But what was the search level associated with the other missing aircraft mentioned?
In many cases, search efforts are minimal, thus the reason for the listed "total disappearance".
In the case of MH370, the search effort, both aerial and sea-based, has been the most extensive, and the most costly in the history of the aviation world.
The initial aerial search efforts by sizeable numbers of multiple engine aircraft, with multiple searchers aboard - that produced precisely nothing - is what remains the most disconcerting feature of the whole MH370 search performance.
One only has to look at the amount of floating debris found from AF447, to see that there was plenty - and it spread out as well.
Admittedly, we're talking a completely different aircraft type as compared to AF447 - but a crash into the ocean surface produces fairly similar results, regardless of aircraft type.
There may be a somewhat higher percentage of composites in an Airbus A330 as compared to the B777 - but there's still a large percentage of an aircraft structure that floats.
I don't buy the line that the Captain of MH370 did a Captain Sullenberger-style Hudson landing on the open ocean, and MH370 stayed fairly intact - despite the fact that the open ocean can sometimes be relatively smooth.
"Relatively smooth" in the open ocean is still rough water, and an aircraft still breaks up. Only floatplanes are designed to land on water - and smooth water at that.
IMO, even after 9 day delay in the start of the search in the SIO - some debris should have been sighted, if patrolling aircraft were within 200-300 miles of the actual crash location.
The fact that, if the actual crash location is between 32 - 39 deg S - as the CSIRO and the ATSB are convinced - then the floating wreckage, after 9 days and more, would have been initially making its way in the general direction of South-Western Australia - where flights were originating from - and this makes the lack of wreckage sighting even more inexplicable.
Wreckage from MH370 should have been within the flight paths of the searching aircraft to and from YPPH & YPEA, and should have been sighted from them - unless the searchers only switched on, when over the calculated search zone, and switched off, once they left the outlined zone.
If the actual crash location was further North along the 7th arc, that would explain the lack of wreckage sighting - as the wreckage would have been moving Westwards and away from primary searchers almost immediately after the crash.