Narrative:

Advised by center medford now 1800 overcast, 900 broken rain, 1 1/2 mi visibility. Tops rising moderate to severe turbulence. Non flying passenger getting flight sickness. Asked for higher altitude, given 22000'. Pilot was aware that he was about to be turned over to medford approach. Passenger condition was the concern. Center assigned 18000' descent started at 500 FPM, increased to 1000 FPM, up and down drafts 2000-3000 FPM. HSI set on localizer back cruise DME 110.3, 320 degrees inbound at ashie D18.0, aircraft heading 270 degrees to intercept. Ashie descending through 18000, up and down drafts 1000-2000'. Medford approach corrected heading for localizer back course. Inbound on back course still descending, up and down drafts. 14 DME inbound HSI slave comp system went out. Changed over to secondary system. Localizer-G/south set on oed VOR and called for missed approach. Approach control questioned the missed approach and was advised of loss of HSI slave comp system. Advised aircraft to climb to 10000' contact center. Contacted center to advise loss of equipment. Vacuum system on coplts side was reset to magnetic comp. Right side vacuum comp tumbled with turns and turbulence. Magnetic comp spinned and dipped in severe turbulence. Center gave gyro out approach to ILS. Pilot still trying emergency procedure to get HSI and lost equipment back on line. Center turned on ILS DME runway 14, approximately samie D14.4, turned over to medford approach, aircraft tracking inbound on ILS on second ILS G/south. Descending to 8000' approach asked what radial we were on and said that center still had aircraft on radar and we were headed 180 degrees from the 140 degrees inbound. In evaluating the loss of equipment I advised approach I was declaring an emergency and was climbing back to 10000'. Approach asked what type of emergency we were declaring. I advised of the equipment failure and the error in the direction between approach, center and aircraft. Center advised that roseburg rbg was VFR and asked if I could track the rbg and center would give MVA for the descent. Aircraft was VFR at rbg and returned to medford VFR under the WX. Synopsis: back course started from too high altitude. Dg on copilot side badly located and out of reach of pilot in severe turbulence. When questioned by approach of heading while shooting the ILS, there was a question in the pilot's mind of what radial the approach was speaking of because aircraft was on ILS and not a VOR approach. When approach advised center had aircraft heading 180 degrees from the inbound course, pilot became concerned and feels the actions taken in declaring the emergency, before more equipment failed, was in best judgement at the time conditions. Holding an assigned altitude was impossible due to the severe turbulence. Pilot was making constant power changes and pitch changes. HSI and slave comp found to be faulty and has been replaced. Copilot dg has been replaced so pilot can reach and reset from the left seat. Medford, or, is surrounded by mountains. Approach does not have radar and after aircraft are turned over from sea center the medford approach is relying on old methods. Mfr needs approach radar. Approach had assigned a holding pattern at samie at 10000' after the missed approach. Two other aircraft were also holding (one at 9000') due to the up and down drafts and the loss of the slave comp, and problem with the vacuum comp, it was impossible to enter and maintain a pattern.

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Original NASA ASRS Text

Title: HSI COMPASS SYSTEM FAILURE ON IMC APCH. EMERGENCY DECLARED. VECTORED TO VFR CONDITIONS.

Narrative: ADVISED BY CENTER MEDFORD NOW 1800 OVCST, 900 BROKEN RAIN, 1 1/2 MI VIS. TOPS RISING MODERATE TO SEVERE TURB. NON FLYING PAX GETTING FLT SICKNESS. ASKED FOR HIGHER ALT, GIVEN 22000'. PLT WAS AWARE THAT HE WAS ABOUT TO BE TURNED OVER TO MEDFORD APCH. PAX CONDITION WAS THE CONCERN. CENTER ASSIGNED 18000' DSCNT STARTED AT 500 FPM, INCREASED TO 1000 FPM, UP AND DOWN DRAFTS 2000-3000 FPM. HSI SET ON LOC BACK CRUISE DME 110.3, 320 DEGS INBND AT ASHIE D18.0, ACFT HDG 270 DEGS TO INTERCEPT. ASHIE DSNDING THROUGH 18000, UP AND DOWN DRAFTS 1000-2000'. MEDFORD APCH CORRECTED HDG FOR LOC BACK COURSE. INBND ON BACK COURSE STILL DSNDING, UP AND DOWN DRAFTS. 14 DME INBND HSI SLAVE COMP SYSTEM WENT OUT. CHANGED OVER TO SECONDARY SYS. LOC-G/S SET ON OED VOR AND CALLED FOR MISSED APCH. APCH CTL QUESTIONED THE MISSED APCH AND WAS ADVISED OF LOSS OF HSI SLAVE COMP SYS. ADVISED ACFT TO CLB TO 10000' CONTACT CENTER. CONTACTED CENTER TO ADVISE LOSS OF EQUIP. VACUUM SYS ON COPLTS SIDE WAS RESET TO MAG COMP. RIGHT SIDE VACUUM COMP TUMBLED WITH TURNS AND TURB. MAG COMP SPINNED AND DIPPED IN SEVERE TURB. CENTER GAVE GYRO OUT APCH TO ILS. PLT STILL TRYING EMER PROC TO GET HSI AND LOST EQUIP BACK ON LINE. CENTER TURNED ON ILS DME RWY 14, APPROX SAMIE D14.4, TURNED OVER TO MEDFORD APCH, ACFT TRACKING INBND ON ILS ON SECOND ILS G/S. DSNDING TO 8000' APCH ASKED WHAT RADIAL WE WERE ON AND SAID THAT CENTER STILL HAD ACFT ON RADAR AND WE WERE HEADED 180 DEGS FROM THE 140 DEGS INBND. IN EVALUATING THE LOSS OF EQUIP I ADVISED APCH I WAS DECLARING AN EMER AND WAS CLBING BACK TO 10000'. APCH ASKED WHAT TYPE OF EMER WE WERE DECLARING. I ADVISED OF THE EQUIP FAILURE AND THE ERROR IN THE DIRECTION BTWN APCH, CENTER AND ACFT. CENTER ADVISED THAT ROSEBURG RBG WAS VFR AND ASKED IF I COULD TRACK THE RBG AND CENTER WOULD GIVE MVA FOR THE DSCNT. ACFT WAS VFR AT RBG AND RETURNED TO MEDFORD VFR UNDER THE WX. SYNOPSIS: BACK COURSE STARTED FROM TOO HIGH ALT. DG ON COPLT SIDE BADLY LOCATED AND OUT OF REACH OF PLT IN SEVERE TURB. WHEN QUESTIONED BY APCH OF HDG WHILE SHOOTING THE ILS, THERE WAS A QUESTION IN THE PLT'S MIND OF WHAT RADIAL THE APCH WAS SPEAKING OF BECAUSE ACFT WAS ON ILS AND NOT A VOR APCH. WHEN APCH ADVISED CENTER HAD ACFT HDG 180 DEGS FROM THE INBND COURSE, PLT BECAME CONCERNED AND FEELS THE ACTIONS TAKEN IN DECLARING THE EMER, BEFORE MORE EQUIP FAILED, WAS IN BEST JUDGEMENT AT THE TIME CONDITIONS. HOLDING AN ASSIGNED ALT WAS IMPOSSIBLE DUE TO THE SEVERE TURB. PLT WAS MAKING CONSTANT PWR CHANGES AND PITCH CHANGES. HSI AND SLAVE COMP FOUND TO BE FAULTY AND HAS BEEN REPLACED. COPLT DG HAS BEEN REPLACED SO PLT CAN REACH AND RESET FROM THE LEFT SEAT. MEDFORD, OR, IS SURROUNDED BY MOUNTAINS. APCH DOES NOT HAVE RADAR AND AFTER ACFT ARE TURNED OVER FROM SEA CENTER THE MEDFORD APCH IS RELYING ON OLD METHODS. MFR NEEDS APCH RADAR. APCH HAD ASSIGNED A HOLDING PATTERN AT SAMIE AT 10000' AFTER THE MISSED APCH. TWO OTHER ACFT WERE ALSO HOLDING (ONE AT 9000') DUE TO THE UP AND DOWN DRAFTS AND THE LOSS OF THE SLAVE COMP, AND PROB WITH THE VACUUM COMP, IT WAS IMPOSSIBLE TO ENTER AND MAINTAIN A PATTERN.

Data retrieved from NASA's ASRS site as of August 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.