Separation issue over Bight, 20/9/13

[David Knudsen]

The ATSB have released an update on their findings here

Summary:

Loss of separation between Airbus A330 VH-EBO and Airbus A330 VH-EBS near Adelaide SA on 20 September 2013

On 20 September 2013, a loss of separation occurred between an Airbus A330 aircraft, registered VH-EBO (EBO) operating a scheduled passenger service from Sydney, New South Wales to Perth, Western Australia, and an Airbus A330 aircraft, registered VH-EBS (EBS), operating a scheduled passenger service from Perth to Sydney. Both aircraft were within radar surveillance coverage at the time of the occurrence.

Airservices Australia advised that EBS was cruising at flight level (FL) 390. The flight crew of EBO were cleared to climb from FL 380 to FL 400 and the aircraft commenced the climb. Soon after, the controller cancelled the clearance and the aircraft descended back to FL 380. The flight crew of EBS received a resolution advisory alert from their aircraft’s traffic collision avoidance system. However, EBO’s flight crew advised that they did not receive any indications on their traffic collision avoidance system of the presence of EBS. A full system test conducted on EBO’s traffic collision avoidance system after the incident confirmed it was not functioning.

Recorded data from the two aircraft showed that the minimum vertical separation was 650 ft when the two aircraft were 4.1 NM (8 km) apart laterally. The minimum lateral separation was 1.6 NM (3 km) when the aircraft were 870 ft apart vertically. At that time both the vertical and lateral separation were increasing as the aircraft were on separate one-way routes. The vertical and radar separation standards were re-established a short time later. (A loss of separation occurs at that flight level when two aircraft are within 1,000 ft [305 m] vertically and 5 NM [9.26 km] horizontally of each other).

The ATSB investigation is continuing and will include:
• further analysis of the ATC radar and audio data and the recorded data from the two aircraft
• analysis of the context in which the controller’s actions occurred
• examination of the TCAS computer and related components from VH-EBO
• review of the reliability and availability rates of TCAS.

The fact that EBO's TCAS was found to be "not functioning" is surprising, I'd have thought it would have some pretty decent self-test functions.

[Kazuya H]

Here is the link to the article on SMH.

http://www.smh.com.au/travel/travel-...010-2va5i.html

Second last paragraph:
"Qantas said in a statement that while the traffic collision avoidance system on the Perth-bound plane was working intermittently, this "wasn't a contributing factor to the incident".

Looks like it was working, but only intermittently.

Here is the link to Qantas response:
http://www.qantasnewsroom.com.au/qan...incident-a330s

[Robert S]

It was pleasing to see that Fairfax's article today grew up and spelt it out - "The initial report makes clear that the planes, which can carry up to 300 passengers, would not have hit each other even if they had continued on their paths before the alert was made."

Disappointing the industry people pushing agendas were fuelling and validating the nonsense flowing in the media on the day it happened. I still wonder what they think they were achieving by doing so. You're not going to get proper safety outcomes by playing the headless chicken game.

[Rich W]

Bit embarrassing for Alan Joyce. I saw an interview he did on Channel 10 while on the new Jetstar Dreamliner. When asked about the separation issue he said something like, "Well that's why people trust and travel on Qantas because we have experienced pilots and the excellent equipment and safety standards on our aircraft that prevented any collision".

Looks a bit embarrassing if one of your avoidance systems wasn't working correctly in a potentially critical moment.