3. No power until 600'. Not permitted under BA's ops. You have to be in the stable configuration normally by 1000' but ALWAYS at 500'. We have a call at 500 with a reply "stable" or "Go Around".
Stable= Gear and land flap down, approach power set and speed no more that touchdown speed +15kts. I can tell you for a fact they were stable. And I mean fact.
If that is the case then the engines must have
lost power between 1000ft and 600ft. If the initial report is correct, the engines did not respond to A/T or pilot commanded changes at 600ft. If the thrust was already set at stable approach conditions, then the failure to respond to commands would have meant they remained at the selected thrust setting, no?
To land 300m short means they must have had significantly less thrust than that required to make a "normal" landing, so the power setting must have changed (degraded) in the interim.