Narrative:

On a flight from keflavick iceland to winnipeg, canada on sep/fri/04, we had been re-routed from our original flight plan to a new fix of N6330 W080 direct pikmo intersection direct cywg. Between the navigation fix of N6330 W080 and pikmo intersection we were instructed to contact edmonton center. After checking with edmonton center, center advised us that we were 13 mi off course. My other pilot and I checked and rechked our inputs into the aircraft's FMS as well as our paper flight plan and both concurred that the correct inputs were made. We then verified the correct navigation fixes that we had been cleared to and both of us were in agreement that the proper entries were made. Not long after this event occurred, we began to experience problems with the captain's side instrumentation that further led to concern in the cockpit. These problems consisted of fluctuations in the set altimetry, set mach speed, and other fluctuations on the captain's side EFIS display. Upon landing at winnipeg, canada we experienced a hard failure of the aircraft, which was determined to be the aircraft's arp (air data reference panel) computer. The flight was terminated and maintenance was dispatched from ZZZ to travel to winnipeg to repair the aircraft. Per general dynamics maintenance technician, I was informed that the arp computer is linked to the aircraft's iaps (integrated autoplt system) and has direct interface to the aircraft's air data computer (air data computer) as well as ahrs (attitude heading reference system) system. Appropriate steps per dassaults and rockwell collins prescribed maintenance procedures were taken and the aircraft was returned to service. Callback conversation with reporter revealed the following information: the initial determination by manufacturer representative maintenance was arp failure. On the next flight a similar failure occurred after 2 hours in flight. Successful completion of the flight was made using the reversion mode of the navigation system. The problem was, at this point, suspected to be faulty switches in the arp which was replaced. On a third flight a similar failure occurred during an arrival after about 2 hours of flight. The manufacturer and avionics provider has had the aircraft for analysis for several weeks. The determination has been that there is an overheating problem associated with the cross tie bus between the air data computers.

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Original NASA ASRS Text

Title: DISCOVERED 13 MI OFF COURSE BY CTR, A FALCON 50 CREW COULD NOT VERIFY IT WITH THEIR INSTRUMENTATION. LATER IN THE FLT FAILURES BEGAN TO APPEAR INDICATING A FAILURE RELATED TO THE AIR DATA REF PANEL ACCORDING TO THE SYS INTERNAL DIAGNOSTIC SYS.

Narrative: ON A FLT FROM KEFLAVICK ICELAND TO WINNIPEG, CANADA ON SEP/FRI/04, WE HAD BEEN RE-ROUTED FROM OUR ORIGINAL FLT PLAN TO A NEW FIX OF N6330 W080 DIRECT PIKMO INTXN DIRECT CYWG. BTWN THE NAV FIX OF N6330 W080 AND PIKMO INTXN WE WERE INSTRUCTED TO CONTACT EDMONTON CTR. AFTER CHKING WITH EDMONTON CTR, CTR ADVISED US THAT WE WERE 13 MI OFF COURSE. MY OTHER PLT AND I CHKED AND RECHKED OUR INPUTS INTO THE ACFT'S FMS AS WELL AS OUR PAPER FLT PLAN AND BOTH CONCURRED THAT THE CORRECT INPUTS WERE MADE. WE THEN VERIFIED THE CORRECT NAV FIXES THAT WE HAD BEEN CLRED TO AND BOTH OF US WERE IN AGREEMENT THAT THE PROPER ENTRIES WERE MADE. NOT LONG AFTER THIS EVENT OCCURRED, WE BEGAN TO EXPERIENCE PROBS WITH THE CAPT'S SIDE INSTRUMENTATION THAT FURTHER LED TO CONCERN IN THE COCKPIT. THESE PROBS CONSISTED OF FLUCTUATIONS IN THE SET ALTIMETRY, SET MACH SPD, AND OTHER FLUCTUATIONS ON THE CAPT'S SIDE EFIS DISPLAY. UPON LNDG AT WINNIPEG, CANADA WE EXPERIENCED A HARD FAILURE OF THE ACFT, WHICH WAS DETERMINED TO BE THE ACFT'S ARP (AIR DATA REF PANEL) COMPUTER. THE FLT WAS TERMINATED AND MAINT WAS DISPATCHED FROM ZZZ TO TRAVEL TO WINNIPEG TO REPAIR THE ACFT. PER GENERAL DYNAMICS MAINT TECHNICIAN, I WAS INFORMED THAT THE ARP COMPUTER IS LINKED TO THE ACFT'S IAPS (INTEGRATED AUTOPLT SYS) AND HAS DIRECT INTERFACE TO THE ACFT'S ADC (AIR DATA COMPUTER) AS WELL AS AHRS (ATTITUDE HDG REF SYS) SYS. APPROPRIATE STEPS PER DASSAULTS AND ROCKWELL COLLINS PRESCRIBED MAINT PROCS WERE TAKEN AND THE ACFT WAS RETURNED TO SVC. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE INITIAL DETERMINATION BY MANUFACTURER REPRESENTATIVE MAINT WAS ARP FAILURE. ON THE NEXT FLT A SIMILAR FAILURE OCCURRED AFTER 2 HRS IN FLT. SUCCESSFUL COMPLETION OF THE FLT WAS MADE USING THE REVERSION MODE OF THE NAV SYS. THE PROB WAS, AT THIS POINT, SUSPECTED TO BE FAULTY SWITCHES IN THE ARP WHICH WAS REPLACED. ON A THIRD FLT A SIMILAR FAILURE OCCURRED DURING AN ARR AFTER ABOUT 2 HRS OF FLT. THE MANUFACTURER AND AVIONICS PROVIDER HAS HAD THE ACFT FOR ANALYSIS FOR SEVERAL WKS. THE DETERMINATION HAS BEEN THAT THERE IS AN OVERHEATING PROB ASSOCIATED WITH THE CROSS TIE BUS BTWN THE AIR DATA COMPUTERS.

Data retrieved from NASA's ASRS site as of July 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.