Graf Zeppelin 1931 Polar Flight

Figured is a Zeppelin card from the 1931 Polar Flight. The card has an on-board cancellation of July 25th and was dropped in Leningrad the same day. The card was then sent by plane from Leningrad to Berlin on July 27th, no Berlin arrival stamp. What is unusual is that the typical transit date to Berlin for the Polar Flight is July 31st so this card made it on an earlier flight. How unusual is this?

I know nothing about anything about this subject, but do think that it is a fantastic cover with all of the different cancellations and the stamp.

The overprint on the stamp is specific to the flight like the overprint for the 1933 Chicago World's Fair flight.

Beautiful cover, and I also know nothing about it - I am looking forward to see more of your collection - Thanks
Rene

The Russian airmail cancel is commonly found with one of two dates -- 27 July or 31 July. Mail was dropped in Leningrad on the outbound flight (25 July) of the LZ-127 and and on the return flight (29 July). The 27 July Russian airmail flight cancel would indicate this was dropped at Leningrad on the outbound flight.

Is the earlier date uncommon? Michel does not list it.

I have been trying to get into the discussion group at ezep.de and can not make contact with Dieter who I assume approves the registration for the group. Any ideas?
George

I haven't had any luck contacting Dieter in more than 2 years. At this point, the study group and Zeppelin Post Journal are basically dead.

I do see that the message board is still active. Any idea who Talltrees is? Very active poster.