flight fuel management activities.

These fuel and alternate provisions have been captured in the draft CASR air transport operations Parts for which the commencement date has yet to be determined. In recognition of the importance of the issues and rather than wait for the commencement of these CASR Parts, CASA incorporated the changes into the draft Civil Aviation Amendment (Fuel and Oil Requirements) Regulations 2018 (CAR 234) and the accompanying subordinate Civil Aviation (Fuel Requirements) Instrument 2018. The regulation commencement is anticipated to be coincident with the publication of AIP amendment 96, 16 August 2018 AIRAC date.


ATSB comment:

The ATSB notes the CASA response and will continue to monitor CASA's development and delivery of changes to relevant requirements and guidance.

Response date: 05 July 2019
Response from: CASA
Action status: Monitor
Response text:

On 5 July 2019, CASA provided the following additional information.

In relation to ATSB Safety Recommendations AO-2014-190-SR-042 and AO-2014-190-SR-043 regarding Fuel Planning and In flight Fuel Management CASA provides the following.

Civil Aviation Regulations, 1988 Compilation 98 (the version in force currently) was registered on 4 April 2019 and included an amended CAR 234 establishing the mechanism to prescribe Fuel and Oil requirements for operations.

CAR 234 provides that CASA may issue a legislative instrument prescribing the requirements relating to fuel for aircraft. Instrument 29/18 is that instrument.

In addition to, and in support of, the regulatory provisions relating to fuel requirements noted above CASA updated CAAP 234. The Latest version is version 2.1 (June 2019) and provides additional guidance on fuel management and requirements.

CASA has publicised and promoted these changes with a comprehensive advice page recently updated 23 June 2019 and can be accessed via the CASA website (www.casa.gov.au/aircraft/fuel).

CASA seeks ATSB’s acknowledgement of CASA actions in this regard and views the safety findings as fully addressed and therefore be formally closed.

ATSB comment date: 25 July 2019
ATSB comment:

On 25 July 2019, the ATSB responded to CASA and advised it had reviewed CASR 121, CASR 135 and the CASA 29/18 instrument. However, other than reference to the four specified remote islands, the ATSB could not see any detailed provisions for fuel planning of flights to isolated aerodromes. The instrument did not specify when alternates are required. CASR 121.165 and CASR 135.140 required operator’s to outline their own alternate aerodrome requirements, but we have not seen a MOS or guidance as to what is expected (and whether this will include provisions for isolated aerodromes). CASR 135.190 included some in-flight fuel planning/management requirements for flights without a destination alternate aerodrome but there was no apparent equivalent for CASR 121. However, this dealt more with the inflight fuel management safety issue and recommendation [AO-2014-190-SR-11] than the fuel planning safety issue and recommendation. The term ‘isolated aerodrome’ was used once in the CAAP 234-1 in paragraph 5.4.6 in relation to in-flight fuel management aspects.

The ATSB asked CASA the following questions:

  1. Can CASA confirm whether there are or will be specific requirements for fuel planning of flights to isolated aerodromes (other than the four specified remote islands)?
  2. If there will not be any specific requirements for such isolated aerodromes, can CASA outline how the fuel planning requirements in instrument 29/18, CASR 121 and CASR 135 (and any associated MOS or guidance document) address the risk of planning flights to isolated aerodromes?
Response date: 31 October 2019
Response from: CASA
Action status: Monitor
Response text:

On 31 October 2019, CASA provided the following response to the ATSB questions and some additional information.

CASA Instrument 29/18 will be deleted upon the commencement of the future flight operational CASR Parts in March 2021. Its requirements will be appropriately transcribed into relevant Manuals of Standards.

ATSB question 1: Can CASA confirm whether there are or will be specific requirements for fuel planning of flights to isolated aerodromes (other than the four specified remote islands)?

CASA is planning on introducing rules related to all isolated aerodromes in Part 121. These rules will be contained in the Part 121 Manual of Standards and will be part of the Part 121 alternate aerodrome requirements. An indicative plain English draft of some potential MOS content is available for the ATSB to review within the Part 121 Technical Draft MOS that was part of Part 121 public consultations in 2015 and 2018. However, the legal draft of the Part 121 MOS is yet to be the subject of industry working group consultation or public consultation and therefore the exact final requirements cannot yet be stated with certainty. These consultation activities are planned for later this year (2019).

CASA is not currently planning to specify any requirements related to isolated aerodromes for operations under any other CASR part. Effectively, CASR Part 135 broadly replicates the existing remote islands rules contained in CAO 82.0 and replicates existing alternate aerodrome fuel policies contained in CASA Instrument 29/18. As aerial work air ambulances will be regulated under the future CASR as medical transport operations (a subset of air transport operations) these operations will be captured by Part 121 or Part 135 depending on the type of aircraft used.

Part 133 has not incorporated these remote island rules for rotorcraft due to the limited range of existing rotorcraft. If longer range rotorcraft (such as powered lift or tiltrotor aircraft) were introduced into use by the Australian aviation industry in the future, then CASA would evaluate whether the remote islands rules should be applied to Part 133.

CASA currently considers that the introduction of fully ICAO based isolated aerodrome rules to lower capacity air transport operations under Part 135 does not yet meet an appropriate safety versus cost threshold.

ATSB question 2: If there will not be any specific requirements for such isolated aerodromes, can CASA outline how the fuel planning requirements in instrument 29/18, CASR 121 and CASR 135 (and any associated MOS or guidance document) address the risk of planning flights to isolated aerodromes?

As mentioned, future CASR Part 135 will not include rules related to isolated aerodromes although Part 121 is planned to do so. CASA considers that the risks associated with planning flights to onshore isolated aerodromes are the subject of adequate risk defences by the alternate aerodrome criteria contained within the Part 91 MOS which are applicable to Part 135 and replicate existing alternate aerodrome policies. Australia’s imposition of alternate minima on destination aerodromes, for the Part 135 sector, is considered to provide an appropriate balance of safety and cost at the present time and for the introduction of Part 135 in March 2021.

ATSB comment date: 05 March 2020
ATSB comment:

The ATSB notes that the draft manual of standards (MOS) for Part 121 released for consultation in July 2018 defined an isolated aerodrome as follows:

isolated aerodrome means a destination aerodrome for which there is no alternate aerodrome suitable for a given aeroplane type i.e. insufficient range capability, or if the fuel required (for a turbine aeroplane) to fly to the nearest suitable alternate aerodrome is greater than the fuel required to hold at the destination for 90 minutes.

The draft MOS also stated that each Part 121 flight was required to include destination alternate fuel, which for a destination aerodrome that is an isolated aerodrome meant:

  1. for piston-engine aeroplanes, the amount of fuel required to fly for 45 minutes plus 15 percent of the flight time planned at cruising level, including final reserve fuel, or two hours, whichever is less; or
  2. for turbine-engine aeroplanes, the amount of fuel required to fly for two hours at the cruise altitude and at the normal cruise consumption above the destination aerodrome, including final reserve fuel.

Assuming that the final requirements stated in the draft MOS are similar, this changes would be broadly in line with the fuel planning requirements for isolated aerodromes in ICAO Annex 6 Part I (at least for Part 121 operations).

The ATSB will wait for the final wording of the MOS for part 121 before reassessing CASA’s safety action in response to this recommendation.

Last update 17 March 2020