Tim
Do IFR circuits shoot the missed approach (as per RW) and back round to the ILS,
The IFR TNG never touches down on the runway and does not do a true TNG. Only a VFR TNG touches down and then builds speed to takeoff again. The IFR TNG plane always goes missed and is told to contact departure.
That is because in real world TNG is a VFR type practice for Pilots and IFR does not have a actual TNG practice but a instrument approach practice which always must execute the missed approach. FS trys to follow the same rule logic.
What if there's no ILS - would they fly a VOR/NDB/RNAV procedure?
That depends on the weather engine that ATC combines into the approach. If the airport is VMC (thats based on visibility and cloud cover) and no ILS exist then ATC uses what appears to be a vectors to final 30 degree intercept angle to final. This is a hardcode in the .dll which sets the AI plane/user up for a fake looking ILS approach which uses a distance from the threshold (varible 10 to 108 Nmiles) and a 2000 ft AGL at every single airport.
If the airport is IMC and no ILS exist then ATC looks down through the approach code to find some kind of Loc, LDA, SDA, BC, GPS, RNAV, VOR, NDB with or without a DME. ATC uses a pecking order of priority if more then one approach type exist where a ILS is the top priority and NDB with no DME is the least priority.
Or do they just fly the visual pattern but "IFR"?
If the airport is IMC and the FP is IFR ATC will never leave you stranded like it does with VFR flying into a IMC airport. If no approach code exist ATC is going to tell the IFR FP plane to do TNG's with missed approach or land on the active runway regardless. At that point ATC is reverting back to a hard code .dll which is a visual because it exhausted alll means to find some type of approach in the coding.
here are some rules
AI User (when applicable) Plane TNG based on VFR or IFR FP and airport VMC vs IMC
TNG VFR plus airport VMC
1. TNG compiled as VFR and airport is VMC the runway pattern owns the altitude and the pattern turn.
2. There is no interaction with ATC other then Tower and Ground so the runway pattern code controls TNG turn and altitude behavior for all AI planes.
3. The User Plane asking for TNG will be told what way to turn by Tower but altitude is the Pilots resposibilty based on the downwind leg.
4. FS only allows 3 TNG at one time. If you have 4 TNG's the 4th must wait until one of the 3 expire in time. If the first 3 never expire in time the 4th TNG will time out and never depart the stand.
5. 3 tng's is usually too many any way. That is because tower clears them to land abeam the threshold on downwind. You wanting to takeoff from that airport on a FP or do a TNG will sit there forever or until a timing space happens which is not likely as long as 3 are in the pattern.
6. My crosswind runway technique works well for this senerio since TNG's can be on one runway and you/other planes can use another runway based on asking ground for a active runway or in the case of AI using the closest runway center line vs parking spot.
TNG VFR plus airport IMC
1. No VFR flight is allowed to takeoff and fly TNG's or if a user plane is caught on top while doing VMC TNG's it is not allowed to continue the TNG unless they file a IFR FP. That changes everything because now the TNG is in ATC approach control and not TNG Runway control.
2. If a AI Plane executing VFR TNG and caught in a weather change on top it continues as if the weather never changed including wind change.
TNG IFR is much different because in real world it is not a valid practice or approved from a safty standpoint.
TNG IFR plus airport is VMC
1. Runway pattern and altitude is owned by ATC and the compiled FP.
2. The altitude in the compiled FP is honored unlike when VFR VMC TNG is being executed.
Note: these work very well when mountains are around a airport so the pattern altitude is not used but the FP altitude is used.
3. Keep the FP altiude less then 10,000 ft so any plane capible of flying greater then 250 kts IAS stays below that speed.
note: speed and altitude compiled in the FP for IFR TNG in VMC airport conditions is somewhat proportial to distance of downwind leg.
4. TNG on a IFR FP (VMC or IMC) never touches the runway but always goes missed. Tower tells the IFR FP plane to contact departure which decides which way to turn and climb to the missed approach altitude. Only then does ATC now tell the AI plane to climb to the compiled altitude which sets it up for the next missed approach.
Note: again we do not practice IFR TNG's in real world but practive IFR approaches and missed approaches. In real world to save time and we practice IFR approach procedures under the hood then the instructor may very well have you touch the runway (out from under the hood at minimums) and then takeoff again. However if we are practicing approach procedures in real world weather IMC we always execute the missed approach as the correct procedure. Same with AI on a IFR TNG but altitude is FP altitude after missed approach altitude.
5. If ILS exist than ATC uses the approach ILS code for turn to final and FAF altiudes. If no ILS exist ATC uses the fake hardcode that resembels a ILS approach code with a distance to threshold turn to final and a fixed FAF 2000 ft altitude.
Now If we do force a TNG when on IFR and IMC airport conditions most everything is the same as VMC but there is a weather engine element added to ATC.
1. When the AI on a TNG FP or User plane asking for a TNG takes off the Tower tells the plane to contact departure. The control turn and climb to whatever is in the compiled FP is honored and approaved by ATC.
2. If a ILS exist, ATC will instruct the plane to final outside the FAF T_Waypoint (varible downwind distance again based on speed, altitude and seperation if other AI are landing) and descend from the compiled FP altitude to the FAF altitude in the ILS approach code. The airplane will go missed and not execute the actual TNG.
3. If a ILS does not exist then ATC looks for a pecking order of what I call weather related approaches (anything other then a ILS) in the approach code for that runway. If it only finds a VORDME it tells the AI to execute the vectors to final for that approach using the FAF T_waypoint and the FAF altiude as per the VORDME approach code.
4. If no type approach code is written ATC falls back on the hardcode which is actually a visual code and tells the AI plane to execute the TNG which is actually a missed approach until the time expires for a TNG.
confused?
I am
and I wrote this
