AN E120 CAPT ABORTED TKOF AFTER RECEIVING A FLAP CTL FAULT WARNING. WHEN CLR OF THE RWY; HE ATTEMPTED A RESET OF THE SYS BY FOLLOWING THE CHKLIST PROCS. HE THEN RETURNED TO THE GATE AND SUBSEQUENTLY ENCOUNTERED TWO MORE INCIDENTS WITH THE FLAP CTL FAULT BEFORE FERRYING THE ACFT TO THE COMPANY MAINT FACILITY. ACFT EQUIP PROB FLAP CTL FAULT.
Synopsis
AN E120 CAPT ABORTED TKOF AFTER RECEIVING A FLAP CTL FAULT WARNING. WHEN CLR OF THE RWY; HE ATTEMPTED A RESET OF THE SYS BY FOLLOWING THE CHKLIST PROCS. HE THEN RETURNED TO THE GATE AND SUBSEQUENTLY ENCOUNTERED TWO MORE INCIDENTS WITH THE FLAP CTL FAULT BEFORE FERRYING THE ACFT TO THE COMPANY MAINT FACILITY. ACFT EQUIP PROB FLAP CTL FAULT.
Narrative
DURING TKOF INBOUND FLAP CTL FAULT OCCURRED; ABORTED TKOF. WHILE CLR OF RWY ATTEMPTED RESET OF SYS; IN ACCORDANCE WITH CHKLIST. RETURNED TO GATE. MAINT RESET SYS AND SIGNED OFF ACFT FOR FLT. SYS FAULTED 20 MINS LATER AT GATE. REPLACED CTL UNIT NEXT DAY. SYS CHKED GOOD; BUT LATER FAULTED AGAIN PRIOR TO FIRST LNDG AFTER REPAIRS. ACFT FERRIED FLAPS UP TO COMPANY MAINT FACILITY. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE PARAMETERS THAT NEED TO BE MET FOR CORRECT FLAP EXTENSION INDICATIONS COMPARE THE FLAP HANDLE POS; JACK SCREWS AND FLAP SWITCHES; AND CTL BOX INFO. ALL OF THIS IS MONITORED BY THE COMPUTER. THE SYS ALSO CHKS FOR DISSYMETRY AS WELL AS ASYMMETRY. THE ACFT HAS 3 FLAP SECTIONS ON EACH WING: THE OUTBOARD; THE NACELLE FLAP; AND THE INBOARD FLAP SECTION. ANY ERRATIC PRESSURE ON A MICROSWITCH COULD SET OFF THE FAULT INDICATION; SO A LOT CAN GO WRONG IN THE PROCESS. IN FACT; THIS RPTR'S COMPANY HAS AN INCIDENT RPTING SYS WHICH RPTR STATES HAS 'ONE HUGE SECTION' JUST FOR FLAP PROBS ON THE E120. THE CAPT WAS VERY FRUSTRATED BY THE DIFFICULTY IN DETERMINING WHAT WAS CAUSING THE PROB. HE ASSUMES THAT THE MECHS AT THE MAINT BASE HAD TO RUN THROUGH THE ENTIRE SYS TO GET TO THE ROOT CAUSE OF THE PROB. IN THE FINAL ANALYSIS; THIS RPTING CAPT BELIEVES THAT ALL OF THE RUN AROUND MIGHT JUST BE FROM A FLAP PROX SWITCH THAT IS OUT OF WHACK.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.