Air carrier crew has a problem with navigation system (gfms).

Attributes
ACN	473360
Time
Date	200005
Day	Fri
Local Time Of Day	1801 To 2400
Place
Locale Reference	intersection : volls
State Reference	TN
Altitude	msl single value : 10000
Environment
Light	Night
Aircraft 1
Controlling Facilities	tracon : bna.tracon
Operator	common carrier : air carrier
Make Model Name	B727 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Navigation In Use	other other
Flight Phase	descent : intermediate altitude
Route In Use	arrival star : volls.5
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
ASRS Report	473360
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : multi engine pilot : instrument pilot : commercial
Events
Anomaly	aircraft equipment problem : critical
Independent Detector	other flight crewa
Resolutory Action	flight crew : overcame equipment problem
Consequence	other
Supplementary
Problem Areas	Aircraft Flight Crew Human Performance
Primary Problem	Aircraft

Narrative:

Location: volls intersection. On the volls 5 arrival into bna, the gfms counts down approaching volls. The waypoint light illuminates, warning you of waypoint passage. The next point is listed as bna. Passing volls the gfms counts away from volls intersection instead of to bna. The aircraft is in the dead reckoning mode, although there is no notice of this on the gfms screen. There is no notice of any kind on the gfms screen. The aircraft is simply flying a heading. In bna there is nothing to hit, but if this occurred in slc, it would cause a huge safety hazard. Something needs to be done to check the software on these units to ensure they are doing what they should.

Original NASA ASRS Text

Title: ACR CREW HAS A PROB WITH NAV SYS (GFMS).

Narrative: LOCATION: VOLLS INTXN. ON THE VOLLS 5 ARR INTO BNA, THE GFMS COUNTS DOWN APCHING VOLLS. THE WAYPOINT LIGHT ILLUMINATES, WARNING YOU OF WAYPOINT PASSAGE. THE NEXT POINT IS LISTED AS BNA. PASSING VOLLS THE GFMS COUNTS AWAY FROM VOLLS INTXN INSTEAD OF TO BNA. THE ACFT IS IN THE DEAD RECKONING MODE, ALTHOUGH THERE IS NO NOTICE OF THIS ON THE GFMS SCREEN. THERE IS NO NOTICE OF ANY KIND ON THE GFMS SCREEN. THE ACFT IS SIMPLY FLYING A HDG. IN BNA THERE IS NOTHING TO HIT, BUT IF THIS OCCURRED IN SLC, IT WOULD CAUSE A HUGE SAFETY HAZARD. SOMETHING NEEDS TO BE DONE TO CHK THE SOFTWARE ON THESE UNITS TO ENSURE THEY ARE DOING WHAT THEY SHOULD.

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.