Narrative:

During climb-out we were given a heading to join the 240 radial off of den VOR. As we were in the climb/cruise configuration; I input the 240 radial track off of den; but was at a loss as to how far I should put that point in space before we made our turn towards hbu VOR on our way to our destination. I queried ATC for a distance we would likely stay on this 240 radial; but was given a vague answer. So I input a 40 mile DME [waypoint] on the 240 radial as a starting point with the next fix being hbu VOR. We joined up on the 240 radial and we became busy with checklist; the threat of thunderstorms in the area; and our passenger's desire to go to a different airport. As a result; I didn't notice--some minutes later--that the airplane had reached 240/40 DME waypoint and had turned toward hbu. We; of course; were not cleared to hbu yet; so ATC called and asked if we had been given a different routing. It was at that time I realized we had a navigational error. ATC cleared us to hbu and the flight proceeded without incident.I should have just flown 'green needles' using normal navigation mode with joining and staying on the 240 radial off of den until given a further clearance. My haste in getting the FMS involved and lack of awareness that we had reached the point in space and had turned to hbu without clearance allowed us to take part in a navigational error.

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Original NASA ASRS Text

Title: A C-560XLS First Officer; cleared to intercept a radial off a VOR with no subsequent routing elected to make a waypoint to fly to at 40 DME and then closed the resulting route discontinuity by bringing up and executing the first 'on course' waypoint in their route. Later; distracted by other duties; the flight crew failed to note they had arrived at their 'fix' and were turning toward the en route fix without having been cleared to do so. ATC quickly reminded them they hadn't been cleared to do so...and then provided that clearance.

Narrative: During climb-out we were given a heading to join the 240 radial off of DEN VOR. As we were in the climb/cruise configuration; I input the 240 radial track off of DEN; but was at a loss as to how far I should put that point in space before we made our turn towards HBU VOR on our way to our destination. I queried ATC for a distance we would likely stay on this 240 radial; but was given a vague answer. So I input a 40 mile DME [waypoint] on the 240 radial as a starting point with the next fix being HBU VOR. We joined up on the 240 radial and we became busy with checklist; the threat of thunderstorms in the area; and our passenger's desire to go to a different airport. As a result; I didn't notice--some minutes later--that the airplane had reached 240/40 DME waypoint and had turned toward HBU. We; of course; were not cleared to HBU yet; so ATC called and asked if we had been given a different routing. It was at that time I realized we had a navigational error. ATC cleared us to HBU and the flight proceeded without incident.I should have just flown 'green needles' using normal NAV mode with joining and staying on the 240 radial off of DEN until given a further clearance. My haste in getting the FMS involved and lack of awareness that we had reached the point in space and had turned to HBU without clearance allowed us to take part in a navigational error.

Data retrieved from NASA's ASRS site as of July 2013 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.