There has been now, to the best of my knowledge, 4 failures associated with the 92 MRGB in the last year or so, all resulting in emergency landings. Fortunately 3 were close to land, so successful. I am quite sure all of us operating it have seen and heard of more. To my mind this does not make it an extremely remote possibility. In fact our historical evidence so far, makes this more of a probability than we like to admit. I wonder how many more failures have been prevented maintenance crews. I know of at least one. There are far too many critical points for failure in the MRGB and transmission system, and not enough capability for either accurate indication of the problem or means to deal with it. The oil bypass system works only if the fault is in the oil cooler, and unfortunately that is only one of several possibilities. In fact if the the leak is in the gearbox itself, this will make the problem worse, by accelerating further the rate of loss of oil from the MRGB. However the emergency checklist very clearly states that this is the course of action upon low pressure warning (RED).
More direction is required here, and I suspect modification. I suspect customers are already starting to ask these questions, as are pilots. Whilst I agree a run dry capability is probably a myth, there are ways to better protect ourselves. We must also consider that if this happens again, we need to have the right conditions for a successful ditching. I would suggest that anything over sea-state 5, with the current float system, (sea-state 6 not approved for use yet!!!!!) and at night would not be conducive to a successful ditching. I think there have been enough warnings about the MRGB system already and unfortunately nothing has really been done, so now we have had the first real wake up call, hopefully something positive will come out of this, and we do not lose any more lives. Time for some very real and serious discussion on the way forward with the 92.