PERTH - A signal detected by a Chinese ship searching the Indian Ocean for flight MH370 is ‘consistent’ with the type emitted from the aircraft black box, according to the Australian ex-military chief in charge of the hunt.

China’s official Xinhua news agency reported Saturday that a black box detector on board the Chinese search ship had picked up a signal at a frequency of 37.5kHz.

The Underwater Acoustic Beacons on the MH370 flight data recorder and cockpit voice recorder both operate at that frequency, a spokesman for Honeywell Aerospace, the manufacturers of the black boxes on board the missing plane, told AFP.

Air Chief Marshal Angus Houston, head of coordination in the search, said the reported characteristics of the signal ‘are consistent with the aircraft black box’. A number of white objects were also sighted on the surface about 90 kilometres from the detection area, he said, according to a statement by the Joint Agency Coordination Centre (JACC). However, he warned: ‘There is no confirmation at this stage that the signals and the objects are related to the missing aircraft.’

In a statement Sunday, the JACC reiterated that the signals had not been verified. Up to 10 military planes, two civil planes and 13 ships will scour the remote waters on Sunday, almost a month to the day since the plane carrying 239 passengers and crew disappeared on a flight from Kuala Lumpur to Beijing on March 8. The hunt will concentrate on about 216,000 square kilometres of the Indian Ocean around 2,000 kilometres (1,200 miles) northwest of Perth.

The Chinese search ship Haixun 01 picked up the pulse signal at about 25 degrees south latitude and 101 degrees east longitude, Xinhua said in a brief dispatch Saturday. Australia has asked China for more information, Houston said, and was considering deploying search assets to the area.

Chinese officials also warned the signal had not yet been identified. ‘Suspected pulse signal picked up by Haixun 01 has not been identified yet,’ the China Maritime Search and Rescue Center said on a verified microblog. Australian Defence Minister David Johnston echoed the words of caution.

‘This is not the first time we have had something that has turned out to be very disappointing,’ he told ABC television. Australian and British vessels are currently involved in a round-the-clock underwater search hoping to pick up a signal from the black box, but the battery powering those emissions is nearing the end of its roughly 30-day life span. The Ocean Shield, which is carrying a US Navy black box detector, and HMS Echo, which has a similar capability, are searching a 240-kilometre track of ocean in hopes of detecting sonic pings from the recorder.

However, progress is painstaking as vessels must move slowly to improve readings, and officials have acknowledged there is no solid evidence the plane went down in that stretch of sea. Anish Patel, president of US black box beacon manufacturer Dukane Seacom, said he was ‘highly sceptical’ about the Chinese report Saturday.

‘I would like to understand why not two signals — there should be a second beacon from either the flight data recorder or the voice recorder. So if the recorders are adjacent or within reasonable proximity... they should have detected possibly two signals,’ he told CNN. ‘So let’s get some additional assets in the water so we can corroborate, before we get everyone’s hopes up, before we disappoint these families one more time I think we need to corroborate.’

But Charitha Pattiaratchi, a professor of coastal oceanography at the University of Western Australia, said the news was exciting. ‘The 35.7 kHz is a man-made noise. There’s not another noise at that frequency,’ he told AFP, adding that this was exactly why black box pingers were set at this frequency.

‘A whale or a dolphin or rain or an underwater earthquake... they have a completely different frequency.’ Earlier in Kuala Lumpur, Transport Minister Hishammuddin Hussein said Malaysia would, in line with international agreements, appoint an independent ‘investigator in charge’ to lead an international team to probe what happened to MH370.

The team will include Australia, China, the United States, Britain and France. Hishammuddin again declined to provide any detail from Malaysia’s ongoing investigation, however, saying he remained focused on finding the plane and its black box. Malaysian authorities believe satellite readings indicate MH370 crashed in the Indian Ocean, far off Australia’s western coastline, after veering dramatically off course. But no proof has been found that would indicate a crash site, and Australian Prime Minister Tony Abbott has described the oceanic search as ‘the most difficult in human history’. Australia on Sunday said it was ‘hopeful’ about a signal detected by a Chinese ship searching for MH370, but cautioned there is no evidence yet that it emanated from the missing plane’s black box.

The signal matches the frequency used by beacons attached to the flight data recorder and the cockpit voice recorder on the Malaysia Airlines Boeing 777, the manufacturers Honeywell Aerospace have said. The search for the jet, which vanished on a flight between Kuala Lumpur and Beijing on March 8, has intensified as time runs out to find the black box, with the batteries powering the beacons nearing the end of a roughly 30-day life span.

Australian Prime Minister Tony Abbott, who is on an official visit to Japan, welcomed news of the underwater signals, but urged caution. ‘We are hopeful but by no means certain. This is the most difficult search in human history, we are searching for an aircraft which is at the bottom of a very deep ocean and it’s a very, very wide search area,’ he told reporters in Tokyo. ‘While we certainly are throwing everything we have at it, and while the best brains and the best technology in the world will be deployed, we need to be very careful about coming to hard and fast conclusions too soon.’ Some analysts greeted the development with optimism, saying a 37.5kHz signal can only be transmitted by an emergency beacon. But others voiced scepticism, including doubts over why there were not two ‘pings’ if both recorders were in the same vicinity.

White objects sighted around 90 kilometres (56 miles) from the area where the signal was detected also raised hopes, but were later reported by China’s official Xinhua news agency to be floating junk unrelated to the missing plane. The Chinese vessel, Haixun 01, picked up the pulse signal with a black box detector during searches Saturday at about 25 degrees south latitude and 101 degrees east longitude, Xinhua said. Air Chief Marshal Angus Houston, the Australian head of coordination in the search, said the signal’s characteristics ‘are consistent with the aircraft black box’, though he warned no link with MH370 had been verified.

Up to 10 military planes, two civil planes and 13 ships will scour the remote waters on Sunday, concentrating on about 216,000 square kilometres of the Indian Ocean around 2,000 kilometres northwest of Perth. The Joint Agency Coordination Centre which Houston leads said Sunday that weather in the search area — which is periodically pounded with storms — was expected to be good, with visibility greater than 10 kilometres.

Anish Patel, president of US black box beacon manufacturer Dukane Seacom, said Saturday he was ‘highly sceptical’ about the Chinese report. ‘I would like to understand why not two signals — there should be a second beacon from either the flight data recorder or the voice recorder. So if the recorders are adjacent or within reasonable proximity... they should have detected possibly two signals,’ he told CNN. ‘So let’s get some additional assets in the water so we can corroborate, before we get everyone’s hopes up, before we disappoint these families one more time I think we need to corroborate.’

But Charitha Pattiaratchi, a professor of coastal oceanography at the University of Western Australia, said the news was exciting. ‘The 35.7 kHz is a man-made noise. There’s not another noise at that frequency,’ he told AFP, adding that this was exactly why black box pingers were set at this frequency. ‘A whale or a dolphin or rain or an underwater earthquake... they have a completely different frequency.’ Australia has asked China for more information on the finding, Houston said, and was considering deploying search assets to the area.

Chinese officials also warned the signal had not yet been identified. ‘Suspected pulse signal picked up by Haixun 01 has not been identified yet,’ the China Maritime Search and Rescue Center said on a verified microblog. Australian and British vessels are also currently involved in a round-the-clock underwater search hoping to pick up a signal from the black box. The Ocean Shield, which is carrying a US Navy black box detector, and HMS Echo, which has a similar capability, are searching a 240-kilometre track of ocean in hopes of detecting sonic pings from the recorder but progress is slow.