"Inevitably, if we don't find any wreckage on the surface we are eventually going to have to, probably in consultation with everybody who has a stake in this, review what to do next," retired Air Chief Marshal Angus Houston said.
That day may come soon.
The new search zone is yielding no results after more than 500 hours of searching by dozens of aircraft.
The Australians have been doing a lot to dampen down expectations of a breakthrough. Australian Prime Minister Tony Abbott has said several times in the last week that the search effort is "extraordinarily difficult."
The Australian Maritime Safety Authority has stopped giving details of objects found in the sea, preferring to say simply "nothing significant found" at the end of a day's searching.
Read more: http://www.nbcnews.com/storyline/missing-jet/analysis-pessimism-grows-search-missing-mh370-drags-n68586
Copyright 2015 Nexstar Broadcasting, Inc. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.