[egbert]

Here is my interpretation and speculation based on Matti's and Alex' inputs.

1. The Ju52 with identifier PH + OI, Werk Nr . 3225 , left Mamaia (Konstanza), stopped in Pipera (Bucharest)=fact.

Next Matti's and my speculations:
2. Next -why a new briefing in Pipera after flying a mere 200km only, or, stop for refueling?
Instead they changed planes to another Ju52 with identifier PO+GO, WerkNr. 501326, SKZ , sent from OKM to pick them up for the immediate flight towards Berlin, via Arad (which was never reached). Maybe the statement from R.Klemm, that they fueled in Arad, is a mix-up of the eye witness account ?
KK Rosenbaum was a VIP called to Berlin. A Flotillenchef does not fly around in circles, burning valuable time and certainly did not fly 1000km from Mamaia (Konstanza) to Arad and back from Arad 1000km to Varna and than proceed towards Berlin. This is not plausible at all.

3. From Pipera the new JU52 was WNr. 501326, SKZ PO+GO. Flight path from Pipera across the wide plains and starting the West Carpathian mountain range crossing northbound by turning into the valley north, from Orsova to Arid . Just behind Orsova in thick fog the pilot was disoriented and accidentally deviated from the flight path left into the mountain region and crashed 9km n/w of Toplet.

Please see speculated flight path in attached file