A Chinese Ilyushinaircraft returns to Perth International airport after another day fruitlessly searching for missing Malaysia airliner, which lost radio contact five weeks ago.br br A massive international operation is combing a remote area of the southern Indian Ocean, where officials believe Flight MH370 crashed.br br As these planes scour a large search zone, thousands of kilometres west of Australia, for possible floating debris, ships focus on a smaller area where signals have been picked up.br br But Australian Prime Minister Tony Abbott says the transmissions are rapidly fading.br br (SOUNDBITE) (English) AUSTRALIAN PRIME MINISTER, TONY ABBOTT, SAYING:br br "There have been numerous, numerous transmissions recorded, which gives us the high degree of confidence that this is the black box from the missing flight.