Separation issue

Boeing 767-238, VH-EAL

Safety Action

As a result of this and other occurrences, the Bureau of Air Safety Investigation is investigating two perceived safety deficiencies. The first relates to the use of conditional clearances for runway entry and runway crossings by vehicles and aircraft, and the procedures used by air traffic controllers to alert themselves that vehicles and aircraft are on an active runway. The second relates to the inappropriate use of paragraph 29 of the Manual of Air Traffic Services 6-2-3 by aerodrome controllers.

Any safety output issued as a result of this analysis will be published in the Bureau's Quarterly Safety Deficiency Report.

Significant Factors

A conditional clearance authorising the surface movement controller to clear CZH to cross runway 34 was issued to the surface movement controller by the aerodrome controller.
The aerodrome controller's training officer was not aware that a conditional clearance was active when he instructed the aerodrome controller to clear EAL for take off.
There was no tactile memory marker alerting the controllers that an aircraft had been cleared to cross an active runway.
The aerodrome controller did not scan runway 34 before issuing the take-off clearance.
Neither the aerodrome controller nor the training officer cancelled EAL's take-off clearance when they became aware that CZH was crossing runway 34.

Analysis

The investigation revealed that the local practice for issuing a conditional clearance for a taxiing aircraft to cross an active runway might have been deficient. When a taxiing aircraft needed to cross an active runway, coordination was required between the surface movement controller and the aerodrome controller. If traffic conditions permitted, it may have been possible to issue the taxiing aircraft with an immediate clearance to cross the active runway. However, at other times, a taxiing aircraft may have been issued with a conditional clearance, authorising it, for example to cross the active runway after a landing aircraft had vacated the runway.

When a conditional crossing clearance had been issued, the continued safe operation of the system was dependent on both the surface movement controller and the aerodrome controller remembering that this traffic coordination had been arranged and was still pending. Interviews with controllers and observation of current work practices indicated that the coordination between the surface movement controller and the aerodrome controller for conditional clearances was verbal only. Neither controller used any form of memory aid to record the fact that a conditional clearance had been issued and was still pending. In this occurrence, this led the aerodrome controller, at a time of high workload and possible stress, to forget that a conditional crossing clearance was pending.

In addition, the training officer was not aware that a clearance had been coordinated between the surface movement controller and the aerodrome controller. Because the system did not provide any physical record that a conditional clearance was pending, there was no cue to alert the training officer to the fact that this was the case.

The use of memory markers recording actions by annotation or other means, assists controllers in remembering vital operational information in two ways. Firstly, the associated actions that the controller carries out in setting the memory marker assist in the consolidation of a strong memory trace. Secondly, the marker can be checked at any time by the controllers if they are uncertain of the current status of the item or condition that it refers to.

Summary

After landing on runway 27 at Melbourne during land and hold short operations, VH-CZH, a Boeing 737, vacated the runway via the parallel taxiway Echo which crossed runway 34 at a distance of 2,333 m from the threshold. The surface movement controller instructed the crew to hold short of runway 34 because VH-OGK, a Boeing 767, was landing.

VH-EAL, a Boeing 767, was taxiing for a runway 34 intersection departure at taxiway Juliet, 773 m from the runway 34 threshold. The co-pilot was the flying pilot. OGK had just landed on runway 34 and was vacating at the high-speed taxiway Foxtrot, 1,588 m from the runway 34 threshold. The aerodrome controller instructed the crew of EAL to line up and wait.

EAL's crew had noted VH-NKN, a Beech 1900, on final approach for runway 27. When OGK was clear of runway 34, the aerodrome controller cleared EAL for an immediate take-off. NKN was on a practice instrument landing system approach to runway 27 and was approximately at the outer marker. The aerodrome controller requested the crew of NKN to reduce to minimum approach speed.

The pilot in command of CZH reported that he saw OGK vacate runway 34 at taxiway Foxtrot and then received a clearance to cross runway 34. As CZH began to cross the runway, the crew observed EAL lining up with its landing lights on. At about one-half to two-thirds of the way across runway 34, the co-pilot of CZH commented to the pilot in command that it looked like EAL had started to roll for take-off. The pilot in command confirmed this and both pilots monitored EAL's progress. The forward section of CZH was well clear of the runway but the rear section was believed to be obstructing the runway when the crew noticed that EAL's take-off had been rejected. Both pilots observed the spoilers of the B767 extend.

At the time EAL was cleared for immediate take-off, its crew was not aware that CZH was crossing 34 at taxiway Echo. As they started to roll, the pilot in command saw that CZH had crossed about two-thirds of the width of the runway and estimated it would be well clear and so continued with the take-off. When the aircraft was at about 90 kts, the pilot-in-command heard the instruction "stop immediately" transmitted twice, took control from the co-pilot, applied reverse thrust and slowed the aircraft before exiting runway 34 at taxiway Foxtrot.

The controllers

The aerodrome controller was undergoing re-familiarisation training under the supervision of a rated training officer. Both controllers had extensive aerodrome control experience. The surface movement controller had worked at Melbourne tower since April 1998 and was a rated surface movement controller. He was not trained in aerodrome control at Melbourne.

The traffic management plan and outcome

The aerodrome controller had planned for CZH to cross runway 34 after OGK had turned to exit runway 34 via taxiway Foxtrot. A conditional clearance was issued to the surface movement controller to this effect. The conditional clearance was "after Qantas 33 has vacated the runway, cross runway 34", which was acknowledged by the surface movement controller. The training officer said that he was not aware of the interchange. The aerodrome controller's plan, which was endorsed by the training officer was to hold EAL in the lined-up position on runway 34 while CZH crossed the runway and while NKN landed on runway 27.

Although the training officer had endorsed the plan, the speed of NKN on final for runway 27 was erratic and as a result, his mental model changed. He perceived that there was an opportunity for EAL to take off before NKN landed. The training officer considered that the new plan was desirable because another aircraft was on long final for runway 34 and there was a possibility that it would have to go-around behind, or over EAL. The training officer reported that he did not think that the aerodrome controller had noticed the performance of NKN on final, which meant that the opportunity for it to land and the plan to work was diminishing.

The training officer conveyed the new plan to the aerodrome controller, who then cleared EAL for an immediate take-off. The aerodrome controller scanned the runway and noticed CZH crossing at taxiway Echo. The training officer reported that he was not aware that CZH had been cleared to cross runway 34 until after the take-off clearance was issued to the crew of EAL. The controllers both reported that they did not immediately cancel the take-off clearance issued to EAL because they assessed that CZH would be clear of the runway before EAL commenced the take-off roll. The rationale for this decision was based on their interpretation of Chapter 6 of the Manual of Air Traffic Services.

The aerodrome controller monitored the position of NKN, which was "getting close". He did not feel comfortable with the developing situation and instructed EAL to cancel departure. This transmission was made 21 seconds after clearing EAL to take-off. EAL started to roll and the aerodrome controller transmitted "EAL, stop immediately". When EAL continued to accelerate, the aerodrome controller transmitted again "EAL, stop immediately, stop immediately." The crew acknowledged this transmission, applied reverse thrust and slowed before exiting the runway at taxiway Foxtrot. The controllers both reported that the motivator for the cancellation of the take-off clearance was the potential for EAL to conflict with NKN on final to runway 27, rather than the potential for EAL to conflict with CZH, which was crossing on runway 34.

ATS procedures

The Manual of Air Traffic Services includes instructions for the control of departing and arriving aircraft within the traffic circuit and on the movement area of an aerodrome. Chapters 6 and 12 were relevant to this occurrence scenario.

Occurrence summary

Investigation number	199803972
Occurrence date	23/09/1998
Location	Melbourne, Aero.
State	Victoria
Report release date	10/12/1999
Report status	Final
Investigation type	Occurrence Investigation
Investigation status	Completed
Mode of transport	Aviation
Aviation occurrence category	Separation issue
Occurrence class	Incident
Highest injury level	None

Aircraft details

Manufacturer	The Boeing Company
Model	767
Registration	VH-EAL
Serial number	23306
Sector	Jet
Operation type	Air Transport High Capacity
Departure point	Melbourne, VIC
Destination	Sydney, NSW
Damage	Nil

Aircraft details

Manufacturer	Beech Aircraft Corp
Model	1900
Registration	VH-NKN
Sector	Turboprop
Operation type	Air Transport Low Capacity
Departure point	Williamtown, NSW
Destination	Melbourne, VIC
Damage	Nil

Aircraft details

Manufacturer	The Boeing Company
Model	737
Registration	VH-CZH
Serial number	23660
Sector	Jet
Operation type	Air Transport High Capacity
Departure point	Adelaide, SA
Destination	Melbourne, VIC
Damage	Nil

Beech Aircraft Corp B200C, VH-AMB

Safety Action

As a result of this and other occurrences, together with a systemic investigation of the Class G Airspace demonstration, the Bureau of Air Safety Investigation issued interim recommendation IR980253 to the Civil Aviation Safety Authority on 8 December 1998:

"The Bureau of Air Safety Investigation believes that the Class G Airspace Demonstration has served its purpose. In the light of the safety concerns identified by this investigation, BASI recommends that the Civil Aviation Safety Authority should now terminate the demonstration. The results of the demonstration should be subject to a comprehensive evaluation that specifically addresses the safety concerns identified by BASI.

The evaluation process should take into account the time required to:

review and analyse the demonstration;
refine the model where required and conduct a proper safety analysis; and
provide a comprehensive and effective education and training program for any subsequent changes to Class G Airspace.

If this is not achieved, the deficiencies identified in this investigation are likely to be repeated, thereby seriously compromising the successful introduction of future changes to airspace including reintroduction of Class G Airspace incorporating Radar Information Service and National Advisory Frequency".

The Bureau of Air Safety Investigation simultaneously issued the following related interim recommendations to the Civil Aviation Safety Authority:

"IR980260

The Bureau of Air Safety Investigation recommends that the Civil Aviation Safety Authority review program management policies and procedures for current and proposed changes to the aviation system, in the light of experience gained from the present Class G Airspace Demonstration.

IR980261

The Bureau of Air Safety Investigation recommends that the Civil Aviation Safety Authority, the Department of Transport and Regional Services and Airservices Australia review and clarify the roles and responsibilities of the respective organisations in relation to the regulation, design and management of airspace to ensure the safety integrity of the aviation system".

The Bureau of Air Safety Investigation simultaneously issued IR980261 to the Department of Transport and Regional Services and Airservices Australia as IR980256 and IR980257 respectively.

Subsequently, the Minister for Transport and Regional Services announced in Parliament on 9 December 1998 that the demonstration would cease on 13 December 1998.

Significant Factors

The Beech pilot and the Saab crew did not hear the taxi or departure transmissions from each other on the MBZ frequency.
The air traffic control radar was unable to detect aircraft at an altitude that would have enabled the controller to provide pilots with timely traffic information.

Analysis

The pilots of both aircraft were reliant on mandatory radio broadcasts to gain an awareness of other traffic operating within the confines of the MBZ. It is possible that they had simultaneously broadcast their respective taxi reports, thus blocking each other's transmissions. However, it is more likely that radio transmissions were inhibited by terrain shielding, resulting in neither crew being aware of the other aircraft while they taxied and departed. The demonstration procedures created a situation where pilots had one opportunity to become aware of other traffic. If they missed an MBZ broadcast, there was no other formal procedure to provide that information.

If a directed traffic information service had been in place at the time of this occurrence, a potential confliction would have been recognised by a third party. Traffic information would have been provided to the Beech pilot and the Saab crew, even if the MBZ reporting procedures had failed. In the past, the directed traffic information service provided a level of redundancy to the aviation system that was not available during the Class G airspace demonstration.

The radar information service was limited by the inability of the radar to detect aircraft at relatively low altitudes in that area. Despite attempts to obtain a radar advisory service as soon as possible after departing Lismore, the Beech pilot was unable to obtain traffic information from the radar controller. Supplementation of the radar information service with a directed traffic information service in such an area of limited radar coverage, would have enhanced the situational awareness of the respective flight crews. Alternatively, the provision of radar coverage from ground level to the lower limit of controlled airspace, together with a radar information service for taxiing aircraft, would have also minimised the potential for confliction.

A conflict was ultimately avoided because the pilots were using the air traffic control frequency. This was despite the fact that both aircraft were still operating within the MBZ and monitoring the MBZ frequency.

Summary

A Beech 200 was conducting an instrument flight rules (IFR) flight from Lismore to Glen Innes. The pilot gave a departure report to the Brisbane Sector 2 radar controller, and reported climbing through 3,500 ft. The controller advised that there were no other aircraft observed on the radar display. That departure report was also heard by the crew of an IFR Saab SF-340 that had just departed Casino on a flight to Williamtown, via Point Lookout. The Saab was climbing through 2,700 ft when the crew became aware that both aircraft were approximately 5 NM south-west of Lismore. The Saab crew descended to 2,500 ft, in order to establish 1,000 ft vertical separation from the Beech. The Saab crew subsequently saw the Beech pass from left to right, about 1 NM in front of their aircraft, as the Beech climbed through patches of cloud just under the main cloud base of 4,000 ft. The Beech pilot also saw the Saab pass below his aircraft.

Due to their proximity to each other, Lismore, Ballina and Casino aerodromes were encompassed by a non-standard Mandatory Broadcast Zone (MBZ), and used a common radio frequency of 124.2 MHz. The MBZ was approximately 60 NM long and 30 NM wide, and extended from the ground to 5,000 ft above ground level. The intent of the common frequency was to enable pilots operating at any of those aerodromes to hear transmissions from other pilots, so that they could coordinate operations in order to minimise the risk of conflict. Pilots were required to monitor the MBZ frequency when operating within the MBZ. They were also required to broadcast flight details when inbound to, taxiing at, and departing from an aerodrome within the MBZ.

The pilots of both aircraft had made the required broadcasts; however, neither received a response from any other aircraft. While taxiing at Lismore, the Beech pilot had monitored a transmission on the MBZ frequency from another pilot, but disregarded it as that aircraft was operating in the Ballina area. A recording device was installed at Lismore aerodrome to monitor aircraft using that facility. The majority of recorded transmissions from aircraft operating at Lismore were clear. Transmissions recorded from aircraft operating at Ballina and Casino were generally clipped or garbled, and more difficult to understand. The Saab crew later reported that pilots of aircraft on the ground at Lismore were unlikely to hear radio transmissions from aircraft on the ground at Casino, and vice versa.

At the time of the occurrence, both aircraft were operating in non-controlled Class G demonstration airspace. As part of that demonstration, modified procedures had been introduced, including the removal of the directed traffic information service previously provided by flight service, and the introduction of a radar information service provided by air traffic control. The provision of that service to pilots was dependent upon their aircraft being radar-identified. The secondary surveillance radar code from the Beech was not detected by the air traffic control radar system until it had climbed through an altitude of 3,300 ft. The Saab was not detected until it had climbed through approximately 3,000 ft.

Prior to the commencement of the demonstration, pilots of IFR aircraft were provided with traffic information on other IFR aircraft, in accordance with guidelines detailed in the Manual of Air Traffic Services and the Aeronautical Information Publication. Pilots operating an IFR flight from a non-controlled aerodrome were required to contact flight service by radio when taxiing. A flight service officer would then provide traffic information to pilots of conflicting aircraft that were not on the MBZ frequency. Based on that procedure, the Saab crew and Beech pilot would not have been provided with mutual traffic information, as they were both operating on the MBZ frequency at about the same time. However, traffic information was required to be passed to pilots of IFR aircraft climbing or descending through the level of another conflicting IFR aircraft. The overriding intent of the traffic information service was to issue such information if there was any doubt regarding the possibility of a confliction.

The Beech pilot had requested radar service information from air traffic control while taxiing at Lismore. The controller issued the pilot with a secondary surveillance code for the flight and advised that a radar information service would be provided when the aircraft was identified on radar, and that there were no other aircraft observed in the area.

Both aircraft were fitted with dual very high frequency (VHF) radio transmitters and receivers. The pilots were monitoring the MBZ frequency on one receiver while also monitoring the air traffic control frequency on the second receiver, in preparation for requesting a clearance to enter Class E controlled airspace at 8,500 ft. The Beech pilot stated that he normally would not have monitored the air traffic control frequency until passing 4,000 ft, but decided to contact the controller early to request the radar information service. Prior to the commencement of the demonstration period, pilots would normally have simultaneously monitored the MBZ and flight service area frequencies to assist in maintaining their situational awareness during the departure phase.

Occurrence summary

Investigation number	199804984
Occurrence date	10/11/1998
Location	9 km SW Lismore, (NDB)
State	New South Wales
Report release date	22/07/1999
Report status	Final
Investigation type	Occurrence Investigation
Investigation status	Completed
Mode of transport	Aviation
Aviation occurrence category	Separation issue
Occurrence class	Incident
Highest injury level	None

Aircraft details

Manufacturer	Beech Aircraft Corp
Model	200
Registration	VH-AMB
Serial number	BL-131
Sector	Turboprop
Operation type	Aerial Work
Departure point	Lismmore, NSW
Destination	Glen Innes, NSW
Damage	Nil

Aircraft details

Manufacturer	Saab Aircraft Co.
Model	340
Registration	VH-SBA
Sector	Turboprop
Operation type	Air Transport Low Capacity
Departure point	Casino, NSW
Destination	Williamtown, NSW
Damage	Nil

Separation issue involving a Diamond DA 40 and a Cessna 172, Brisbane West Wellcamp, Queensland, on 23 April 2020

Brief

Occurrence Briefs are concise reports that detail the facts surrounding a transport safety occurrence, as received in the initial notification and any follow-up enquiries. They provide an opportunity to share safety messages in the absence of an investigation.

What happened

On 23 April 2020, the pilot of a Diamond DA 40 was conducting a solo navigation flight from Gold Coast, Queensland to Brisbane West Wellcamp (Wellcamp), Queensland. On the same day, the pilot of a Cessna 172 was conducting a return solo navigation flight from Gold Coast and had planned to conduct circuit training at Wellcamp on the return leg.

The standard circuit altitude at Wellcamp is 2,500 ft for piston aircraft utilising a non-standard right-hand circuit for runway 12 to avoid high terrain to the north-east of the runway. At about 1430 Eastern Standard Time, the pilot of the DA 40 overflew active runway 12 at Wellcamp at 3,500 ft with the intention of descending on the dead side^[¹^] to join a right circuit. Around this time, the 172 was approaching the aerodrome from the west. Both pilots reported broadcasting on the common traffic advisory frequency (CTAF).

The pilot of the DA 40 conducted two descending orbits to join at the correct circuit height and as the aircraft turned back towards the runway to join midfield, the pilot detected the 172 on a converging track (Figure 1) and manoeuvred the aircraft to increase separation.

The two aircraft passed within close proximity, resulting in a vertical separation of approximately 100 ft and a horizontal separation of 300 m.

Figure 1: Relative flight paths and position of detected conflict (Diamond DA40 represented by green line, Cessna 172 represented by red line)

Source: Google Earth. Annotated by the ATSB

The 172 pilot had made an inbound call at 10 NM stating that they were, ‘on descent to 2,500 for midfield crosswind for left base runway 12.’ The pilot reported being aware of the requirement to conduct right-hand circuits for runway 12 but recalled hearing traffic already in the circuit area conducting left circuits and elected to follow the existing traffic. A descent to circuit height was conducted on the dead side for a left circuit; however, this resulted in the aircraft tracking in the opposite direction to circuit traffic at the same height. After the 172 pilot observed the DA 40 pass in close proximity, a CTAF call was made to query the runway direction, which was relayed as the published right-hand circuit. The 172 pilot elected to discontinue the approach to Wellcamp and climbed away on the dead side of the circuit before continuing on the navigation exercise.

Operator comments

The operator of the 172 has advised the ATSB that during their internal investigation, it was apparent that there was some confusion as to what direction circuits were actually being conducted prior to the arrival at Wellcamp. Although the query regarding circuit direction was made late by the pilot, this action avoided any further conflict.

Safety message

This incident highlights the need for pilots to consult the En Route Supplement Australia (ERSA) when flying to an unfamiliar aerodrome. As illustrated by this incident, not all non-controlled aerodromes follow the same procedures. Being aware of local traffic procedures helps pilots to anticipate the likely position of other aircraft.

Additionally, this incident reinforces the need for pilots to maintain situational awareness and a vigilant lookout at all times. This is especially important when operating at non-controlled aerodromes where pilots are responsible for monitoring and broadcasting their intentions on the CTAF as effective communication is vital to the prevention of potential conflicts developing. Research conducted by the ATSB has found that insufficient communication between pilots contributes to a breakdown of situational awareness. Further information about operating safely at non-controlled aerodromes can be found on the ATSB website, A pilot's guide to staying safe in the vicinity of non-controlled aerodromes and the CASA website, Radio procedures in non-controlled airspace.

The ATSB SafetyWatch highlights the broad safety concerns that come out of our investigation findings and from the occurrence data reported to us by industry. One of the priorities is Non-controlled airspace.

About this report

Decisions regarding whether to conduct an investigation, and the scope of an investigation, are based on many factors, including the level of safety benefit likely to be obtained from an investigation. For this occurrence, no investigation has been conducted and the ATSB did not verify the accuracy of the information. A brief description has been written using information supplied in the notification and any follow-up information in order to produce a short summary report, and allow for greater industry awareness of potential safety issues and possible safety actions.

__________

Dead side: The area on the opposite side of the runway to where the circuit is flown.

Occurrence summary

Mode of transport	Aviation
Occurrence ID	AB-2020-022
Occurrence date	23/04/2020
Location	Brisbane West Wellcamp
State	Queensland
Occurrence class	Incident
Aviation occurrence category	Separation issue
Highest injury level	None
Brief release date	29/07/2020

Aircraft details

Manufacturer	Diamond Aircraft Industries
Model	DA 40
Sector	Piston
Operation type	Flying Training
Departure point	Gold Coast, Queensland
Destination	Brisbane West Wellcamp, Queensland
Damage	Nil

Aircraft details

Manufacturer	Cessna Aircraft Company
Model	172S
Sector	Piston
Operation type	Flying Training
Departure point	Gold Coast, Queensland
Destination	Gold Coast, Queensland
Damage	Nil

Separation issue involving a Diamond DA40 and a de Havilland Canada DHC-1, Warren Reservoir, South Australia, on 15 September 2019

Brief

What happened

On 15 September 2019, a Diamond DA40 was operating a dual training flight with an instructor and a student pilot on board from Strathalbyn to Parafield, South Australia. The pilot of a de Havilland Canada DHC-1 was also airborne at the same time after departing Parafield on a private flight.

The crew of the DA40 reported that during cruise at 2,500 ft on track for Dam Wall, they received a TCAS alert on an aircraft directly ahead on a reciprocal heading. Shortly after, the instructor observed the outbound DHC-1 at the same altitude, took control of the aircraft, and turned left to increase separation.

The pilot of the DHC-1 reported that upon leaving Sub Station and setting a course to the east, he saw an aircraft in the distance and perceived it not to be a risk as he judged his track would take him south of the inbound aircraft for Parafield. At the position given by the other pilot, he reported he was on climb to 3,500 ft and would have been clear of any aircraft operating at 2,500 ft.

Both the instructor and student of the DA40 and the pilot of the DHC-1 report monitoring the Adelaide Approach radio frequency and did not hear any radio calls from the other aircraft.

Safety message

This incident highlights the need for pilots to maintain situational awareness and a vigilant lookout at all times. Most aircraft conflicts in uncontrolled airspace are due to ineffective communication between pilots operating in close proximity, the incorrect assessment of other aircraft’s positions and intentions, and relying on the radio as a substitute for an effective visual lookout.

The ATSB’s SafetyWatch highlights broad safety concerns that come out of our investigation findings and from the occurrence data reported to us by industry. One of those priorities is Non-controlled airspace.

About this report

Occurrence summary

Mode of transport	Aviation
Occurrence ID	AB-2019-035
Occurrence date	15/09/2019
Location	24 km E of Parafield, South Australia
State	South Australia
Occurrence class	Incident
Aviation occurrence category	Separation issue
Highest injury level	None
Brief release date	24/10/2019

Aircraft details

Manufacturer	Diamond Aircraft Industries
Model	DA40
Sector	Piston
Operation type	Flying Training
Damage	Nil

Aircraft details

Manufacturer	De Havilland Canada/De Havilland Aircraft of Canada
Model	DHC-1
Sector	Piston
Operation type	Private
Damage	Nil

Separation event involving a Cessna 441 and a Beechcraft B200, Dubbo, New South Wales, on 12 November 2018

Brief

What happened

On 12 November 2018 at approximately 1300 Eastern Daylight-saving Time, the pilot of a Cessna 441 was on a westerly approach to Dubbo Airport, New South Wales. On the same day, a Beechcraft B200 and a Piper PA-31 were also on approach to Dubbo; with the B200 inbound from the south-east and the PA-31 from the south-west. Both the 441 and the B200 were given aircraft traffic by Melbourne Centre^[¹^], advising both crews that the B200 was arriving first for runway 05 followed by the 441 and PA-31.

Just prior to reaching the 5 NM point from the airport, the crew of the B200 reported their position on the Dubbo common traffic advisory frequency (CTAF) and requested a position update from the 441. The crew of the 441 advised that they were passing WI. Upon realisation of the potential confliction, the crew of the B200 informed the 441 of their converging track and requested the 441 conduct an orbit to maintain separation. At about the same time the crew of the 441 received a TCAS alert alerting them that the conflicting traffic was 1 NM away. They immediately conducted an orbit to the left until it was clear to resume their approach.

Pilot comments

Pilot of Cessna 441

The pilot advised that throughout their approach, they were in communication with the crew of the PA-31 coordinating their approach via the CTAF. Because of the multiple radio transmissions on the CTAF and with Melbourne Centre, they were unable to communicate with the crew of the B200 earlier.

Safety message

This incident highlights the need for pilots to maintain situational awareness and a vigilant lookout at all times. This is especially important when operating at non-controlled aerodromes where pilots are responsible for monitoring and broadcasting their intensions on the CTAF. Research has found that the most hazardous phases of flight are within 5 NM of an aerodrome and at an altitude below 3,000 ft, as there is a higher traffic density within this area.

Further information about operating safely at non-controlled aerodromes can be found on the ATSB website A pilot's guide to staying safe in the vicinity of non-controlled aerodromes and CASA website Operations at non-controlled aerodromes.

About this report

__________

The Melbourne flight information region (FIR) includes the southern half of Australia and the Southern and Indian oceans. The centre is directly responsible for en route services throughout the FIR.

Occurrence summary

Mode of transport	Aviation
Occurrence ID	AB-2018-121
Occurrence date	12/11/2018
Location	Dubbo
State	New South Wales
Occurrence class	Incident
Aviation occurrence category	Separation issue
Highest injury level	None
Brief release date	21/12/2018

Aircraft details

Manufacturer	Cessna Aircraft Company
Model	441
Sector	Piston
Operation type	Charter
Destination	Dubbo, NSW
Damage	Nil

Aircraft details

Manufacturer	Beech Aircraft Corp
Model	B22
Sector	Piston
Operation type	Aerial Work
Destination	Dubbo, NSW
Damage	Nil

Separation event involving BRM Aero Bristell and Vans RV-8, Bathurst Airport, New South Wales, on 27 April 2018

Brief

What happened

On the afternoon of 27 April 2018, a BRM Aero Bristell was conducting flight training at Bathurst Airport, New South Wales. During final approach to runway 17 at, the crew observed a Van's RV-8 on short final approach to runway 35. The crew of the Bristell conducted a go-around^[¹^] and manoeuvred to the dead side^[²^] of runway 17 to maintain separation and visibility of the RV-8 on final for runway 35 while trying to contact the RV-8 by radio with no response. The Bristell re-joined the circuit and both aircraft landed without further incident.

It was later established that the pilot of the RV-8 had not selected the appropriate radio frequency for Bathurst and was distracted by glider operations on runway 08 and had not seen the Bristell until after landing.

Figure 1: Separation sequence of events at Bathurst Aerodrome

Source: Google Earth image annotated by ATSB

Safety action

As a result of this occurrence, the RV-8 pilot advised the ATSB that they will in future write the relevant frequencies of the destination aerodrome on the flight plan in the pilot notes area, to have them readily available in flight.

Safety message

Maintaining situational awareness of your surroundings is a key element of safe operations in the vicinity of non-towered aerodromes. Pilots should:

maintain effective lookout
use radio to supplement un-alerted see and avoid
be aware that other aircraft may not be on the correct frequency or broadcasting.

Appropriate radio broadcasts made on the correct frequency within 10 NM of non-towered aerodromes whilst maintaining good visual scanning is eight times more effective than normal lookout in detecting and avoiding other traffic.

The ATSB booklet A pilot’s guide to staying safe in the vicinity of non-controlled aerodromes outlines many of the common problems that occur at non-controlled aerodromes, and offers useful strategies to keep yourself and other pilots safe.

The Civil Aviation Safety Authority (CASA) has produced several publications and resources that provide important safety advice for operations at, or in the vicinity of non-towered aerodromes.

About this report

__________

To abandon the landing and make a fresh approach [Cambridge Aerospace Dictionary]
Side of airfield or active runway away from that of the circuit pattern in use. [Cambridge Aerospace Dictionary]

Occurrence summary

Mode of transport	Aviation
Occurrence ID	AB-2018-062
Occurrence date	27/04/2018
Location	Bathurst Airport
State	New South Wales
Occurrence class	Incident
Aviation occurrence category	Separation issue
Highest injury level	None
Brief release date	16/11/2018

Aircraft details

Manufacturer	Van's Aircraft
Model	RV-8
Sector	Piston
Operation type	Private
Departure point	Bathurst Airport, NSW
Damage	Nil

Aircraft details

Manufacturer	BRM Aero S.R.O.
Model	Bristell
Sector	Sport and recreational
Operation type	Flying Training
Departure point	Bathurst Airport, NSW
Damage	Nil

Aircraft separation issue involving Glaser-Dirks DG-1000S and a Cessna aircraft, Bathurst Airport, New South Wales, on 27 April 2018

Brief

What happened

On 27 April 2018 at approximately 0905 Eastern Standard Time, a Glaser-Dirks DG-1000S glider aircraft (the glider) was conducting solo training in the left-hand circuit of runway 08 at Bathurst Airport, New South Wales. As the glider made its downwind radio call, a Cessna aircraft broadcast that it was taxiing for runway 35. The pilot of the Cessna acknowledged a further call made by the glider ground controller that there was a glider training in the circuit area.

Several seconds later the glider turned onto the left base of the circuit and broadcast, “turning left base, runway 08”.

Later, as the glider was turning final for runway 08, the Cessna broadcast its rolling call on runway 35. Recognising the potential separation issue at the intersection points of runways 08 and 35, the glider ground controller called “ABORT, ABORT, ABORT, glider on final runway 08”.

The Cessna pilot brought the aircraft to a full stop prior to the intersection and the glider landed on runway 08 without incident. The Cessna pilot then backtracked and departed from runway 35.

Figure1: Diagram of Bathurst Airport showing indicative aircraft position

Related occurrences

A search of the ATSB database revealed a similar occurrence that took place at Bathurst Airport in 2016:

AO-2016-034

On 13 April 2016, an instructor and student of a Jabiru J170-D aeroplane, registered 24-7750 (7750), conducted a local training flight from Bathurst Airport, New South Wales. At about 1446 Eastern Standard Time, the aircraft arrived in the circuit, and the instructor broadcast that they were joining the circuit on an early downwind for runway 17, for a full-stop landing.

Powered aircraft were operating on runway 17 and gliders (and towing aircraft) were operating on runway 08.

Meanwhile, a student pilot of a Glaser-Dirks DG-1000S glider, registered VH-NDQ (NDQ) was conducting a solo flight at Bathurst. At about 1449, about 90 seconds after the pilot of 7750 had communicated with Glider Ground regarding glider traffic in the air, the pilot of NDQ broadcast on the Bathurst CTAF that they were on left downwind for runway 08.

After 7750 touched down on runway 17, about 100 m before the intersection with runway 08, the pilot sighted a glider (NDQ) on short final for runway 08, at an estimated 100 feet above ground level. The pilot applied full power to cross runway 08 as quickly as possible.

As 7750 landed, the pilot of NDQ assessed that there was the potential for a collision, closed the glider’s airbrakes and initiated a climb to pass over 7750. The glider then landed ahead on runway 08.

The instructor in 7750 lost sight of NDQ as it passed overhead. As 7750 accelerated with a high power setting, the instructor elected to continue a take-off and conducted a circuit before landing safely.

Safety message

While in this case, the incident did not result in a near collision, the safety message remains the same between the two occurrences.

Simultaneous operations on crossing runways can be problematic, particularly where the operation types are different (such as powered flight and gliding operations). Organisations responsible for the coordination and conduct of such activities are encouraged to carefully assess and manage the risks involved. This is particularly important when operations are likely to involve instructional flights and less experienced pilots, where workload and the potential for pilot distraction may be elevated.

This incident highlights the importance of effective communication. The primary purpose of communications on the CTAF is to ensure the maintenance of appropriate separation through mutual understanding by pilots of each other’s position and intentions. Where a pilot identifies a risk of collision, that pilot should alert others as soon as possible to allow a coordinated and effective response.

CAAP 166-1(3) - Civil Aviation Safety Authority.pdf (3.83 MB)

stated that ‘whenever pilots determine that there is a potential for traffic conflict, they should make radio broadcasts as necessary to avoid the risk of a collision’.

About this report

Occurrence summary

Mode of transport	Aviation
Occurrence ID	AB-2018-061
Occurrence date	27/04/2018
Location	Bathurst Airport
State	New South Wales
Occurrence class	Incident
Aviation occurrence category	Separation issue
Highest injury level	None
Brief release date	16/11/2018

Aircraft details

Manufacturer	Glaser-Dirks
Model	Glaser-Dirks DG-1000S
Sector	Sport and recreational
Operation type	Gliding
Destination	Bathurst Airport, NSW
Damage	Nil

Aircraft details

Manufacturer	Cessna Aircraft Company
Sector	Piston
Operation type	Unknown
Departure point	Bathurst Airport, NSW
Damage	Nil

Separation issue involving Aero Commander 500-U and Mooney Aircraft Corp M20J, 28 km south-south-west of Bourke, New South Wales, on 18 January 2018

Brief

What happened

On 18 January 2018, an Aero Commander 500-U departed Cobar, New South Wales (NSW), for Charleville, Queensland (Qld). Another aircraft, Mooney M20J, was also airborne at the same time, flying from Broken Hill, NSW, to Archerfield, Qld.

During cruise at 8,500 ft, the pilot of the 500-U observed traffic on their electronic flight bag (EFB) application in their 10 o’clock position at 10 NM. The EFB application indicated the traffic was within 200 ft of the 500-U’s altitude. The pilot of the 500-U reported that the application displayed the relative positions of the two aircraft remained constant and the distance between them was reducing.

The pilot of the 500-U initiated contact with the crew of the M20J, resulting in the M20J descending to 7,500 ft. Two minutes later, the 500-U pilot observed the M20J passing directly underneath, crossing their track at almost 90 degrees.

Airspace

The aircraft passed each other in Class G airspace. Class G airspace is non-controlled airspace in which IFR^[¹^] and VFR^[²^] aircraft are permitted to operate without a clearance. There is no air traffic control separation service in Class G airspace.

Weather

The pilot of the 500-U reported that a grey haze prevented sighting the M20J until it passed directly underneath.

Safety message

This occurrence highlights the importance of following the altitude requirements for VFR flight (see Figure 1) in uncontrolled airspace. This is especially significant when considering the limitations discussed in the ATSB research report Limitations of the See-and-Avoid Principle.

Figure 1: Table of VFR cruising levels

Source: Aeronautical Information Publication Australia

It also highlights the importance of monitoring area frequency for potential traffic and that electronic aids can be used as a supplementary tool that may enhance maintaining situational awareness.

About this report

__________

Instrument flight rules (IFR): a set of regulations that permit the pilot to operate an aircraft in instrument meteorological conditions (IMC), which have much lower weather minimums than visual flight rules (VFR). Procedures and training are significantly more complex as a pilot must demonstrate competency in IMC conditions while controlling the aircraft solely by reference to instruments. IFR-capable aircraft have greater equipment and maintenance requirements.
Visual flight rules (VFR): a set of regulations that permit a pilot to operate an aircraft only in weather conditions generally clear enough to allow the pilot to see where the aircraft is going.

Occurrence summary

Mode of transport	Aviation
Occurrence ID	AB-2018-010
Occurrence date	18/01/2018
Location	28 km SSW Bourke
State	New South Wales
Occurrence class	Incident
Aviation occurrence category	Separation issue
Highest injury level	None
Brief release date	28/03/2018

Aircraft details

Manufacturer	Aero Commander
Model	500-U
Sector	Piston
Operation type	Private
Damage	Nil

Aircraft details

Manufacturer	Mooney Aircraft Corp
Model	M20J
Sector	Piston
Operation type	Private
Damage	Nil

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