[QUOTE]In reality, whether you say Mayday or Pan makes no difference to the safe conduct of the flight — yes, it affects how ATC and emergency services respond, but that’s procedural, not a measure of correctness especially for a straightforward engine failure.[/QUOTE]
Any ATC out there please correct me if I'm wrong but I would imagine the response for a PAN or MAYDAY would be identical given the aircraft has just rotated, it's not solely the pilots choice of words that dictate the response level.