>> A specialist French naval vessel joins the search for the Egypt Air flight's black boxes on route to the Eastern Mediterranean. It's equipped with three probes, which experts hope will accelerate the search for the Airbus A320. A week after it crashed with 66 people on board, investigators still have no clear picture of its final moments.
Watch as global aerospace correspondent Tim Heffer explains the difficulties the search teams face.>> If the plane happens to have fallen in one of the deepest parts of the Mediterranean, up to 3,000 meters deep, and that's right on the edge of the range of these pingers which put out a signal once every second for 30 days.
Changes in the technology around the way they were agreed in 2010 and those would mean that the signals would go for 90 days instead of 30 days and they would also have a longer range. But those changes aren't coming into effect until 2018. For now, the Egyptians are going to have to use the technology which has been around for decades and that means there isn't much time left.
>> On Thursday, Egyptian investigators said a radio signal had been received from an emergency distress beacon, usually located in the rear of the cabin. This could help narrow the search area of that part of the fuselage near the black boxes to a three mile radius. But experts aren't convinced that the transmitter that sent the signal would have survived the crash.
Negotiations are also underway to contract a second firm to search more than one area. During the flight, the plane sent signals that detected smoke and suggested an increase in temperature at the copilot's window. But until the black boxes are found and recovered, investigators won't rule anything out. Relatives and loved ones searching for answers will have to keep waiting.