seabed. so they need equipment to detect those pieces of aircraft. also the black boxes. they could ask the u.s. for the toe pinger locater used for mh370. the ntsb monitoring the situation, but they re willing and ready to help if needed. rene marsh in washington thanks so much. our next guest, john know all about these sorts of investigations, they are both former heads of the national transportation safety board. jim hall and debra hersman joins us. deborah is now president of the national safety council. so glad both of you could join us unfortunately you have far too much expertise in matters such as these. deborah i ll start with you since you re here. we talk about the location of this debris. not far from that last known communication with the plane. about six miles. what does that tell you? things happen fairly quickly for this plane? it tells you that things happened fairly quickly. it gives you some confidence that the things that we knew from past investigative
perspective when we re talking about teeny tiny microphones looking for teeny tiny black boxes. they create walls. sound can baounce off it and no make it through it. put a sub right above or below one of those, and they re shooting sound to find a sub they can bounce off the therm aa thermales and not see the sub. if the toe pinger locater is being towed behind the vessels in question, they have to be exactly in the right thermal layer in order to detect something? more or less. there s one layer that travels the whole ocean from 2,000 to 4,000 feet. it goes up and down. it s a deep sound channel that sound can get caught in. propagate for miles. the sound can get caught in there and not make it through. parts of it can make it through. that s why that pinger is being deployed. they re towing that pinger down into about 3,000 feet of water where they can actually get into that zone and maybe even pick up