A DC-10 REJECTED TKOF AT 140 KNOTS DUE TO PITCH UP 10 DEGS PRIOR TO V1 WITH NO ELEVATOR INPUT. CAUSED BY ABNORMALLY HIGH STABILIZER TRIM.

Date: 2002-03 · Aircraft: DC-10 Undifferentiated or Other Model · Phase: takeoff

Anomalies: aircraft-equipment-problem-critical|other-acft-pitched-up-on-tkof

Synopsis

A DC-10 REJECTED TKOF AT 140 KNOTS DUE TO PITCH UP 10 DEGS PRIOR TO V1 WITH NO ELEVATOR INPUT. CAUSED BY ABNORMALLY HIGH STABILIZER TRIM.

Narrative

I WAS THE CAPT ON THIS FLT AND WAS THE PLT FLYING. THE TKOF WAS COMMENCED ON RWY 4R USING STANDARD COMPANY PROCS. THE TKOF ROLL WAS CONDUCTED WITH THE YOKE SLIGHTLY FORWARD OR NEUTRAL; AS CALLED FOR IN THE FLT MANUAL. THE ROLL WAS NORMAL IN ALL RESPECTS UNTIL HEARING A SPEED OF 140 KTS. AT THE POINT THE ACFT PITCHED UP; WITH NO UP-ELEVATOR INPUT. WHEN THIS OCCURRED WE WERE SEVERAL KNOTS SHORT OF V1 (145 KTS) AND VR (147 KTS); AND NEITHER SPEED HAD BEEN CALLED MY IMMEDIATE THOUGHT THAT THE ACFT WAS OUT OF BALANCE; THAT THE ABILITY TO ACHIEVE SAFE; STABILIZED FLT MIGHT BE SERIOUSLY IMPAIRED; AND THAT THE SAFETY OF THE CREW AND ACFT WERE IN JEOPARDY. CONSIDERING ALL FACTORS; INCLUDING THE FACT THAT WE HAD A CALCULATED STOP MARGIN OF 2990 FT; I FELT THE SAFEST AND ONLY PRUDENT COURSE OF ACTION WAS TO ABORT THE TKOF. THE REJECTED TKOF PROC I ITEMS WERE ACCOMPLISHED PER THE DC-10 FLT MANUAL. THE ACFT WAS QUICKLY SLOWED TO A NORMAL TAXI SPEED AND WE TAXIED FARTHER DOWN THE RWY TO; AND EXITED AT TXWY W. THE ENGS WERE TAKEN OUT OF REVERSE AT APPROX 60 KNOTS; PER THE DC-10 FLT MANUAL; AND NO ENG PARAMETERS WERE EXCEEDED. UPON EXITING THE ACTIVE RWY; AND AS AN ADDED PRECAUTION PER THE DC-10 FLT MANUAL EMER PROCS; WE ASKED THE TWR IF THEY WOULD SEND OUT THE FIRE TRUCKS; ADVISING THEM THAT WE HAD POTENTIALLY HOT BRAKES. AFTER CLEARING THE RWY WE RAN THE REJECTED TKOF CHKLIST IN ITS ENTIRETY; AND ACCOMPLISHED THE AFTER LNDG CHKLIST. AS CLRED BY THE TWR; I TAXIED THE ACFT ACROSS RWY 4L AND STOPPED ON THE RUN-UP BLOCK ADJACENT TO TXWY R. WE REMAINED IN THE RUN-UP BLOCK UNTIL THE FIRE TRUCKS ARRIVED AND THE PERSONNEL HAD SUFFICIENT TIME TO EXAMINE THE ACFT AND LNDG GEAR. AFTER THEIR EXAMINATION WE WERE TOLD THAT EVERYTHING APPEARED TO BE NORMAL AND THAT ALL TIRES REMAINED INFLATED. ONCE THEY WITHDREW THEIR EQUIP WE COMMENCED A SLOW TAXI TO THE RAMP. AS WE ANTICIPATED RISING BRAKE TEMPS; WE REQUESTED A FIRE TRUCK FOLLOW US UNTIL WE WERE PARKED AT THE RAMP. UPON REACHING THE RAMP WE PARKED WITH THE WHEELS CHOCKED AND PARKING BRAKE OFF. WE THEN SHUT DOWN THE ENGS; ACCOMPLISHED THE SHUTDOWN CHKLIST; AND CONSULTED THE BRAKE COOLING CHART IN THE FLT MANUAL; ADVISING MAINT OF THE REQUIRED TIME. MAINT ADVISED THAT THE WHEELS DID NOT APPEAR TO BE EXCESSIVELY HOT. THE APPROPRIATE ENTRY WAS ENTERED INTO THE MAINT LOG. AS A POINT OF POTENTIAL SIGNIFICANCE; THE ACFT HAD AN INOP APU AND WHEN DEPARTING ZZZ SOME HRS EARLIER WE HAD SOME DIFFICULTIES WITH THE APLC. AT THE TIME; THE TEMP AT ZZZ WAS ON THE ORDER OF -6 DEGS CELSIUS; THE ACFT HAD BEEN SITTING ON THE GND FOR OVER 48 HRS; AND EVERYTHING WITHIN THE COCKPIT; INCLUDING THE APLC; WAS THOROUGHLY COLD-SOAKED. THE APLC DISPLAY WAS NOT WORKING NORMALLY AND AT ONE POINT WE EVEN CHANGED BATTERIES TO SEE IF WE COULD GET IT TO FUNCTION PROPERLY. AGAIN DURING THE SCHEDULED STOPOVER IN ZZZ2 THE COCKPIT HAD NO HEAT AND EVERYTHING WITHIN BECAME COLD-SOAKED. THE TEMP IN ZZZ3 WAS -4 DEGS CELSIUS. WHEN USING THE APLC IT AGAIN DID NOT APPEAR TO FUNCTION COMPLETELY NORMALLY. IT APPEARED TO BE PERFORMING CALCULATIONS; BUT THE DISPLAY WAS NOT NORMAL. SOME TIME LATER; AFTER HAVING THE APLC IN THE WARM OFFICE FOR APPROX 30-45 MINS; THE DISPLAY SUBSEQUENTLY 'UNFROZE' AND APPEARED TO WORK NORMALLY. AT THAT POINT THE SO THEN INPUT THE SAME BOGUS DATA THAT WE HAD COPIED FROM THE 'FROZEN' SCREEN ONTO THE PAPER; INTO THE 'INPUT' SCREEN; 'EXECUTED;' AND IT PRODUCED THE 8.2 STAB TRIM SETTING. HE THEN RE-ENTERED THE CORRECT DATA FROM THE WT AND BALANCE INTO THE APLC; 'EXECUTED;' AND IT GENERATED A STAB TRIM SETTING OF SLIGHTLY OVER 5.0. IT THEN SEEMED CLR THAT THE ACFT HAD PREMATURELY ROTATED APPARENTLY DUE TO AN ABNORMALLY HIGH NOSE-UP STAB TRIM SETTING GENERATED IN ERROR BY A MALFUNCTIONING APLC. MY SUSPICION IS THAT THE EXTREME COLD HAD A DELETERIOUS EFFECT ON THE FUNCTIONING OF THE APLC; CAUSING IT TO PRODUCE SPURIOUS DATA. I BELIEVE A PRECAUTIONARY WARNING SHOULD BE DISSEMINATED TO ALL FLT CREWS; AND PLACED ON ALL APLC'S; ADVISING OF THE POSSIBILITY OF SPURIOUS DATA WHEN USING AN APLC THAT HAS BEEN SUBJECTED TO EXTREME COLD (AND POSSIBLY HEAT). MOST ELECTRONIC DEVICES HAVE WHAT IS CONSIDERED A NORMAL OPERATING TEMP RANGE TO WHICH THE MANUFACTURER HAS TESTED THE DEVICE. I HAVE SEEN NO DATA ON THE NORMAL OPERATING TEMP RANGE OF THE APLC. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE ARPT PERFORMANCE LAPTOP COMPUTER WAS AFFECTED BY COLD SOAKING FOR 48 HRS AT -6 DEGS CELSIUS AND AFTER THE FIRST LEG FOR 1 HR AND 30 MINS AT -4 DEGS CELSIUS. THE RPTR SAID THE CALCULATIONS PRODUCED BY THIS COMPUTER IN THIS INCIDENT LEAVES HIM VERY UNCOMFORTABLE USING THIS LAPTOP COMPUTER IN COLD WX. THE RPTR STATED ALL PRINTED DOCUMENTS FOR ARPT PERFORMANCE CALCULATIONS WERE REMOVED FROM THE AIRPLANE AND FLT BAGS. THE RPTR SAID THE LAPTOP COMPUTER IS THE ONLY SOURCE FOR THE ARPT PERFORMANCE CALCULATIONS AND IF THIS FAILS A CALL TO FLT OPS IS REQUIRED TO GET TRIM DATA. THE RPTR STATED THIS IS THE SECOND TIME IN TWO WEEKS THE LAPTOP COMPUTER DISPLAYED A SPURIOUS FAULT TRANSPONDING NUMBERS ENTERED. THE RPTR SAID THE COMPANY NEVER REVEALED THE OPERATING TEMP LIMITS ON THIS LAPTOP COMPUTER. CALLBACK FROM ACN 541279: THE RPTR STATED THE ARPT PERFORMANCE LAPTOP COMPUTER REPLACED ALL THE PRINTED CHARTS FOR ARPT PERFORMANCE CALCULATIONS FOR TRIM SETTINGS. THE RPTR SAID ABOUT 70 PERCENT OF THE TIME THE COMPUTER WILL NOT START CORRECTLY WITH THE PROPER DISPLAY. THE RPTR SAID THE LAPTOP COMPUTER WAS ACTING SLUGGISHLY AND HARD TO READ BUT ACCEPTED THE ENTERED DATA. THE RPTR STATED ALL INPUTS BY THE RPTR WERE VERIFIED BY THE CAPT AS CORRECT AND THE TRIM RESULTS WERE COMMENTED ON BY THE CAPT AND MYSELF. THE RPTR SAID THE AIRPLANE PITCHED UP 10 DEGS AT 142 KNOTS WITH NO ELEVATOR INPUT STILL BELOW V1 SPEED. THE RPTR STATED THE CAPT ELECTED TO REJECT THE TKOF.

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