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A glass cockpit air carrier crew had a map shift that showed the aircraft about 90 mi from its VOR position.
| Attributes | |
| ACN | 211659 |
| Time | |
| Date | 199206 |
| Day | Wed |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | atc facility : har |
| State Reference | PA |
| Altitude | msl bound lower : 26000 msl bound upper : 26000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zob artcc : zny tracon : oak |
| Operator | common carrier : air carrier |
| Make Model Name | Medium Large Transport, Low Wing, 2 Turbojet Eng |
| Navigation In Use | Other Other |
| Flight Phase | cruise other |
| Route In Use | enroute : on vectors enroute other |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 190 flight time total : 15000 flight time type : 1250 |
| ASRS Report | 211659 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : commercial pilot : instrument |
| Events | |
| Anomaly | aircraft equipment problem : critical |
| Independent Detector | other flight crewa |
| Resolutory Action | flight crew : regained aircraft control |
| Consequence | Other |
| Supplementary | |
| Primary Problem | Aircraft |
| Air Traffic Incident | other |
Narrative:
During cruise flight between klga and kpit, we received a message on both FMC's that we're receiving IRS-only navigation, which means they (FMC's) were not xchking the navigation with VOR and DME. Switching to manual VOR and DME navigation, we realized both EFIS map displays were off approximately 90 mi. We proceeded with manual VOR and DME navigation with no conflict. Center had vectored and given direct routing most of the 50 min flight, so I don't think they suspected our navigation was off. The all 'glass' cockpit aircraft require constant monitoring and at times can be more confusing than conventional aircraft. Callback conversation with reporter revealed the following information: the reporter described this problem as 'morning sickness.' this aircraft, and other glass cockpit aircraft have problems that tend to fix themselves throughout the day, and may never recur again. The reporter said that the aircraft was on the ground at pit, but that the map showed the aircraft to be in the vicinity of slt, about 90 NM to the northeast. His company maintenance gave the system a 'full alignment' and sent it on its way with no know further problems.
Original NASA ASRS Text
Title: A GLASS COCKPIT ACR CREW HAD A MAP SHIFT THAT SHOWED THE ACFT ABOUT 90 MI FROM ITS VOR POS.
Narrative: DURING CRUISE FLT BTWN KLGA AND KPIT, WE RECEIVED A MESSAGE ON BOTH FMC'S THAT WE'RE RECEIVING IRS-ONLY NAV, WHICH MEANS THEY (FMC'S) WERE NOT XCHKING THE NAV WITH VOR AND DME. SWITCHING TO MANUAL VOR AND DME NAV, WE REALIZED BOTH EFIS MAP DISPLAYS WERE OFF APPROX 90 MI. WE PROCEEDED WITH MANUAL VOR AND DME NAV WITH NO CONFLICT. CTR HAD VECTORED AND GIVEN DIRECT ROUTING MOST OF THE 50 MIN FLT, SO I DON'T THINK THEY SUSPECTED OUR NAV WAS OFF. THE ALL 'GLASS' COCKPIT ACFT REQUIRE CONSTANT MONITORING AND AT TIMES CAN BE MORE CONFUSING THAN CONVENTIONAL ACFT. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR DESCRIBED THIS PROBLEM AS 'MORNING SICKNESS.' THIS ACFT, AND OTHER GLASS COCKPIT ACFT HAVE PROBLEMS THAT TEND TO FIX THEMSELVES THROUGHOUT THE DAY, AND MAY NEVER RECUR AGAIN. THE RPTR SAID THAT THE ACFT WAS ON THE GND AT PIT, BUT THAT THE MAP SHOWED THE ACFT TO BE IN THE VICINITY OF SLT, ABOUT 90 NM TO THE NE. HIS COMPANY MAINT GAVE THE SYS A 'FULL ALIGNMENT' AND SENT IT ON ITS WAY WITH NO KNOW FURTHER PROBLEMS.
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.