callsign questions

[myrtleman]

Two queries I wonder if anyone can help me with:

1) Is there any rationale behind Lufthansa callsigns into LHR? Are they in any way related to their departure point and why do some flights retain a numeric callsign?

2) What does a papa stand for at the end of a callsign? I've noticed this especially with unscheduled VS flights into Heathrow and after the BA Gategourmet strike loads of flights the next day (clearly out of place) were coming in with papa at the end of their callsigns.

Thanks,
MM

[point5]

Not sure about the Lufthansa question, but 'Papa' usually implies a positioning flight, e.g. VIR623P positions between LHR and LGW.

[Avman]

You may come across "F" for "Ferry" flight, which some companies use (incorrectly) instead of "P".