What was found
ENROUTE TO KTEB DURING CONFIGURATION FOR LANDING, WHEN GOING FROM FLAPS 5 TO FLAPS 15, FLT CREW RECEIVED A FLAPS FAIL AMBER CAS MESSAGE. RAN QRH PROCEDURE & TRIED TO RESET MULTIPLE TIMES TO NO EFFECT. CREW COMPUTED APPROACH SPEEDS & LANDING DISTANCES THAT CONFIRMED NOT ENOUGH RUNWAY AT KTEB FOR A LEGAL LANDING. DECLARED A PAN PAN & REQUESTED LANDING AT KEWR. AFTER CONFIRMING ALL QRH PROCEDURES, APPROACH SPEEDS & LANDING DISTANCES, ACFT LANDED UNEVENTFULLY. TECHS PERFORMED MECHANICAL & ELECTRICAL FLAP RIGGING CHECKS. GAINED ACCESS TO FLAP CONTROL HANDLE, REMOVED & CLEANED DUST/LINT FROM WITHIN. POST OPS CHECKS GOOD WITH NO FAULTS NOTED. ACFT RETURNED TO SERVICE.