Narrative:

Feedback on waypoints dropped from RNAV departures at dfw. At the gate; after the route was loaded in the GPS; we checked the waypoints. Runway 35L was selected for the departure. On the legs page; the 1100 ft point after takeoff was not listed and the course to the first fix was 358 degrees. The map showed the same data. I re-loaded the SOLDO2; including the runway; and rechked the legs page. This time it showed a departure off runway 35L to intercept the 009 radial. The 009 radial is for a runway 35C departure. The map mode confirmed this setup. I-reloaded the RNAV departure again and got a course of 354 degrees to the first fix. Once again; the map display showed the course well off the right of the runway 35L position. The 1100 ft fix off the end of the runway did not appear in any attempt. After checking the GPS pages for error messages (there were none); I contacted clearance delivery and changed our departure to the DAL8. Except for the RNAV departure; the GPS appeared to operate normally. I made a logbook entry at destination. Neither the first officer nor I could account for this anomaly.callback conversation with reporter revealed the following information: the reporter; with more than 10000 hours in the MD80; was very forthright in his comments regarding the FMS system on his company's aircraft. He feels that unlike more modern aircraft in which the FMS systems are well integrated and consistently reliable; the MD80 systems are a 'mix and match' of original and updated systems. He states there are consistent anomalies about which experienced users are aware and for which they take precautions or are accustomed to making accommodations. Of particular interest regarding the RNAV departure anomalies; he related a recurring example which may be supportive of acn's which report 'waypoints dropping or disappearing.' he was able to demonstrate to a copilot that this did; in fact; occur. After the route is installed in the FMS; it is his practice to 'copy' that route to a separate 'file' in the FMS memory. The use of this 'stored route' is commonly utilized by many pilots for such things as engine out procedures; etc. The reporter used the 'route copy' process to duplicate the cleared route by which the aircraft was programmed to fly. When they encountered a loss of waypoints he was able to then pull up 'route two' and verified that at one time the route did in fact contain the missing waypoints. It is the reporter's opinion that such anomalies; rare in more modern aircraft; are not a big surprise to experienced MD80 pilots. He; once again; feels such problems are likely the result of less perfectly integrated compatibility of the various older and newer components of which the MD80 systems are configured.

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Original NASA ASRS Text

Title: MD80 FLT CREW PROGRAMS SOLDO RNAV SID FROM DFW MULTIPLE TIMES AND GETS DIFFERENT INITIAL DEP LEGS EACH TIME. CREW CANCELS THE RNAV SID AND REQUESTS THE DALLAS SID WHICH UTILIZES RADAR VECTORS VICE RNAV.

Narrative: FEEDBACK ON WAYPOINTS DROPPED FROM RNAV DEPS AT DFW. AT THE GATE; AFTER THE RTE WAS LOADED IN THE GPS; WE CHKED THE WAYPOINTS. RWY 35L WAS SELECTED FOR THE DEP. ON THE LEGS PAGE; THE 1100 FT POINT AFTER TKOF WAS NOT LISTED AND THE COURSE TO THE FIRST FIX WAS 358 DEGS. THE MAP SHOWED THE SAME DATA. I RE-LOADED THE SOLDO2; INCLUDING THE RWY; AND RECHKED THE LEGS PAGE. THIS TIME IT SHOWED A DEP OFF RWY 35L TO INTERCEPT THE 009 RADIAL. THE 009 RADIAL IS FOR A RWY 35C DEP. THE MAP MODE CONFIRMED THIS SETUP. I-RELOADED THE RNAV DEP AGAIN AND GOT A COURSE OF 354 DEGS TO THE FIRST FIX. ONCE AGAIN; THE MAP DISPLAY SHOWED THE COURSE WELL OFF THE R OF THE RWY 35L POSITION. THE 1100 FT FIX OFF THE END OF THE RWY DID NOT APPEAR IN ANY ATTEMPT. AFTER CHKING THE GPS PAGES FOR ERROR MESSAGES (THERE WERE NONE); I CONTACTED CLRNC DELIVERY AND CHANGED OUR DEP TO THE DAL8. EXCEPT FOR THE RNAV DEP; THE GPS APPEARED TO OPERATE NORMALLY. I MADE A LOGBOOK ENTRY AT DEST. NEITHER THE FO NOR I COULD ACCOUNT FOR THIS ANOMALY.CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR; WITH MORE THAN 10000 HOURS IN THE MD80; WAS VERY FORTHRIGHT IN HIS COMMENTS REGARDING THE FMS SYSTEM ON HIS COMPANY'S ACFT. HE FEELS THAT UNLIKE MORE MODERN ACFT IN WHICH THE FMS SYSTEMS ARE WELL INTEGRATED AND CONSISTENTLY RELIABLE; THE MD80 SYSTEMS ARE A 'MIX AND MATCH' OF ORIGINAL AND UPDATED SYSTEMS. HE STATES THERE ARE CONSISTENT ANOMALIES ABOUT WHICH EXPERIENCED USERS ARE AWARE AND FOR WHICH THEY TAKE PRECAUTIONS OR ARE ACCUSTOMED TO MAKING ACCOMMODATIONS. OF PARTICULAR INTEREST REGARDING THE RNAV DEP ANOMALIES; HE RELATED A RECURRING EXAMPLE WHICH MAY BE SUPPORTIVE OF ACN'S WHICH RPT 'WAYPOINTS DROPPING OR DISAPPEARING.' HE WAS ABLE TO DEMONSTRATE TO A COPLT THAT THIS DID; IN FACT; OCCUR. AFTER THE RTE IS INSTALLED IN THE FMS; IT IS HIS PRACTICE TO 'COPY' THAT RTE TO A SEPARATE 'FILE' IN THE FMS MEMORY. THE USE OF THIS 'STORED RTE' IS COMMONLY UTILIZED BY MANY PLTS FOR SUCH THINGS AS ENG OUT PROCS; ETC. THE RPTR USED THE 'RTE COPY' PROCESS TO DUPLICATE THE CLRED RTE BY WHICH THE ACFT WAS PROGRAMMED TO FLY. WHEN THEY ENCOUNTERED A LOSS OF WAYPOINTS HE WAS ABLE TO THEN PULL UP 'RTE TWO' AND VERIFIED THAT AT ONE TIME THE RTE DID IN FACT CONTAIN THE MISSING WAYPOINTS. IT IS THE RPTR'S OPINION THAT SUCH ANOMALIES; RARE IN MORE MODERN ACFT; ARE NOT A BIG SURPRISE TO EXPERIENCED MD80 PLTS. HE; ONCE AGAIN; FEELS SUCH PROBLEMS ARE LIKELY THE RESULT OF LESS PERFECTLY INTEGRATED COMPATIBILITY OF THE VARIOUS OLDER AND NEWER COMPONENTS OF WHICH THE MD80 SYSTEMS ARE CONFIGURED.

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.