B767-300 FLT CREW INITIATES IRS QUICK ALIGN PROCEDURE WHILE IN POSITION FOR TKOF. COMPLETE LOSS OF IRS NAV LOST WHEN TKOF IS COMMENCED BEFORE ALIGNMENT IS COMPLETE.

Date: 2007-08 · Aircraft: B767-300 and 300 ER · Phase: initial_climb

Anomalies: aircraft-equipment-problem-critical|deviation-discrepancy-procedural-clearance|other-overwt-landing

Synopsis

B767-300 FLT CREW INITIATES IRS QUICK ALIGN PROCEDURE WHILE IN POSITION FOR TKOF. COMPLETE LOSS OF IRS NAV LOST WHEN TKOF IS COMMENCED BEFORE ALIGNMENT IS COMPLETE.

Narrative

WITH THE BENEFIT OF TIME TO DISCUSS WHAT EACH CREW MEMBER SAW HERE IS WHAT SEEMS TO HAVE OCCURRED: WE HAD A NORMAL PRE-FLT; ENG START AND TAXI OUT. WE WERE CLRED INTO POSITION AND HOLD ON RWY. WE ANTICIPATED SOME TIME THERE AND INITIATED A QUICK ALIGN. PRIOR TO ENTERING RWY DATA INTO RWY 4R OF THE CDU WE WERE CLRED FOR TKOF. THE IRU MODE SELECTORS WERE POSITIONED TO NAV AND WE EXPECTED THE ALIGN LIGHTS TO GO OUT. THE FO RELEASED THE PARKING BRAKE AFTER ACKNOWLEDGING THE CLRNC FOR DEP. THE TKOF ROLL WAS NORMAL. SHORTLY AFTER LIFTOFF; THE ADI AND HSI DISPLAYS WENT BLANK; THE AUTOTHROTTLES DISCONNECTED SHORTLY THEREAFTER AND YAW DAMPERS HAD AMBER LIGHTS IN EACH SWITCH. THE FO USED THE IVSI AND ALTIMETER TO CLB STRAIGHT AHEAD. NO COURSE GUIDANCE WAS AVAILABLE. THE IRU'S WERE SWITCHED TO ATT BY THE CAPT. THIS PARTIALLY RESTORED THE BLUE-SIDE-UP BROWN-SIDE-DOWN IMAGE OF THE ADI SPHERE; PITCH LINES WERE VISIBLE BUT NO DEGREE MARKINGS. (NO NORMAL ADI CRT MARKINGS OUTSIDE THE BLUE-BROWN SPHERE WERE VISIBLE.) WE ATTEMPTED TO SWITCH FMC; EFI; AND IRS TO ALTN. THIS MADE NO IMPROVEMENT. THE CAPT DECLARED AN EMER WITH ATC AND WE WERE VECTORED TO THE ILS FINAL APCH. MAINTAINING ALT WAS ACCOMPLISHED BY CROSS CHKING THE IVSI AND ALTIMETER; HEADING WAS MAINTAINED BY THE RELIEF PLT RELAYING THE MAGNETIC COMPASS HDG. OUR VOR AND ILS RAW DATA WAS SUSPECT UNTIL WE WERE CONFIRMED ON FINAL BY ATC AND OUR MINIMAL RAW DATA COINCIDED WITH THE ATC CTLR'S RADAR-VERIFIED POSITION. OUR ILS RAW DATA CONSISTED OF THE MAGENTA BAR FOR THE COURSE AT THE BOTTOM EDGE OF THE HSI; THE MAGENTA GLIDE SLOPE INDICATOR ON THE RIGHT SIDE OF THE HSI CRT AND THE ASSOCIATED DEVIATION DOTS FOR EACH. NO COMPASS ROSE OR COMPASS ARC WAS DISPLAYED. (NONE OF THE NORMAL DISPLAY ON THE HSI CRT WAS VISIBLE.) THE ATC CTLR GAVE US TURNS DOWN FINAL OF FIVE DEG INCREMENTS TO GET US TO AND KEEP US ON CTRLINE. (WE HAD NO WIND DATA DISPLAYED.) GLIDE SLOPE WAS FAIRLY EASY TO MAINTAIN. WE GAINED GND CONTACT BELOW 2500 FT MSL AND ACQUIRED THE RWY SHORTLY THEREAFTER; WE WERE OVERWT; BUT MADE A VERY GENTLE TOUCHDOWN AND USED THRUST REVERSERS TO DECELERATE UNTIL APPLYING MANUAL BRAKES BELOW 100 KIAS.CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: REPORTER STATED THE PROBLEM AROSE WHEN THEY GOT TO THE END OF THE RUNWAY AND DID NOT HAVE SUFFICIENT TIME TO COMPLETE THE QUICK ALIGN PROCEDURE; WHICH INVOLVES ENTERING THE TAKEOFF RUNWAY INFORMATION IN THE CDU. SINCE THEY KNEW THEY WERE SHORT ON TIME; THEY REVERTED TO THE OLD PROCEDURE OF SIMPLY CYCLING THE IRU SWITCHES TO ALIGN AND BACK TO NAV. THEY WERE CLEARED FOR TAKEOFF WITHIN A FEW SECONDS AND LOST ALL NAV AND ATT DATA ON INITIAL CLIMB IN IMC. REPORTER SUGGESTS HIS ACR INSERT A WARNING NOTE IN THE QUICK ALIGN PROCEDURES PAGE CLARIFYING THAT THE OLD PROCEDURE IS NOW INVALID AND WILL RESULT IN LOSS OF NAV AND ATT DATA.

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Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.