the southern corridor

先生の↓の記事のfollow-upです。BBCから。

Flight MH370 'crashed in south Indian Ocean' - Malaysia PM

The announcement by Prime Minister Najib Razak came at a late-night news conference in Kuala Lumpur.
It was based on new analysis by British satellite firm Inmarsat, which provided satellite data, and the UK's Air Accidents Investigation Branch (AAIB).

The firms "have concluded that MH370 flew along the southern corridor, and that its last position was in the middle of the Indian Ocean, west of Perth," Mr Razak said.

"This is a remote location, far from any possible landing sites. It is therefore with deep sadness and regret that I must inform you that, according to this new data, flight MH370 ended in the southern Indian Ocean."

http://www.bbc.com/news/world-asia-26716572

the southern corridorのcorridorには「国際航空協定による特定空路」の意味があります。ここのsouthernはオーストラリア西部のインド洋南部周辺を指すと思われます。（Ume）