I have been using flight simulator for many years and love msfs. But several things I still don’t understand about aviation.
So question number 1. Why are some ILS offset? I know some reasons eg San Franci/sco having 2 ILS, one being offset to allow dual approaches. Others it might be to avoid an I have been using flight simulator for many years and love msfs. But several things I still don’t understand about aviation.
So question number 1. Why are some ILS offset? I know some reasons eg San Francisco having 2 ILS, one being offset to allow dual approaches. Others it might be to avoid an obstruction!
But others seem to have no explanation - and several actually have a RNAV approach which is straight in on the rwy course.
So, can some one enlighten me please
Richard
Sorry about the confused message but I have tried editing it with no success!!
I hope the question can be understood
I believe some are just off/incorrect. PAED in Anchorage is one of them. It’s lined up to the right of the runway. I’m no pro, but I just chalk it up to the sim not being 100% accurate.
A couple of possibilities: limitations of where the ground equipment can be placed on the airport, and an offset that’s needed for the approach course to clear terrain.
Also some addon free airports are slightly out. EGAC I downloaded is great but off compared to the msfs default
Here are some “Coles Notes” explanations. The subjects can be quite involved!
An offset approach is used for several reasons.
One is for a simultaneous approach, that type maintains separation between aircraft on parallel runways.
A second is terrain avoidance, whether that be buildings, hills, or even just populous areas.
An RNav approach is often used in runways that do not have an ILS, but it can be conducted on those that do as well.
It uses a plane’s own positioning system to determine that plane’s altitude, alignment and distance from a runway and acts similar to an ILS, guiding the plane in laterally and vertically to the runway.
I think a couple of caveats here. The plane must have the requisite AP/GPS equipment installed to do an RNAV approach I think, not RWP here, and I do not do RNAV as a rule, preferring ILS approaches.
However, years ago, in FS-98, and FS2002, and FSX, I have done many ILS approaches into KSFO with 747 and no issues. I have most likely 10,000 hours in all three of those
In MSFS, because of several limiting issues (one being the ATC/AP/NAV) system in the game being WIP (work in progress) I have NOT been successful here. Since the 787/747 and others need (if equipped) the FMS to work in harmony with the AP system, I have been unsuccessful in attempting and executing many of them. ATC routinely fails to descend my flight soon enough, and I struggle to get plane low enough to even catch glide slope for landing, if the FMS/AP system even sees it. FSX and XP-11 both operate fine, with FSX being about 20 years old and XP-11 also having some gray hair.
This game for me has been frustrating and several times I have removed it swearing never to return, alas, my favorite fighter is here, the DC Designs F-14 (pay ware-my entry into USN was one month after F-14 was introduced into Fleet Air)- and it’s a real kick in the pants to fly around. It will be even better, when TACAN is implemented into game, as some navigation process might be easier. I have not been XP user for long, only 6 months or so, but on first 737 flight (same evening as install was completed) was able to successfully setup and complete the ILS approach for Boeing Field. So, it’s not really me, as it’s MSFS not working properly.
NOTE: Recently, public statements have been made, saying this is really a VFR game, because of the scenery and excellent graphics in it. SO, now I understand that the IFR and ILS Systems are on the second tier to get implemented and setup correctly, so I am spending more time in XP because those systems work, and the planes I fly operate in it like they should. MSFS does work, but not in an established and predictable way for IFR/ILS flight preparation. I do not know when or even if, that level of flight operations will ever be implemented in this game. It is NOT a professional sim experience as it stands now. It’s a cash cow for Asobo and Microsoft because everyone wants to see their house from the air. I do not give a rat’s backside, about seeing my house, I want to implement professional and well-established flight preparation and execution. This may not be the place for that to happen for a while. This is still just a game.
Just wanted to share that I use the Navigraph data (with the full description of charts) and ever since I had no issues with nav data in the sim anymore.
We can of course have a long debate about how one would just expect MSFS to incorporate these things properly themselves but if you’re serious about it and don’t mind spending a little extra on a lot of extra nav features, this could be something for you too.
Here is a link to a place I get my ILS charts. Is any of them different than you get on with Navigraph? I am curious.
LTS - Altus AFB Airport | SkyVector
Scroll to bottom of the page, and select any chart, please compare it to one you get and tell me it is different.
There is no difference usually, companies like Jeppesen, NavBlue, Lido etc. use those exact charts to produce their charts. Shouldn’t be any difference. Only thing which is sometimes different in Europe is that non-precision approaches are published as non-CDFA, Jeppesen, Navblue etc. usually make these approaches into CDFA. Not sure about FAA.
I’m not sure what this would help though? This would be even more dangerous since two aircraft are now converging towards each other instead of flying parallel to each other, in the end, over the threshold they will be same distance from each other they would have been in the first place. Also when going around, one of the two aircraft will be crossing the other extended centerline or runway. There are a lot of techniques and procedures to keep aircraft on “dependent” parallel approaches separated, making an ILS offset is not one of those to my knowledge.
This must be something FAA, I have never seen or heard about this. Seems like a lot of effort with visual segment maneuvering and what not. Would be easier just to make a visual approach 
.
I know at KLAS there is one ILS serving two parallel runways. You have to excecute a sidestep onto the the runway not aligned with the ILS. But yes…converging! I’d rather have an RNAV with LPV!
Some ILSs are offset for reasons of terrain clearance. (LOWI).
Some are offset because of airport infrastructure limitations. This is the case with the offset runway 22R approach at KJFK. There is no room past the threshold at the opposite end of the runway (the 04L end) to construct a localizer antenna on the centerline. They would have had to build it the water of Jamaica bay, and that is a protected wildlife refuge.
Some airports have two independent ILS systems for certain runways - one offset and one not. Runway 04L/22R at Detroit is an example. The ILZ-Z approaches are not offset and the ILS-Y approaches are offset 2 degrees. The offset localizers are used only when they are conducting simultaneous parallel approaches to the adjacent runways 04R/22L in IFR conditions. (The runway separation is less that 3000 feet).
The most extreme offsets in the USA are the two LDA approaches to runway 19 at KDCA, which are offset 40 degrees. These are localizers only (no glideslope). The offset is to keep arriving aircraft over the Potomac river and out of the prohibited airspace over the US Capitol and White House. These approaches have high minimums because aircraft have to make a last minute right turn (visually) to align with the runway
This topic was automatically closed 30 days after the last reply. New replies are no longer allowed.