tirsdag 8. april 2014

Malaysian - 8. april

MH370 Tragedy: Ocean debris left by jet depends on angle, speed




Exactly how the plane hit the water makes a big difference to the teams undertaking the painstaking search for the wreckage.
Investigators have frustratingly little hard data to work out how Malaysia Airlines Flight 370 came down in the Indian Ocean on March 8 with 239 people on board.
Here are some possible scenarios:
  • A STEEP DIVE:
If the plane ran out of fuel at its normal cruising altitude and the pilots were incapacitated, the autopilot would stop working and the aircraft could dip into an increasingly steep and rapid dive, aviation experts said.
Under this scenario, the plane could hit the water nose-first and close to perpendicular with the surface, piercing the ocean like an arrow.
The wings and tail would be torn away and the fuselage could reach a depth of 30 meters or 40 meters within seconds, then sink without resurfacing. Wing pieces and other heavy debris would descend soon afterward.
Whether buoyant debris from the passenger cabin — things like foam seat cushions, seatback tables and plastic drinking water bottles — would bob up to the surface would depend on whether the fuselage ruptured on impact, and how bad the damage was.
“It may have gone in almost complete somehow, and not left much on the surface,” said Jason Middleton, an aviation professor at Australia’s University of New South Wales.
Any floating debris left would be in a relatively contained area, but would begin drifting apart. Most would eventually become waterlogged and sink, though items such as foam seat cushions could float almost indefinitely, Middleton said.
  • AN INTENTIONAL DITCH:
Commercial flight crews train to bring a plane down in water with a minimum of damage.
They dump fuel, slow the plane down to the absolute minimum speed needed to maintain control, and try to ease the plane into the water at a shallow angle.
Middleton said the ditching of hijacked Air Ethiopia Flight 961 in the Comoros Islands in 1996 is a dramatic example of what could be expected to happen next.
Video of the crash shows the plane’s left wing dipping first into a flat ocean, which rips off an engine and drags the aircraft onto its left side.
Debris flies off in all directions before the nose digs in and the plane flips and breaks apart. Just 50 of the 175 people aboard survived.
“You have the prospect of the plane smacking into the side or front of a wave crest, with one engine or wing dipping in first and the whole thing cartwheeling, and the airplane is going to break up,” Middleton said.
Debris would be spread over a wide area.
Heavy pieces would likely sink quickly, but items such as galley parts and items from overhead compartments could float for a long time, said John M. Cox, an air safety consultant and former airline pilot.
  • A MIDAIR EXPLOSION:
Investigators also must consider the possibility that an explosion ripped the plane apart at high altitude.
If that occurred, chunks of the plane would fall to earth at different speeds according to their weight and other factors, said Geoff Dell, an aviation and accident investigation expert at Australia’s Central Queensland University.
Wreckage could be spread over an area of several kilometers (miles), as happened when a bomb disintegrated Pan Am Flight 103 over the Scottish town of Lockerbie in 1988.
  • THE HOPE AGAINST HOPE:
The ditching of US Airways Flight 1549 into the Hudson River in 2009 shows that a jetliner can be brought down in water without loss of life.
But Graham Edkins, a former Australian government senior air crash investigator, said it requires an almost unbelievable confluence of skill, conditions and luck.
“On a bright and sunny day, with no waves and no wind, and the captain can see everything and is very experienced, you can see it is possible to get the plane on the water in a way that everyone could get out,” Middleton said.
Conditions in the part of the Indian Ocean where the plane is believed to have gone down are nothing like those in New York that helped pull off the “Miracle on the Hudson.” Swells in the region average around 5 meters (16 feet).
Even if the plane landed relatively intact in the water, it would immediately start to sink, giving those on board little time to escape — into waters of around 8 C (46 F) in a remote region with no immediate hope of rescue. --AP

Able Seaman Clearance Divers Matthew Johnston and Michael Arnold embarked on Australian Defence Vessel Ocean Shield, scan the water for debris in the search zone in the southern Indian Ocean for the missing Malaysian Airlines flight MH370. REUTERS PHOTO

Teams scour sea for signals



Air Chief Marshal Angus Houston: "Until we stop the pinger search, we will not deploy the submersible"

Teams searching for the missing Malaysian plane say they will wait for further contact with signals picked up over the weekend before using a submersible down to search for debris.
An Australian ship has heard signals that officials said could be consistent with "black box" flight recorders.
It has not been able to reacquire them since Sunday, however.
Australian officials said it was key to re-find the signals before using a submersible in a search for wreckage.
Flight MH370 went missing on 8 March with 239 people on board. The Beijing-bound plane lost contact with air traffic controllers shortly after taking off from Kuala Lumpur.
Malaysian officials say that - based on satellite data - they believe the plane crashed into the southern Indian Ocean, west of the Australian city of Perth, thousands of kilometres from its intended flight path.
In Beijing, relatives of missing passengers held a vigil to mark one month since the plane disappeared.
'Better fix' Speaking at Pearce Airbase in Perth, Australian Defence Minister David Johnston said that several days of "intense action" were ahead as search teams tackled "this difficult, complex task" while black box pingers were still believed to be active.

US Navy image taken on 1 April 2014 shows the Bluefin 21 Artemis autonomous underwater vehicle (AUV) being hoisted back on board the Australian navy vessel Ocean Shield after successful buoyancy testing in the Indian Ocean. If the search area can be narrowed using the listening device, the submersible can be sent down
Towed pinger locator

Australian vessel Ocean Shield has been using a towed pinger locator to listen for transmissions from the plane's flight recorders. Over the weekend, it heard signals on two separate occasions, the first time for more than two hours.
On the second occasion two distinct pinger returns were audible, something said to be consistent with transmissions from both the flight data recorder and the cockpit voice recorder.
Air Chief Marshall Angus Houston, who heads the agency overseeing the search for the plane, said that Ocean Shield had had no further contact with any transmissions since then.
He said that work involving the towed pinger locator would continue for several days, adding that the Bluefin 21 underwater drone would not be deployed unless more transmissions were received.
"If we can get more transmissions we can get a better fix on the ocean floor, which will enable a much more narrowly focussed visual search for wreckage," he said. 


Authorities 'cautiously hopeful' of positive developments in next few days in search for MH370

Published on Apr 7, 2014
The towed pinger locator sits on the deck of the Australian Defence Vessel Ocean Shield during the search for the black boxes of missing Malaysian Airlines flight MH370 in this picture released by the Australian Defence Force on April 5, 2014. Authorities are "hopeful" that there would be positive developments in the next few days, said Malaysia's Acting Transport Minister Hishammuddin Hussein. -- PHOTO: REUTERS



KUALA LUMPUR - Authorities are "cautiously hopeful" that there would be positive developments in the next few days in the search for Malaysia Airlines flight MH370, said Malaysia's acting Transport Minister Hishammuddin Hussein.
He cited new signals detected by Australian navy vessel Ocean Shield, saying the developments were the "most promising leads" so far in the search for the plane that disappeared on March 8.
"Two separate signal detections have occurred 1,650 km north-west of Perth within the northern part of the defined search area. The first detection was held for approximately
2 hours and 20 minutes. HMAS Ocean Shield then lost contact before conducting a turn and attempting to re-acquire the signal,'' he told a press briefing on Monday.
“The second detection on the return leg was held for approximately 13 minutes. On this occasion, two distinct pinger returns were audible. This would be consistent with transmissions from both the flight data recorder and the cockpit voice recorder."

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