This contract has always been based upon the manning of a single aircraft at each base. No second standby is required.
As the contract process progressed in 2012, first one and then a second EC225 ditched in the North Sea during oil and gas crew change operations and the DfT witnessed the chaos that can occur when an entire type is grounded.
At this point the contract changed from being one aircraft per base and 'convince us of how many spares you need to maintain 98%' to two aircraft per base. If you have two aircraft per base then if one type is grounded, or otherwise not available, then you can redistribute aircraft and still have one aircraft per base.
Oh wait a minute, we have one type unavailable now. And we are getting eight extra aircraft. This is fascinating isn't it?
