What was found
DURING TAXI TO TAKEOFF, THE NO TAKEOFF CAUTION APPEARED ON THE EICAS. SIMULATNEOUSLY, THE PARK BRAKE PRESS LOW MESSAGE WAS ILLUMINATED. THE CREW TAXIED BACK TO GM BASE AND ANOTHER AIRCRAFT WAS UTILIZED FOR THE FLIGHT. UPON TROUBLESHOOTING, THE PARK BRAKE SWITCH WAS FOUND TO BE FAULTY. THE CONTACT PLUNGER HAD DETERIORATED, THUS NOT ACTUATING THE CONTACTS. SWITCH HAS BEEN REQUESTED. (M)