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Error in FMS software dropped out waypoints and, with aircraft on autoplt, aircraft made premature turn. Approach controller intervened and turned flight crew aircraft immediately. At the same time reporter flight crew received a TCASII alert and reports an near midair collision.
| Attributes | |
| ACN | 334244 |
| Time | |
| Date | 199604 |
| Day | Wed |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | atc facility : msp |
| State Reference | MN |
| Altitude | msl bound lower : 11000 msl bound upper : 11000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | tracon : msp artcc : tncf |
| Operator | general aviation : corporate |
| Make Model Name | Gulfstream IV |
| Operating Under FAR Part | Part 91 |
| Navigation In Use | Other Other |
| Flight Phase | descent other |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | Other |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| ASRS Report | 334244 |
| Person 2 | |
| Affiliation | Other |
| Function | flight crew : first officer |
| Qualification | pilot : cfi pilot : atp |
| Experience | flight time last 90 days : 100 flight time total : 10600 flight time type : 240 |
| ASRS Report | 334242 |
| Events | |
| Anomaly | aircraft equipment problem : less severe conflict : nmac non adherence : clearance other anomaly other other spatial deviation |
| Independent Detector | other controllera |
| Resolutory Action | controller : issued new clearance other |
| Consequence | Other |
| Miss Distance | horizontal : 1000 vertical : 100 |
| Supplementary | |
| Primary Problem | Aircraft |
| Air Traffic Incident | Pilot Deviation |
Narrative:
We were using the SPZ8000 with the NZ2000, 4.0 software. I was looking outside, the first officer was changing frequency when the aircraft turned to a 300 degree heading, which was not supposed to happen until passing the next intersection. I asked the first officer if we had passed that point and he didn't know. Approach control told us to make an immediate left turn, at the same time we got an RA on the TCASII. We called honeywell after we got on the ground and found out that the software was a glitch in the program that allows the aircraft to make an incorrect heading change prior to your selected heading change. The flight plan read from-to, when it switched to-to prior to the selected point we should have been aware of this problem but honeywell engineer hasn't informed all users of it. We should have been more aware of our position, but weren't. This system is in many corp and air carrier aircraft. We train, and nowhere during this training did anybody mention this problem. We are currently changing to the 4.1 software so as not to have this program problem again. Supplemental information from acn 334242: while I was changing navigation #1 and navigation #2 back to 11L, we crossed wolus intersection. Next we received an EICAS message, 'coupled data invalid.' I questioned the PF what he did to receive this message. He stated he did not touch anything. We checked the FMS's, and all other data and could not find any discrepancies. I suspect that the PF did indeed either push a navigation #1 selector button while having LNAV selected. This pilot is not what one would consider an expert FMS operator. Very shortly after we landed I called honeywell, the manufacturer of the FMS, to determine why and how this happened. He said there is a well known glitch in our current version of the software (4.0) that would cause the FMS to skip 2 waypoints, as though you have passed them.
Original NASA ASRS Text
Title: ERROR IN FMS SOFTWARE DROPPED OUT WAYPOINTS AND, WITH ACFT ON AUTOPLT, ACFT MADE PREMATURE TURN. APCH CTLR INTERVENED AND TURNED FLC ACFT IMMEDIATELY. AT THE SAME TIME RPTR FLC RECEIVED A TCASII ALERT AND RPTS AN NMAC.
Narrative: WE WERE USING THE SPZ8000 WITH THE NZ2000, 4.0 SOFTWARE. I WAS LOOKING OUTSIDE, THE FO WAS CHANGING FREQ WHEN THE ACFT TURNED TO A 300 DEG HDG, WHICH WAS NOT SUPPOSED TO HAPPEN UNTIL PASSING THE NEXT INTXN. I ASKED THE FO IF WE HAD PASSED THAT POINT AND HE DIDN'T KNOW. APCH CTL TOLD US TO MAKE AN IMMEDIATE L TURN, AT THE SAME TIME WE GOT AN RA ON THE TCASII. WE CALLED HONEYWELL AFTER WE GOT ON THE GND AND FOUND OUT THAT THE SOFTWARE WAS A GLITCH IN THE PROGRAM THAT ALLOWS THE ACFT TO MAKE AN INCORRECT HDG CHANGE PRIOR TO YOUR SELECTED HDG CHANGE. THE FLT PLAN READ FROM-TO, WHEN IT SWITCHED TO-TO PRIOR TO THE SELECTED POINT WE SHOULD HAVE BEEN AWARE OF THIS PROB BUT HONEYWELL ENGINEER HASN'T INFORMED ALL USERS OF IT. WE SHOULD HAVE BEEN MORE AWARE OF OUR POS, BUT WEREN'T. THIS SYS IS IN MANY CORP AND ACR ACFT. WE TRAIN, AND NOWHERE DURING THIS TRAINING DID ANYBODY MENTION THIS PROB. WE ARE CURRENTLY CHANGING TO THE 4.1 SOFTWARE SO AS NOT TO HAVE THIS PROGRAM PROB AGAIN. SUPPLEMENTAL INFO FROM ACN 334242: WHILE I WAS CHANGING NAV #1 AND NAV #2 BACK TO 11L, WE CROSSED WOLUS INTXN. NEXT WE RECEIVED AN EICAS MESSAGE, 'COUPLED DATA INVALID.' I QUESTIONED THE PF WHAT HE DID TO RECEIVE THIS MESSAGE. HE STATED HE DID NOT TOUCH ANYTHING. WE CHKED THE FMS'S, AND ALL OTHER DATA AND COULD NOT FIND ANY DISCREPANCIES. I SUSPECT THAT THE PF DID INDEED EITHER PUSH A NAV #1 SELECTOR BUTTON WHILE HAVING LNAV SELECTED. THIS PLT IS NOT WHAT ONE WOULD CONSIDER AN EXPERT FMS OPERATOR. VERY SHORTLY AFTER WE LANDED I CALLED HONEYWELL, THE MANUFACTURER OF THE FMS, TO DETERMINE WHY AND HOW THIS HAPPENED. HE SAID THERE IS A WELL KNOWN GLITCH IN OUR CURRENT VERSION OF THE SOFTWARE (4.0) THAT WOULD CAUSE THE FMS TO SKIP 2 WAYPOINTS, AS THOUGH YOU HAVE PASSED THEM.
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.