John - I'm not joking - RadarBox is correct in that KLM1115 IS EHAM - ESSA, and PH-PAD is the Piper Archer. I see that Airframes.org has the same information as RB is displaying for you - PH-PAD doing flight KLM1115 (don't know where they get their info from, though).
So either RB is mixing up two flights, or PH-PAD is transmitting the callsign in error. Anyone else out there with a different explanation?
I've certainly never seen anying similar in RadarBox myself.
Rod