direction. the aircraft at that point wasn't going through a sort of a structural mechanical issue that was causing it to rapidly lose altitude in any way. it was able to make a controlled turn and then make a controlled climb, and then sustain that climb for 20 minutes before making a controlled descent to about 4,000 feet out over on the other side of the malaysian peninsula. so it's useful information for investigators. how much further forward does it take them, really they say they need the black box to complete the picture, erin. >> interesting that nick is using the word control for the ascent to 39,000 and the descent to 4,000 feet. nick, you have also learned the plane was equipped with the four emergency locator transmitters. i know people assume it might have been. you were actually able to confirm this. these are designed to transmit a plane's location to emergency satellites when they're triggered by a crash. ie if it lands in the ocean or something. they should have been triggered, but they weren't.