[Pieter H]

JC,
thanks a lot for confirming the timing, I've been struggeling with that question for years.
I have only one remark, which is related to the reaction time. From all French reports I've seen the following pattern appears: typically the reaction time after a mission command came in from the central Force Aérienne was at least half an hour; the time to translate the high level command into a detailed mission target, course, objectives etcetera. I strongly suspect the commands for F1C/AC1 and GR I/35 were issued at the same time (the 10.00 you mention), and the GR I/35 Potez took off at 10.30.

So if I assume that Ferran took off at 10.30 and de Scitivaux 5 minutes later it was 10.35 French time. Now the initial order was to fly to the Schelde estuary for escorting Latécoère float planes they were supposed to meet there. Calais to Vlissingen is probably 20 minutes flight, 10.55. But I can not imagine de Scitivaux then immediately abandoned his orriginal order, so he must have been flying there for say 5-10 minutes looking for his colleagues before deciding to fly on. We're 11.05 earliest by then.
Flying from Vlissingen to IJmuiden - still assuming that his identification is correct - is easily another 30 minutes, so we're by now well past 11.30 French time, or 10.50 Dutch local time. With all uncertainties this makes the time of his encounter with the "3-engined Arado-style" aircraft 11.00 Dutch time, give or take 10 minutes.

Which makes it even more difficult to identify any suitable candidate, since this was after the third and effectively last Ju52 wave, and activities in the air over the Dutch coast were quickly coming to much lower level.
These are the options if I use the very large time window 10.30-11.30 local time:
- the last T8W left Scheveningen beach at around 10.00-10.15 (the damaged R1 returning to Schellingwoude) but there are no reports it was attacked). That makes the T8W scenario again unlikely.
- The only Ju52 activity in the Valkenburg area were 6 a/c of I./KGzbV.1 that were still flying around loaded, not having landed. At 10.15 they started their return flight whereupon one was shot down at Zoelen at 10.30. I've difficulty seeing any relation between this loss and the Potez.
- Between 10.00 and 11.30 some 13 IV./KGzbV.1 Ju52's were still flying over the Den Haag - Hoek van Holland area, having failed to land at Ypenburg. They were at least for a time escorted by Bf109's, although these might have been forced to return earlier. But all fates of these 13 a/c are known and none seems to have been shot down by enemy fighters, they all made controlled emergency landings.
- Between 10.40 and 11.40 Fokker C10's from Bergen (some 20km N. of IJmuiden) attacked Valkenburg air field (along the coast S. of IJmuiden) but reported no "enemy" aircraft in that area.
- Towards 12.00 the Luftwaffe was back in force, with 7./JG3 shooting down two C10's west of Rotterdam and 3./ZG1 and 1./JG20 shooting down five No.600 Sqn Blenheims. So it seems logical to assume de Scitivauz had left the scene by then.

So although this has been a very valuable discussion with some very useful new inputs, I'm still at a complete loss as to what the presumed victim of de Scitivaux could have been. Hélas.
But I keep on hoping for fresh inputs!

Cheers, Pieter