Kudos for ingenuity but from my understanding, flying over land is preferred than over an ocean as there are options available in case of emergency. So isn't this jeopardizing flights for fuel savings?
Seems like an insignificant risk, and cutting the flight time by 10% might do more to reduce risk than staying over land.
Of course, we don't know what happened to mh17, which might have also glided into the ocean.
Given modern aircraft design, flying over open water makes good sense.
Multi-engine failures on a twin engine aircraft are the rarest of the rare events and so far there have been less than a handful such events in record and as such, in my comment I assumed that gliding would imply a single engine failure as is implied by ETOPS which you failed to note.
The quoted flight as a result of a massive fuel leak and ignorance on the captain's part to notice fuel imbalance led to dual engine failure.
Also, ETOPS itself has multiple ratings and the A330-200 (in the quoted flight) was certified for ETOPS120 or 120 minutes away from an emergency field on the flight plan and not 180. The new 300+ series rated with ETOPS180 and beyond have a higher composite content to reduce weight and perhaps more fuel efficient engines (ETOPS implies single engine failure).
Source: I have a PPL and over 2500 hours in FS.
This assumption is the problem and grandparent was very correct to point out the obvious misunderstanding that would result.
Maybe this is the typical wording used by pilots, but to laymen gliding means something else.
Without any power, airliners can't really glide much. Of the few cases of all-out engine failures, even fewer make it safely to land or water - most of which that did were at their cruising altitude at the time of failure. With only memorable exception being the hudson river ditch.
In-fact, during the landing or take-off, even a single engine failure can catch the crew off guard and is among the worst case scenarios pilots are "trained" for.
One great success story was, of course, the Gimli Glider: