Busy morning shift on the Scottish FIR sector........PA28 called me whilst I was on the phone...rough running engine......my response what are your intentions......will attempt field landing......confirmed SOB asked to squack 7700.....I call D and D and advise of situation...they straight away advise RCC who launch Rescue 177 Seaking from Prestwick to last known position.....I then suggest to PA28 that maybe he should call mayday......at this response he agree's!!.....now able to maintain 1500ft and will attempt to return to Cumbrnauld about 20 miles away.....I ask another aircraft on frequency to try and get visual with PA28 and shepphard him back towards Cumbernauld just incase the engine stops and he has to land out....eventually the aircraft lands safely with cracked cylinder......little oil left and I guess a few minutes left before seizure!!!!.......................my point is....if things doent seem right please please call mayday as soon as possible.......its amazing how those words will capture the attention of ATC.....
