As an Australian navy vessel continues to comb the Indian Ocean for signs of missing Malaysian Airlines flight MH370, the mammoth scale of the challenge is becoming ever clearer.
The Ocean Shield detected electronic signals consistent with transmissions from black boxes on Tuesday – one for more than 20 minutes and a second for 13 minutes.
Amid fears the black box battery could be close to expiring, the depths at which the plane may have come to rest have been analysed in this Washington Post infographic.
The maximum known depth of the ocean floor below the Ocean Shield is known to be around 15,000 feet – just shy of three miles.
That’s deeper than the length of the Empire State Building (1,250ft), further than the maximum depth to which a giant squid can swim (2,600ft), beyond the maximum known depth of a sperm whale dive (3,280ft) and exceeding where the wreck of the Titanic came to rest (12,500ft).
The Ocean Shield is towing pinger locators in a search area of about 84,000 sq miles, 1,000 miles north west of Perth.
Royal Navy survey ship HMS Echo is also taking part in the search, as is a Chinese vessel, Haixun 01.
Flight MH370, bound for Beijing from Kuala Lumpur, disappeared on 8 March with 239 people on board
Of the two signals detected this week, Air Chief Marshall Angus Houston, chief co-ordinator of the Joint Agency Coordination Centre, cautioned: “We haven’t found the aircraft yet.
“We cannot confirm it is from MH370 until we have found some wreckage. We need a good position on the ocean floor to search."
This Washington Post graphic originally featured in this article has been removed at the paper's request.