Patch from Melchior Franz:

Patch from Melchior Franz:

It seems that the airport database was changed some day and the End?Flags
changed from floats to strings. The database definition, though, was not
adapted and still created number entries. Reading out these flags led to
access to memory, that was never initialized. While it didn't cause crashes
during normal use, it actually caused one when I ran fgfs in ddd. Seems,
that the concerned memory region wasn't zeroed out then and hence uncovered
the bug.

Of course, the runways.mk4 database has to be re-created with the new
definitions.