Post by Tom/CalClassic on Aug 9, 2008 0:08:44 GMT -5
21 General / General Discussion / Re: Airport Approach Jul 23rd, 2008, 8:26am
Started by DavidM | Post by Tom Gibson
Hi,
A reply from FSAviator:
This post is aimed at those with no aircrew experience, but who have studied the 2008 Propliner Tutorial, and who are now ready to attempt realistic classic era propliner approaches to complex airfields. As others have explained KMDW was a major commercial airfield that had at least two ILS by 1955. In the absence of radar vectors each LOC was usually intercepted by flying down a Radio Range course to the LOC. The interception points (intersections) would have been about (or exactly) where they are now.
If we download e.g.;
naco.faa.gov/d-tpp/0807/00081ILD13C.PDF
we can treat each 'modern' VOR = Omni Range as a Radio Range and the current LOC interception radials FROM the modern VORs as nothing more than the old Range courses FROM the original Range adjusted for modern MAGVAR, because in many cases that is literally true. The LOC interception points such as the intersection HEBKU are geographically over the same place/building as in 1955 even though the magnetic track to get there from anywhere else in 2008 is different from 1955 due to MAGVAR.
Remember if we use old plates we will fly down the old mag track to the wrong place with the wrong offset and wrong bearing from KMDW. We need the current plates with the current MAG tracks for current MAGVAR to turn over the correct places towards the correct places down the current (not 1955) MAG bearing between those same places.
Actually we need 2002 MAGVAR in FS9 but 2008 MAGVAR is close enough when 1955 MAGVAR may be way out.
So after DPA (just like the current real procedure) we track 085 (the Dupage Range old East course), or after ORD we track 188 (the old ORD Range south course). We will have been holding at either (Omni/Radio) Range descending from airways to establish those LOC interception tracks at 2600 QNH in both cases. In any fast piston propliner we will normally have reduced our profile drag to 140 KIAS (deploying FLAP 1 if necessary) before beginning the approach from the hold so that we can use AP. APC may impose this on us to maintain approach spacing anyway.
We maintain 2600 QNH until we intercept the LOC. Then we descend at about 700 VSI to maintain 2000 QNH and simultaneously turn to track 135 down the LOC course to RWY 13C(entral). On intercepting the glideslope at 2000 QNH we begin descent to our personal minima, but never lower than the FAA minima specified on the plate. Late in the approach, after we have broken out below cloud, and have confirmed visual with 13C we will be told when (and if) to adjust our approach to land on 13L or 13R as required by TWR at that time.
If we never see the runways due to our personal minima, and the variable cloud base and visibility, as showers pass through the approach, we must now note that the missed approach procedure then cites headings to intercept the EON Range old North course (001 radial). After locating the EON Range old North course we track 181 to EON southbound on the North course. In the missed approach we climb to and maintain 2100 QNH.
Now we must use the bearing selector (OBS knob) on VOR1 = RANGE 2 to turn that trainable loop aerial to a bearing of 120=300 and watch the VOR1 needle for passage through the CGT Range old West course which runs along that bearing. After crossing the old CGT Range West course we may and must climb back to 2600 QNH. We enter the EON hold. Now we await re-clearance to the DPA hold for another attempt, (if the problem was showers) or we may decide to seek a diversion clearance (if the problem was fog / very low cloud).
Once upon a time there may have been NDBs where there are now only intersections such as HEBKU. We don't need them. When approaching major commercial airfields with ILS approaches, (and no older type of approach available in 2008 ), we simply tune VOR2 to the 'Range' and VOR1 = ILS to the LOC (in this case I-MDW). Once we are on the LOC we retune VOR 2 to the Range we will need for the missed approach (now) in case we go missed. In this case that is EON and we need to use the VOR 2 bearing selector to train the loop 001=181. If we go missed we will then have plenty of time to tune the CGT Range on VOR 1 (currently being used for ILS) and point its loop 120=300 with its bearing selector.
When tuning the Ranges in FS9 we will be using the modern VHF frequency of the modern Omni Range (usually) at the old Radio Range location. It really makes little difference whether we dial some VHF numbers or some HF numbers. The modern VOR has 360 radials not four, but we will be using only the modern radials that were (usually) the original four Range courses to the original (correctly offset) LOC intercept locations. Those Omni Range radials which are the old Radio Range courses are on the current plate.
The current procedures at KMDW (mostly) do not support the era before ILS approaches, but at such major locations procedural ILS approaches probably go all the way back to the 1940s and we can fly the relevant classic era procedural approaches that applied before all approaches to KMDW were radar vectored.
Notice that all the information above is on the current FAA plate at the cited URL. I have just explained how those with no aircrew experience should use it within MSFS. The real approach is valid during total radar failure at KMDW in 2008. At least one needs to be. Most real approaches to KMDW in 2008 require radar vectors, or radar monitoring, and that includes the only surviving VOR approach. For that reason we cannot use an RMI with a local VOR to simulate a 'realistic' RDF approach from before the ILS era.
KMDW is unusual, (among major commercial airfields), in still having a visual approach for use by aircraft of all sizes which does allow us to simulate vintage or even pioneer era propliner approaches from the south west. *In MSFS only* ignore the requirement for radar positioning to the visual approach. Simply follow Interstate 55 towards the airfield, keeping the line feature close on your left (as always), maintaining 3000 QNH. Then follow the procedures within;
naco.faa.gov/d-tpp/0807/00081I-55_VIS13C.PDF
With sufficient study of the relevant ILS plates for the other runways, and the 'worked example' above, it should be possible to plan and fly procedural approaches to 31 or 04 at KMDW from the applicable Final Approach Fixes (FAF). QFU 22 has no procedural approaches. However nothing prevents circling to land on (joining the visual circuit for) the other runways from these 'worked example' QFU 13 approaches if the wind direction dictates.
The same applies to other major and complicated locations, all around the world, but all such locations require more experience and effort to interpret the plates than the simpler locations used for propliner training within the Propliner Tutorial.
All current plates for the USA are always at;
naco.faa.gov/index.asp?xml=naco/online/d_tpp
and can be searched by state, or city, or ICAO flight plan codes, and it is easy to link to them individually in a forum post. Just copy the URL into the post as above.
For other nations see
www.calclassic.com/propliner_tutorial_charts.htm
FSAviator
Started by DavidM | Post by Tom Gibson
Hi,
A reply from FSAviator:
This post is aimed at those with no aircrew experience, but who have studied the 2008 Propliner Tutorial, and who are now ready to attempt realistic classic era propliner approaches to complex airfields. As others have explained KMDW was a major commercial airfield that had at least two ILS by 1955. In the absence of radar vectors each LOC was usually intercepted by flying down a Radio Range course to the LOC. The interception points (intersections) would have been about (or exactly) where they are now.
If we download e.g.;
naco.faa.gov/d-tpp/0807/00081ILD13C.PDF
we can treat each 'modern' VOR = Omni Range as a Radio Range and the current LOC interception radials FROM the modern VORs as nothing more than the old Range courses FROM the original Range adjusted for modern MAGVAR, because in many cases that is literally true. The LOC interception points such as the intersection HEBKU are geographically over the same place/building as in 1955 even though the magnetic track to get there from anywhere else in 2008 is different from 1955 due to MAGVAR.
Remember if we use old plates we will fly down the old mag track to the wrong place with the wrong offset and wrong bearing from KMDW. We need the current plates with the current MAG tracks for current MAGVAR to turn over the correct places towards the correct places down the current (not 1955) MAG bearing between those same places.
Actually we need 2002 MAGVAR in FS9 but 2008 MAGVAR is close enough when 1955 MAGVAR may be way out.
So after DPA (just like the current real procedure) we track 085 (the Dupage Range old East course), or after ORD we track 188 (the old ORD Range south course). We will have been holding at either (Omni/Radio) Range descending from airways to establish those LOC interception tracks at 2600 QNH in both cases. In any fast piston propliner we will normally have reduced our profile drag to 140 KIAS (deploying FLAP 1 if necessary) before beginning the approach from the hold so that we can use AP. APC may impose this on us to maintain approach spacing anyway.
We maintain 2600 QNH until we intercept the LOC. Then we descend at about 700 VSI to maintain 2000 QNH and simultaneously turn to track 135 down the LOC course to RWY 13C(entral). On intercepting the glideslope at 2000 QNH we begin descent to our personal minima, but never lower than the FAA minima specified on the plate. Late in the approach, after we have broken out below cloud, and have confirmed visual with 13C we will be told when (and if) to adjust our approach to land on 13L or 13R as required by TWR at that time.
If we never see the runways due to our personal minima, and the variable cloud base and visibility, as showers pass through the approach, we must now note that the missed approach procedure then cites headings to intercept the EON Range old North course (001 radial). After locating the EON Range old North course we track 181 to EON southbound on the North course. In the missed approach we climb to and maintain 2100 QNH.
Now we must use the bearing selector (OBS knob) on VOR1 = RANGE 2 to turn that trainable loop aerial to a bearing of 120=300 and watch the VOR1 needle for passage through the CGT Range old West course which runs along that bearing. After crossing the old CGT Range West course we may and must climb back to 2600 QNH. We enter the EON hold. Now we await re-clearance to the DPA hold for another attempt, (if the problem was showers) or we may decide to seek a diversion clearance (if the problem was fog / very low cloud).
Once upon a time there may have been NDBs where there are now only intersections such as HEBKU. We don't need them. When approaching major commercial airfields with ILS approaches, (and no older type of approach available in 2008 ), we simply tune VOR2 to the 'Range' and VOR1 = ILS to the LOC (in this case I-MDW). Once we are on the LOC we retune VOR 2 to the Range we will need for the missed approach (now) in case we go missed. In this case that is EON and we need to use the VOR 2 bearing selector to train the loop 001=181. If we go missed we will then have plenty of time to tune the CGT Range on VOR 1 (currently being used for ILS) and point its loop 120=300 with its bearing selector.
When tuning the Ranges in FS9 we will be using the modern VHF frequency of the modern Omni Range (usually) at the old Radio Range location. It really makes little difference whether we dial some VHF numbers or some HF numbers. The modern VOR has 360 radials not four, but we will be using only the modern radials that were (usually) the original four Range courses to the original (correctly offset) LOC intercept locations. Those Omni Range radials which are the old Radio Range courses are on the current plate.
The current procedures at KMDW (mostly) do not support the era before ILS approaches, but at such major locations procedural ILS approaches probably go all the way back to the 1940s and we can fly the relevant classic era procedural approaches that applied before all approaches to KMDW were radar vectored.
Notice that all the information above is on the current FAA plate at the cited URL. I have just explained how those with no aircrew experience should use it within MSFS. The real approach is valid during total radar failure at KMDW in 2008. At least one needs to be. Most real approaches to KMDW in 2008 require radar vectors, or radar monitoring, and that includes the only surviving VOR approach. For that reason we cannot use an RMI with a local VOR to simulate a 'realistic' RDF approach from before the ILS era.
KMDW is unusual, (among major commercial airfields), in still having a visual approach for use by aircraft of all sizes which does allow us to simulate vintage or even pioneer era propliner approaches from the south west. *In MSFS only* ignore the requirement for radar positioning to the visual approach. Simply follow Interstate 55 towards the airfield, keeping the line feature close on your left (as always), maintaining 3000 QNH. Then follow the procedures within;
naco.faa.gov/d-tpp/0807/00081I-55_VIS13C.PDF
With sufficient study of the relevant ILS plates for the other runways, and the 'worked example' above, it should be possible to plan and fly procedural approaches to 31 or 04 at KMDW from the applicable Final Approach Fixes (FAF). QFU 22 has no procedural approaches. However nothing prevents circling to land on (joining the visual circuit for) the other runways from these 'worked example' QFU 13 approaches if the wind direction dictates.
The same applies to other major and complicated locations, all around the world, but all such locations require more experience and effort to interpret the plates than the simpler locations used for propliner training within the Propliner Tutorial.
All current plates for the USA are always at;
naco.faa.gov/index.asp?xml=naco/online/d_tpp
and can be searched by state, or city, or ICAO flight plan codes, and it is easy to link to them individually in a forum post. Just copy the URL into the post as above.
For other nations see
www.calclassic.com/propliner_tutorial_charts.htm
FSAviator