While flying triss RNAV SID; txk transition from dfw; MD81 flight crew notices a break in the FMS ro...

Attributes
ACN	702570
Time
Date	200607
Local Time Of Day	0601 To 1200
Place
Locale Reference	intersection : shero
State Reference	TX
Altitude	msl single value : 31000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zfw.artcc
Operator	common carrier : air carrier
Make Model Name	MD-81
Operating Under FAR Part	Part 121
Navigation In Use	other
Flight Phase	cruise : level
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
ASRS Report	702570
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
ASRS Report	702569
Events
Anomaly	aircraft equipment problem : critical non adherence : clearance non adherence : published procedure other spatial deviation
Independent Detector	aircraft equipment other aircraft equipment : nav display other controllera
Resolutory Action	flight crew : overcame equipment problem flight crew : returned to intended or assigned course
Supplementary
Problem Areas	Aircraft Chart Or Publication
Primary Problem	Aircraft

Narrative:

Cleared triss.txk. Normal preflight FMS procedures performed during preflight. Once airborne approaching triss intersection noticed what appeared to be a discontinuity (ie; no magenta line) on navigation display. Captain had same lack of magenta line on his navigation display; too. Referenced FMS for any discontinuity; but there wasn't one. While trying to figure out what was up; ARTCC called to remind us to make turn towards shero intersection (about a 10 degree turn from triss to shero using heading sel and reprogrammed TRISS2.txk in FMS. Captain executed input and selected navigation. Magenta line reappeared for routing from triss to shero. Then; txk vanished from view on navigation display and magenta line then showed a routing from shero direct to matie -- no txk. Saw this occur with my own eyes! Captain then manually input a route from shero to txk then matie. Selected navigation. Later captain to write up FMS for corrupt navigation data.callback conversation with reporter revealed the following information: the reporter reiterated the dichotomy of a break in the map route display and the lack of a route discontinuity warning on the CDU. Reporter was uncertain; however; whether the route display was picked up again after txk; only that it stopped at triss. He was absolutely certain; though; that txk did in fact disappear when the correction was made and the magenta route line went direct to matie from shero.

Original NASA ASRS Text

Title: WHILE FLYING TRISS RNAV SID; TXK TRANSITION FROM DFW; MD81 FLT CREW NOTICES A BREAK IN THE FMS RTE WITH NO COMMENSURATE RTE DISCONTINUITY ON THE CDU. ATTEMPTS TO RECONCILE THE RTE RESULTED IN MISSING WAYPOINTS. MANUAL ENTRY OF ALL WAYPOINTS ON THE SID/TRANSITION WERE REQUIRED.

Narrative: CLRED TRISS.TXK. NORMAL PREFLT FMS PROCS PERFORMED DURING PREFLT. ONCE AIRBORNE APCHING TRISS INTXN NOTICED WHAT APPEARED TO BE A DISCONTINUITY (IE; NO MAGENTA LINE) ON NAV DISPLAY. CAPT HAD SAME LACK OF MAGENTA LINE ON HIS NAV DISPLAY; TOO. REFERENCED FMS FOR ANY DISCONTINUITY; BUT THERE WASN'T ONE. WHILE TRYING TO FIGURE OUT WHAT WAS UP; ARTCC CALLED TO REMIND US TO MAKE TURN TOWARDS SHERO INTXN (ABOUT A 10 DEG TURN FROM TRISS TO SHERO USING HDG SEL AND REPROGRAMMED TRISS2.TXK IN FMS. CAPT EXECUTED INPUT AND SELECTED NAV. MAGENTA LINE REAPPEARED FOR ROUTING FROM TRISS TO SHERO. THEN; TXK VANISHED FROM VIEW ON NAV DISPLAY AND MAGENTA LINE THEN SHOWED A ROUTING FROM SHERO DIRECT TO MATIE -- NO TXK. SAW THIS OCCUR WITH MY OWN EYES! CAPT THEN MANUALLY INPUT A RTE FROM SHERO TO TXK THEN MATIE. SELECTED NAV. LATER CAPT TO WRITE UP FMS FOR CORRUPT NAV DATA.CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR REITERATED THE DICHOTOMY OF A BREAK IN THE MAP RTE DISPLAY AND THE LACK OF A RTE DISCONTINUITY WARNING ON THE CDU. RPTR WAS UNCERTAIN; HOWEVER; WHETHER THE RTE DISPLAY WAS PICKED UP AGAIN AFTER TXK; ONLY THAT IT STOPPED AT TRISS. HE WAS ABSOLUTELY CERTAIN; THOUGH; THAT TXK DID IN FACT DISAPPEAR WHEN THE CORRECTION WAS MADE AND THE MAGENTA RTE LINE WENT DIRECT TO MATIE FROM SHERO.

Data retrieved from NASA's ASRS site as of January 2009 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.

While flying triss RNAV SID; txk transition from dfw; MD81 flight crew notices a break in the FMS route with no commensurate route discontinuity on the CDU. Attempts to reconcile the route resulted in missing waypoints. Manual entry of all waypoints on the SID/transition were required.