Missing Malaysia Airlines flight MH370: First underwater mission fails as nothing is found and ocean proves too deep for submarine

After only six hours of its planned 16-hour mission on the sea bed, the Bluefin 21 exceeded its maximum depth limit of 4,500 metres

The first underwater attempt to locate wreckage from the missing Malaysia Airlines flight MH370 has ended in disappointment after the search area proved too deep for the submersible Bluefin 21 vehicle.

Just six hours into an initial planned 16-hour mission, the seabed dropped beyond the sub's maximum depth limit of 4,500 metres (15,000 feet).

What little information was gained from the sea bed has now been analysed but, according to officials, has thrown up no items of interest.

The authorities leading the search had described the Bluefin 21's efforts as their best hope in finding the Boeing 777's "black box" flight recorders, from which no signal has been detected for a full week.

Search crews had previously warned that the ocean's depth would stretch the unmanned submersible to its very limit. The Bluefin 21 has a built-in safety feature which forces it to return to the surface once its limit is exceeded.

Weather permitting, the sub will embark on a second mission later today, search organisers said. It will be moved away from the outer edges of the designated search area, where it is believed the deeper water is located.

Vehicles with a deeper range have been requested by the search organisers, but until one arrives Bluefin 21 will remain the best and only option.

Meanwhile, officials were still waiting for the results of analysis on an oil slick found about 5.5km (3.4 miles) from the area where the last underwater sounds were detected, said Angus Houston, the head of a joint agency coordinating the search off Australia's west coast.

The process will take several days, and while Houston said the oil does not appear to be from any of the ships in the area, he cautioned against jumping to conclusions about its source.

Australian Prime Minister Tony Abbott raised hopes last week when he said authorities were "very confident" the four strong underwater signals that were detected were from the black boxes on MH370, which disappeared on 8 March during a flight from Kuala Lumpur, Malaysia, to Beijing with 239 people on board.

But Houston warned that while the signals are a promising lead, the public needs to be realistic about the challenges facing search crews in the extremely remote, deep patch of ocean - an area he called "new to man".

"I would caution you against raising hopes that the deployment of the autonomous underwater vehicle will result in the detection of the aircraft wreckage. It may not," Houston said. "However, this is the best lead we have, and it must be pursued vigorously. Again, I emphasize that this will be a slow and painstaking process."

Houston, a retired Australian chief air marshal, called the mission "one of the largest search and rescue, search and recovery operations that I've seen in my lifetime".

Read more: Plane 'thrown around like fighter jet to dodge radar'
Did jet's co-pilot make last-gasp phone call before it disappeared?

Stefan Williams, a professor of marine robotics at the University of Sydney, explained that while the "pings" detected by the Australian navy's Ocean Shield vessel were recorded at a specific depth, the search crews knew relatively little around the surrounding ocean floor.

"Maybe some areas where they are doing the survey are a little bit deeper than they are expecting," he said. "They may not have very reliable prior data for the area, so they have a general idea. But there may be some variability on the sea floor that they also can't see from the surface.

"What they're going to have to be looking for is contrast between hard objects, like bits of a fuselage, and that silty bottom," Williams added. "With the types of sonars they are using, if stuff is sitting up on top of the silt, say a wing was there, you could likely see that ... but small items might sink down into the silt and be covered and then it's going to be a lot more challenging."

Around 11 ships and as many planes join the visual search of the surface of the Indian Ocean on Tuesday, scouring an area over 62,000 square km (24,000 square miles), around 2,200 km (1,400 miles) northwest of Perth.

It is expected to be one of the final attempts to find floating debris, with more than a month of searches has so far not turning up a single item linked to the plane. Houston yesterday described the chances of now finding any wreckage on the surface as "greatly diminished".

Start your day with The Independent, sign up for daily news emails
Arts and Entertainment
The Doctor and Clara have their first real heart to heart since he regenerated in 'Deep Breath'
TV
News
people
Life and Style
Apple showed no sign of losing its talent for product launches with the new, slightly larger iPhone 6 making headlines
techSecurity breaches and overhyped start-ups dominated a year in which very little changed (save the size of your phone)
News
The official police photograph of Dustin Diamond taken after he was arrested in Wisconsin
peopleDownfall of the TV star charged with bar stabbing
PROMOTED VIDEO
Have you tried new the Independent Digital Edition apps?
ebooks
ebooksA year of political gossip, levity and intrigue from the sharpest pen in Westminster
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
Independent Dating
and  

By clicking 'Search' you
are agreeing to our
Terms of Use.

iJobs Job Widget
iJobs General

Recruitment Genius: Business Manager

£32000 - £40000 per annum: Recruitment Genius: A Business Manager is required ...

Recruitment Genius: Operations Manager

£45000 - £55000 per annum: Recruitment Genius: This is an exciting opportunity...

Recruitment Genius: Panel & Cabinet Wireman

£20000 per annum: Recruitment Genius: Panel Wireman required for small electro...

Recruitment Genius: Electronics Test Engineer

£25000 - £27000 per annum: Recruitment Genius: An SME based in East Cheshire, ...

Day In a Page

A timely reminder of the bloody anniversary we all forgot

A timely reminder of the bloody anniversary we all forgot

Who remembers that this week we enter the 150th anniversary year of the end of the American Civil War, asks Robert Fisk
Downfall of Dustin 'Screech' Diamond, the 'Saved By The Bell' star charged with bar stabbing

Scarred by the bell

The downfall of the TV star charged with bar stabbing
Why 2014 was a year of technological let-downs

Why 2014 was a year of technological let-downs

Security breaches and overhyped start-ups dominated a year in which very little changed (save the size of your phone)
Cuba's golf revolution: But will the revolutionary nation take 'bourgeois' game to its heart?

Will revolutionary Cuba take 'bourgeois' golf to its heart?

Fidel Castro ridiculed the game – but now investment in leisure resort projects is welcome
The Locked Room Mysteries: As a new collection of the genre’s best is published, its editor Otto Penzler explains the rules of engagement

The Locked Room Mysteries

As a new collection of the genre’s best is published, its editor explains the rules of engagement
Amy Adams on playing painter Margaret Keane in Tim Burton's Big Eyes

How I made myself Keane

Amy Adams hadn’t wanted to take the role of artist Margaret Keane, because she’d had enough of playing victims. But then she had a daughter, and saw the painter in a new light
Ed Richards: Parting view of Ofcom chief. . . we hate jokes on the disabled

Parting view of Ofcom chief... we hate jokes on the disabled

Bad language once got TV viewers irate, inciting calls to broadcasting switchboards. But now there is a worse offender, says retiring head of the media watchdog, Ed Richards
A look back at fashion in 2014: Wear in review

Wear in review

A look back at fashion in 2014
War with Isis: The West needs more than a White Knight

The West needs more than a White Knight

Despite billions spent on weapons, the US has not been able to counter Isis's gruesome tactics, says Patrick Cockburn
Return to Helmand: Private Davey Graham recalls the day he was shot by the Taliban

'The day I was shot by the Taliban'

Private Davey Graham was shot five times during an ambush in 2007 - it was the first, controversial photograph to show the dangers our soldiers faced in Helmand province
Revealed: the best and worst airlines for delays

Revealed: the best and worst airlines for delays

Many flyers are failing to claim compensation to which they are entitled, a new survey has found
The stories that defined 2014: From the Scottish independence referendum to the Ice Bucket Challenge, our writers voice their opinions

The stories that defined 2014

From the Scottish independence referendum to the Ice Bucket Challenge, our writers voice their opinions
Stoke-on-Trent becomes first British city to be classified as 'disaster resilient' by the United Nations

Disaster looming? Now you know where to head...

Which British city has become the first to be awarded special 'resilience' status by the UN?
Finally, a diet that works: Californian pastor's wildly popular Daniel Plan has seen his congregation greatly reduced

Finally, a diet that works

Californian pastor's wildly popular Daniel Plan has seen his congregation greatly reduced
Say it with... lyrics: The power of song was never greater, according to our internet searches

Say it with... lyrics

The power of song was never greater, according to our internet searches