CE560XL flight crew departing GJT is cleared direct JNC V8 TRUEL which requires a 180 degree course reversal at JNC. The FMC accomplishes this reversal well before reaching JNC prompting a query from the Controller.
Synopsis
CE560XL flight crew departing GJT is cleared direct JNC V8 TRUEL which requires a 180 degree course reversal at JNC. The FMC accomplishes this reversal well before reaching JNC prompting a query from the Controller.
Narrative
We departed Runway 29 on a 270 heading; our clearance was JNC V8 TRUEL. Departure cleared us direct JNC on course. We were on the inbound radial to the VOR requiring a 180 degree turn to go on course. I had the VOR on my side. The Pilot Flying was using the FMS. When the FMS commanded a left turn I noticed we were still a couple miles from the VOR. I figured with the altitude and the turn we would be pretty close to the VOR. About half way through the turn the Controller said; 'I see your turning.' I said; 'we had been to the VOR and were heading outbound.' She didn't say anything else; but from the way she said it; it made me think she thought we were to fly past the VOR before turning.This is an unusual situation. Many times I have been given a clearance direct to a fix or VOR and then on course; sometimes requiring a 30 or 40 degree change. In theses cases we do not fly over or past the fix; but turn to intercept the course outbound. I may be making more of this than is needed; but when a 180 change is needed I'm not sure of the correct answer.
Second reporter narrative
Departed GJT as pilot flying. Clearance was ROCKIE7 departure (vector); left turn heading 270; V8 TRUEL. After we were airborne and switched to Denver Departure; the Controller gave us this clearance; 'Cleared direct JNC intercept V8 on course.' I was flying in FMS with NAV captured and auto-pilot on; going direct to JNC. We were already on V8 airway going the wrong direction toward JNC. The FMS led the turn and we started our turn somewhere between 4-5 miles from JNC. I didn't think much of it because the departure didn't depict JNC as a flyover point. We were well clear of terrain; climbing through 14;500' going to 16000'. We were 180 degrees out from the desired course. This seemed to be a normal lead turn. It wasn't until the Controller said; 'it appears you turned prior to JNC;' that I thought she wanted us to fly over the VOR and then proceed on course. There was nothing else said from the Controller about our early turn and we continued to track on course. We were already intercepting the airway outbound from JNC when ATC contacted us. This is why we didn't turn back around to cross the VOR or take any 'corrective action.'Today; we were given the same clearance and departure. We departed from Runway 11 this time. It sounded like the same Controller. I'm not sure though. This time she gave us a normal heading and clearance to intercept V8 outbound from JNC (without going to JNC first) as we were climbing through 14;000' going 16;000'. The obvious answer to avoid this is to clarify the clearance. But; when you think you're doing the right thing with the info provided; it's kind of hard to question the Controller. You always have to monitor the auto-pilot. JNC is not a flyover point on this departure or in the FMS. We can easily make it a flyover point; if that is required. The trick is knowing if it is a flyover point to the Controller. The clearance was to go direct to JNC; which is fine; if we were going west after JNC. I've never come across the situation of having to intercept a radial you are already on and reverse direction 180 degrees that isn't clearly written on the departure. The departures in and around mountainous airports can be very tricky to navigate. If a VOR is a flyover point; it is usually depicted in the graphic and text areas. This departure was a vector departure. With only the navaids on the chart. There is very little text description about reaching a certain altitude before turning on course or crossing a VOR first.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.