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Incidents related to Issue 2 incidents related to this issue.

Issue: automation requirements may conflict (Issue #160)
Description: Satisfaction of one automation functional or certification requirement may lead to the violation of another.

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  2. Accession Number: 397400
    Synopsis: A B737-500 FLC FAILS TO MONITOR THEIR FMS WHILE LOSING AIRSPD AT FL240. ACFT HAD BEEN SET UP FOR XING BANDS AT 14000 FT WHILE MAINTAINING 300 KTS OR BETTER.
    Narrative: ENRTE IAH-ONT. CROSS PSP 24000 FT, SPD 300 KTS OR BETTER. ON FMC IN PATH DSCNT, ATC KEPT US AT FL240 AND DELAYED OUR DSCNT TO CROSS BANDS AT 14000 FT. ACFT WAS ON AUTOPLT AND VNAV ENGAGED. DURING THIS DELAY ACFT STARTED TO SLOW DOWN VERY SLOWLY. WE WERE BUSIED IN COCKPIT WITH CHKLISTS AND BRIEFING APCH. WHEN WE ASKED ATC FOR LOWER, HE SAID, 'STAND BY.' HE LATER ASKED OUR SPD WHICH HAD SLOWED TRYING TO STAY IN PATH FOR BANDS AT 14000 FT. FMC ACFT WHEN IN PATH DSCNT MODE WILL SLOW TO MAINTAIN PATH BUT WHEN THAT IS EXCEEDED DUE TO NOT GETTING DSCNT FROM ATC IN TIME, IT MAKES OTHER XING RESTR IN SID. ATC ASKED US HOW FAST OR HAD WE SLOWED. WE SAID, 'YES, A LITTLE, TO MAINTAIN IN ORDER TO CROSS BANDS AT 14000 FT.' ATC SAID AN MD80 WAS BEHIND US. IT HAD NOT CAUSED A PROB BUT IN THE FUTURE PLEASE INFORM THEM OF SLOWING WHICH WE KNOW WE SHOULD HAVE DONE. WE WERE BUSY AND FORGOT TO CALL HIM WHEN WE STARTED TO SLOW. WE WERE GOING TO, BUT HE MENTIONED IT FIRST.

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  4. Accession Number: 403254
    Synopsis: A320 ACFT ON SID DEP AND SHORTLY AFTER TKOF FLC HAD TCASII RA DIRECTING A DSCNT WITH TARGET SUPERIMPOSED ON ACFT. FLC FOLLOWED THE RA UNTIL BREAKING OUT OF CLOUDS AT 900 FT AT WHICH TIME GPWS SOUNDED AND FLC SAW TALL BUILDINGS. THEY CONTINUED WITH ATC CLRNC AND THE FALSE WARNING CONTINUED THROUGH MOST OF THE FLT.
    Narrative: UPON DEP FROM LGA RWY 13, WHITESTONE CLB, PASSING APPROX 1000 FT AGL, TCASII TA 'TFC, TFC' SOUNDED. AT THE TIME WE WERE IN IMC CONDITIONS. IMMEDIATELY AFTER THAT RA 'REDUCE VERT SPD' CAME ON WITH TCASII TARGET SUPERIMPOSED ON OUR ACFT SYMBOL. WE BEGAN REDUCING CLB WHEN RA 'DSND, DSND' SOUNDED WITH VERT SPD COMMAND OF GREATER THAN 2000 FPM ANNUNCIATED. TARGET STILL DIRECTLY ON TOP OF US WITH RELATIVE ALT DISPLAYED. WE IMMEDIATELY COMMENCED DSCNT AND EXITED CLOUDS AT 900 FT AGL AT WHICH TIME GPWS WARNING CAME ON SAYING 'TOO LOW, TERRAIN' BY THIS TIME SPD HAD BUILT UP TO 280 KTS. I THEN DECIDED IT WAS BETTER TO TAKE A CHANCE ON HITTING ANOTHER AIRPLANE VERSUS THE SURE THING OF COLLIDING WITH THE GND, AND DIRECTED THE FO TO RESUME CLB AND DEP WHILE I TURNED XPONDER TO TA ONLY. AT THIS TIME ATC GAVE US A NEW HDG AND ALT AND I RPTED THE TCASII RA MANEUVER. ALL THIS TIME EITHER A TA, RA OR GPWS WARNING HAD BEEN GOING ON AND FOR A WHILE 'DSND, DSND' AND 'TOO LOW, TERRAIN' WERE BEING BROADCAST SIMULTANEOUSLY. THE COCKPIT INDEED WAS A CACOPHONY OF BELLS, WHISTLES AND FLASHING LIGHTS. THIS SHOWS THE DANGER OF BLINDLY FOLLOWING TCASII DIRECTIONS. THE PHANTOM TARGET FOLLOWED US ALMOST ALL THE WAY TO OUR DEST AT RELATIVE ALT. IF WE HADN'T POPPED OUT WHEN WE DID AND SEEN BUILDINGS IN FRONT OF US IT COULD HAVE BEEN A MUCH DIFFERENT STORY. WE ARE TAUGHT TO IMMEDIATELY RESPOND TO AN RA AND AT THAT ALT YOU CAN LITERALLY FIND YOURSELF 'BTWN A ROCK AND A HARD PLACE.' CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR CAPT HAD NOT HAD FEEDBACK ON THE CAUSE OF THE FALSE TARGET, BUT WAS PLANNING TO FOLLOW UP. AND, HE SAYS HE WILL CONTACT ASRS IF HE HAS ANY INFO TO PASS ON. RPTR HAD BEEN ON VACATION AND WAS JUST GETTING BACK TO WORK, SO HE WILL TRY. HOWEVER, AS HE SAYS, SINCE THE PROB WENT AWAY ENRTE, MAINT PROBABLY WOULDN'T DO MUCH. RPTR CAPT WAS COUNSELED ABOUT THE SUPPRESSION BUS PROB IN OTHER ACFT AND A SUPERIMPOSED TARGET IS HIGHLY SUSPECT.
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