LEAR 45 AT 15000 FT DIVERTED DUE TO REPEATED R ENG NACELLE OVERHEAT. RECURRING PROB CAUSED BY OVER SENSITIVE SENSORS AND INADEQUATE INSULATION.

Narrative

DURING CLBOUT IN IMC; WE RECEIVED RED WARNING LIGHTS; CAS; TRIPLE CHIME WARNING; INDICATING R ENG PYLON OVERHEAT. I; AS PF; RETARDED THE R ENG TO FLT IDLE; AND CALLED FOR THE QRH AND HAD THE COPLT RUN THE APPROPRIATE PROC. WHILE PROC IN PROGRESS; I INFORMED ATC OF INTENT TO RETURN TO DEP ARPT (ZZZ1). THE PROB WAS CLRED; AND ONCE AGAIN; WE TURNED S TO CONTINUE TO ORIGINAL DEST OF FLL. 2 OR 3 MINS LATER; PROB RECURRED. THEN I ASKED FOR WX AT COMPANY MAINT FACILITY LOCATED NEARBY AT ZZZ; AND WAS CLRED DIRECT. THE R ENG NACELLE HEAT HAD TO REMAIN OFF; BUT THE R ENG WORKED NORMALLY; WITH THE R PYLON OVERHEAT WARNING AGAIN EXTINGUISHED. WE MONITORED THE ENG PARAMETERS; WATCHED FOR SIGNS OF ICING; AND DIVERTED TO ZZZ WITHOUT FURTHER INCIDENT. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE NACELLE OVERHEAT WARNING IS A RECURRING PROB ON THE LEAR 45 AND HAS HAPPENED 3 TIMES TO THE RPTR WITH 2 SEPARATE AIRPLANES. THE RPTR SAID A PICCOLO TUBE DISTRIBUTES THE HOT PNEUMATIC AIR INTO THE PYLON AND IT IS BELIEVED A COMBINATION OF OVERLY SENSITIVE HEAT SENSORS AND INADEQUATE INSULATION IS CAUSING THE PROB. THE RPTR STATED THIS IS JUST WHAT MAINT SUSPECTS AND IS JUST THEORY.