AN MD11 FREIGHTER ATTEMPTS A LEVELOFF AT THE MISSED APCH ALT OF 2000 FT BUT IS UNABLE TO ACCOUNT SEVERE TURB AND LOSS OF ACFT CTL. A CAWS ALERT HAD BEEN RECEIVED AT 1200 FT MSL WITH ACFT FINALLY LEVELING AT 9880 FT AT ANC; AK.
Synopsis
AN MD11 FREIGHTER ATTEMPTS A LEVELOFF AT THE MISSED APCH ALT OF 2000 FT BUT IS UNABLE TO ACCOUNT SEVERE TURB AND LOSS OF ACFT CTL. A CAWS ALERT HAD BEEN RECEIVED AT 1200 FT MSL WITH ACFT FINALLY LEVELING AT 9880 FT AT ANC; AK.
Narrative
DURING AN INITIAL APCH INTO THE ANC ARPT; A RPT WAS RECEIVED CAUTIONING ACFT OF MODERATE TURB BELOW 7000 FT MSL ALL THE WAY TO THE LNDG SURFACE. VISIBILITY AT THE ARPT WAS BETTER THAN 3 MI. APCH AND TWR PROVIDED VARYING WIND CONDITIONS DURING THE APCH AND OTHER ACFT RPTED WINDSHEAR DURING APCHS FOR LNDGS. RWY 14 WAS IN USE AT THE TIME OF THIS EVENT. APCH CLRED OUR FLT FOR A VISUAL APCH TO RWY 14. THE APCH WAS BACKED UP WITH THE ILS SERVING RWY 14 WITH THE DATABASE APCH AS WELL AS PERTINENT DATA SELECTED IN THE NAV RAD PAGE. THE MISSED APCH WAS BRIEFED WITH THE VISUAL APCH REQUIREMENTS WITH 2000 FT PRESELECTED IN THE ALT WINDOW AND A HDG OF 190 DEGS PRESELECTED ON THE FCP. THE TURB EXPERIENCED MADE IT DESIRABLE TO DISCONNECT THE AUTOFLT SYS AND HAND FLY THE APCH. AUTOTHROTTLES REMAINED ENGAGED. DSNDING FROM APPROX 1200 FT A CAWS ANNUNCIATION OCCURRED WITH 'WINDSHEAR; WINDSHEAR; WINDSHEAR.' I PROMPTLY DECLARED 'MISSED APCH/GAR' TO THE FO. THE ACFT AT THIS TIME WAS NOW IN MODERATE TO SEVERE; BECOMING CONTINUOUSLY SEVERE WINDSHEAR AND TURB. DURING THE FLAP RETRACTION; GEAR RETRACTION; I INSTRUCTED THE FO TO ANNOUNCE THE MISSED APCH AND NATURE OF THE MISS DUE TO SEVERE TURB. THE FO WAS BUSY SCANNING AND ATTEMPTING TO ASSIMILATE THE INFO BEING RENDERED BEFORE US AND DID NOT PROVIDE THIS INFO IMMEDIATELY TO ANC TWR. HOWEVER; WITHIN MOMENTS; THE CTLR ASKED IF WE HAD A PROB. TO THIS INQUIRY THE FO REPLIED WITH THE NATURE OF OUR PROBS. THE TURB WAS SEVERE TO THE POINT THAT ACFT CTL WAS IMPAIRED. AN ATTEMPT WAS MADE TO CAPTURE 2000 FT AND THE EFFORTS WERE MADE TO LEVEL THE ACFT. FULL FORWARD YOKE PRESSURE TO THE STOP WAS APPLIED WITH NO RESULTANT LEVELOFF. THROUGHOUT THIS PERIOD; I REMIND THE READER; THE ACFT WAS IN SEVERE TURB. THE ACFT ACCELERATED QUICKLY TOWARDS THE VMO RED BARBER POLE SPD TAPE AND 350 KIAS. I REDUCED THE THROTTLES TOWARD THE IDLE POS DURING THE EXCURSIONS; BUT THE ACFT CONTINUED TO ACCELERATE INTO THE LOW END OF THE VMO BARBER POLE. THE CTLR RECLRED US TO LEVEL AT 3000 FT AND WHEN IT BECAME EVIDENT THIS WAS NOT GOING TO BE EXECUTED; RECLRED A LEVELOFF AT 9000 FT. COMPLETE ACFT CTL WAS STILL NOT POSSIBLE UNTIL 9880 FT HAD BEEN REACHED WHEN FINALLY ATMOSPHERIC CONDITIONS IMPROVED. THE ACFT WAS MANUALLY FLOWN TO 9000 FT; LEVELED AND AUTOFLT ENGAGED. DURING THIS EVENT; A TCASII RA ANNUNCIATED DICTATING TO 'DSND/DSND.' ATC; PREVIOUS TO THIS RA; ASKED THE OTHER ACFT IF THEY HAD OUR ACFT IN SIGHT. I ALSO HAD VISUAL CONTACT WELL PRIOR TO THE RA. ATC STATED TO THE OTHER ACFT TO MAINTAIN VISUAL SEPARATION FROM OUR ACFT. IN ADDITION; OUR ACFT ALSO SUFFERED A DUAL FMC FAILURE DURING THE PERIOD OF TURB. I BELIEVE THIS WAS CAUSED BY THE NATURE OF THE WX CONDITION. FMC FUNCTIONS WERE ABLE TO BE RESTORED WITHIN A FEW BRIEF MINS. A LNDG WAS MADE TO RWY 14. THE WIND COMPONENT WAS APPROX +/-10 KTS ON LNDG. I TELEPHONED AND SPOKE WITH THE TWR SUPVR ON DUTY. I EXPLAINED THE CIRCUMSTANCES. HE STATED NO ACFT CONFLICT OCCURRED AND NO RPT WOULD BE FORTHCOMING REGARDING THIS MATTER.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.