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B autoplt on B737-800 flying akuna RNAV SID from dfw turns wrong way approaching bemmr waypoint. Flight crew manually corrects track to comply with the SID.
| Attributes | |
| ACN | 702026 |
| Time | |
| Date | 200606 |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | atc facility : d10.tracon |
| State Reference | TX |
| Altitude | msl single value : 10000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | tracon : d10.tracon |
| Operator | common carrier : air carrier |
| Make Model Name | B737-800 |
| Operating Under FAR Part | Part 121 |
| Flight Phase | climbout : initial |
| Route In Use | departure sid : akuna2.mcl |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| ASRS Report | 702026 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Events | |
| Anomaly | aircraft equipment problem : critical non adherence : published procedure other spatial deviation |
| Independent Detector | other flight crewa |
| Resolutory Action | flight crew : overcame equipment problem flight crew : returned to intended or assigned course |
| Consequence | other |
| Supplementary | |
| Problem Areas | Aircraft |
| Primary Problem | Aircraft |
Narrative:
During departure climb out from dfw on the AKUNA2 (mcl transition) RNAV standard instrument departure (at approximately the bemmr fix with the autoplt B engaged and VNAV; LNAV and cmd displayed on our flight mode annunciators); my copilot noticed that the autoplt B was turning the aircraft in the wrong direction. Shortly thereafter; the autoplt disengaged on its own; but no autoplt disconnect aural warning sounded. My first officer immediately turned (hand flew) the aircraft back to reintercept the 'pink' line on the RNAV SID. It appears that we may have laterally exceeded the ATC 'expected' maximum deviation from the SID of .5 NM (as stipulated on the dfw RNAV bulletin). Our deviation was west of the bemmr intersection. After reengaging the autoplt B; the autoplt operated normally for the remainder of the flight. Also; autoplt a worked normally as well. As a precaution we wrote up the discrepancy in our maintenance logbook so as to have the autoplt system checked out for future flight.
Original NASA ASRS Text
Title: B AUTOPLT ON B737-800 FLYING AKUNA RNAV SID FROM DFW TURNS WRONG WAY APCHING BEMMR WAYPOINT. FLT CREW MANUALLY CORRECTS TRACK TO COMPLY WITH THE SID.
Narrative: DURING DEP CLBOUT FROM DFW ON THE AKUNA2 (MCL TRANSITION) RNAV STANDARD INSTRUMENT DEP (AT APPROX THE BEMMR FIX WITH THE AUTOPLT B ENGAGED AND VNAV; LNAV AND CMD DISPLAYED ON OUR FLT MODE ANNUNCIATORS); MY COPLT NOTICED THAT THE AUTOPLT B WAS TURNING THE ACFT IN THE WRONG DIRECTION. SHORTLY THEREAFTER; THE AUTOPLT DISENGAGED ON ITS OWN; BUT NO AUTOPLT DISCONNECT AURAL WARNING SOUNDED. MY FO IMMEDIATELY TURNED (HAND FLEW) THE ACFT BACK TO REINTERCEPT THE 'PINK' LINE ON THE RNAV SID. IT APPEARS THAT WE MAY HAVE LATERALLY EXCEEDED THE ATC 'EXPECTED' MAX DEV FROM THE SID OF .5 NM (AS STIPULATED ON THE DFW RNAV BULLETIN). OUR DEV WAS W OF THE BEMMR INTXN. AFTER REENGAGING THE AUTOPLT B; THE AUTOPLT OPERATED NORMALLY FOR THE REMAINDER OF THE FLT. ALSO; AUTOPLT A WORKED NORMALLY AS WELL. AS A PRECAUTION WE WROTE UP THE DISCREPANCY IN OUR MAINT LOGBOOK SO AS TO HAVE THE AUTOPLT SYSTEM CHKED OUT FOR FUTURE FLT.
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.