What was found
SHORTLY AFTER DEPARTING, DIVERTED BACK TO DEPARTURE DUE TO A RIGHT BLEED AIR FAIL WARNING. THIS WAS A LIVE PART 135 FLIGHT, NO EMERGENCY WAS DECLARED, WHILE THE CREW LANDED SAFELY BACK AT AIRPORT. IN TROUBLESHOOTING THE DISCREPANCY TECHNICIANS FOUND A PIN HOLE THE PLASTIC/EVA TUBING RUN ALONG THE RIGHT ENGINE NACELLE. THIS SMALL PIN HOLE ALLOWED FOR ENOUGH AIR PRESSURE TO ESCAPE, CAUSING THE BLEED AIR WARNING SWITCH TO LOSE THE 2 PSI REQUIRED TO EXTINGUISH THE WARNING ANNUNCIATOR. THE TUBING WAS REPLACED AND A SATISFACTORY OPERATIONAL CHECK OF THE BLEED AIR WARNING SYSTEM HAS BEEN COMPLETED.