CAPT OF A WDB OVERSHOT DSCNT ALT DURING DSCNT ON A STAR ARR DUE TO MISPROGRAMMING THE ACFT'S FMC.
Synopsis
CAPT OF A WDB OVERSHOT DSCNT ALT DURING DSCNT ON A STAR ARR DUE TO MISPROGRAMMING THE ACFT'S FMC.
Narrative
I MISREAD THE FMC. I ASSUMED WE HAD PASSED BREMER INTXN THAT HAD AN ALT RESTR OF 12000 FT. I READ THE NEXT INTXN'S ALT WHICH STATED 11000B-10000A. I SET THE ALT SELECTOR TO 10000 FT FAILING TO SECURE ACKNOWLEDGEMENT FROM THE FO. THE FO CALLED MY ATTN TO THE FACT THAT I WAS DSNDING AT 11000 FT WHICH WAS 1000 FT BELOW THE ALT RESTR. I QUICKLY CLBED BACK TO APPROX 11500 FT BUT WAS BELOW THE INTXN'S ALT. NO MENTION WAS MADE BY ATC NOR US. I BELIEVE THE PROB OCCURRED FOR 2 REASONS: 1) WE HAD AND WERE FLYING DAY 2 OF A CIRCADIAN RHYTHM VIOLATING TRIP (LEFT LAX THE EVENING BEFORE) AT XA15 HRS. FLEW ALL NIGHT TO PHL THEN ATTEMPTED TO SLEEP FROM XX00 LCL PHILADELPHIA TIME (DAYLIGHT) UNTIL APPROX XY00. SLEEP WAS INTERRUPTED BY HOTEL CLEANERS SEVERAL TIMES. MY WHOLE CREW WAS TIRED. 2) I FAILED TO FOLLOW PRESCRIBED PROC REGARDING ALT CLRNCS AND ALT SELECTOR KNOB; I SET THE NEXT ALT IN MY DSCNT (ON AP) AND TOOK MY HAND AWAY FROM THE KNOB WITHOUT WAITING FOR MY FO'S ACKNOWLEDGEMENT OF THE NEW ALT'S INTRODUCTION. THE OBVIOUS SOLUTION TO PREVENT THIS IN THE FUTURE IS TO NOT HAVE CREWS FLY THESE TYPE OF TRIPS; BUT OF EVEN MORE IMPORTANCE; IS TO FOLLOW ALT RPTING AND CHANGING PROCS CORRECTLY.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.