Interesting comments regarding gliding experience.
Giving a clue to my age, about 50 years ago in NZ, a DC3 was caught on the wrong side of a standing wave and sank about 7,000 feet into the side of a mountain in a nose high attitude on full power.
The general view of the gliding community at the time was that had the pilots had any sailplane experience they would have recognized their predicament and flown out of it.
Obviously no standing waves out in the Atlantic, but the situation for the crew seems eerily similar