LEAR 35 FLT CREW REPORTS YAW DAMPER AND FUEL BALANCE PROBLEMS AT FL240 AND DIVERT TO NEAREST SUITABLE ARPT.

2008-07 · NASA ASRS report 797624

Date: 2008-07 · Aircraft: Learjet 35 · Phase: cruise

Anomalies: aircraft-equipment-problem-less-severe

Synopsis

LEAR 35 FLT CREW REPORTS YAW DAMPER AND FUEL BALANCE PROBLEMS AT FL240 AND DIVERT TO NEAREST SUITABLE ARPT.

Narrative

NARRATIVE FROM ACN #797762: ON JUL/XA/08 THE FLT STARTED IN ZZZ WITH A DEST OF ZZZ. THE PURPOSE OF THE FLT WAS TO TAKE A MEDICAL TEAM TO ZZZ AND DROP THEM OFF SO THEY COULD HARVEST A HEART AND A LIVER. OUR DEP TIME OUT OF ZZZ WAS XA30. IT WAS A CLR VFR DAY AND THE FLT WAS NORMAL UNTIL ABOUT 12000 FT WHEN THE PRIMARY YAW DAMPER JERKED THE TAIL AROUND A LITTLE AS IF IT KICKED OFF; SO WE SWITCHED TO THE SECONDARY. I HAND FLEW THE ACFT UP TO ABOUT 14000 FT; AT WHICH TIME I TURNED ON THE AUTOPLT AND WAS FLYING IN NAV MODE. WE LEVELED OFF AT FL240 AND I NOTICED THAT THE ACFT DID NOT WANT TO HOLD A COURSE AND HAD A R ROLLING TENDENCY; SO MY FO SUGGESTED THAT I FLY IT IN HDG MODE TO SEE IF IT DID ANY BETTER. FLYING IN HDG MODE HELPED TO LEVEL THE WINGS AND HOLD A COURSE FOR A FEW MINS. I NOTICED AGAIN THAT THE ACFT WAS NOT HOLDING A HDG AND WAS STILL TRYING TO ROLL TO THE R. AT THIS POINT WE GOT A MASTER CAUTION WITH A LOW FUEL LIGHT; SO WE WENT TO THE FUEL PANEL TO SEE WHAT WAS GOING ON. WE NOTICED THAT WE HAD AN IMBAL IN THE R WING OF ABOUT 400 LBS LESS THAN THE L WING (L WING HAD 1100 LBS AND R WING HAD 700 LBS); SO WE TRIED TO XFER OUT OF THE L WING TO EVEN THE LOAD BUT THE FUEL DID NOT SEEM TO WANT TO XFER. AT THE SAME TIME WE NOTICED THAT WE HAD BURNED ALMOST 1000 LBS IN 20 MINS; AND THAT WE HAD BURNED ALL THE FUEL IN THE L TIP; BUT STILL HAD 150 LBS IN THE R TIP. WE VISUALLY CHKED THE TIPS TO SEE IF WE WERE LOSING FUEL AT THE CAPS; BUT COULD NOT SEE ANY LEAKS. THE FUEL IN THE R TIP WAS CAUSING THE R ROLLING TENDENCY AND WAS BECOMING HARD TO CTL; SO ASKED FOR PRIORITY HANDLING AND DECLARED AN EMER. THE CTLR TURNED US TOWARDS ZZZ AND GAVE US A DSCNT. DURING THE DSCNT THE ACFT WAS STILL TAKING A LOT OF L INPUT TO HOLD THE WINGS LEVEL. WE SAW WHAT WE THOUGHT WAS ZZZ AND LINED UP ON FINAL; BUT IT TURNED OUT TO BE ZZZ; ASKED FOR LNDG CLRNC; AND WE LANDED WITHOUT ANY FURTHER PROBS. WHEN WE SHUT THE ACFT DOWN WE HAD ZERO FUEL IN THE L TIP; 800-850 LBS IN THE L WING; 600 LBS IN THE R WING AND 150 LBS IN THE R TIP. WHEN WE GOT OUT AND DID A WALKAROUND; EVERYTHING WAS NORMAL EXCEPT THAT THE R ENG HAD A STRONG SMELL OF FUEL AS IF IT WAS RUNNING EXCESSIVELY RICH. WE FIRST BELIEVED THAT THE ACFT HAD A JET PUMP FAILURE IN THE R TIP WHICH LEFT FUEL IN THE R TIP TANK CAUSING THE IMBAL AND ACFT CTL PROBS. OUR DIRECTOR OF OPS AND DIRECTOR OF MAINT FLEW OVER TO HELP DIAGNOSE THE PROB AND AFTER REFUELING THE ACFT WE FOUND THAT WE ACTUALLY HAD A FLAPPER VALVE IN THE R TIP TANK THAT HAD FAILED. THE PROB WAS PURELY MECHANICAL AND THERE WAS REALLY NOTHING THAT COULD HAVE BEEN DONE TO PREVENT THIS FROM HAPPENING. ALL OF THE CTLRS DID A GREAT JOB IN HANDLING OUR SITUATION. THEY GAVE US EXACTLY WHAT WE NEEDED WITH NO QUESTIONS ASKED AND HELPED US TO FIND A SAFE PLACE TO LAND.

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

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