IFR in Uncontrolled Airspace
Some time ago, we had a little situation that I was reminded of last night. Bathurst, NB (CZBF) is below the base of controlled airspace, which is "above 12,500". This means, for those who don't know, that 12,500 is actually uncontrolled, but anything above that is. An aircraft departed CZBF westbound, with an IFR clearance to "maintain 10,000 in controlled airspace." This means exactly what it says: when you enter controlled airspace, you had better be at 10,000. Before entering controlled airspace, ATC doesn't have the authority to direct your flight, so you may do what you want. This pilot departed and reported climbing to 10,000, and everything seemed normal.
We also had an IFR aircraft cruising at FL230 who began descent into CZBF from the west. With our traffic at 10,000, and therefore in uncontrolled airspace, our obligation is to clear this aircraft out of controlled airspace and inform him of the traffic. Both were on radar, so radar traffic information was passed. As the two closed, the Dash 8 pilot informed us that he didn't have the traffic in sight, and was planning to stop his descent at 11,000 and asked us to inform him when they passed. While the tracks were not exactly opposite (the eastbound Dash 8 would pass about 2NM north of the westbound aircraft), they didn't want to drop below 11,000 anyway. Then, the controller working the two airplanes noticed that the westbound aircraft had taken a turn to the right of about 20°, this making his track coincide nicely with that of the Dash 8 about 10NM ahead. Since the pilot said nothing about climbing above 10,000 and the Dash 8 had already told us he was stopping at 11,000, nothing more was thought at this point. Then, after "putting out a fire" somewhere else in the sector, the controller noticed that the westbound aircraft had climbed through 10,000, still pointing at the Dash 8. The pilot was querried, and he responded that he was "deviating for a buildup,"and had climbed to 11,000. A perfectly legitimate manoeuver, but given that he had been told about the Dash 8's position and intentions, it's awfully interesting that the pilot would choose not to say anything either to the controller or the other pilot. As it turns out, they passed fairly close (not enough to engage TCAS, but enough to excite the Dash 8 pilot and bug the controller) to each other both laterally and vertically.
The pilot of the westbound aircraft was perfectly within his rights to maneouver without approval of ATC, since he was operating within Class G airspace. The choice of maneouver is a question, given that he had been told of the position and intentions of the Dash 8 (who didn't like what he saw). But I'm recommending that a pilot keep someone in the picture when he decides to do something that's not expected of him. His last words indicated he was climbing on course to 10,000, but obviously that had changed. Had he done what he had told us he was doing, they wouldn't have been traffic for one another. Had he told us about his modified plan, this information could have been passed to the Dash 8 (if he didn't hear it directly from the pilot over the radio) and they may have chosen to act accordingly and steer away from him themselves.
We also had an IFR aircraft cruising at FL230 who began descent into CZBF from the west. With our traffic at 10,000, and therefore in uncontrolled airspace, our obligation is to clear this aircraft out of controlled airspace and inform him of the traffic. Both were on radar, so radar traffic information was passed. As the two closed, the Dash 8 pilot informed us that he didn't have the traffic in sight, and was planning to stop his descent at 11,000 and asked us to inform him when they passed. While the tracks were not exactly opposite (the eastbound Dash 8 would pass about 2NM north of the westbound aircraft), they didn't want to drop below 11,000 anyway. Then, the controller working the two airplanes noticed that the westbound aircraft had taken a turn to the right of about 20°, this making his track coincide nicely with that of the Dash 8 about 10NM ahead. Since the pilot said nothing about climbing above 10,000 and the Dash 8 had already told us he was stopping at 11,000, nothing more was thought at this point. Then, after "putting out a fire" somewhere else in the sector, the controller noticed that the westbound aircraft had climbed through 10,000, still pointing at the Dash 8. The pilot was querried, and he responded that he was "deviating for a buildup,"and had climbed to 11,000. A perfectly legitimate manoeuver, but given that he had been told about the Dash 8's position and intentions, it's awfully interesting that the pilot would choose not to say anything either to the controller or the other pilot. As it turns out, they passed fairly close (not enough to engage TCAS, but enough to excite the Dash 8 pilot and bug the controller) to each other both laterally and vertically.
The pilot of the westbound aircraft was perfectly within his rights to maneouver without approval of ATC, since he was operating within Class G airspace. The choice of maneouver is a question, given that he had been told of the position and intentions of the Dash 8 (who didn't like what he saw). But I'm recommending that a pilot keep someone in the picture when he decides to do something that's not expected of him. His last words indicated he was climbing on course to 10,000, but obviously that had changed. Had he done what he had told us he was doing, they wouldn't have been traffic for one another. Had he told us about his modified plan, this information could have been passed to the Dash 8 (if he didn't hear it directly from the pilot over the radio) and they may have chosen to act accordingly and steer away from him themselves.
posted by Michael at
09:05
