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Incidents related to Issue 10 incidents related to this issue.

Issue: automation may not work well under unusual conditions (Issue #150)
Description: Automation may work well under normal conditions but, due to design limitations, not have the desired behavior under unusual conditions, such as those close to the margins of its operating envelope. This can lead to unsafe conditions.

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  2. Accession Number: 128714
    Synopsis: ACR WDB TURN 90 DEGREES TO THE RIGHT BEFORE THE FLT CREW NOTICED THAT THE TURN WAS SUPPOSED TO BE TO THE LEFT.
    Narrative: WE WERE TOLD TO HOLD AT JUPITER INTXN SE AT 10000'. THE AUTOPLT WAS ENGAGED AND CTLING THE ACFT. UPON ARR AT JUPITER (WE WERE FLYING NBOUND ON A1 TOWARD JUPITER) I ROTATED THE AUTOPLT HDG COMMAND BUG TO THE LEFT TO A HDG OF 156 DEGS FOR DIRECT ENTRY TO THE LEFT-HAND PUBLISHED HOLDING PATTERN AT JUPITER INTXN. SINCE WE WERE HDG 17 DEGS ON A1 TOWARD JUPITER AND I ROTATED THE HDG BUG TO 156 DEGS, THE AUTOPLT TURNED THE ACFT TO THE RIGHT INSTEAD OF TO THE LEFT AS DESIRED. I SHOULD HAVE MOVED IT IN SMALL INCREMENTS TO THE LEFT. WHILE THIS WAS HAPPENING I WAS DSNDING AND SLOWING AND FAILED TO NOTICE THE ACFT WAS TURNING RIGHT INSTEAD OF LEFT. THE CAPT DISCOVERED MY MISTAKE AFTER WE HAD TURNED ABOUT 90 DEGS TO THE RIGHT. WE IMMEDIATELY STARTED A LEFT TURN BACK TO 156 DEGS. BY THE TIME WE GOT TURNED AROUND WE WERE 22 DME FROM NARITA VOR INSTEAD OF THE 32 DME WE WERE SUPPOSED TO BE. ALTHOUGH I BELIEVE THE CAUSE OF THIS INCIDENT TO BE PLT ERROR, I BELIEVE THERE WERE SOME CONTRIBUTING FACTORS. THERE WAS A STUCK MIC ON THE FREQ WE WERE WORKING AND THIS CAUSED A LOT OF CONFUSION AND A DELAY IN RECEIVING HOLDING INSTRUCTIONS. I THINK THERE IS A FLAW IN THE DESIGN OF THE WDB AUTOPLT. IF YOU TURN THE BUG TO THE LEFT, THE ACFT SHOULD TURN TO THE LEFT.

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  4. Accession Number: 357872
    Synopsis: B737-300 FLC HAS A DIFFICULT TIME WITH THE APCH WHEN THE AUTOPLT FAILS TO TRACK THE LOC COURSE DURING AN IAP ILS APCH PROC INTO DEN.
    Narrative: ON A DOG LEG L BASE TO INTERCEPT ILS LOC RWY 35L AT DIA, DSNDING OUT OF 13000 TO 10000 FT. AUTOPLT A ENGAGED ON HDG SELECT, VOR LOC ARMED, #1 NAV TUNED IN MANUAL AND IDENTED. IHSI IN THE MAP MODE. APFDS INDICATED CAPTURE ON VOR LOC AND ACFT INITIATED L TURN TO TRACK THE LOC INBOUND. HOWEVER, THE ACFT CONTINUED ITS L TURN TO APPROX HDG OF 320 DEGS. MAP SHOWS W OF COURSE. APCH INQUIRES, RAW DATA VERIFIES, SELECT HDG MODE AND DIAL IN 020 DEGS TO REINTERCEPT. APFDS ARMS IN THE APCH MODE (NOW CLRED ILS RWY 35L APCH). APFDS INDICATES CAPTURE BUT ACFT IS NOT RESPONDING CORRECTLY -- DISCONNECT AUTOPLT AND ATTEMPT TRANSITION TO RAW DATA. BY THIS TIME WE ARE HIGH AND I AM CONFUSED AS TO WHAT IS GOING ON. APCH QUERIES US ON OUR ABILITY TO COMPLETE THE APCH. WE RESPOND THAT WE SHOULD BE ABLE TO RECAPTURE AND COMPLETE THE APCH. AT THIS TIME I AM HAND FLYING AND WE ARE STILL W OF COURSE. GND CONTACT IN COMING INTO VIEW AND WE SEE THE TERMINAL, WE ARE LINED UP ON THE TWR BTWN RWY 34 AND RWY 35L. WE GET CLRNC TO LAND ON RWY 34. I HAVE HAD APPROX 3 YRS EXPERIENCE ON EFIS B757 EQUIP. I HAVE NEVER EXPERIENCED ANYTHING LIKE THIS AND HAVEN'T A CLUE WHAT HAPPENED. IF IT WAS AN ERROR ON MY PART, I DON'T KNOW WHAT. THIS IS MY THIRD OR FOURTH IN THIS ACFT. MY LAST TIME TO FLY EFIS (1500 TOTAL HRS IN B757) WAS 1992. WE CURRENTLY FLY 5 B737 BASIC ACFT, 2 B737 ADVANCED, 2 B737-300 HARD BALL, AND 1 B737-300 EFIS ACFT. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE CAUSE OF THE INCIDENT ISN'T KNOWN. MAINT HAS NOT GIVEN THE RPTR ANY INFO RELATIVE TO THE NATURE OF THE FAILURE TO CAPTURE THE ILS COURSE. THE PIC SAID THAT HE HAD INITIALLY OVERSHOT THE ILS COURSE ON THE INITIAL VECTOR BUT WAS UNDER THE GS. ATC THEN HELD HIM TO AN ALT THAT TOOK THE ACFT THROUGH THE GS. THE ACFT AT THAT POINT WENT TO A 320 DEG HDG, PASSING THROUGH THE LOC COURSE. RPTR ALSO SAID THAT HE HAS HAD 1 OTHER EVENT OF A PARALLEL NATURE WHERE HE WAS HIGH AND FAST. THE SOFTWARE SYS IN THE ADVANCED B737-300 SEEMS TO 'LOSE ITS LOCK' ON THE ILS WHEN THIS SCENARIO IS PRESENTED TO IT. RPTR ALSO ADDED THAT IN THE RPTED EVENT, THAT HIS ILS COURSE INDICATOR WENT FROM R DEV TO A FULL L DEV. THE FO'S DID NOT. SEEMED TO BE A DISCONTINUITY BTWN THE #1 AND #2 ILS COURSE SENSING.

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  6. Accession Number: 364790
    Synopsis: 3 ENG WDB ENCOUNTERED TURB. AUTOTHROTTLES AND AUTOPLT DISCONNECTED AND ACFT GAINED 250 FT. THIS RESULTED IN A TCASII TA.
    Narrative: DEVIATING FOR WX APPROX 50 MI WNW OF CEW AT 37000 FT. ENCOUNTERED WX (TURB) NOT VISIBLE ON RADAR THAT HAD MODERATE TURB. AT THE ONSET OF TURB, THE AUTOTHROTTLE (R) AND AUTOPLT DISCONNECTED. AIRSPD AND ALT INCREASED SLIGHTLY AND 5-10 SECONDS LATER, WE HAD A TA, MAX ALTDEV WAS APPROX 250 FT.

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  8. Accession Number: 367191
    Synopsis: MD80 SUPER 80 WHILE DEVIATING AROUND WX DSNDED A FEW HUNDRED FT BELOW ASSIGNED ALT WHEN AUTOPLT FAILED TO MAINTAIN ALT.
    Narrative: DEVIATING AROUND TSTMS IN AREA. WX RADAR DID NOT SHOW ANY WX. BUT, GOT INTO SOME TURB. ACFT AIRSPD BEGAN TO SLOW. ACFT BEGAN TO DSND OFF ALT. TURNED OFF AUTOPLT AND AUTOTHROTTLES AND HAND FLEW ACFT. WE HAD DSNDED A FEW HUNDRED FT OFF OF OUR ASSIGNED ALT DUE TO TURB WE ENCOUNTERED.

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  10. Accession Number: 383607
    Synopsis: FLC OF MD83 MAKING A CAT II LNDG HAS LOSS OF ACFT CTL DUE TO RWY COVERED WITH SNOW AND ICE. BRAKING RPTED AS FAIR BUT ACTUALLY NIL.
    Narrative: I WAS FLYING AS FO IN AN MD80. THE FLT WAS FROM SEA TO ANC. WX IN ANC WAS 600 FT OVCST, 1/4 MI VISIBILITY WITH BLOWING SNOW AND MIST. THE WIND WAS 330 DEGS AT 14 KTS, AND WE WERE LNDG RWY 6R. RWY 6R WAS COVERED WITH SNOW AND ICE WITH BRAKING ACTION RPTED AS FAIR. BECAUSE OF THE LOW WX MINIMA, AND THE FACT THAT THE CAPT WAS RESTR TO A CAT II LNDG (DUE TO BEING A NEW CAPT), WE FLEW A CAT II AUTOLAND APCH. THE APCH WAS NORMAL AND THE AUTOLNDG WAS NORMAL. UPON ROLLOUT THE ACFT DEVIATED (1/4 DOT RMI) FROM THE CTRLINE (ALSO NORMAL), AND INITIATED A CORRECTION N. THE CORRECTION WAS CORRECT AND WITHIN NORMAL LIMITS, BUT THE ACFT BEGAN TO SLIDE TOWARD THE N SIDE OF THE RWY. THE CAPT DISCONNECTED THE AUTOPLT AND TOOK OVER MANUALLY. BRAKING AND STEERING WERE INEFFECTIVE, SO THE ACFT WAS BROUGHT TO A STOP AND DIRECTIONAL CTL MAINTAINED USING DIFFERENTIAL REVERSE THRUST. THE ACFT RAN OVER AND DESTROYED 5 RWY EDGE LIGHTS. THE ACFT WAS INSPECTED ON THE TXWY BY MAINT AND NO DAMAGE WAS FOUND. CONTRIBUTING FACTORS WERE BALD, BUT WITHIN LIMITS OF WEAR, MAIN TIRES. A 14 KT XWIND AND A RWY BRAKING CONDITION OF NIL, BUT RPTED AS FAIR. ADDITIONAL FACTORS MAY BE ATTRIBUTED TO THE FEDERAL REQUIREMENT THAT THE LOW TIME CAPT MAKE A CAT II AUTOLAND. THE CAT II AUTOLAND RESTRICTS THE PLT FROM DEVELOPING A FEEL FOR THE ACFT UNTIL AFTER LNDG. A CAT II LNDG FROM AN ILS, THAT IS, NOT AN AUTOLNDG, MIGHT HAVE PREVENTED THE RWY DEV.

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  12. Accession Number: 386371
    Synopsis: AN ACR MD11 FLC SLOWED, AT CTLR REQUEST, TO A SPD THAT WAS NEAR ALPHA SPD FOR THE ACFT'S CONFIGN AND THEN ENTERED A TURN. THE INCREASED BANK ANGLE CAUSED THE AUTOFLT SYS TO REACT AS IT SHOULD TO PREVENT A STALL BY HAVING THE AUTOTHROTTLES GO TO FULL PWR WHICH THEN CAUSED THE ACFT TO EXCEED NORMAL AUTOPLT PITCH CORRECTION FORCES AND THE ACFT STARTED TO CLB.
    Narrative: DURING DSCNT INTO MIA WE WERE CLRED FROM 10000 FT TO 9000 FT AND ASKED TO SLOW TO 210 KTS. JUST PRIOR TO ALT CAPTURE AND AT SPD OF 210 KTS CLEAN, WE WERE GIVEN A TURN FROM 180 DEG HDG TO 270 DEGS. AS WE STARTED TO TURN, WE APCHED V-MIN AND EXTENDED SLATS. AT THE SAME TIME, DUE TO ALPHA CONDITIONS, PWR CAME UP AND ACFT STARTED TO CLB. WE DISCONNECTED AUTOPLT AND AUTOTHROTTLES AND DSNDED BACK TO 9000 FT. THE CLB WAS TO 9500 FT. CTLR MADE NO MENTION OF THE ALT EXCURSION. WE CONTINUED THE APCH WITHOUT ANY FURTHER PROBS.

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  14. Accession Number: 387000
    Synopsis: MDT ACFT IN CRUISE ON STAR ENCOUNTERED 5 SECONDS OF SEVERE TURB. AUTOPLT DISCONNECTED AND ACFT PITCHED UP CLBING 600 FT BEFORE FLC COULD TAKE CTL AND RETURN TO ASSIGNED ALT. ATC RPTED MD11 10 MI AHEAD.
    Narrative: WE WERE FLYING THE STAR 'CINCE TWO' ARR AT FL240. SUDDENLY WE PICKED UP SOME LIGHT TURB THAT BECAME MODERATE, THEN BECAME SEVERE FOR AT LEAST 5 SECONDS, CAUSING THE AUTOPLT TO SELF DISENGAGE, AND ALLOWING THE AIRPLANE TO DEVIATE FROM ITS ALT BY 500 OR 600 FT HIGH. WE TOLD CTR (INDIANAPOLIS 134.0) WHAT JUST HAPPENED, AND WE WERE COMING BACK DOWN TO FL240. THEY TOLD US THAT WE WERE FOLLOWING A HVY MD11. ON OUR TCASII IT WAS SHOWING MORE THAN 10 NM AWAY, BTWN 10 AND 15 NM, NOT MORE NOT LESS.

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  16. Accession Number: 387511
    Synopsis: AN ACR B737 HITS THE WAKE OF A B727 DURING AN APCH. THE RPTR FEELS THAT THE WAKE EFFECT WAS ENHANCED BECAUSE HE HAD THE SPD BRAKES EXTENDED.
    Narrative: WE WERE BEING VECTORED TO AN ILS APCH TO RWY 27 AT IAH. WE WERE TOLD TO KEEP 250 KTS UNTIL TURNING FINAL. WE WERE APPROX 3 MI BEHIND AND ABOVE A COMPANY B727. I HAD SPD BRAKES OUT TO HELP SLOW AND DSND TO 2000 FT MSL. AT APPROX 5000 FT WE ENCOUNTERED THE B727'S WAKE TURB. THE ACFT ROLLED L TO APPROX 20-30 DEGS. THE AUTOPLT WAS ON AS WELL AS AUTOTHROTTLES. THE ROLL RATE WAS BRISK DUE TO SPD BRAKES BEING OUT. THE AUTOPLT TRIED TO ROLL R AND IT DID (BRISKLY) TO APPROX 15 DEGS R. I PROMPTLY DISCONNECTED THE AUTOPLT AND CORRECTED WITH AILERON AND RUDDER AND THEN RESECURED THE SPD BRAKES. FLT LANDED UNEVENTFULLY. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR WAS FLYING A B737-300 WHEN HE HIT THE WAKE OF A COMPANY B727-200. HE SAW THE B727 AHEAD OF HIM AND ALTHOUGH THE CTLR HAD URGED HIM TO KEEP HIS SPD UP HE DECIDED TO SLOW WHILE DSNDING AND HE ESTIMATED HIS DISTANCE AT 4.5 NM BASED ON HIS TCASII DISPLAY WHEN HE HIT THE WAKE. DURING THE INITIAL ROLL, THE AUTOPLT WAS ENGAGED AND THE FO ALLOWED IT TO ATTEMPT A RECOVERY. HOWEVER, WHEN THE AUTOPLT ROLLED BEYOND THE WINGS LEVEL POS DURING THE RECOVERY, THE FO DISCONNECTED IT AND CONTINUED THE APCH MANUALLY.

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  18. Accession Number: 391024
    Synopsis: A B737-300 ENCOUNTERS SEVERE CLR AIR TURB IN ITS CLB TO FL270. THE AUTOPLT REVERTS TO CTL WHEEL STEERING AND THE ACFT OVERSHOT TO FL279 BEFORE ACFT CTL IS OBTAINED.
    Narrative: ON CLB OUT OF BWI, ON THE SWANN TWO DEP, WE ENCOUNTERED MODERATE TO SEVERE TURB AT APPROX 26500-27000 FT. OUR LEVELOFF ALT WAS FL270. THE AUTOPLT WAS ENGAGED. INITIALLY THE AUTOPLT ATTEMPTED TO LEVEL AT FL270 BUT THE TURB THRUST US INTO A VERT CLB AND ROLLED THE ACFT FROM L TO R AND BACK. THE AUTOPLT DISCONNECTED AND REVERTED TO CTL WHEEL STEERING. OUR BANK ANGLE REACHED 30-40 DEGS EACH SIDE OF LEVEL. THE TURB LASTED APPROX 15 SECONDS. WE IMMEDIATELY NOTIFIED ATC OF THE TURB AND DSNDED TO FL270. NO INJURIES WERE SUSTAINED IN THE CABIN. THE TURB WASN'T VIOLENT BUT JUST ROLLED THE ACFT FROM SIDE TO SIDE EVEN THOUGH WE HAD FULL AILERON DEFLECTION IN THE OPPOSITE DIRECTION. NO CONFLICT WAS NOTED WITH ATC TFC AND THE FLT PROCEEDED TO PVD WITHOUT FURTHER PROBS. NORMAL APCH AND LNDG AT PVD. THERE WAS NO INDICATION OF WX ON OUR RADAR AND NO RPTS OF TURB FROM ATC. SUPPLEMENTAL INFO FROM ACN 391148: THE AUTOPLT WAS UNABLE TO MAINTAIN HEADING AND ALT AND REVERTED TO CTL WHEEL STEERING AT ABOUT 26500 FT. THE SUDDEN UPSURGE WAS TOO GREAT FOR THE AUTOPLT TO CAPTURE FL270. WE REGAINED CTL OF ACFT AT 27900 FT AND DSNDED BACK TO FL270.

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  20. Accession Number: 410608
    Synopsis: FLC OF A HAWKER 700 EXPERIENCES SEVERE WAKE TURB 8 MI IN TRAIL OF A B757 ON STEPDOWN DSCNT VECTOR.
    Narrative: WHILE BEING VECTORED FOR AN APCH TO MSP WE EXPERIENCED WHAT I BELIEVE WAS SEVERE WAKE TURB. WE WERE ON AN ASSIGNED HDG AT 11000 FT AND ASSIGNED SPD OF 250 KTS. IT STARTED WITH MAYBE 5 SECONDS OF STEADY BUT VERY LIGHT TURB. I COMMENTED ON THE STRANGE FEEL TO THE PNF. AS I SAID THAT, THE AIRPLANE ROLLED INTO A 90 DEG BANK TO THE R INSTANTLY. I DISENGAGED THE AUTOPLT AND RECOVERED BY HAND FLYING THE AIRPLANE. BY THE TIME THE WINGS WERE LEVEL WE HAD LOST 700 FT OF ALT. THE PNF CALLED APCH CTL TO TELL HIM WHAT HAD HAPPENED. THE CTLR SAID THAT WE WERE 8 MI IN TRAIL OF A B757. I CALLED BOTH THE TWR AND TRACON AFTER LNDG AND TALKED FURTHER WITH THEM. GIVEN THE SPD OF THE B757 AND OUR AIRPLANE (250 KTS) THE CTLRS WERE SURPRISED THAT THE WAKE TURB WAS SO SEVERE. THEY STATED THAT USUALLY THAT SEVERE OF TURB IS ASSOCIATED WITH SLOWER SPDS AND THE ASSOCIATED DRAG FROM FLAPS, ETC. THERE WAS 1 PAX ON BOARD. THERE WERE NO INJURIES TO CREW OR PAX. OUR PAX WAS SCARED BUT OTHERWISE UNHARMED. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATES THAT HIS REVIEW WITH ATC BROUGHT ADDED QUESTIONS SINCE THE B757 WAS CLEAN AND AT 250 KTS. BOTH ACFT WERE ON RADAR VECTORS AND ON THE EXACT SAME FLT PATH AND SPDS. THE IN TRAIL SEPARATION SHOULD HAVE BEEN AMPLE TO AVOID SUCH A WAKE TURB ENCOUNTER. RPTR WAS SURPRISED WHEN AUTOPLT WAS DISENGAGED THAT THERE WAS NO CTL INPUT ALREADY ACTIVE. INQUIRING OF THE MANUFACTURER THEY LEARNED THAT IN EXTREME CTL CHANGES THE AUTOPLT GOES INTO A COAST MODE UNTIL IT CAN DETERMINE IF THE EXTREME IS A FALSE INPUT OR NOT. THE AUTOPLT THEN RESPONDS WITH CORRECT INPUT. RPTR SAYS YOU LEARN SOMETHING NEW ALL THE TIME. IN HIS 23 YRS OF FLYING HE HAS NEVER EXPERIENCED ANYTHING AS SEVERE AS THIS. THE ACFT WAS A HAWKER 700.
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