Australia has declined to say whether its Jindalee over-the-horizon (OTH) radar system tracked MH370, the Malaysian Airlines 777-200 flight that disappeared over the South China Sea on March 8 with 239 people aboard.

Officially, Jindalee has a range of 3,000 km (1,900 mi.), about 1,500 km less than the distance to the point where MH370 disappeared, but the Royal Australian Air Force system is reputed to be able to reach the South China Sea, depending on atmospheric conditions.

China also has such sensors, which, unlike most radars, cannot be avoided by dropping below their horizons. However, they do not continuously monitor their entire fields of view; instead they focus on one patch at a time. And Australia’s system is not always operational.

Asked whether Jindalee had tracked MH370 and whether foreign authorities had asked Australia for information from the system, a spokesperson for the defense dept. says Australia is “closely engaged with the Malaysian authorities coordinating the search mission.” This includes the assignment of two Lockheed Martin P-3C Orion maritime aircraft to the search.

“As part of this international effort, any information relating to flight MH370 is passed to Malaysian authorities who are responsible for providing updated public information on efforts to locate MH370,” the spokesperson says in response to Aviation Week’s questions.

Australia issues only limited information about Jindalee, whose three enormous antenna installations are spaced across the Outback.