Airbus A320 Route Problem - UM600.
Not sure if this is the right forum but I will post here anyway.
There have been a number of occasions where Airbus A320 Aircraft (from at least 3 Airlines) have turned Left at waypoint ALMOK on UM600 in the OBBB FIR when their Flight Plan and Route Clearance has been to remain on UM600 from TUMAK to KUMBO. This is a dangerous situation and, at the moment anyway, only seems to happen with A320 Aircraft. The Flight Plan that is sent via AFTN is correct according to OBBB AIP. Somehow the Route entered into the FMC is not correct (not in accordance with OBBB AIP) and does not match the Filed Flight Plan sent via AFTN. Some pilots have advised us that they don't know why the Aircraft made the turn onto UA453.
We are currently liaising with the Airlines concerned but I was wondering if anyone has any ideas?