tag:blogger.com,1999:blog-7834826019588534175.post8448058099810606219..comments2023-09-20T06:10:29.485-04:00Comments on The Marine Installer's Rant: Sonar technology used in the Malaysia Airlines flight 370 searchBill Bishop - Parmainhttp://www.blogger.com/profile/11554223870035485145noreply@blogger.comBlogger5125tag:blogger.com,1999:blog-7834826019588534175.post-85259959717503290582014-05-04T08:59:22.620-04:002014-05-04T08:59:22.620-04:00Karl, I did some digging. The plane was originally...Karl, I did some digging. The plane was originally delivered with four ELT's. Only one of the ELT's is physically installed in the 777 aircraft. It's located in the cabin ceiling about amidships with an external antenna located just above it. The other three were associated with rescue gear like life rafts. They operated on internal batteries and are supposed to actuate with when encountering sufficient G forces. Some versions have a water switch. I think there are a couple of scenarios why they didn't send a signal. As you mentioned if the aircraft sank quickly, is a likely one. Another is if the batteries weren't changed they could have lost their charge. The aircraft was twelve years old, and the carrier seems to have less than a pristine maintenance record. The thing I din't talk about was the SOFAR channel. This is a deep water layer that can act as a sound wave guide allowing sound to travel in some cases very long distances. The Ocean Shield had well over 2 1/2 hours of beacon signal acquisition from its towed array. But this doesn't mean the aircraft was necessarily in that immediate vicinity. I suspect though it's in the general area and hence the now expanded search. The Ocean Shield is still in the area, but marinetraffic.com didn't show any other vessels hanging around with it. The HMS Echo which was also in the area with Ocean Shield is now just offshore from Perth.Bill Bishop - Parmainhttps://www.blogger.com/profile/11554223870035485145noreply@blogger.comtag:blogger.com,1999:blog-7834826019588534175.post-29611010029484938782014-04-26T12:02:07.131-04:002014-04-26T12:02:07.131-04:00One perplexing issue is why none of approx. 5 ELTs...One perplexing issue is why none of approx. 5 ELTs (the aviation equivalent of an EPIRB) on board the aircraft managed to get even one signal to a satellite. They don't broadcast from underwater, suggesting that the plane sunk before they could be activated or that their was not a satellite in view prior to sinkinh. Some of the ELT satellites are geo-stationary, but only in certain parts of the world. It also appears the most ELTs are old generation without integral GPS, instead relying on triangulation to obtain a fix, a time-consuming process. It also appears that they are not designed to float free of the aircraft to the surface, since they are primarily intended for terrestrial use.Karl in NYhttps://www.blogger.com/profile/02233082722631532086noreply@blogger.comtag:blogger.com,1999:blog-7834826019588534175.post-67914466830935962652014-04-25T15:08:44.474-04:002014-04-25T15:08:44.474-04:00Very well done description. Wish the networks wer...Very well done description. Wish the networks were this good at explaining this. Thank you. Alfexhttps://www.blogger.com/profile/11537332938729476712noreply@blogger.comtag:blogger.com,1999:blog-7834826019588534175.post-44499265045952658842014-04-21T11:00:26.508-04:002014-04-21T11:00:26.508-04:00Lucid and yet easy to understand. Thanks for this,...Lucid and yet easy to understand. Thanks for this, Bill.Rhyshttps://www.blogger.com/profile/00598445145507204424noreply@blogger.comtag:blogger.com,1999:blog-7834826019588534175.post-39175152052462256492014-04-16T03:35:05.848-04:002014-04-16T03:35:05.848-04:00Another example of a well-informed specialist blog...Another example of a well-informed specialist blogger taking us far beyond what general journalists can reasonably be expected to do. The best overall explanation of the MA370 sensing challenge I've read. Thanks!<br /><br />It seems inconceivable that this aircraft and its passengers might end up as the latter-day equivalent of Amelia Earhart, Fred Noonan and Earhart's Lockheed Electra. <br /><br />dbostromhttps://www.blogger.com/profile/13885863615343906724noreply@blogger.com