My opinions only, no facts here:
With the Australian Prime Ministers comments today (Apr. 10, US time, a day later down under), it is beginning to sound like the discovery of MH 370 is fairly certain, according to some, but not all authorities and commentators. But, as an empirical scientist, I keep scratching my head about the contradictions outlined below (note that these contradictions may simply be the result of errors in news reporting and/or errors regarding my interpretations of hard data).
The initial detection of pings by the ship Ocean Shield was said to be from when the TPL-25 (Towed Pinger Locator) sensor was being towed at less than 1000 feet depth (the sensor was later lowered to a much greater depth, read below). But let us look at this initial contact with the pings. The Ocean Shield was towing a U.S.-developed sensor, the TPL-25. According to a navy.mil site, the TPL-25 can be lowered to depths of as much as 20,000 feet, but can only detect a signal from a distance of ONE MILE from its source (this may be a nautical mile? = 1.15 American miles). So, if the TPL-25 was initially being towed at ~1000 feet depth, how did it detect a signal emitted from the bottom of the ocean (~14,800 feet deep at this location) far beyond its claimed detection range?
Let us carry this logic further. After the initial detection, the TPL-25 was lowered from ~1000 feet to 4600 feet. This lowering of the TPL-25 involves a very wide turn of the ship and a pass back over the initial ping detection site. Note that even at the new 4600 foot depth, the TPL-25 is still theoretically beyond its designed detection range (14,800 4,600 = 10,200 feet = way over 1 American mile or 1 nautical mile). The answer to this conundrum could be that very ideal conditions exist in this part of the southern Indian Ocean. Although it may be a myth, it is claimed that under very ideal conditions, pings from a black box can be detected 3 miles (American or nautical?) from their source. BUT REMEMBER, after the TPL-25 was lowered to 4600 feet, the ping signal was detected continuously for more than two hours. The TPL-25 is typically towed at a speed of 3 to 5 knots (3.5 to 5.8 miles per hour). This implies that the TPL-25 was towed a lateral distance of 7 to 11.6 miles at 4600 feet depth while continuously detecting the pings from ~14,800 feet. Based upon this information, we have to accept that the TPL-25 can detect a ping signal from a source MORE than 3 miles distant and more than three times its engineered capability. It has been stated widely in the press that the TPL-25 can detect a black box from 2 nautical miles (2.3 miles) or American miles; this disagrees with the official data sheets and is still considerably less than 3 American miles and does not discredit my observations above.
Not including the very earliest detection of pings by a Chinese ship, and after four confirmed contacts with pings (the most recent fifth one has been dismissed by authorities), the official search area is still inexplicably large (+800 square miles). With four confirmed ping contacts and assuming a maximum detection range of 1 to ~3 miles from the ping source, triangulation (or quadulation) of the signal source should have narrowed the source location very, very greatly. In my opinion only, we should be narrowed down to a small fraction of the present search area.
I dont know what the overall answers are. But for now, I will accept that the TPL-25 sensor can detect black box signals from more than 3 times greater than its claimed engineered capability. However, in the slim chance that nothing is found on the ocean bottom at the reported ping locations, I will weigh in with an explanation in the future. If the authorities find the plane near-to the present search location, my greatest compliments are extended to all involved in the search.
