A320 / A346, en-route, Eastern Indian Ocean, 2012

A320 / A346, en-route, Eastern Indian Ocean, 2012

Summary

On 18 January 2012, ATC error resulted in two aircraft on procedural clearances in oceanic airspace crossing the same waypoint within an estimated 2 minutes of each other without the prescribed 1000 feet vertical separation when the prescribed minimum separation was 15 minutes unless that vertical separation existed. By the time ATC identified the loss of separation and sent a CPDLC message to the A340 to descend in order to restore separation, the crew advised that such action was already being taken. The Investigation identified various organisational deficiencies relating to the provision of procedural service by the ANSP concerned.

Description

On 18 January 2012, in daylight hours, an Airbus A320-200 being operated by Tiger Airways on a scheduled passenger flight from Singapore to Perth WA lost separation against an Airbus A340-600 being operated by Etihad Airways on a scheduled passenger flight from Sydney to Abu Dhabi whilst both aircraft were under procedural control from the same ATS Sector in oceanic airspace.

Investigation

An Investigation was carried out by the Australian Transport Safety Bureau (ATSB) based on the fact that ATS in the oceanic area concerned was provided by the Australian ANSP.

The area involved was within the Indian (IND) Sector of Airservices Australia’s West Procedural Airspace Group located at Melbourne. As there was no radar or Automatic Dependent Surveillance Broadcast (ADS-B) coverage in the sector, both aircraft were under procedural control, where planned separation depended on crew position reports and estimates or on automatic updating of position using ADS-C. Routine communication with aircraft utilised a combination of methods including HF and CPDLC. Aircraft positions were shown on an Air Situation Display (ASD) which was dependent on controllers receiving and inputting position reports and estimates. The prescribed separation in the airspace involved was 1000 feet vertically or 15 minutes laterally when transiting the same position.

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