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#1
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"Jim Cummiskey" wrote in message
... Actually, no. If you think about it, if you approach the numbers at a ~30 deg angle, and a "proper" downwind to base turn is made at a ~45 deg angle, there will be no conflict whatsover. How do you figure that? Firstly, the "45 degree key point" taught students for where to turn base is just a rule of thumb...base turns are made much earlier and much later than that, depending on factors other than just following a rote procedure. Secondly, the flight path of an airplane flying 90 degrees to the runway heading on base intersects the flight path of an airplane flying 30 degrees to the runway heading, heading straight for the numbers. Since the flight paths intersect, there certainly IS a potential for a conflict. I'd agree that the odds of there being a conflict on the downwind leg (rather than the base leg) are low (though not nonexistent since extended downwinds are a common enough procedure, especially at towered airports), but to say that "there will be no conflict whatsoever" is hugely and inappropriately optimistic. Pete |
#2
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Hi,
Recently, Peter Duniho posted: "Jim Cummiskey" wrote in message ... Actually, no. If you think about it, if you approach the numbers at a ~30 deg angle, and a "proper" downwind to base turn is made at a ~45 deg angle, there will be no conflict whatsover. How do you figure that? Firstly, the "45 degree key point" taught students for where to turn base is just a rule of thumb...base turns are made much earlier and much later than that, depending on factors other than just following a rote procedure. Secondly, the flight path of an airplane flying 90 degrees to the runway heading on base intersects the flight path of an airplane flying 30 degrees to the runway heading, heading straight for the numbers. Since the flight paths intersect, there certainly IS a potential for a conflict. This thoery is correct, AFAICT. However, in practice that should get the controller issuing such a clearance fired. I don't *ever* want to be on a straight-in 5 mile final if other traffic is going to wind up on some random variant of base at the same time. That said, There are many times at controlled airports (and even more at uncontrolled airports) when there are aircraft on base and final (and everywhere else) at the same time. The controllers call out those positions and issue a clearance if the other traffic is in sight. I've also had controllers call my base turn during heavy traffic. IOW, the controller's job is to insure spacing. As Jim hasn't mentioned whether there was other traffic inbound or in the pattern, I'd think that would be an important factor in whether he was right or wrong to be off-center. If there was no traffic, there'd be no conflict and the controller was just being manipulative. If there was traffic, and the controller didn't call it out, that might be grounds for complaint. After all is said and done, the FARs make it quite clear who the PIC is, and one requirement is that they're in the cockpit. Neil |
#3
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"Neil Gould" wrote in message link.net... IOW, the controller's job is to insure spacing. As Jim hasn't mentioned whether there was other traffic inbound or in the pattern, I'd think that would be an important factor in whether he was right or wrong to be off-center. If there was no traffic, there'd be no conflict and the controller was just being manipulative. If there was traffic, and the controller didn't call it out, that might be grounds for complaint. After all is said and done, the FARs make it quite clear who the PIC is, and one requirement is that they're in the cockpit. He's wrong whether or not there was other traffic. He did not follow the controller's instruction. |
#4
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#5
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I would interpret her clearance to mean I should report
5 miles out on the extended runway center line. There could be traffic issues that caused her to request you follow this path to the runway. "Jim Cummiskey" wrote in message ... Hi, all. Ran into this one flying back from KOSH a couple weeks ago: I check in with the KPRC controller "20 Miles NE" of Love Field in Prescott, AZ. She clears me with "Cleared Straight-in Runway 21L, Report 5 miles final." I fly directly towards the numbers. My heading was approximately 240 (hence, I'm ~30 deg off of the extended centerline). At 5 miles from the airport (still offset from the centerline), I report "5 mile final." She questions my position and gets all snippy (indeed, darn right rude) that I am "not on final" since I am not on the extended centerline. She patronizingly cautions me to be "careful about this." Hence, the question is "What does 'Cleared Straight-in; Report X miles Final" really mean?" Is it. . . . (1) You must fly directly from your current position to a point on the extended centerline that is X miles from the numbers, and then report (sounds like a base to me). or (2) You can fly directly from your current position to the numbers (thus "straight-in"), and report when you are X miles away. I obviously vote for #2, but the controller clearly thought otherwise (it seems to me that if 30 deg = "straight-in" in the IFR domain, it ought to work well enough for VFR situations). Regardless, it is potentially dangerous when controllers and pilots define things differently. Which definition is right? Regards, Jim |
#6
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She said cleared "straight in" for runway 21L. That (to me) is to come in
on the final approach path, i.e. extended runway centerline. I think tower controllers always give you a position to enter the airport traffic pattern. They either give you a downwind, base or "straight in" (i.e. final). In your situation I think I would have adjusted course to intercept the final approach fix or the runway centerline 5 miles out which ever was greater. Further, it might have been a concern of hers that from your position 240 degrees coming in to 21L you would cross the final approach path of 21R on short final. If she assumed you'd be on the extended center line of 21L she might have cleared someone on 21R at the same time making a dangerous situation. Kobra (no expert) "Jim Cummiskey" wrote in message ... Hi, all. Ran into this one flying back from KOSH a couple weeks ago: I check in with the KPRC controller "20 Miles NE" of Love Field in Prescott, AZ. She clears me with "Cleared Straight-in Runway 21L, Report 5 miles final." I fly directly towards the numbers. My heading was approximately 240 (hence, I'm ~30 deg off of the extended centerline). At 5 miles from the airport (still offset from the centerline), I report "5 mile final." She questions my position and gets all snippy (indeed, darn right rude) that I am "not on final" since I am not on the extended centerline. She patronizingly cautions me to be "careful about this." Hence, the question is "What does 'Cleared Straight-in; Report X miles Final" really mean?" Is it. . . . (1) You must fly directly from your current position to a point on the extended centerline that is X miles from the numbers, and then report (sounds like a base to me). or (2) You can fly directly from your current position to the numbers (thus "straight-in"), and report when you are X miles away. I obviously vote for #2, but the controller clearly thought otherwise (it seems to me that if 30 deg = "straight-in" in the IFR domain, it ought to work well enough for VFR situations). Regardless, it is potentially dangerous when controllers and pilots define things differently. Which definition is right? Regards, Jim |
#7
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#8
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Jim Cummiskey wrote:
Actually, no. Actually, yes. If you think about it ... What makes you think I haven't? ... if you approach the numbers at a ~30 deg angle, and a "proper" downwind to base turn is made at a ~45 deg angle, there will be no conflict whatsover. When you reach the point in your training where you start flying at towered airports, you'll discover that there's no such thing as a "proper" pattern. Downwind and base legs (as well as upwind and crosswind legs) are extended and shortened for a wide variety of reasons, to allow planes in and out of the airport effectively. Especially when the airport is busy. You'll also discover that there are larger, faster airplanes - some even with jet engines - that fly larger patterns, and that can affect (and can be affected by) traffic farther away from the airport. You may have already discovered this flying around the pattern at your home airport. If not, you may want to discuss this with your instructor before he lets you solo. Regardless, a plane flying "to the numbers" from 30 degrees off the downwind side will cross every possible base leg to that runway. It will also cross every possible downwind leg at some point. For example, a plane on downwind set up for a 1/2 mile base leg could collide with the inbound plane 0.866 miles downwind from the numbers. On the other hand, if that inbound plane were to set up for a 5 mile final, there would be no possible conflict for any pattern configuration inside those 5 miles. That's a great reason for a tower controller to ask for it. |
#9
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"Brien K. Meehan" wrote in message ... Regardless, a plane flying "to the numbers" from 30 degrees off the downwind side will cross every possible base leg to that runway. It will also cross every possible downwind leg at some point. For example, a plane on downwind set up for a 1/2 mile base leg could collide with the inbound plane 0.866 miles downwind from the numbers. On the other hand, if that inbound plane were to set up for a 5 mile final, there would be no possible conflict for any pattern configuration inside those 5 miles. That's a great reason for a tower controller to ask for it. It's a good reason if she has or anticipates other traffic. |
#10
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"Brien K. Meehan" wrote in message ... Regardless, a plane flying "to the numbers" from 30 degrees off the downwind side will cross every possible base leg to that runway. It will also cross every possible downwind leg at some point. For example, a plane on downwind set up for a 1/2 mile base leg could collide with the inbound plane 0.866 miles downwind from the numbers. On the other hand, if that inbound plane were to set up for a 5 mile final, there would be no possible conflict for any pattern configuration inside those 5 miles. That's a great reason for a tower controller to ask for it. It's a good reason if she has or anticipates other traffic. Ity's probably time for the OP'er to say he now sees he may have been in error. The good thing about posting the quesiton is that it also may have made some readers more aware of what ATC instructions mean. As an aside, a long tiome ago I was making an ILS into BED after dark, and tower asked me for a landing light so they could see where I was (this was a long time ago). Now that was a time when I did not comply with tower -- a landing light in the clouds is a good way to really screw up night vision. I told them the landing light would have to wait until I had the runway in sight. |
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