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conflicting definition of circling approach???

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Take this MHTG (Toncontin) chart for reference:http://www.costaricaaviation.com/charts/mh...RDME_RWY_01.PDFI have a question about this specific approach, but first, let me ask this:I have seen the definition of a circling approach as any approach with a circle put into the pattern.Yet elsewhere I have seen it defined as any approach where you set up for one runway, and then once you are down to decision height and have a visual of the field, you are to circle and land, maintaining visual with the field the whole time, on a different runway.Which definition is correct?RhettAMD 3700+ (@2310 mhz), eVGA 7800GT 256 (Guru3D 93.71), ASUS A8N-E, PC Power 510 SLI, 2 GB Corsair XMS 2.5-3-3-8 (1T), WD 250 gig 7200 rpm SATA2, CoolerMaster Praetorian case

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The second definition you have is more correct. Without going into too much detail because my brain is running on fumes now, it provides you an option where you can go to another runway as long as you can use normal safe operating maneuvers and that you have the airport insight visually all the time. There are other reasons for the circle minimums, more then 30 degrees off of the approach end of the runway, doesn't cross the end of the runway and the approach descent angle is too steep. There are other rules in the TERPS for setting up an airport instrument approach but someone might be able to better explain that then me because I need to go to bed now!

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as cessna said the second one is the traditional definition.in this case it is simply terrain that is dictating that a straight into runway 1 is not allowed in the TERPS guidance, so they give you the option of circling.circling also entails a distance from the airfield by aircraft category. if memory serves me correct it is.A - 1.3nmB - 1.5nmC - 1.7nmD - 2.1nmE - 4.0nm (not authorized for this approach)this is the distance that you have terrain clearance at the defined circling altitude. this is what they mean in the second caution note.

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>as cessna said the second one is the traditional definition.>>in this case it is simply terrain that is dictating that a>straight into runway 1 is not allowed in the TERPS guidance,>so they give you the option of circling.>Ok, so my second question about the above chart is,the minimums listed for the Circling approach are 5620-2. I take that to mean 5620 feet ASL and 2 miles visibility for civilian aircraft.Does that mean you are supposed to be at 5620 ASL on final, 1.7 nm from the runway end? (looking at the vertical height guide). RhettAMD 3700+ (@2310 mhz), eVGA 7800GT 256 (Guru3D 93.71), ASUS A8N-E, PC Power 510 SLI, 2 GB Corsair XMS 2.5-3-3-8 (1T), WD 250 gig 7200 rpm SATA2, CoolerMaster Praetorian case

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>Ok, so my second question about the above chart is,>the minimums listed for the Circling approach are 5620-2. I>take that to mean 5620 feet ASL and 2 miles visibility for>civilian aircraft.the minimums are simply 2sm of FLIGHT visibility at the decision height (which in this case is 5,620'). on a foggy day an airport could be reporting 1sm in BR for a runway with an ILS, but you could have 2-3sm of FLIGHT visibility.>Does that mean you are supposed to be at 5620 ASL on final,>1.7 nm from the runway end? (looking at the vertical height>guide). yes you are correct. you circle at or above the DA (decision altitude). once you leave this altitude you are implicitly doing a visual approach from that point forward. if at any time visual contact with the runway is lost during a circle a missed approach must be initiated. you are then starting the missed approach procedure, but you will always first turn towards the runway.the AIM 5-4-20(f) states:"...Pilots should remain at or above the circling altitude until the aircraft is continuously in a position from which a descent to a landing on the intended runway can be made at a normal rate of descent using normal maneuvers. Circling may require maneuvers at low altitude, at low airspeed, and in marginal weather conditions. Pilots must use sound judgment, have an indepth knowledge of their capabilities, and fully understand the aircraft performance to determine the exact circling maneuver since weather, unique airport design, and the aircraft position, altitude, and airspeed must all be considered..."some airlines do not allow circling approaches.fyi i checkedcat D is 2.3nmE is 4.5nmalso note that even though only circling mins are published, you can still land straight in. this is why they have the note about steep descent rate if you see the runway at the MAP on the approach. the circle simply is a tool for them to increase the minimums. the AIM states 5-4-20©:"c. Straight-in Minimums are shown on the IAP when the final approach course is within 30 degrees of the runway alignment (15 degrees for GPS IAPs) and a normal descent can be made from the IFR altitude shown on the IAP to the runway surface. When either the normal rate of descent or the runway alignment factor of 30 degrees (15 degrees for GPS IAPs) is exceeded, a straight-in minimum is not published and a circling minimum applies. The fact that a straight-in minimum is not published does not preclude pilots from landing straight-in if they have the active runway in sight and have sufficient time to make a normal approach for landing. Under such conditions and when ATC has cleared them for landing on that runway, pilots are not expected to circle even though only circling minimums are published. If they desire to circle, they should advise ATC."hope this helps

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>>yes you are correct. you circle at or above the DA (decision>altitude). So you could circle ANYWHERE in the descent, as long as you did it before 1.7 nm to runway, and notified ATC?Do you mean that the chart says that a pilot could, if desired, circle at THAT (1.7 nm from runway end, at 5620 ASL) point? Referring back to the approach plate, I thought the circle was done at 7nm from runway end...no closer to the runway.Why does the chart show a circle done at 7nm out? I thought that was the circle. I didn't realize the circle was supposed to be done at the decision height. Is that correct?How would a big jet like a 757 be able to make such a tight circle so close to the threshold?>>also note that even though only circling mins are published,>you can still land straight in. this is why they have the note>about steep descent rate if you see the runway at the MAP on>the approach. the circle simply is a tool for them to increase>the minimums. the AIM states 5-4-20©:>Going straight-in from 5620 ASL and 1.7 nm out from MHTG would indeed be a very steep descent rate.RhettAMD 3700+ (@2310 mhz), eVGA 7800GT 256 (Guru3D 93.71), ASUS A8N-E, PC Power 510 SLI, 2 GB Corsair XMS 2.5-3-3-8 (1T), WD 250 gig 7200 rpm SATA2, CoolerMaster Praetorian case

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>So you could circle ANYWHERE in the descent, as long as you>did it before 1.7 nm to runway, and notified ATC?>>Do you mean that the chart says that a pilot could, if>desired, circle at THAT (1.7 nm from runway end, at 5620 ASL)>point? i think you are a little confused. the Missed Approch Point is the VOR/DME which would be :) ) or 0nm if using a GPS overlay on this. this BY COINCIDENCE is 1.7nm from the runway, so the MAP is where the circle should begin for a category c aircraft, cat d would be earlier since you ONLY have 2.5nm of protection from the runways edge, so that would be at 0.8 DME (1.7 + 0.8 = 2.5nm). remember that the numbers i gave before are circling MAXIMUM distances, so yes you circle at 1.7nm (or whatever the maximum distance if its a different category a/c) or less if you desire. typically we will pick the runway as a FIX in the FMS and put a 2nm circle around it to show us approx where this point is.the IAF is in all likeliohood the VOR as i doubt radar vectors are that good in honduras. the FAF (the maltese cross) is 7DME once you are established inbound at the appropriate altitude (8,000'MSL in this case).ATC or the tower will tell me whether i am circling or not. in a non radar environment then i will tell them and make the mandatory radio reports (procedure turn outbound, inbound, etc). typically they will tell you what direction to circle also if it is not mandated by the procedure. generally a standard traffic pattern (left trafic pattern) would prevail if no such special mention is made and you are operating in a nonradar environment.if this was night and i had to land here and i am at 18,000'MSL this is how i would fly the approach if cleared (assuming a category c a/c)i would proceed to TNT and enter the hold as shown. once established in the hold i would descend to 9,000' MSL. at 9,000' MSL i would exit the hold on the 198 radial outbound and descend to 8,000' MSL. at 7 DME i will perform a valid procedure turn (see below) and become established inbound on the 198 radial while not exceeding 10 DME (but if i think i would go past 10 DME i would use an appropriate MSA altitude and stay at 9,000' until back within 10 DME). once established inbound and i am at 7 DME, i will initiate a descent to 6,700' MSL and start a timer. at 5 DME i will descend to the DA which is 5,620', but really fly it at 5,700' as the altitude alerter is only in units of hundreds. once the airport is in sight and at the MAP i would start my circle by entering a left downwind and maintaining a visual with the airport. abeam the runway start my descent and turn base within 1.7nm (cat c) and land on runway 19. if at any point on the downwind i lose visual contact i initiate a climbing left turn, probably a heading of 330, towards the runway and join the 008. at 6500' MSL or 6.5 DME, probably a little less than 6.5 DME as it says to stay within 6.5 DME, i would make a left turn back towards the VOR and climb to 9,000' and enter the hold.no doubt this is a pretty demanding approach during the day and very difficult at night.>Referring back to the approach plate, I thought the circle was>done at 7nm from runway end...no closer to the runway.>>Why does the chart show a circle done at 7nm out? I thought>that was the circle. I didn't realize the circle was supposed>to be done at the decision height. Is that correct?yes it is done at or above the decision ALTITUDE (sorry to be nitpicky but i think you do want to use the correct terminology as the decision height is an above ground altitude - 2,326' in this case) which is 5,620' MSL here. some companies will round this number up to 5,700' since the altitude alerters generally do not have tens of feet in them.i do not see a 7nm circle on the plate. the 7 DME is the point at which the procedure turn on the outbound leg is made at 8,000'. it is also the point at which you can descend down to 6,700' MSL once you are established inbound on the 198 radial. the circle at 10nm is to show you to remain within 10 DME of the VOR on the procedure turn (i think, as i have not used NOAA plates in awhile).one thing i do not expect a simulator pilot to know is you do not have to fly the procedure turn as depicted. the standard procedure turn left of the final approach course shows where the terrain protection from 7DME to 10DME is. thus since we only have 3nm to do a procedure turn i would do a 90/270 or 80/260 turn to keep me as close as possible to 7DME (i realize this is beyond the scope of this but i think you would like the insight). if the procedure turn is drawn as a teardrop or other nonstandard shape then you must fly it as depicted, but in this case at 7DME on a 198 heading (assuming no wind), a right turn to a 288 hdg for 1 minute followed by a 270 degree turn to the left to rejoin the 198 radial inbound on a 018 heading (a 90/270 turn) would be perfectly acceptable.>How would a big jet like a 757 be able to make such a tight>circle so close to the threshold?yes the 757 is quite the manueverable beast that it is, but the pax definitely won't like it. this is why airlines generally do not allow circling approaches or mandate the CA perform it. as far as 1.7nm out, that again depends on the category of the aircraft. kris, is the 757 a c or d a/c?>Going straight-in from 5620 ASL and 1.7 nm out from MHTG would>indeed be a very steep descent rate.yes way too steep, hence the warning. using a standard rule of thumb for a Visual Descent Point (VDP which gives you a rough 3deg glide slope) the height agl is roughly 2400' which divided by 3 gives me 8 NM. So my VDP would be (8-1.7) 6.3 DME from the VOR, which is even past the final descent point and pretty much at the FAF. no wonder they mandate this as a circling approach! :-)hope this helps.

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Thank you and cessna for the info here on this strange (to me anyway) approach...>if this was night and i had to land here and i am at>18,000'MSL this is how i would fly the approach if cleared>(assuming a category c a/c)>This airport doesn't allow this approach at night, at least that's what I am told.>at the MAP i would start my circle by entering a left downwind>and maintaining a visual with the airport. abeam the runway>start my descent and turn base within 1.7nm (cat c) and land>on runway 19. But what if the winds were out of the north? What gets me is, that it appears that pilots landing at Runway 01, are doing left-hand turns in the Southwest quadrant of the approach area. That means they are doing turns where they initally lose sight of the airfield (inbound on 18 radial, they hit the DA, and do a left-hand turn), which is a no-no for a circling approach! This confuses me.Do you think they are losing visual?Due to AVSIM's odd rules I won't link directly to a video, but if you google the term, "toncontin approach" you will see a link to YouTube, which has several videos of this approach...the one I'm referring to is "757-200 at Toncontin" and it shows the 757 doing left-hand turns to final.>>no doubt this is a pretty demanding approach during the day>and very difficult at night.>Yes it is in the sim, too! I have seen some comment on this approach on the 'net, and apparently, they don't do this approach at night. In fact the airport is closed after 9 or 10 pm, until 6 am.>i do not see a 7nm circle on the plate. the 7 DME is the point>at which the procedure turn on the outbound leg is made at>8,000'. Oh, I was mistaking the procedure turn for the circle. You see, I didn't realize the circle was not depicted on the plate. I guess it never is??>one thing i do not expect a simulator pilot to know is you do>not have to fly the procedure turn as depicted. Thanks for that info, I will keep it in mind especially here.>yes way too steep, hence the warning. using a standard rule of>thumb for a Visual Descent Point (VDP which gives you a rough>3deg glide slope) the height agl is roughly 2400' which>divided by 3 gives me 8 NM. So my VDP would be (8-1.7) 6.3 DME>from the VOR, which is even past the final descent point and>pretty much at the FAF. no wonder they mandate this as a>circling approach! :-)I think the VASI boxes are angled at 5 degrees (5.3 now that I look at the chart, and only for Cat A and b aircraft) at MHTG, which is a lot more angle than the 3-3.3 deg they typically are. I have not decompiled the .bgl file to check on this yet.You see, I am thinking about writing this approach into FS, if that's possible, so that the AI will use it. Presently the AI do a straight-in and they contact the ground. :(Your info, especially how you would fly it, is most helpful. I do wonder how you would do a Rwy 01 with a circle... and you CAN'T circle in the southeast quadrant...too much terrain...RhettAMD 3700+ (@2310 mhz), eVGA 7800GT 256 (Guru3D 93.71), ASUS A8N-E, PC Power 510 SLI, 2 GB Corsair XMS 2.5-3-3-8 (1T), WD 250 gig 7200 rpm SATA2, CoolerMaster Praetorian case

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>This airport doesn't allow this approach at night, at least>that's what I am told.It says that for USAF operations but I don't see any other comment limiting time of usage. It might be in their airport directory though.>But what if the winds were out of the north? >>What gets me is, that it appears that pilots landing at Runway>01, are doing left-hand turns in the Southwest quadrant of the>approach area. That means they are doing turns where they>initally lose sight of the airfield (inbound on 18 radial,>they hit the DA, and do a left-hand turn), which is a no-no>for a circling approach! This confuses me.>Do you think they are losing visual?If the winds are out of the north they would just fly straight in after flying past the VOR like it says on the plate.>Oh, I was mistaking the procedure turn for the circle. You>see, I didn't realize the circle was not depicted on the>plate. I guess it never is??No Circle-to-land doesn't mean you have to do any turns to land. What you would do is fly the approach to the MAP and when you get the runway in sight then you would enter the pattern and then land.>I think the VASI boxes are angled at 5 degrees (5.3 now that I>look at the chart, and only for Cat A and b aircraft) at MHTG,>which is a lot more angle than the 3-3.3 deg they typically>are. I have not decompiled the .bgl file to check on this>yet.That is because it is a PAPI not a VASI. The slower aircraft guys will usually fly the higher descent angle which would be one red three white. The faster aircraft would fly the visual with two red and two white usually which might be 3.3 degrees.>Your info, especially how you would fly it, is most helpful. >I do wonder how you would do a Rwy 01 with a circle... and you>CAN'T circle in the southeast quadrant...too much terrain...You would fly to the west of the airport and make a right hand pattern.

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>If the winds are out of the north they would just fly straight>in after flying past the VOR like it says on the plate.>I know straight-in can be done, as I have done it in the sim. But I don't know if that is really done by the big jets in the real world...read on...Look at this link, where they say: "An airplane landing at runway 01 at TGU must circle inside the basin below the mountaintops."http://www.brianbaute.com/archives/2005/05...rt_honduras.phpIf what that site says is true, they are not simply flying straight-in approaches to Rwy 01. They are circling for it also.I have never seen any indication that any mainline jet-size aircraft is doing a straight-in there. Do you think that is possible that they are all circling w/left-hand pattern into Runway 01? Or is that bogus information?RhettAMD 3700+ (@2310 mhz), eVGA 7800GT 256 (Guru3D 93.71), ASUS A8N-E, PC Power 510 SLI, 2 GB Corsair XMS 2.5-3-3-8 (1T), WD 250 gig 7200 rpm SATA2, CoolerMaster Praetorian case

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>>>Your info, especially how you would fly it, is most helpful.>>>I do wonder how you would do a Rwy 01 with a circle... and>you>>CAN'T circle in the southeast quadrant...too much terrain...>>You would fly to the west of the airport and make a right hand>pattern. You mean left hand pattern.If you were to land 19, then you would dog over to the left (west) from the MAP and make a right hand pattern.To fly this approach to rwy 01, once you cross the MAP, proceed directly towards the airport visually, begin descending out of the MDA as well, and as you fly overhead, begin a left turn. Work the turn so that you don't overshoot the final and end up east of the centerline, and work your descent so that you can cross the threshold at a proper height.To fly this approach to rwy 19, once you cross the MAP, make a small left hand turn to put yourself west of the airport, begin descending out of the MDA as well, and when you are spaced out adequately to the west, but still within the confines of the circling area, make a normal, tight right hand traffic pattern to 19.

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>To fly this approach to rwy 01, once you cross the MAP,>proceed directly towards the airport visually, begin>descending out of the MDA as well, and as you fly overhead,>begin a left turn. Work the turn so that you don't overshoot>the final and end up east of the centerline, and work your>descent so that you can cross the threshold at a proper>height.Why would you turn left? Is everyone thinking the missed instructions dashed line is part of the approach segments?>To fly this approach to rwy 19, once you cross the MAP, make a>small left hand turn to put yourself west of the airport,>begin descending out of the MDA as well, and when you are>spaced out adequately to the west, but still within the>confines of the circling area, make a normal, tight right hand>traffic pattern to 19.That is normal but what is the left turn you are describing in the fist paragraph?

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>>Why would you turn left? Is everyone thinking the missed>instructions dashed line is part of the approach segments?>No, it is so that you can get down. The minimums on this approach is a MDA of 5620'msl and 2sm visibility for Cat A/B and 5620'msl and 3sm visibility for Cat C/D. That means you are 2326' above the touchdown zone elevation when you see it through the fog at 2 or 3 miles away. I would like to see you get even a C152 down onto that touchdown zone in a qualifying stabilized manner from 2300' up on a 2 mile final. Let alone a jet. Certainly if you see it from miles away on a clear blue sunny day, you might be able to make a straight in approach to the runway, maybe even without snagging any branches or people's laundry with your main gear. You are certainly free to try it as a straight-in, but I have a feeling you'll be breaking other rules regarding stabilized approaches and low flying over terrain or people.>>That is normal but what is the left turn you are describing in>the fist paragraph?So that you can fly a left traffic pattern to Rwy 01. You can't fly a right pattern to Rwy 01. The chart note prohibits that.

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I am a little sorry. I missed this on the approach plate.*Circling not authorized E of Rwy 01-19.With that said, I would fly a right hand traffic pattern if circling which would be to the W of the airport. Sorry for the confusion.This is why TWO people review these plates and discuss.FYI to me it looks like not terrain thats limiting it to the E but a security area (MHP1). There is another one SE of the airport (MHP4). Again, I am assuming MHP is a security or restricted area. Since this is the Honduran capital i think it is a safe assumption.This approach would be a wonderful interviewing approach plate. It appears to have a little of everything in it.I'll still take the river visual to 19 into DCA as my favorite approach. Some of the GPS ones that are coming out look neat with the curved segments, etc into airports like Palm Springs....http://map.aeroplanner.com/plates/FaaPlate...00545RRY13R.PDF

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I tired it in the F28 and it wasn't too bad. I wish I could have fraps record more then 30 seconds though.

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