Narrative:

Our departure runway was runway 8L at atl; and we were assigned the geetk two RNAV departure. The controller at atl; operating in an efficient manner; cleared us for takeoff so that we had minimum separation from the dc-9 ahead; the previous departure from runway 8L. On initial contact; the departure controller advised us to maintain 250 KTS; which communicated to us that we probably had traffic spaced tightly to us ahead and behind. I was hand flying the aircraft; with the flight director coupled to the FMS for lateral guidance. At 5.9 NM from klegg intersection; the FMS instructed the flight director to command a left turn towards zelan. I felt we were too far from klegg; so I continued direct klegg. Our honeywell FMS systems are very well known to cut corners; especially on sharper turns. So I wanted to wait a minute. I was looking at a flight director which was commanding a 30 degree left turn; and ignoring it. I did not like doing that. At about four and a half miles south of klegg; I gave in to the pressure from the automation and married up with the flight director. I thought I would stay on course; since I had begun the turn what felt like quite a while after the flight director commanded me to; in reality it was probably only 30 seconds later. In the turn; at 330 degrees; the flight directors changed direction and commanded a 5 degree bank to the right. I began to take out the bank. At that moment; the departure controller stated; 'did you start that turn already?' when I heard that; I knew we were still cutting the corner too much; and immediately and sharply rolled the aircraft into a right turn. I never actually started turning right; because; without hesitation; the departure controller assigned a 320 degree heading for us. A couple of seconds later; he instructed us; in a concerned tone; to maintain 8000 ft. We leveled off at 8; he held us on a 320 degree heading until we were north of the SID course to give us proper spacing with the air carrier ahead; then gave us 10000 ft; direct zelan; and a phone number to call. On landing; I called atl departure on the phone and explained what happened from our end. He informed me that since the controller took such quick action; there was no conflict and no action would be taken against us. He informed me that if a conflict would have resulted; it would be labeled pilot deviation from the SID; to which I agreed. I told him; in the future; perhaps tower should give our airline's aircraft a little more room from the aircraft ahead; and that this is likely to happen again. He said that would not be possible; but he would report the incident to the FAA in a manner which would not identify our flight or us; but would identify the problem with the FMS. Recently; our company filed /west as our equipment suffix. We did this for a number of weeks on all our honeywell FMS aircraft; because of this problem. We only accepted the atlanta five departure. Currently; we file /left and have been told that the FMS software was updated to correct this problem. We are always to follow the automation and maximize autoplt usage. In the future; I will engage the autoplt at 500 ft on departure from atl. This will allow me to more closely monitor the TCAS and SID compliance. If I see the FMS commanding an early turn; I will disengage the autoplt and fly the SID using my judgement. I no longer trust the honeywell FMS. If I am in a situation where I will be assigned a SID out of atl that contains sharp turns; I will not accept the SID and request to be refiled as /west. I am also submitting this report to NASA only and am not using my company's safety reporting program. While I know no legal action would be taken; I do not want to have to defend myself to the chief pilot. I am only submitting this report in an attempt to bring attention to this continuing problem with the honeywell FMS; which still exists but has been marked as corrected. I have heard from other pilots that a 'carpet dance' comes from submitting these reports. I wish I had a way to communicate this problem with my peers because I believe this will happen again. Its just a matter of having the right circumstances. I agree that something like this is a pilot deviation from the SID. I wouldhate to see someone get violated for doing as they were told and following the automation; or flying with the autoplt on; because someone else designed the FMS to deviation from course.callback conversation with reporter revealed the following information: the reporter advised the FMS systems on these aircraft do not display the programmed turn radii on the navigation display. Instead; they fly towards the active waypoint until such time or place as a turn towards the next waypoint is initiated. At that point the original waypoint disappears and the system programs a route direct to the next waypoint. He was unable to advise whether -- in the instance reported -- that track was the charted track between klegg and zelan or something unique based on turn rate; winds; ground speed; etc. He advised he has foregone coupled autoflt on these departures and; instead; flies them in a heading mode; mentally estimating an appropriate point at which to initiate a standard rate turn. He advised that others have modified the programming to make waypoints 'flyover' vice 'flyby'; thus ensuring that the aircraft will track towards the active fix until reaching it. He conceded such a practice was contrary to the suggestion that the procedures be flown in autoflt but that failure to make such interventions will result in deviations as reported herein. He reiterated his concern about the failure of the company's actions to resolve the problem. He also noted that the performance of the aircraft equipped with universal FMS systems is fault free.

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Original NASA ASRS Text

Title: AN E145 CAPT DETAILS FAILURE OF THE HONEYWELL FMS TO FLY THE GEETK RNAV SID FROM ATL WITHIN THE REQUIRED TURN PARAMETERS.

Narrative: OUR DEP RWY WAS RWY 8L AT ATL; AND WE WERE ASSIGNED THE GEETK TWO RNAV DEP. THE CTLR AT ATL; OPERATING IN AN EFFICIENT MANNER; CLRED US FOR TKOF SO THAT WE HAD MINIMUM SEPARATION FROM THE DC-9 AHEAD; THE PREVIOUS DEP FROM RWY 8L. ON INITIAL CONTACT; THE DEP CTLR ADVISED US TO MAINTAIN 250 KTS; WHICH COMMUNICATED TO US THAT WE PROBABLY HAD TFC SPACED TIGHTLY TO US AHEAD AND BEHIND. I WAS HAND FLYING THE ACFT; WITH THE FLT DIRECTOR COUPLED TO THE FMS FOR LATERAL GUIDANCE. AT 5.9 NM FROM KLEGG INTXN; THE FMS INSTRUCTED THE FLT DIRECTOR TO COMMAND A L TURN TOWARDS ZELAN. I FELT WE WERE TOO FAR FROM KLEGG; SO I CONTINUED DIRECT KLEGG. OUR HONEYWELL FMS SYSTEMS ARE VERY WELL KNOWN TO CUT CORNERS; ESPECIALLY ON SHARPER TURNS. SO I WANTED TO WAIT A MINUTE. I WAS LOOKING AT A FLT DIRECTOR WHICH WAS COMMANDING A 30 DEG L TURN; AND IGNORING IT. I DID NOT LIKE DOING THAT. AT ABOUT FOUR AND A HALF MILES S OF KLEGG; I GAVE IN TO THE PRESSURE FROM THE AUTOMATION AND MARRIED UP WITH THE FLT DIRECTOR. I THOUGHT I WOULD STAY ON COURSE; SINCE I HAD BEGUN THE TURN WHAT FELT LIKE QUITE A WHILE AFTER THE FLT DIRECTOR COMMANDED ME TO; IN REALITY IT WAS PROBABLY ONLY 30 SECONDS LATER. IN THE TURN; AT 330 DEGS; THE FLT DIRECTORS CHANGED DIRECTION AND COMMANDED A 5 DEG BANK TO THE R. I BEGAN TO TAKE OUT THE BANK. AT THAT MOMENT; THE DEP CTLR STATED; 'DID YOU START THAT TURN ALREADY?' WHEN I HEARD THAT; I KNEW WE WERE STILL CUTTING THE CORNER TOO MUCH; AND IMMEDIATELY AND SHARPLY ROLLED THE ACFT INTO A R TURN. I NEVER ACTUALLY STARTED TURNING R; BECAUSE; WITHOUT HESITATION; THE DEP CTLR ASSIGNED A 320 DEG HDG FOR US. A COUPLE OF SECONDS LATER; HE INSTRUCTED US; IN A CONCERNED TONE; TO MAINTAIN 8000 FT. WE LEVELED OFF AT 8; HE HELD US ON A 320 DEG HDG UNTIL WE WERE N OF THE SID COURSE TO GIVE US PROPER SPACING WITH THE ACR AHEAD; THEN GAVE US 10000 FT; DIRECT ZELAN; AND A PHONE NUMBER TO CALL. ON LNDG; I CALLED ATL DEP ON THE PHONE AND EXPLAINED WHAT HAPPENED FROM OUR END. HE INFORMED ME THAT SINCE THE CTLR TOOK SUCH QUICK ACTION; THERE WAS NO CONFLICT AND NO ACTION WOULD BE TAKEN AGAINST US. HE INFORMED ME THAT IF A CONFLICT WOULD HAVE RESULTED; IT WOULD BE LABELED PLT DEV FROM THE SID; TO WHICH I AGREED. I TOLD HIM; IN THE FUTURE; PERHAPS TWR SHOULD GIVE OUR AIRLINE'S ACFT A LITTLE MORE ROOM FROM THE ACFT AHEAD; AND THAT THIS IS LIKELY TO HAPPEN AGAIN. HE SAID THAT WOULD NOT BE POSSIBLE; BUT HE WOULD RPT THE INCIDENT TO THE FAA IN A MANNER WHICH WOULD NOT IDENTIFY OUR FLT OR US; BUT WOULD IDENTIFY THE PROBLEM WITH THE FMS. RECENTLY; OUR COMPANY FILED /W AS OUR EQUIP SUFFIX. WE DID THIS FOR A NUMBER OF WEEKS ON ALL OUR HONEYWELL FMS ACFT; BECAUSE OF THIS PROBLEM. WE ONLY ACCEPTED THE ATLANTA FIVE DEP. CURRENTLY; WE FILE /L AND HAVE BEEN TOLD THAT THE FMS SOFTWARE WAS UPDATED TO CORRECT THIS PROBLEM. WE ARE ALWAYS TO FOLLOW THE AUTOMATION AND MAXIMIZE AUTOPLT USAGE. IN THE FUTURE; I WILL ENGAGE THE AUTOPLT AT 500 FT ON DEP FROM ATL. THIS WILL ALLOW ME TO MORE CLOSELY MONITOR THE TCAS AND SID COMPLIANCE. IF I SEE THE FMS COMMANDING AN EARLY TURN; I WILL DISENGAGE THE AUTOPLT AND FLY THE SID USING MY JUDGEMENT. I NO LONGER TRUST THE HONEYWELL FMS. IF I AM IN A SITUATION WHERE I WILL BE ASSIGNED A SID OUT OF ATL THAT CONTAINS SHARP TURNS; I WILL NOT ACCEPT THE SID AND REQUEST TO BE REFILED AS /W. I AM ALSO SUBMITTING THIS RPT TO NASA ONLY AND AM NOT USING MY COMPANY'S SAFETY RPTING PROGRAM. WHILE I KNOW NO LEGAL ACTION WOULD BE TAKEN; I DO NOT WANT TO HAVE TO DEFEND MYSELF TO THE CHIEF PLT. I AM ONLY SUBMITTING THIS RPT IN AN ATTEMPT TO BRING ATTENTION TO THIS CONTINUING PROBLEM WITH THE HONEYWELL FMS; WHICH STILL EXISTS BUT HAS BEEN MARKED AS CORRECTED. I HAVE HEARD FROM OTHER PLTS THAT A 'CARPET DANCE' COMES FROM SUBMITTING THESE RPTS. I WISH I HAD A WAY TO COMMUNICATE THIS PROBLEM WITH MY PEERS BECAUSE I BELIEVE THIS WILL HAPPEN AGAIN. ITS JUST A MATTER OF HAVING THE RIGHT CIRCUMSTANCES. I AGREE THAT SOMETHING LIKE THIS IS A PLT DEV FROM THE SID. I WOULDHATE TO SEE SOMEONE GET VIOLATED FOR DOING AS THEY WERE TOLD AND FOLLOWING THE AUTOMATION; OR FLYING WITH THE AUTOPLT ON; BECAUSE SOMEONE ELSE DESIGNED THE FMS TO DEV FROM COURSE.CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR ADVISED THE FMS SYSTEMS ON THESE ACFT DO NOT DISPLAY THE PROGRAMMED TURN RADII ON THE NAV DISPLAY. INSTEAD; THEY FLY TOWARDS THE ACTIVE WAYPOINT UNTIL SUCH TIME OR PLACE AS A TURN TOWARDS THE NEXT WAYPOINT IS INITIATED. AT THAT POINT THE ORIGINAL WAYPOINT DISAPPEARS AND THE SYSTEM PROGRAMS A RTE DIRECT TO THE NEXT WAYPOINT. HE WAS UNABLE TO ADVISE WHETHER -- IN THE INSTANCE RPTED -- THAT TRACK WAS THE CHARTED TRACK BETWEEN KLEGG AND ZELAN OR SOMETHING UNIQUE BASED ON TURN RATE; WINDS; GND SPD; ETC. HE ADVISED HE HAS FOREGONE COUPLED AUTOFLT ON THESE DEPS AND; INSTEAD; FLIES THEM IN A HDG MODE; MENTALLY ESTIMATING AN APPROPRIATE POINT AT WHICH TO INITIATE A STANDARD RATE TURN. HE ADVISED THAT OTHERS HAVE MODIFIED THE PROGRAMMING TO MAKE WAYPOINTS 'FLYOVER' VICE 'FLYBY'; THUS ENSURING THAT THE ACFT WILL TRACK TOWARDS THE ACTIVE FIX UNTIL REACHING IT. HE CONCEDED SUCH A PRACTICE WAS CONTRARY TO THE SUGGESTION THAT THE PROCS BE FLOWN IN AUTOFLT BUT THAT FAILURE TO MAKE SUCH INTERVENTIONS WILL RESULT IN DEVS AS RPTED HEREIN. HE REITERATED HIS CONCERN ABOUT THE FAILURE OF THE COMPANY'S ACTIONS TO RESOLVE THE PROBLEM. HE ALSO NOTED THAT THE PERFORMANCE OF THE ACFT EQUIPPED WITH UNIVERSAL FMS SYSTEMS IS FAULT FREE.

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.