ALT BUST.

Narrative

ON JAN; 1994; AT XA30Z THE ACFT I WAS 'CAPTAINING' PASSED THROUGH OUR ASSIGNED ALT OF FL260 AND LEVELED AT FL250. AT THE TIME OF THE INCIDENT; WE WERE 85 MI E OF ROC ENRTE FROM KBAF TO KBUF ON THE FIRST OF 3 LEGS. THE ACFT WAS ON THE AUTOPLT WITH NAV AND FLT LEVEL CHANGE SELECTED FOR THE DSCNT FROM FL410 INTO THE APCH. THE WX IN BUFFALO WAS 3 SCATTERED 5 OVCST WITH VISIBILITY DOWN TO 1/2 MI IN LIGHT RAIN AND FOG. PRIOR TO THE DSCNT CLRNC TO FL260; WE HAD PICKED UP THE ATIS ANC COMPLETED THE DSCNT CHKLIST. I WAS REVIEWING THE APCH PROC IN PREPARATION FOR THE CREW BRIEFING WHEN THE CLRNC TO DSND WAS ISSUED. UPON RECEIPT OF THE CLRNC TO FL260; FO READ BACK THE CLRNC AND RESET THE ALT SELECTOR. I LOOKED UP TO CONFIRM THAT HE HAD SET FL260; WHICH HE DID; AND THEN RESET THE AUTOPLT TO RECOMMENCE THE DSCNT. I THEN PROCEEDED TO GIVE THE APCH BRIEFING TO THE FO; DURING THE DSCNT; WHICH HE ACKNOWLEDGED. AS WE LEVELED; THE FO WAS SETTING UP THE ILS QDM AND DIALING IN THE APPROPRIATE FREQ. I WAS ADDING PWR TO MAINTAIN SPD IN THE LEVEL OFF WHEN ATC CLRED US TO CONTINUE THE DSCNT AND CALL ALT LEAVING. IT WAS THEN THAT WE REALIZED WE HAD LEVELED AT FL250 WHICH WAS NOW SET IN THE WINDOW. WE ARE STILL UNSURE OF WHEN THE CHANGE FROM FL260 TO FL250 OCCURRED OR HOW IT OCCURRED. THIS INCIDENT HAS IDENTIFIED 2 PROBS THAT WE HAVE TO CORRECT OR COMPENSATE FOR AS A FLC. FIRSTLY IS THE TENDENCY IN TODAY'S AUTOMATED FLT DECKS TO BE BUSY WITH TASKS OTHER THAN THE PRIMARY ONE OF FLYING THE ACFT; ESPECIALLY DURING CLB AND DSCNT. STERILE COCKPITS BELOW 10000 FT IS NOT GOOD ENOUGH ANYMORE. THE MORE CAPABLE THE ACFT; THE MORE VIGILANCE SEEMS TO BE REQUIRED. THE OTHER PROB IS A DESIGN RELATED SHORTCOMING IN THE ACTUAL ALT SELECTOR FUNCTION OF SPZ8000. UNLIKE OLDER SELECTORS WITH RATCHETING OR MECHANICAL RESISTANCE; THIS SELECTOR IS EXTREMELY SMOOTH. THE RESULT IS THAT IS CAN BE DIFFICULT TO SET AND IS EASILY BUMPED OFF ITS SETTING WHEN THE COURSE OR HDG KNOBS ARE MOVED. THIS IS ESPECIALLY TRUE WHEN ENCOUNTERING TURB OR DURING HEAVY COCKPIT WORKLOADS. TO FIX THE PROBLEMS; WE HAVE INSTITUTED NEW COCKPIT RESOURCE MGMNT PROCS. FIRSTLY; WE WILL NOT ALLOW FOR NONESSENTIAL TASKS TO BE PERFORMED DURING THE TRANSITION TO OR FROM CRUISE FLT AND AT NO TIME WILL BOTH PLTS HAVE THEIR ATTN DRAWN AWAY FROM THE FLT INST. SECONDLY; THE PLT SETTING THE ALT IN THE SELECTOR WILL ANNOUNCE THAT IT IS SET AND THEN ANNOUNCE THAT IT IS INDICATED AFTER BOTH PLTS CONFIRM ITS CORRECTNESS. LASTLY; EVERY EFFORT WILL BE MADE TO COMPLETE APCH BRIEFINGS AND SETUPS DURING LEVEL FLT WHERE THE PNF CAN CONCENTRATE FULLY ON THAT TASK AND THE PF CAN MONITOR SAME. SUPPLEMENTAL INFO FROM ACN 262036: CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE KNOB IS ALSO POSITIONED IN BTWN THE COURSE SELECT AND HDG SELECT KNOBS ON THE FO'S SIDE. THEREFORE; THE KNOB COULD EASILY BE BUMPED TO A DIFFERENT ALT WHILE TURNING EITHER OF THE OTHER 2 KNOBS.