23 March 2014
The search for flight MH370, which disappeared more than two weeks ago, is now being led by Australia in an area 2,500 kilometres south-west of Perth.
A new Chinese satellite image shows a large floating object south-west of where possible debris was earlier captured by a commercial satellite company.
Chinese and Japanese planes have arrived in Western Australia to join the search effort to try and verify if the objects are from the missing Boeing 777.
Aaron Halstead, a manager with the Royal Flying Doctor Service in Melbourne, has extensive experience in sea and air search and rescue operations.
He has sailed through the “really remote” search area on trips from Antarctica’s Heard Island to Perth on icebreaker ships and smaller ocean-going yachts.
“What you’re talking about is an expansive ocean that is exactly the same with nothing in between for eight days,” he told ABC News Online.
“It is a vast expansive ocean and it is unimpeded from west to east – there is nothing in the way.”
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Mr Halstead says scanning that part of the ocean from the air is difficult.
“Having been involved in a lot of aerial searches myself, I can say you lose depth perception,” he said.
“I know the crews are really skilled at this but you’re dealing with swell. You can imagine that with the peaks and troughs of the swell, as it drops over the back of the swell, you’ve only got to be flying past and blink at that moment and miss something.
“Hence why they’ve got 10 sets of eyes on a plane – it really is human eyeball work. It is about looking out and scouring that area, and hopefully somebody catches something that someone else didn’t see.”
Search crews are trained to know the size and scale of objects at varying heights above the ocean.
“A US Air Force pilot gave a good analogy about the initial search area which was to imagine looking from Los Angeles to New York and trying to find three people on the ground,” Mr Halstead said.
“So for example in this area, it might be the same size as Tasmania, so you’re saying we’re trying to find two people in Tasmania.”
Unrelated debris, changing weather patterns complicate search
Prime Minister Tony Abbott has revealed that one of the objects is reported to have been a wooden pallet.
“Obviously we have now had a number of very credible leads and there is increasing hope, no more than hope, that we might be on the road to discovering what did happen,” he said.
Mr Halstead says it is common to see that kind of debris floating in the ocean, but it “generally isn’t clustered”.
“I’ve seen boats upside down, like small zodiacs drifting in the ocean that might be five to six metres long,” he said.
“Or some of the fishing vessels will throw rubbish overboard or there might be pallets blown overboard.
“What they’re looking for is obviously large objects that do stand out … but they’re looking for clues that are clustered together.”
Changing weather can also impede the search by affecting visibility.
“You’ve got weather pouring off the Antarctic continent and it might seem a long way away but it’s actually driving the weather patterns,” Mr Halstead said.
“Then you have the circumpolar current, which is essentially going in a west-east flow around Antarctica, which drives underneath Australia, driving that weather pattern.
“The circumpolar current moves at about one nautical mile an hour. So if you look over four days that means, depending on the size of the debris and how it’s dragged by the water, it can move 100 nautical miles in four days. That’s nearly 200km.”
He says when you add that into the mix, weather patterns change very quickly.
“It can go from absolutely glorious sunshine, then you’ll suddenly be in a storm, and then it’ll all of a sudden clear within a couple of hours,” he said.
Dimensions of the Boeing 777-200ER
- Wing span: 60.9 metres
- Overall length: 63.7 metres
- Tail height: 18.5 metres
- Fuselage diameter: 6.19 metres
Yesterday authorities reported that despite better visibility and weather conditions, searches failed to find any sign of the missing airliner.
Mr Halstead says the biggest swell he has seen is around 18 metres, but points out that even moderate conditions are difficult to search in.
“Even with six to seven metre swells … with the size object they’re talking about in a swell like that, you’d only have to have the swell moving slowly through the ocean and the plane flying faster than the swell for them to miss it,” he said.
“So it’s really important that they do sweeps back and forward across that terrain.”
Halstead confident continued searches will recover debris
Mr Halstead says ships as well as aircraft play an important role in the search.
“Ships can have a lot of eyes at actual water level,” he said.
They’ve got to keep searching, keep throwing resources at it because there’s really credible leads right now.Aaron Halstead, aeromedical rescue specialist
“I’m confident that they will find those objects that were identified on the satellite as long as they are still buoyant.
“It’s just a matter of tracking over that terrain and looking at the marker buoys and GPS, tracking the currents [and] direction, and working out the speed at say one nautical mile an hour with the circumpolar current.
“You can actually work this out relatively accurately and I’m confident they will find the objects that are there.
“They’ve got to keep searching, keep throwing resources at it because there’s really credible leads right now.”
Chances of survival in rough ocean limited without equipment
With the plane now having been lost for over two weeks, the chances of survival for the 239 on board are growing slimmer.
Mr Halstead says surviving long-term on the water in such a remote area would only be possible with significant supplies.
“There’ve been people pulled from the ocean there that have survived in life rafts, there’s certainly some well-documented cases of that,” he said.
“But I would say that is a rather cold part of the world … it’s not survivable long-term unless you are well prepared.
“However as we’ve seen recently miracles can happen. But you’d need to be well prepared that’s for sure.”