On 19th May 2016, flight MS804 was lost at sea south of Greece in a water depth of 3,000m. DOS was contacted to offer a solution to find the aircraft and to recover the flight recorders, aircraft debris and other material lying on seabed. After less than 4 days from the start of operations in the field, both flight recorders were found and recovered from a depth of 3020m.
DOS was able to offer a solution to investigators where a single support vessel would deploy a fully integrated 6000m depth rated spread.
A spread able to cover the seabed with long range side scan sonar, which would be equipped with several flight recorder pinger locator systems, and be able to recover debris with an ultra-deep ROV. The full spread was permanently fitted on board our vessel SV John Lethbridge, which eliminated long mob/demob times and/or long calibration periods.
A detailed side scan sonar survey of the site, with MAKiX, was carried out in less than 3 days. After two sonar lines (less than a day), the aircraft wreckage area was detected through DOS’s upgraded systems and was carefully geographically positioned for the next phase – inspection.
Spotted by MAK iX
Appart from beacon locator sensors, fitted on tow fish for this particular mission, MAK iX appears to be a formidable tool for flight recorder detection. In addition to its highly dynamic imagery, the low frequency mode offers a decisive advantage: frequency used by all flight-recorders’s beacons (37kHz) fall into the MAK iX low frequency listening bandwidth (centred on 30kHz).
This means that emissions from flight recorders will also make periodical acoustic marks on sonar profiles, allowing detecting/confirming the target within or outside the imagery range!
Illustration below is a generic side scan imagery and is not related to MS804.
From survey to ROV operations
Having achieved this, operations were switched from sonar to ROV work without the need for an extra port call, involving demobilisation and remobilization, as all the systems were permanently operational on the SV John Lethbridge and the survey personnel can operate both at will.
At this point a very detailed visual survey of the debris field was began, oriented by the instructions of the investigators and principally, at this stage, the Airbus team. A database of located debris items was created. Airbus engineers on board were able to identify the parts of the aircraft and selected those required for recovery. All items were geo-referenced in the database and could be and were relocated very quickly when selected for recovery.
4 days later
After less than 4 days from the start of operations in the field, both flight recorders were found and recovered from a depth of 3020m and transferred to shore via an Egyptian Navy vessel.
The close cooperation between the Egyptian authorities (the CEA), the French aircraft accident investigation department (the BEA), Airbus and the legal, forensic and medical authorities and their representatives allowed for fast and efficient operations covering all aspects of the project and were instrumental in the rapid and successful conclusion of the mission.
DOS were particularly impressed by the quality of personnel from all the above cited organisations which we worked with and by the spirit of cooperation and comradeship which permeated this team during this difficult operation.
MS804 crashes on mediterranean sea during a flight from Paris to Cairo
SV John Lethbridge starts transit to Alexandria
SV John Lethbridge leaves UK and transit to Egypt.
DAY 0 - Vessel arrives in Alexandria
Port call at Alexandria: Egyptian authorities, Airbus, BEA, legals and DOS crew arrive onboard John Lethbridge
DAY 1 - SV John Lethbridge transits to site
Vessel John Lethbridge travels to search area.
Day 2 - Equipment calibrations
As before every new operation, vessel and subsea equipment are calibrated, water characteristics are measured.
DAY 2 - Survey operations start
MAK iX multi-sensor plateform is deployed on search area and SV John Lethbridge run survey lines.
DAY 3 - MS804 crash site is located
Crash site is spotted by MAK iX imagery: debris signatures and beacon emissions are visible on sonar profiles.
DAY 4 - ROV is deployed on crash site
ROV Comanche 6000 arrives on site at 3020m depth and start visual survey.
DAY 4 - CVR flight recorder located and recovered
The Universal Locator Beacon (ULB) guides the Comanche 6000 to a first beacon: unfortunately this one has been ejected from the flight recorder. Further visual inspections lead the ROV team to the Cockpit Voice Recorder (CVR)
DAY 5 - FDR flight recorder located and recovered
ROV team find the Flight Data Recorder (FDR) during the following visual inspection.
DAY 5 - Salvage of plane debris begins
Under supervision of Egyptian Authorities as well as Airbus and BEA specialists, critical plane parts are recover to surface for investigation.
DAY XX - Recovery of body remains begins
End of debris salvage. Under supervision of Egyptian and French legals, body remains are recovered for identification.