You're going to be hearing a lot about a near-miss between two Qantas planes in South Australia over the next few days. People will be using the technical phrase "loss of separation" to describe what happened between the two aircraft, but what the hell does that mean?
Over the Great Australian Bight a few hours ago, two Qantas planes narrowly avoided each other on the crossing from Perth To Sydney. At one point, the two aircraft came within just over 200 metres of each other. The Civil Aviation Safety Authority's (CASA) official statement at this point reads thusly:
There was an incident that involved a loss of separation...
Separation in this context refers to the minimum safe distance mandated by the safety authority that all commercial planes must respect. In Australia, Separation means that planes must stay away from each other to the tune of 1000 feet (304.8 metres) vertically and 5-nautical miles (9.26 kilometres) horizontally. Quite a distance, but you have to remember that planes travel at hundreds of kilometres per hour.
So when CASA says that the planes were involved in an incident that involved "a loss of separation" it means that the planes punched into each other's safe zone.
At this point, it looks like the loss of separation occurred when one of the planes received permission from Air Traffic Control to climb when the Traffic Collision Avoidance System issued a RA, or required action, to avoid the other aircraft.
At least that's the story Qantas is going with.
Update: Indications are that the loss of separation occurred when one of our aircraft received clearance to climb from Air Traffic Control.
— Qantas Airways (@QantasAirways) September 20, 2013
The Australian Transportation Safety Board is still unsure of whether it will formally investigate the incident.
Picture by Simon_sees