MH370: Somewhere out there

Lest we forget, the seafloor search for the missing 777 airliner is underway. Here's the ATSB's weekly update.

A preparatory survey of 150,000 sq km of very rugged seabottom southwest of Australia has been completed. It's considered the most promising. The survey allows sonar towfish to be operated close to the sea floor without running into a cliff. 

Here's a diagram from a presentation about one of the sonar-search ships, Fugro Equator.

Here's one of the sonar-imaging towfish:

More than 96% of that mapped area still awaits a plane-hunting towfish, so it's too early to say whether the towfish are going to find anything based on the sparse satellite signals. 

Having read the Journal of Navigation article by Inmarsat on the analytical methods, I'm confident they're looking in the right place.
The biggest mystery has been the complete lack of MH370 debris in the water or on a beach. Here's the big picture of ocean currents:

I continue to hold to the theory that some massive system failure, such as an oxygen fire that disabled key electronics, was responsible but there's no proof of that ... or anything else. Some useful information might be contained in the 777's maintenance logs, but Malaysia hasn't released those yet.