AN MD83 CREW EXPERIENCED A RUNAWAY STAB TRIM. FLT CREW PULLED THE INCORRECT ALTERNATE STAB CIRCUIT BREAKERS DURING THE QRH PROC REMOVING ALL STAB TRIM AND MAKING CTLED FLT VERY DIFFICULT.

Date: 2006-06 · Aircraft: MD-83 · Phase: approach

Anomalies: aircraft-equipment-problem-critical|deviation-discrepancy-procedural-published-material-policy

Synopsis

AN MD83 CREW EXPERIENCED A RUNAWAY STAB TRIM. FLT CREW PULLED THE INCORRECT ALTERNATE STAB CIRCUIT BREAKERS DURING THE QRH PROC REMOVING ALL STAB TRIM AND MAKING CTLED FLT VERY DIFFICULT.

Narrative

I WAS THE FO (AND PNF). WHILE ON FINAL APCH; THE CAPT WAS GETTING CONFIGURED FOR LNDG. AT 2000 FT; AFTER HE CALLED FOR FLAPS 23 DEGS; HE INDICATED HE HAD A TRIM PROB. HE HAD STARTED A GO AROUND; AND STATED HE HAD A RUNAWAY STABILIZER. HE HAD ALREADY COMPLETED THE RED BOXED ITEMS; AND CALLED FOR THE RUNAWAY STABILIZER EMER CHKLIST. I CALLED ATC; AND TOLD THEM WE WERE GOING AROUND; AND TO STAND BY. THEY IMMEDIATELY GAVE US A HDG AND ALT TO MAINTAIN. I STARTED THE EMER CHKLIST. AT THE SAME TIME; THE CAPT WAS HAVING AN INCREASINGLY DIFFICULT TIME CTLING THE AIRPLANE; SO WE CLEANED UP THE FLAPS. WE DECLARED AN EMER; AND TOLD ATC WE WOULD LIKE TO TURN BACK TO THE ARPT. WE ALSO TOLD THEM WE WOULD LIKE THE LONGEST RWY. THEY TOLD US THAT RWY X WAS THE LONGEST RWY; AND WE COULD CIRCLE BACK TO THE ARPT AS NECESSARY. WITH THE CTL FORCES NECESSARY TO MAINTAIN LEVEL FLT; WE ASKED FOR A BLOCK ALT. THEY GAVE US 3000 FT TO 5000 FT. WE COMPLETED THE EMER CHKLIST; AND THE TRIM STOPPED AT -.5 UNITS DOWN. THE CAPT STATED THAT THE AIRPLANE WAS VERY DIFFICULT TO CTL BELOW 200 KTS. HE STATED THAT WE WOULD LAND AT FLAPS 11; AT ABOUT 200 KTS. AT THIS POINT; I WAS ABLE TO TALK TO THE FLT ATTENDANTS BRIEFLY. CAPT HAD ME TELL THEM WHAT THE PROB WAS; TO PREPARE FOR AN EMER LNDG AS BEST AS THEY COULD. I ALSO TOLD THEM NOT TO PLAN AN EVACUATION; AND THAT THEY HAD LESS THAN 7 MINUTES TO LNDG. THE AIRPLANE WAS FULL; WITH A CABIN AND A FLT DECK JUMPSEATER. WE CAME AROUND ON FINAL; SET THE FLAPS TO 11 DEGS; ARMED THE SPOILERS AND AUTO BRAKES (MED). WE TOUCHED DOWN AT 200 KTS. THE AUTO BRAKE FAIL LIGHT CAME ON; AND THE CAPT USED MANUAL BRAKING TO STOP THE AIRPLANE. WE EXITED AT TXWY X AND STOPPED. ARFF EQUIP CAME OVER AND WE ESTABLISHED COM. WE ASKED THEM TO LOOK AT THE MAIN LNDG GEAR; AS WE HAD HOT BRAKES. THE BRAKES CONTINUED TO HEAT UP; AND WE STATED THAT WE WANTED TO MOVE TO AVOID OVERHEATING THEM ANYMORE. AT THIS POINT; ARFF PERSONNEL HAD A DIFFICULT TIME COMMUNICATING WITH EACH OTHER. AFTER WE FINALLY GOT THE TRUCKS TO MOVE; WE STARTED TO TAXI TO GATE. THE BRAKES IMMEDIATELY STARTED TO COOL DOWN. WE CALLED OPS; TOLD THEM WE WOULD BE COMING TO THE GATE; STOPPING SHORT; WOULD LIKE TO BE TOWED ONTO THE GATE; AND THE CABIN DOOR TO BE OPENED AS QUICKLY AS POSSIBLE. WE REQUESTED ARFF TO FOLLOW US TO THE GATE; IN CASE THE BRAKES OVERHEATED AGAIN. ARPT PERSONNEL WERE READY FOR US WHEN WE PULLED UP; AND WE GOT ALL THE PAX OFF OF THE AIRPLANE THROUGH THE FORWARD CABIN DOOR. AT THE GATE; ARFF PUT FANS UP TO THE BRAKES; AND THEY COOLED DOWN QUICKLY. AT THE GATE; WHEN I WAS LATER ABLE TO LOOK AT THE EMER CHKLIST; I DISCOVERED THAT I HAD MISIDENTIFIED THE 3 CIRCUIT BREAKERS TO BE PULLED. I HAD THE JUMPSEATER PULL THE 'AUTOPLT AND ALTERNATE LONGITUDINAL CIRCUIT BREAKERS (D-9; 10 AND 11)' INSTEAD OF THE PRIMARY LONGITUDINAL TRIM CIRCUIT BREAKERS;' LOCATED BEHIND THE CAPT'S LOWER SEAT BACK. BOTH OF THE 3 CIRCUIT BREAKERS ARE PAINTED WHITE. THE SITUATION HAPPENED EXTREMELY FAST; AND DUE TO NUMEROUS CALLS FROM ATC; I HAD TO RESTART THE CHKLIST NUMEROUS TIMES. SINCE WE HAD A FLT DECK JUMPSEATER; IT WAS DIFFICULT TO OBSERVE THE CIRCUIT BREAKER PANEL.SUPPLEMENTAL INFO FROM ACN 701378: AFTER OUR WRITE UP AND REVIEWING THE QRH; WE DISCOVERED THAT THE WRONG CIRCUIT BREAKERS HAD BEEN PULLED. IT WAS VERY TIME SENSITIVE AND THE JUMPSEATER ASSISTED IN PULLING THREE WHITE CIRCUIT BREAKERS LOCATED TOGETHER. THEY WERE THE ONES FOR THE ALTERNATE TRIM. DURING THE CHKLIST WE ASSUMED THIS WAS CORRECT; BECAUSE THIS WAS THE ONLY THING THAT STOPPED THE RUNAWAY CONDITION. HOW; I DON'T KNOW; BUT IT DID. THE FO WAS ABLE TO SEE PAST MY SEAT AND THE JUMPSEATER'S LEG AND MISSED ONLY ONE WORD ON THE CHKLIST; WHERE IT DESCRIBES THE POSITION OF THE CIRCUIT BREAKERS; IE (LOWER). THIS WAS NOT A NORMAL SIMULATOR TYPE EXPERIENCE WHERE OFTEN YOU HAVE TIME AND MILEAGE TO CONDUCT AN EMER. WE WERE SO BUSY; I COULD DO NOTHING BUT TRY SPDS AND CONFIGURATIONS TO KEEP THE ACFT FLYING. IT WAS A HANDFUL TO SAY THELEAST. THE FO DID A SUPERB JOB IN REMINDING ME OF THE OFTEN FORGOTTEN ITEMS AND KEPT IN THE LOOP AT ALL TIMES. WE CERTAINLY DID THIS TOGETHER AND I WOULD NEVER WANT TO DO IT AGAIN; BUT IF I HAD TO; IT WOULD BE WITH HIM.

Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.