Could searchers’ sonars have al­ready missed wreck­age of Flight 370?


Amid ris­ing frus­tra­tions over the ex­pen­sive, so-far fruit­less search for van­ished Malaysia Air­lines Flight 370, ex­perts are ques­tion­ing the com­pe­tence of the com­pany in charge, in­clud­ing whether crews may have passed over the sunken wreck­age with­out even notic­ing.

Such carp­ing in a small, fiercely com­pet­i­tive and highly spe­cial­ized in­dus­try isn’t un­usual — and some of the strong­est com­ments have come from a com­pany whose bid for the lu­cra­tive job failed. But oth­ers have also crit­i­cized what they sus­pect is shoddy work, in­ap­pro­pri­ate equip­ment use and a fo­cus on speed over thor­ough­ness by the Dutch un­der­wa­ter sur­vey com­pany hired by Aus­tralia to find the plane that van­ished in the In­dian Ocean on March 8 last year with 239 peo­ple aboard.

There are also calls for the gov­ern­ment to re­lease the grow­ing moun­tain of sonar data col­lected so far, which skep­tics say could show whether searchers have over­looked holes in the dragnet big enough to con­ceal a frag­mented Boe­ing 777.

Aus­tralian author­i­ties say they are con­fi­dent in the ef­forts by the com­pany lead­ing the search, Fu­gro Sur­vey Pty. Ltd. But the sec­ond-guess­ing has grown as time goes by with still no phys­i­cal trace of the plane.

“It strikes me as odd that you’re hir­ing a com­pany that doesn’t have the as­sets, doesn’t have the track record,'' said Steven Saint Amour, an air­craft re­cov­ery ex­pert based in An­napo­lis, Mary­land.

Fu­gro has got­ten some con­fi­dence from the dis­cov­ery of an un­charted wreck of a 19th cen­tury mer­chant ship 3,900 me­tres (12,800 feet) un­der­wa­ter. This bodes well be­cause pieces from the plane would be roughly 10 times as big as the bits of de­bris searchers found from the wrecked ship, Fu­gro search di­rec­tor Paul Kennedy said.

Kennedy, who has two decades’ ex­pe­ri­ence in deep-sea sonar tow­ing, dis­misses much of the crit­i­cism as com­mer­cial ri­valry and frus­tra­tion at miss­ing out on a ma­jor con­tract. He also de­fends his com­pany’s equip­ment and meth­ods.

“I don’t re­ally buy into those ar­gu­ments with the other peo­ple. We just get on with our work,'' he said.

Some crit­ics ar­gue that Fu­gro could have easily missed the plane be­cause they say its search ships are mis­us­ing 75 kHz sides­can sonar de­vises called “tow­fish” that are dragged above a ragged seabed that av­er­ages a depth of 4,000 me­tres (13,000 feet).

The tow­fish were used to de­clare a cor­ri­dor 2,000 me­tres (6,600 feet) wide clear of wreck­age. But some ar­gue that that dis­tance is too far to use such an acous­tic sys­tem be­cause the sonar im­age gets worse the far­ther the sig­nal trav­els.

The im­age is said not to de­grade with more mod­ern equip­ment called Syn­thetic Aper­ture Sonar, or SAS.

There have been calls to use SAS, but Kennedy calls it a de­vel­op­ing tech­nol­ogy with some ques­tions about its re­li­a­bil­ity. Be­cause the search is in such a re­mote re­gion, Fu­gro opted for es­tab­lished tech­nol­ogy with ready sup­plies of spare parts.

Aus­tralian safety of­fi­cials say the cor­ri­dor isn’t too wide, and the equip­ment was tested thor­oughly dur­ing sea tri­als.

Many ex­perts want the raw sonar data re­leased now, or at least re­viewed by an out­side party to en­sure noth­ing has been over­looked.

Of­fi­cials have re­fused, say­ing that do­ing the huge amount of work needed to re­view and an­a­lyze the data so it could be un­der­stood by the public would be an un­war­ranted dis­trac­tion from search du­ties.

If noth­ing is found, the search will end next year af­ter a with­er­ing 120,000 square kilo­me­tres (46,000 square miles) of re­mote ocean floor up to 6.5 kilo­me­tres (4 miles) deep have been combed with sonar and video.

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