A and C
I believe there are 30-40 inhibited Grob 2500 engines in stores. So they should be able to keep ~20 of the fleet running until the planned OSD of 2025 even with the very low 1600hr TBO (unless anyone knows of a different TBO?). It would need careful management, so now is the time to get the SF25s with fixed-pitch props and normally aspirated Rotax on order to replace the Vigilant. Lead time for a fleet-wide replacement of Vigilant is probably 3 years or so with SF25s.
I believe that some Vigilants have engines running on condition with 4000hrs+ on them before the 'pause'. Not great for a youth flying organisation, even for a powered glider!!!
I'm guessing this is the delay in letting everyone know what is happening - they will need to axe some Vigilant units or turn them into Viking units unless they have found some more Grob 2500s? I'm also guessing that OSD for Vigilant will need to come forward and a line for replacement put into the ABC from 2016 to 2020 and then a sustainment line put in the ABC from thence on.
CPL Clott