Narrative:

During the past 15 days; cleveland center has filed 3 pilot deviations for identical incidents. The incidents all involved air carrier aircraft routed out of dtw via the MAARS1 SID and the aco transition. On this route the aircraft should fly the dxo 106 radial over maars intersection to the sphre intersection before turning toward aco. What is happening is that these aircraft are getting to maars and making an immediate right turn toward aco. The FAA has tried to raise awareness of everyone involved. Here is an analysis that was prepared at cleveland center after the first two incidents: cleveland ARTCC filed two pilot deviations regarding identical; but separate incidents. Problem scenario: aircraft flying from detroit metropolitan to points southeast; file via the maars one departure; akron transition. The computer code for this route is: dtw.MAARS1.aco. The problem occurs when aircraft get to maars intersection. Instead of continuing on the transition; some then make a right turn and proceed direct to aco. (Note: this may occur after a route revision has been entered in the FMS prior to the aircraft reaching maars.) this is a serious compromise to air safety. An air carrier captain onboard when their deviation occurred advised that he was certain that the FMS was properly configured prior to departure because he; the pilot; and another check airman in the jump seat had discussed it. When the cleveland center controller asked them if they were turning direct to aco; the captain was very surprised to see that the aco transition routing in the FMS had changed to maars direct aco. The captain was very concerned about the problem he had encountered. Upon returning to dtw; he contacted a maintenance technician to discuss the problem. They ran test scenarios in the aircraft by entering the maars departure route into the database five separate times. While working differing scenarios; ie; a clearance direct maars on course; the system dropped the aco transition routing and replaced it with maars direct aco. This happened on three of the five test scenarios they ran. The captain is elevating this situation within his company. He is also willing to assist in correcting the problem by sharing his findings with any interested parties. Conclusion: cleveland center does not know the exact cause of the problem. However; it does seem to be associated with the FMS database. Concerted effort needs to be applied to pinpoint and resolve this problem. Until that time every effort must be made to maximize the awareness of control personnel and flight crews. In december the MAARS1 SID will be revised in such a way that will correct this problem. Until that time; everyone must be alert to the potential problem. I believe a safety alert bulletin should be issued.callback conversation with reporter revealed the following information: the reporter stated that this anomaly has now occurred 7 times involving various aircraft and different air carrier's: B757; rj; and A319. A commercial database producer and an FMS component mfg were contacted in order to investigate the events but could not duplicate the behavior in a simulator. However; the reporter has spoken with pilots involved in the deviations and has determined that according to the pilots in every case the aircraft FMS was programmed correctly. However at some point along the routing a turn was made toward aco. This creates a potential conflict with aircraft arrivals into another busy area airport. The reporter knows that a planned revision will correct this issue; but until then he feels as many pilots as possible should be notified in order to help prevent an airborne conflict. The reporter noted that the maars one is composed of the main SID; MAARS1.maars and two transitions: MAARS1.aco and MAARS1.himez. There is a possibility that pilots are not selecting the MAARS1. Aco transition but instead leaving MAARS1.mars without any transition. Since aco is the next fix; the aircraft would turn at maars intersection; the end of MAARS1.mars SID coding.

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Original NASA ASRS Text

Title: A ZOB CONTROLLER REPORTS PILOTS FAILING TO SELECT A DTW MAARS ONE TRANSITION CAUSING A TRACK DEV. THIS OMISSION MAY BE COMMON TO OTHER SID DEVIATIONS NATIONWIDE.

Narrative: DURING THE PAST 15 DAYS; CLEVELAND CENTER HAS FILED 3 PILOT DEVIATIONS FOR IDENTICAL INCIDENTS. THE INCIDENTS ALL INVOLVED AIR CARRIER AIRCRAFT ROUTED OUT OF DTW VIA THE MAARS1 SID AND THE ACO TRANSITION. ON THIS ROUTE THE AIRCRAFT SHOULD FLY THE DXO 106 RADIAL OVER MAARS INTERSECTION TO THE SPHRE INTERSECTION BEFORE TURNING TOWARD ACO. WHAT IS HAPPENING IS THAT THESE AIRCRAFT ARE GETTING TO MAARS AND MAKING AN IMMEDIATE RIGHT TURN TOWARD ACO. THE FAA HAS TRIED TO RAISE AWARENESS OF EVERYONE INVOLVED. HERE IS AN ANALYSIS THAT WAS PREPARED AT CLEVELAND CENTER AFTER THE FIRST TWO INCIDENTS: CLEVELAND ARTCC FILED TWO PILOT DEVIATIONS REGARDING IDENTICAL; BUT SEPARATE INCIDENTS. PROBLEM SCENARIO: AIRCRAFT FLYING FROM DETROIT METRO TO POINTS SOUTHEAST; FILE VIA THE MAARS ONE DEPARTURE; AKRON TRANSITION. THE COMPUTER CODE FOR THIS ROUTE IS: DTW.MAARS1.ACO. THE PROBLEM OCCURS WHEN AIRCRAFT GET TO MAARS INTERSECTION. INSTEAD OF CONTINUING ON THE TRANSITION; SOME THEN MAKE A RIGHT TURN AND PROCEED DIRECT TO ACO. (NOTE: THIS MAY OCCUR AFTER A ROUTE REVISION HAS BEEN ENTERED IN THE FMS PRIOR TO THE AIRCRAFT REACHING MAARS.) THIS IS A SERIOUS COMPROMISE TO AIR SAFETY. AN ACR CAPT ONBOARD WHEN THEIR DEVIATION OCCURRED ADVISED THAT HE WAS CERTAIN THAT THE FMS WAS PROPERLY CONFIGURED PRIOR TO DEPARTURE BECAUSE HE; THE PILOT; AND ANOTHER CHECK AIRMAN IN THE JUMP SEAT HAD DISCUSSED IT. WHEN THE CLEVELAND CENTER CONTROLLER ASKED THEM IF THEY WERE TURNING DIRECT TO ACO; THE CAPTAIN WAS VERY SURPRISED TO SEE THAT THE ACO TRANSITION ROUTING IN THE FMS HAD CHANGED TO MAARS DIRECT ACO. THE CAPTAIN WAS VERY CONCERNED ABOUT THE PROBLEM HE HAD ENCOUNTERED. UPON RETURNING TO DTW; HE CONTACTED A MAINTENANCE TECHNICIAN TO DISCUSS THE PROBLEM. THEY RAN TEST SCENARIOS IN THE AIRCRAFT BY ENTERING THE MAARS DEPARTURE ROUTE INTO THE DATABASE FIVE SEPARATE TIMES. WHILE WORKING DIFFERING SCENARIOS; IE; A CLEARANCE DIRECT MAARS ON COURSE; THE SYSTEM DROPPED THE ACO TRANSITION ROUTING AND REPLACED IT WITH MAARS DIRECT ACO. THIS HAPPENED ON THREE OF THE FIVE TEST SCENARIOS THEY RAN. THE CAPTAIN IS ELEVATING THIS SITUATION WITHIN HIS COMPANY. HE IS ALSO WILLING TO ASSIST IN CORRECTING THE PROBLEM BY SHARING HIS FINDINGS WITH ANY INTERESTED PARTIES. CONCLUSION: CLEVELAND CENTER DOES NOT KNOW THE EXACT CAUSE OF THE PROBLEM. HOWEVER; IT DOES SEEM TO BE ASSOCIATED WITH THE FMS DATABASE. CONCERTED EFFORT NEEDS TO BE APPLIED TO PINPOINT AND RESOLVE THIS PROBLEM. UNTIL THAT TIME EVERY EFFORT MUST BE MADE TO MAXIMIZE THE AWARENESS OF CONTROL PERSONNEL AND FLIGHT CREWS. IN DECEMBER THE MAARS1 SID WILL BE REVISED IN SUCH A WAY THAT WILL CORRECT THIS PROBLEM. UNTIL THAT TIME; EVERYONE MUST BE ALERT TO THE POTENTIAL PROBLEM. I BELIEVE A SAFETY ALERT BULLETIN SHOULD BE ISSUED.CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE REPORTER STATED THAT THIS ANOMALY HAS NOW OCCURRED 7 TIMES INVOLVING VARIOUS ACFT AND DIFFERENT ACR'S: B757; RJ; AND A319. A COMMERCIAL DATABASE PRODUCER AND AN FMS COMPONENT MFG WERE CONTACTED IN ORDER TO INVESTIGATE THE EVENTS BUT COULD NOT DUPLICATE THE BEHAVIOR IN A SIMULATOR. HOWEVER; THE REPORTER HAS SPOKEN WITH PILOTS INVOLVED IN THE DEVIATIONS AND HAS DETERMINED THAT ACCORDING TO THE PILOTS IN EVERY CASE THE ACFT FMS WAS PROGRAMMED CORRECTLY. HOWEVER AT SOME POINT ALONG THE ROUTING A TURN WAS MADE TOWARD ACO. THIS CREATES A POTENTIAL CONFLICT WITH ACFT ARRIVALS INTO ANOTHER BUSY AREA ARPT. THE REPORTER KNOWS THAT A PLANNED REVISION WILL CORRECT THIS ISSUE; BUT UNTIL THEN HE FEELS AS MANY PILOTS AS POSSIBLE SHOULD BE NOTIFIED IN ORDER TO HELP PREVENT AN AIRBORNE CONFLICT. THE REPORTER NOTED THAT THE MAARS ONE IS COMPOSED OF THE MAIN SID; MAARS1.MAARS AND TWO TRANSITIONS: MAARS1.ACO AND MAARS1.HIMEZ. THERE IS A POSSIBILITY THAT PILOTS ARE NOT SELECTING THE MAARS1. ACO TRANSITION BUT INSTEAD LEAVING MAARS1.MARS WITHOUT ANY TRANSITION. SINCE ACO IS THE NEXT FIX; THE ACFT WOULD TURN AT MAARS INTXN; THE END OF MAARS1.MARS SID CODING.

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.