Aviation In Canada

Monday, March 28, 2005

Clearance Limit Interpretation Issue

Last summer, I had an encounter with a pilot and his interpretation of a clearance that lad to more questions than answers. Here's the setup:

Inbound to Moncton from Toronto, the aircraft was vectored off course for traffic, about 150NM from CYQM. When past the traffic, he was given the clearance, "cleared direct Moncton." When he came over to my frequency upon starting descent, I noticed he wasn't on the track I expected of him. When querried, the pilot said he was going directly to CASID, the IF for runway 06. I asked who gave him that clearance, and his response was, "Well, sir, we were cleared 'direct Moncton' and from our point of view it's all the same." I was expecting him to fly direct to the Moncton VOR. Even if his interpretation is right, and he is allowed to go to one of the fixes, I believe he still stretched it since ruwnay 11 was advertised as active on the ATIS.

So, now we get to the point of this post. What does "cleared direct Moncton" mean? The Moncton VOR? The Moncton NDB? The Moncton airport as a geographical location? I was taught in my ATC training days the clearance limit issued as the airport (which is often the case when an aircraft leaves the FIR in which the flight begins) meant to the enroute navigation facility serving the airport. Making this the VOR, in this case. But this was always ambiguous to me, in that there are airways based on the Moncton NDB, too, and it is of a stronger power output than the average locator beacon associated only with an approach which could mean the NDB could be considered an enroute facility. What about an airport without a VOR? The NDB? And if no NDB, either?

So I asked a few pilots I know. What I learned in this surprised me. There seemed no divide between age or experience. There seemed no difference related to recreational, airline or other IFR flying (like charter flying or MEDEVAC, for example). The divide had no obvious basis but its own existence. About half of the pilots thought very strongly it meant a facility as I suggested above, and the other half believed it meant the airport as a location. To clarify the two points, if headed from CYYZ to CYYR, the pilot were cleared "direct Goose Bay", one group would not hesitate to enter YYR (the Goose Bay VOR) into the FMS, and the other group would argue they should put in CYYR (the Goose Bay Airport). Oddly enough, nobody mentioned the YR NDB or the UYR TACAN (mind you, there were no military pilots that would have reason to fly to a TACAN in the group I mentioned it to).

Looking it up in the AIP Canada, I found nothing to support either side. I still haven't found it written anywhere. It's my belief that it wasn't written since pre-RNAV days, nobody could navigate directly to an airport -- it had to be some kind of ground based NAVAID. So let's have it. Comments, please, on what you feel is right. And why, if you can back it up. I'm still expecting you to use an enroute facility. Should I be? What would you do? Maybe the rules need to be updated.