As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING A TEST RUN FOLLOWING AN ENGINE CHANGE OF THE NR 1 ENGINE, THE NR 1 ENGINE FAILED TO RETURN TO IDLE WHEN THE NR 1 START SWITCH WAS BROUGHT FROM FLIGHT TO IDLE POSITION. SUBSEQUENT TROUBLE-SHOOTING FOUND THAT THE SWITCH WOULD ALSO FAIL FROM IDLE TO FLIGHT POSITIONS. THIS CONDITION, IF NOT REALIZED BY THE FLIGHT CREW, COULD RESULT IN AN UNDERPOWERED SINGLE ENGINE TAKE-OFF. THIS IS NOT THE FIRST FAILURE OF THIS TYPE WITH THIS SWITCH.