Narrative:

Departing ind on the DAWNN4 departure FMS indicated course 174 degrees to dawnn intersection as depicted on the ind 10-3 chart. However; the course depicted is actually 4 miles right of the actual course when checked against the radial from the vhp VOR as depicted on the chart. The error was discovered when ATC directed us to fly a heading to intercept the departure leg to dawnn. We responded that the assigned heading would not intercept the course as depicted on the departure. ATC said it would. I then tuned the radial on the VOR and sure enough it indicated the assigned heading would work fine. The FMS course still indicated the correct course; but was actually paralleling the real course 4 miles off. We continued using the VOR for navigation until after the dawnn intersection. Since the error was detected early; there was no course deviation. The FMS functioned normally after that fix. A discrepancy was recorded in the maintenance log; and maintenance checked the FMS at the next station and could find [any] problems. It would seem to be a problem with the FMS database on that particular departure. The hazard is that this error was not detected even though all proper preflight procedures were followed. The runway and departure were loaded and checked against the chart. All courses and fixes were verified correct and displayed correctly. Despite this; the FMS course was still providing incorrect navigational data. By questioning ATC's heading assignment; the error was discovered and corrected before it became a problem. Investigate and determine if a database problem exists on the ind dawnn four departure or implement procedures that would detect such a problem during the preflight process.

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Original NASA ASRS Text

Title: The stored IND DAWNN4 SID database in a EMB145's FMC contains a programming error which makes the aircraft fly a track four miles right of the charted course. ATC vectored the aircraft toward the correct radial and the crew flew the charted VOR course.

Narrative: Departing IND on the DAWNN4 Departure FMS indicated course 174 degrees to DAWNN Intersection as depicted on the IND 10-3 chart. However; the course depicted is actually 4 miles right of the actual course when checked against the radial from the VHP VOR as depicted on the chart. The error was discovered when ATC directed us to fly a heading to intercept the departure leg to DAWNN. We responded that the assigned heading would not intercept the course as depicted on the departure. ATC said it would. I then tuned the radial on the VOR and sure enough it indicated the assigned heading would work fine. The FMS course still indicated the correct course; but was actually paralleling the real course 4 miles off. We continued using the VOR for navigation until after the DAWNN Intersection. Since the error was detected early; there was no course deviation. The FMS functioned normally after that fix. A discrepancy was recorded in the maintenance log; and Maintenance checked the FMS at the next station and could find [any] problems. It would seem to be a problem with the FMS database on that particular departure. The hazard is that this error was not detected even though all proper preflight procedures were followed. The runway and departure were loaded and checked against the chart. All courses and fixes were verified correct and displayed correctly. Despite this; the FMS course was still providing incorrect navigational data. By questioning ATC's heading assignment; the error was discovered and corrected before it became a problem. Investigate and determine if a database problem exists on the IND DAWNN four departure or implement procedures that would detect such a problem during the preflight process.

Data retrieved from NASA's ASRS site as of April 2012 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.