I understand that but these ad-hoc subs are done last munuit and not planned. WW crew or M/F crew can be used. It will depend on which fleet has spare capacity and although it is more cost effective to use M/F crew, the decision will be taken on which crew are available at the time, not whether they trigger days off after or not.

The crewing levels go up and down on each fleet depending which seasonal routes we have been allocated. Sometimes there are imbalances on each fleet, some over crewed and some under crewed. So the decisions which Fleet would be used to do a longhaul aircraft sub on a shorthaul route would be taken on the day, depending on which crew were available. Of course roster wise, M/F would be more cost effective but that would not prevent BA using WW crew if they were the crew that they had most of available that day.

We have often done these subs in the past during disruption to get the schedule back on tract but the reason we are doing this a lot at the moment during disruption, is more to do with the extra aircraft available at the moment, rather than the fact that M/F can work both long-haul and short haul.