Narrative:

We departed teb on the ruudy 2 departure initially flying the published procedure. As always; flying in the northeast corridor; especially departing from teb requires careful attention and strict adherence to the procedures. It is a busy environment and requires quick and accurate thinking. Having reviewed the departure procedure I was anticipating a possible vector to coltsneck VOR (col). However I was admittedly a little thrown when the controller asked us to fly heading 240 and intercept the col 350 radial to col. This is certainly not a strange assignment. In fact it is probably common and expected by regular users of teb airport; which we are not. It was a busy phase of flight and an unexpected assignment; but still should have easily been handled without incident. However; for unexplained reasons; I was not thinking accurately. In my hurriedness to enter the appropriate course into the avionics system; I mistakenly interpreted the reciprocal course for the 350 degree radial as 190 degrees. Once I had the (inaccurate) course entered; the indications showed that we were just flying through the course. I told the pilot flying that we are going through the course now and we need to turn back left to intercept. He began a left turn to intercept the course. During the turn as asked; 'wait; what is the course?' I responded; '190.' he then corrected me; stating that the inbound course would be 170. I entered the current course; 170; and stated that it is in fact still further to our right. As he was turning back to the right to intercept the proper course; the ATC controller advised that we were left of course and assigned us a hard right turn to a heading of 250 to intercept the radial. By this time we were already approaching the correct radial and as we made the turn to heading 250; we quickly intercepted the course. All of this happened in a very short amount of time and resulted in what probably looked like a very sloppy; round turn to intercept a course. But by making a sloppy intercept; we could have very well encroached upon newark's (ewr) airspace. Obviously the route we were given is designed to take us just down the west side of ewr. This is why flying is this airspace requires accurate thinking and reacting. My inaccurate thinking; mistakenly converting the reciprocal of 350 to 190; could have potentially caused a traffic conflict. Fortunately my co-worker was thinking more clearly than I. Although not to try and excuse my dumb mistake; it would seem to me that perhaps on this particular departure there may be a better way to assign this course. When routing RNAV aircraft on an RNAV departure procedure; perhaps it would make more sense to assign a 'course to a fix;' rather than a 'radial to a VOR.' in other words; although the outcome is the same; a 'course to' and a 'radial to' are technically not the same thing. Long range navigation systems do not fly a 'radial' the same way a VOR receiver would. As for myself; I have been flying professionally for over fifteen years; and yet I am still learning with every flight. I will slow down; I will pause; I will think clearly; I will double check my math; and I will confirm course entries with the other pilot just as I would with an altitude entry.

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Original NASA ASRS Text

Title: A Falcon 50 Captain entered an incorrect inbound course to a navaid on the TEB RUUDY 2 departure and as the crew detected his error and began corrections; ATC called with a track deviation alert.

Narrative: We departed TEB on the RUUDY 2 Departure initially flying the published procedure. As always; flying in the Northeast corridor; especially departing from TEB requires careful attention and strict adherence to the procedures. It is a busy environment and requires quick and accurate thinking. Having reviewed the departure procedure I was anticipating a possible vector to Coltsneck VOR (COL). However I was admittedly a little thrown when the Controller asked us to fly heading 240 and intercept the COL 350 radial to COL. This is certainly not a strange assignment. In fact it is probably common and expected by regular users of TEB airport; which we are not. It was a busy phase of flight and an unexpected assignment; but still should have easily been handled without incident. However; for unexplained reasons; I was not thinking accurately. In my hurriedness to enter the appropriate course into the avionics system; I mistakenly interpreted the reciprocal course for the 350 degree radial as 190 degrees. Once I had the (inaccurate) course entered; the indications showed that we were just flying through the course. I told the pilot flying that we are going through the course now and we need to turn back left to intercept. He began a left turn to intercept the course. During the turn as asked; 'Wait; what is the course?' I responded; '190.' He then corrected me; stating that the inbound course would be 170. I entered the current course; 170; and stated that it is in fact still further to our right. As he was turning back to the right to intercept the proper course; the ATC Controller advised that we were left of course and assigned us a hard right turn to a heading of 250 to intercept the radial. By this time we were already approaching the correct radial and as we made the turn to heading 250; we quickly intercepted the course. All of this happened in a very short amount of time and resulted in what probably looked like a very sloppy; round turn to intercept a course. But by making a sloppy intercept; we could have very well encroached upon Newark's (EWR) airspace. Obviously the route we were given is designed to take us just down the west side of EWR. This is why flying is this airspace requires accurate thinking and reacting. My inaccurate thinking; mistakenly converting the reciprocal of 350 to 190; could have potentially caused a traffic conflict. Fortunately my co-worker was thinking more clearly than I. Although not to try and excuse my dumb mistake; it would seem to me that perhaps on this particular departure there may be a better way to assign this course. When routing RNAV aircraft on an RNAV departure procedure; perhaps it would make more sense to assign a 'course to a fix;' rather than a 'radial to a VOR.' In other words; although the outcome is the same; a 'course to' and a 'radial to' are technically not the same thing. Long Range Navigation systems do not fly a 'radial' the same way a VOR receiver would. As for myself; I have been flying professionally for over fifteen years; and yet I am still learning with every flight. I will slow down; I will pause; I will think clearly; I will double check my math; and I will confirm course entries with the other pilot just as I would with an altitude entry.

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.