Possibly, due to shortage of spare parts, could it be some otherwise repairable aircraft were "written off" and used as parts planes, depending on the kind of damage and the need for certain parts?
I imagine that whether or not an aircraft was written off was a rather subjective process and depended largely on the availability of parts and manpower as well as the specific needs of the unit at that time, regardless of the % of damage. If spare parts were scarce and replacements unlikely, isn't it possible that a plane could jump from a 60% damaged yet possibly repairable, to 60% damaged and unrepairable, just so the plane could be scavenged for needed parts?
Just a thought. To me, anything over 50% damaged would be a huge undertaking to repair. Maybe not though. I suppose that the % rating would be based on cost and/or availability of parts as well as required manhours and availability of manpower in addition to the subjective part of the analysis which would largely depend on the the needs and combat situation of the unit.
If they didn't have enough pilots to fly all the aircraft in the unit, and replacements of both were slow to arrive, then it seems more likely that the available manpower would be spent to keep the current undamaged aircraft airworthy rather than repair a heavily damaged yet still salvagable and possibly still airworthy aircraft...especially if there was a likelihood of the unit moving to another field soon.
I'd be interested to know if you find any official documentation suggesting how they might have determined what was repairable and what wasn't.
