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A DC10 flight crew is subjected to a 'dr indications,' for a period of 1 hour and 30 mins, GPS signal interruption on their FMS system on a flight from the west coast to hnl, hi.
| Attributes | |
| ACN | 563890 |
| Time | |
| Date | 200210 |
| Day | Mon |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | atc facility : zoa.artcc |
| State Reference | CA |
| Altitude | msl single value : 31000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zoa.artcc |
| Operator | common carrier : air carrier |
| Make Model Name | DC-10 Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Flight Phase | cruise : level |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp pilot : commercial pilot : instrument |
| Experience | flight time last 90 days : 50 flight time total : 15000 flight time type : 50 |
| ASRS Report | 563890 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : second officer |
| Qualification | pilot : flight engineer |
| ASRS Report | 563891 |
| Events | |
| Anomaly | aircraft equipment problem : critical non adherence : clearance other anomaly other other spatial deviation |
| Independent Detector | aircraft equipment other aircraft equipment : fms other flight crewa other flight crewb |
| Resolutory Action | none taken : anomaly accepted other |
| Supplementary | |
| Problem Areas | Navigational Facility Aircraft Flight Crew Human Performance ATC Facility |
| Primary Problem | Navigational Facility |
Narrative:
Approximately XA05Z (passed fir), had a navigation unreliable indication on FMS (intermittently). Plotted position and reported long range navigation intermittently unreliable to ATC (sfo). Continued to hnl based on plotting accuracy and FMS indications -- all satellite -- had strong signals. Degrade indications came on about 3-5 mins alternating between captain/first officer side. Had passenger turn off computer, no change. Initially plotted every 10 mins, then plotted every 20 mins. FMS heading and xtrack indications all normal within .06. At XB30Z, intermittently degrades ceased and was normal rest of flight. Continued to plot position every 20 mins.
Original NASA ASRS Text
Title: A DC10 FLC IS SUBJECTED TO A 'DR INDICATIONS,' FOR A PERIOD OF 1 HR AND 30 MINS, GPS SIGNAL INTERRUPTION ON THEIR FMS SYS ON A FLT FROM THE WEST COAST TO HNL, HI.
Narrative: APPROX XA05Z (PASSED FIR), HAD A NAV UNRELIABLE INDICATION ON FMS (INTERMITTENTLY). PLOTTED POS AND RPTED LONG RANGE NAV INTERMITTENTLY UNRELIABLE TO ATC (SFO). CONTINUED TO HNL BASED ON PLOTTING ACCURACY AND FMS INDICATIONS -- ALL SATELLITE -- HAD STRONG SIGNALS. DEGRADE INDICATIONS CAME ON ABOUT 3-5 MINS ALTERNATING BTWN CAPT/FO SIDE. HAD PAX TURN OFF COMPUTER, NO CHANGE. INITIALLY PLOTTED EVERY 10 MINS, THEN PLOTTED EVERY 20 MINS. FMS HEADING AND XTRACK INDICATIONS ALL NORMAL WITHIN .06. AT XB30Z, INTERMITTENTLY DEGRADES CEASED AND WAS NORMAL REST OF FLT. CONTINUED TO PLOT POS EVERY 20 MINS.
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.