• Sonar image taken during the search for MH370 which Williamson and Associates say should eb revisited (Australian Transport Safety Bureau)
Australian authorities searching for MH370 are being urged to urgently re-examine sonar images which experts say bear ‘all the hallmarks’ of a debris field.
Brianna Roberts

21 Oct 2015 - 8:18 AM  UPDATED 21 Oct 2015 - 4:15 PM
  • Update: go to the end of this article for a full response from the ATSB 

The Australian Transport and Safety Bureau (ATSB), which released the images as part of a report on the search last month, says it’s examined the images and believes the sonar records are "consistent with the surrounding geological formations".

But US firm Williamson & Associates, which is involved in deep sea searches, said the images bore a striking similarity to the underwater debris field an Air France Flight plane which crashed in 2009.

Williamson & Associate’s Special Projects Manager Rob McCallum told SBS the images had “all the hallmarks” of a debris field.

“It’s the right shape, the right size and in the right location, within a search area for a major airliner,”

He urged the search team to revisit the site, saying doing so would not cost a lot of money or take a lot of time.

“For someone to look at this and say this isn’t a target of interest, means either they have information they’re not sharing, or they’ve made a mistake. And on a search of this size and complexity, you can’t afford to make mistakes.”

Sonar images of the Air France crash. Source: EPA.

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The ATSB said in a written response to Reuters that geophysicists, sonar data specialists and its quality assurance team were satisfied that the structures in the sonar records were "consistent with the surrounding geological formations".

"Based on analysis of all of the data, there are no indications that there is anything possessing the characteristics of an aircraft debris field," it said.

Dutch company Fugro NV, the firm heading the search for the missing plane, did not respond to requests for comment.

The ATSB said in a September 23 update, the ship Fugro Discovery would resurvey "several" sites identified by sonar contact as being of possible interest in the 120,000 sq km search area.

Other experts say the ATSB could have instead used an autonomous underwater vehicle (AUV) to resurvey the sites. An AUV provides the most accurate search readings but cannot be deployed in rough winter weather.

Williamson & Associates was one of the rejected bidders for the contract to search for MH370.

McCallum said the firm expected to “cop a bit of flack” for speaking out, but said it couldn’t just sit back and say nothing.

“You can’t have a question mark this large hanging over imagery like that. It needs to be investigated,” he said.

A piece of the plane found washed up on the French island of Reunion in July this year provided the first direct evidence that the plane had crashed into the sea, in one of the world’s most baffling aviation mysteries.

No further trace has been found.

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Sonar images taken during the search for MH370.

With Reuters.

Full response from ATSB to SBS News

The images of the two sonar contacts included in the Operational Search Update released on 1 October were a very small sample of extensive data collected on several passes made at lower altitude, varying range scales and sonar frequencies with the deep tow system on board Fugro Discovery. Three separate additional passes were made over contact FE0116 using both 75 kHz and 410 kHz side scan sonar.     

The data was assessed, holistically, by expert geophysicists and sonar data specialists on board the vessel, in the Fugro sonar data analysis team and independently by the ATSB’s sonar data quality assurance team. Their assessment was made in the context of the adjacent geology and the broader geology found in the search area. It also took account of the known characteristics of comparable aircraft debris fields.

All of the experts are satisfied that the structures in the sonar records are consistent with the surrounding geological formations and with the geology found in the search area. Based on analysis of all of the data, there are no indications that there is anything possessing the characteristics of an aircraft debris field and therefore a visual imaging run at very low altitude using the camera on the tow fish was unnecessary.     

Other Category 2 contacts have been identified in the course of the underwater search. While they are not considered to be an immediate priority, some will be examined more closely using either the Hugin 4500 AUV or the deep tow search systems as opportunities arise. 

You can find more information on the classification of sonar contacts in our factsheet Sonar Contacts here.

We note that Williamson has not  brought their analysis to the attention of the ATSB for discussion or review. We consider it unprofessional to draw conclusions based on the limited information provided by the images in the search update report. We know that this kind of public commentary is very distressing for the families of those on board the aircraft.