The first stage involved placing a special concrete blanket across the depressurised pipeline.
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2.
The ATSB believe the plane became depressurised, leaving the pilot and passengers unconscious and the plane flying automatically until it ran out of fuel.
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3.
One of the goals of the Japanese test, which is being conducted over two weeks, will be to measure the amount of seabed that can be sufficiently depressurised to release collectable gas.