[Adriano Baumgartner]

It seems this applied only for multi-engined aircraft, I believe.

There was some kind of rule, if memory does not fail me, but I do not remember from where I took notes. Certainly not from an Official Source like that you are looking for:
* Flights up to 4 hours flying time > 1 Feindflüge = 1 Frontflüge
* Flights from 04:01hs up to 07:59hs > 1 Feindflüge = 2 Frontflüge
* Flights of more than 8 hours > 1 Feindflüge = 3 Frontflüge

However, I have not seen up today, how night-fighter sorties of more than 4 hours were recorded on Flugbüche (maybe if some of you do have this kind of register we can list, at least some entries)...and am not sure if this rule applied overall to all branches of LW services (certainly for Wekusta, Aufklärer Staffelns, etc.) we do have entries that prove this rule.

RAF Bomber Command and Coastal Command (seaplanes) airmen often flew sorties up to 11 hours (or more on the case of the Sunderlands)....and some B-29 airmen later flew some of the longest WW2 sorties recorded.

This is a fascinating subject indeed.

It would be quite interesting to know the procedures for convertion. If the crewmembers were allowed to submit their own adjustements on their Flugbüche, which were then signed by their C.O.'s (Staffelkapitäne and Kommandeure and Kommodore), or if the Adjutant had to specify, amongst the monthly total of sorties, how many would be graded up to 2 or 3 Frontflüge, thus giving an overall total higher.

This "LW internal and Administrative procedures" must be the "cat's jump" as we use to say down here....

Really nice thread JU55DK.

A.