[Nick Beale]

As far as I konw, the columns for durch and ohne Feindeinwirkung represent the loss of an aircraft as far as the unit is concerned - it is either destroyed, missing or so badly damaged that it is taken away or repair and the unit needs to replace it. It may return to service at a later date with the same unit or another one.

Aircraft are recorded as given up to Überholung or to Industrie and I understand that to mean that they were worn out in some respect (perhaps engine wear or structural fatigue) that required prolonged work. Again that aircraft was removed from the unit's strength and should be replaced. Again such an aircraft will probably see more service, perhaps on operations or maybe in a training school.

The only purpose in requiring such a return must be to record the true position, so that supplies can be sent to the right place, new orders can be placed with the factories and so on. I do not recall seeing anything in the Gen.Qu. loss reports which deals with overhaul or transfer to other units, only with loss or damamge through combat or accident.