Hi
CONF iture,
I took the EPR levels from page 2 of the most recent AAIB Interim Report, where it states: "...at a height of about 720ft the thrust of the right engine reduced to approximately 1.03 EPR (Engine Pressure Ratio); some seven seconds later the thrust on the left engine reduced to approximately 1.02 EPR" and further on in the same paragraph: "...The FMVs responded to this command and opened fully but with no appreciable change in the fuel flow to either engine."
...keeping the Vref would have been a better option than keeping the Glide Slope.
An interesting hypothesis. F30 on the 777 is the most you can hang out, i.e. it is drag flap with little corresponding increase in lift compared with F25. I would put forward that Vref30+5 is, with *significant* thrust being produced, quite a bit faster than Vx in this situation. Maintaining speed at 'bug' (1.3Vs+5) with F30 would lead to intersecting the ground plane some distance short: not a real improvement on what happened. There is the possibility of some help from ground effect but a) it's not over flat terrain and b) the aircraft is in its 'dirtiest' config. and bleeding energy fast. I don't think we'll ever know for sure what the optimal course of action might have been, unless someone runs some *very* detailed computer analyses (NOT in a simulator). I have a hunch that the answer will be different for each second that goes by on the approach.
It would be time to implement such exercise in sim training, not to cover all possibilities but just to make aware of different options and consequences.
I've done total engine failures as part of conversion/recurrent training on several types, including the 777. However, the situations have been (deliberately) set up to be 'survivable', i.e. a more than evens chance of getting the thing down on the runway in one piece, given average skill levels. The BA38 (and possibly the recent RYR) were both at the edge of the envelope and to try and train for rare incidents like these would probably leave the impression that in real life you'd be lucky if you weren't dead. A bit negative, not to mention the best recovery techniques are probably peculiar to each incident, so there is little 'generic' help to take away with you...