Loss of separation

Communications

The reason the HF operator was unable to establish two-way communication with the crew of IVC could not be determined. A formal procedure for notifying the controller that the HF radio operator could not pass the instruction to the crew of IVC may not have ensured that a separation standard existed, as an incorrect instruction had been issued. However, it may have prompted a more timely reassessment of the situation by the controller. In other circumstances, a formal procedure may alert the controller in sufficient time for action to be taken before separation standards are infringed.

Air Traffic Controller

A review of the controller's training records indicated that he had an adequate understanding of the concept of lateral separation. However, his misapplication of a lateral separation point may have reflected his lack of proficiency due to inexperience in working the particular sector of airspace.

On 16 June 2004, a Boeing 747-400, registered GC-IVC (IVC), was en-route from Melbourne to Singapore on airway A576. The aircraft was approaching the boundary between the Brisbane flight information region (FIR) and the Bali FIR at flight level (FL) 340. Concurrently, a second 747, registered 9V-SPE (SPE), was en-route from Sydney to Singapore on airway G326. That aircraft was also approaching the boundary between the Brisbane FIR and the Bali FIR at FL 340.

The controller recognised that he had to resolve a potential confliction between SPE and a third aircraft. In resolving that confliction, the controller created a new confliction between IVC and SPE. In response, the controller instructed the crew of IVC to reach FL320 by waypoint ATMAP (see Annex A). That requirement was intended to achieve vertical separation between the aircraft prior to any loss of lateral separation¹. However, the required lateral separation point was 94 NM south-east of waypoint ATMAP on airway A576. The incorrect requirement led to an infringement of separation standards.

Following a scan of the air situation display, the controller realised that he had issued an incorrect requirement. The controller then issued a second requirement, via the high frequency (HF) radio operator, for IVC to descend to reach FL320 by 80 NM to the south-east of waypoint ATMAP. The controller reported that this requirement was based on the application of a required navigation performance (RNP) 10 separation standard². This standard was not authorised for use within the Bali FIR. Upon issuing the requirement, the controller handed over to another controller and went on a scheduled break.

Over a period of 10 minutes and 37 seconds, the HF radio operator made 12 unsuccessful attempts to contact the crew of IVC. The oncoming controller realised that the HF radio operator had not been able to make contact with the crew of IVC. He also realised that RNP 10 was not an authorised standard. By that time the authorised separation standards had already been infringed. The oncoming controller then successfully instructed the crew of IVC to descend their aircraft immediately to FL320, via a controller pilot data link communication³ (CPDLC) message to the crew of another aircraft.

The controller involved in this occurrence had completed his field training in April 2004. A review of his training records indicated that he had approximately five weeks' experience on that sector of airspace. According to his check and standardisation supervisor, the controller demonstrated a satisfactory level of competency on completion of his sector-specific training.

The controller was rostered to work an afternoon shift, which commenced at approximately 1500 eastern standard time. During the shift the controller had a break of one hour, returning to the console at approximately 1930. The incident occurred at 2038. There was no evidence that fatigue played a part in the incident.

Coordination of high frequency radio communications

The controller issued the requirement to the crew of IVC to reach FL320 by waypoint ATMAP while that aircraft was within reliable very high frequency (VHF) radio range. However, when the controller realised the error in the requirement, that aircraft had passed outside VHF radio range. The controller attempted to issue the amended requirement to the crew of IVC through a HF radio operator, because the crew of IVC had not nominated CPDLC on their flight plan as a means of communication with ATC.

The HF radio operator was unable to establish two-way communication with the crew of IVC, to pass the amended requirement, despite repeated attempts. The controller was not aware that the HF radio operator was unable to issue the instruction to the crew of IVC.

The controller did not confirm with the HF radio operator that the instruction had been passed to the crew of IVC, and there was no published procedure requiring him to do so. Although there was a requirement for the HF radio operator to notify the controller that the instruction was not passed to the crew of IVC, there was no formal procedure to facilitate that notification.

¹ Lateral separation is considered to exist when there is at least a 1 NM buffer between the possible positions of two aircraft (ICAO PANS-ATM, Chapter 5 in CASA Manual of Standards Part 172 10.8.1.1).
² For RNP10, the approval process must show that the total navigation system error in each dimension must not exceed +/- 10 NM for 95 per cent of the flight time on any portion of any single flight:
a) the true position of the aircraft must be within 10 NM of the programmed route centre line; and
b) the true distance to way-points must be within 10 NM of the displayed distance to waypoints.' (International Civil Aviation Organization, 1999, Manual on required navigation performance [RNP], second edition, p. 6).
³ Controller Pilot Data Link Communications (CPDLC): A means of communications between a controller and pilot using text-based messages via an ATC data link (Manual of Air Traffic Services, part 10, effective 10 June 2004).

On 22 March 2004, at about 0435 Coordinated Universal Time (UTC), a Boeing Company 767-338ER, registered VH-OGB, and a Boeing Company 767-319, registered ZK-NCF, were involved in a serious incident in the Ujung Pandang Flight Information Region (FIR).

OGB was southbound and NCF was northbound on air route B473, between waypoint OLENG and waypoint OPABA. The crew of OGB advised Ujung Control that they were at OLENG at 0423 and were level at flight level (FL) 350. The crew later reported that they requested approval from Ujung Control to climb their aircraft to FL370. Ujung Control subsequently approved that request. During that climb, and passing approximately FL355, the crew of OGB received a traffic advisory on their aircraft's traffic alert and collision avoidance system (TCAS), followed by a resolution advisory, about NCF. The resolution advisory instructed the crew of OGB to descend their aircraft. The crew complied with the resolution advisory and descended their aircraft to FL350. The crew later reported that, during the descent manoeuvre, they saw NCF pass 600 ft above their aircraft.

NCF was northbound on air route B473, between waypoint OLENG and waypoint OPABA and was level at FL360. The crew later reported that they received a TCAS resolution advisory on OGB, travelling in the opposite direction. The crew of NCF climbed their aircraft in response to the resolution advisory. The crew later reported that they observed OGB on their TCAS, pass 400 ft below them.

The Australian Transport Safety Bureau (ATSB) was advised of the serious incident and commenced an investigation. The crew of OGB was interviewed and data from that aircraft's quick access recorder was analysed. As the incident occurred within Indonesian territory, the Indonesian National Transportation Safety Committee (NTSC) had the responsibility to conduct an investigation in accordance with Annex 13 to the Convention on International Civil Aviation.

On 26 March 2004, the NTSC informed the ATSB that they had commenced an investigation into the incident and the ATSB appointed an accredited representative to that investigation. The NTSC, being the investigation agency of the country in which the incident occurred, will be preparing the report and has control over the public release of any investigation findings.

As a result of another occurrence within an Indonesian FIR, which involved aircraft from the same Australian operator, that operator implemented new procedures to be followed when its aircraft are operating in Indonesian FIRs (see ATSB occurrence report number 200402411).

The Bureau will publish the NTSC report, when released by the NTSC, on the ATSB website.

1. The driver of the catering vehicle became disorientated and entered runway 34L.

When the ADC issued the take-off clearance to the crew of the Airbus, the catering vehicle was a significant distance from both the Airbus and runway 34L. In the circumstances the ADC would have had no indication that the vehicle was likely to enter the runway and pose a potential collision threat to the Airbus.

There was little, if any, action that the ADC could have taken to resolve the situation when it became apparent to him that the vehicle would enter the runway because:

• The catering vehicle was not radio equipped;
• The Airbus crew was committed to the take-off, if not already airborne; and
• Any alert provided to the crew of the Airbus by the ADC may have exacerbated the problem, given the relative position of the aircraft to the vehicle at that time.

While a runway incursion by a vehicle driven by the holder of a category 2 ADA may have been reasonably unforeseeable, this occurrence has identified a significant risk to the safety of operations at Sydney airport.

A means of detecting knowledge gaps and evaluating the ongoing proficiency of qualified drivers may have identified a knowledge deficiency in the area of taxiway and runway markings recognition and in other areas of knowledge that may have contributed to this incursion. Such quality assurance would enable SACL, as the authority responsible for the management and control of surface vehicles operating on, or in the vicinity of, the airside area of the airport, to recognise and address systemic deficiencies in driver competence on an ongoing basis. That would give SACL the opportunity to mitigate any resultant risks.

The driver of the catering vehicle was properly licensed, and had been driving on perimeter roads and apron areas of the airport for two years. Despite her training, the driver may not have been operationally familiar with taxiway and runway markings because she had not operated on runways or taxiways since she obtained her ADA.

None of the training programs included advice to drivers about recommended actions they could take that might assist them should they become lost or disorientated while driving airside. Such a procedure may have reduced the risk of a collision with the departing Airbus in these circumstances by:

• reducing the likelihood of a runway incursion in the first instance; and
• reducing the time the catering vehicle remained on the runway following the incursion.

Sequence of events

On 24 August 2003, at about 0935 Eastern Standard Time, a motor vehicle involved in catering duties on the international apron area at Sydney airport entered runway 34 left (34L) at taxiway Golf without the driver having first received a clearance from air traffic control to enter the runway. At that time, an Airbus A330-341(Airbus) aircraft had just become airborne from runway 34L. The aircraft passed directly over the vehicle while it was on the runway. The runway incursion by the vehicle resulted in an infringement of runway separation standards.

The driver of the vehicle was authorised to drive only on the perimeter roads, airside roads and apron areas. The driver was not aware that she had entered the runway and was not authorised, or trained, to drive on taxiways or runways. The driver eventually realised that she had entered an area of the airport with which she was not familiar. She attempted to return to the apron and was subsequently escorted from the movement area by an airport operations officer.

Sydney Airport Corporation Limited (SACL)

SACL was the airport licence holder and operator of Sydney airport at the time of the occurrence. In accordance with the legislation current at the time of the occurrence, SACL was ultimately responsible for the proficiency of drivers operating airside at Sydney Airport.

Under the Airports (Control of On-Airports Activities) Regulations 1997, part 4, division 4, s124, the airport operator was required to publish an Airside Vehicle Control Handbook (AVCH) for the airport over which it had control. The Sydney airport AVCH contained particulars for the management and control of surface vehicles operating on, or in the vicinity of, the airside area of Sydney airport. The stated 'intent of the requirements for airside operation of vehicles set out in the AVCH [was] to ensure the safe and orderly movement of staff, passengers, aircraft and vehicular traffic'.

SACL was responsible for issuing an authority to drive airside (ADA) to a driver who had an employment requirement to operate a vehicle airside. That responsibility could be delegated to an 'Approved Issuing Authority' (AIA).

'An Approved Issuing Authority is a company or organisation to which SACL delegated the responsibility to carry out the training, testing, and issuance of an ADA for the Airport' and was generally delegated to those organisations that employed airside drivers. SACL maintained overall responsibility for the training and testing standards of Approved Issuing Authorities at Sydney airport. The AVCH stated that AIAs 'must:

• Provide the SACL Manager Safety with reasonable access to its records and premises to enable the SACL Manager Safety to carry out audits to ensure that the AIA is maintaining satisfactory standards in the carrying out of its functions as an AIA; and
• Train and test its employees and employees of its Subsidiaries to drive Airside to the standard required by the SACL Manager Safety'.

Training

Training for a category 2 ADA included information on the recognition of perimeter roadway markings, apron roadway markings, live taxiway crossing markings, runway and taxiway markings. It did not require the driver to be trained in the use of a radio. The catering vehicle was not equipped, nor was it required to be equipped, with a radio suitable for use on an airport to enable two-way communication with air traffic control.

The driver of the vehicle held a current category 2 ADA, having been trained about 2 years previously. A category 2 ADA authorised the driver of an authorised vehicle to operate the vehicle on perimeter roads, airside roads and apron areas of the airport in accordance with the AVCH.

The AVCH specified the prerequisites for applying for the category 2 ADA. They included a requirement for drivers to hold a current State or Territory driver's licence and complete at least 4 hours of driving airside either as an observer or preferably as the driver under the supervision of another driver with at least a category 2 ADA.

Drivers were also required to demonstrate 12 practical and theoretical competencies to an approved training officer.

Category 2 ADA training did not include recommended actions or guidelines for drivers should they become lost or disorientated while driving airside.

Driver reference materials

The airport operator, SACL, produced a pocketbook for use by drivers with a category 2 ADA, and another for use by drivers with either a category 3 or a category 4 ADA. Holders of a category 3 ADA were authorised to operate an authorised vehicle on all movement areas excluding runway strips. Holders of a Category 4 ADA were authorised to operate on all airside areas which included an authorisation to enter a runway strip in accordance with airport procedures. The pocketbooks were intended to be 'a quick reference guide to explain the main rules which apply to all drivers operating airside'. The driver involved in this runway incursion had been provided with a copy of the category 2 driver's pocketbook.

The Category 2 pocketbook did not include recommended actions or guidelines for drivers should they become lost or disorientated while driving airside.

Air traffic control (ATC)

Air Traffic Controllers provided an Air Traffic Service to aircraft on that part of the Sydney aerodrome used for take-off, landing and taxying, excluding the apron areas, for the purpose of preventing collisions between aircraft and obstructions. The aerodrome controller (ADC) was responsible for authorising aircraft, personnel and vehicles to cross a runway or to operate on a runway strip.

The Manual of Air Traffic Services required ADCs to visually scan the length of the runway prior to issuing a take-off clearance and immediately before the take-off is commenced to confirm that the runway was free from obstacles including vehicles and other aircraft. Vehicle operators and pilots were also required to obtain a clearance from ATC prior to entering an active runway, and air traffic controllers operating from the control tower maintained a routine visual surveillance of the manoeuvring area of the airport.

A review of the recorded radar data showed that, when the controller issued a clearance to the crew of the Airbus to enter the runway, the vehicle was in the vicinity of bay 59 on the international apron. That was approximately 2.78 km from the Airbus and approximately 0.83 km from the intersection of taxiway Golf and runway 34L. When the Airbus commenced its take-off roll, the vehicle was near the intersection of taxiway Golf and taxiway Yankee. That was approximately 2.77 km from the Airbus and 0.5 km from the intersection of taxiway Golf and runway 34L.