IvanK Posted January 27 Posted January 27 (edited) See attached jpg. I am on the selected VOR course but the FD is giving me a fly right indication ?? Edited January 27 by IvanK 1
Zabuzard Posted January 27 Posted January 27 Which exact station and map are you tuned to? Often the VOR/ILS vehicles are placed next to the runway, not exactly on the runway (it is just a tool to get there until you see it visually, not to glide down all the way on the concrete).
Snappy Posted January 27 Posted January 27 (edited) 12 minutes ago, Zabuzard said: Which exact station and map are you tuned to? Often the VOR/ILS vehicles are placed next to the runway, not exactly on the runway (it is just a tool to get there until you see it visually, not to glide down all the way on the concrete). The latter shouldn’t matter though, I mean @IvanK is not complaining that he is not getting guidance straight towards to the runway, in fact he didn’t mention runways or an approach at all. The issue seems to be that the HSI shows he‘s dead-on on the selected radial , with the HSI needle centered, but the FD gives a significant fly-right indication. Edited January 27 by Snappy 1
Zabuzard Posted January 27 Posted January 27 That can have various causes. Could you possibly attach a track or is it not reproducible?
Bremspropeller Posted January 27 Posted January 27 @Bananabrai and myself have seen similar issues flying down the ILS at Akrotiri. Myself in an F1 on Banana's wing (him in the F-4E). He also had a split between the FD and the HSI. The ILS Localizer is usually always (a few exceptions apply, such as e.g. Bergen) exactly down the runway. Since my ILS needle (raw data) was centered, it's not an ILS-sided issue. 1 So ein Feuerball, JUNGE!
AvroLanc Posted January 27 Posted January 27 14 hours ago, IvanK said: See attached jpg. I am on the selected VOR course but the FD is giving me a fly right indication ?? You need to set the command heading to the same radial/course (with the HEADING SET knob). The FD will only give correct commands with a suitable heading set.
Snappy Posted January 27 Posted January 27 (edited) 2 hours ago, AvroLanc said: You need to set the command heading to the same radial/course (with the HEADING SET knob). The FD will only give correct commands with a suitable heading set. Not how I interpret the manual. What you wrote applies if you put the inner FD knob (of the mode selector knob) to HDG. With both the mode selector knob and the inner FD knob set to VOR/ILS I would expect guidance onto the selected radial or ILS localiser course, unless of you are outside of reception range of the tuned ground station, which would be an exception. Edited January 27 by Snappy 1
AvroLanc Posted January 27 Posted January 27 1 hour ago, Snappy said: Not how I interpret the manual. What you wrote applies if you put the inner FD knob (of the mode selector knob) to HDG. With both the mode selector knob and the inner FD knob set to VOR/ILS I would expect guidance onto the selected radial or ILS localiser course, unless of you are outside of reception range of the tuned ground station, which would be an exception. Yep, you can get bank steering guidance on the ADI to the selected radial, but you also must use the HEADING SET knob to set the command course. Direct quote from HB manual: “The HSI Heading Set knob is used to set a desired TACAN course for bank steering presentation on the ADI. As the bank steering is based on the heading marker position, if it is not set properly, bank steering on the ADI will not be correct to intercept the desired course” Go try it. It works.
IvanK Posted January 27 Author Posted January 27 (edited) The image was Taken about 20-30nm inbound to a TACAN. I have seen an F4 DCS tutorial that talks about the Flight Director using both the selected course and and the selected Heading to derive a "blended" fly to command. This might explain what I am seeing in the picture. However I don't see any reference to this "blended" operation in any of the publicly available F4 manuals or USAF Instrument flying manuals. In addition I have not seen this sort of blended behavior in any real world Flight director use. It is my understanding that once the course is selected the FD will then generate an internal command to intercept the selected radial at a programmed intercept angle (typically 30 degrees) until getting close then the FD eases of the intercept angle to achieve a smooth progressive intercept. The F4E flight manual actually says in the intercept case the HSI heading marker must be set to the same value as the selected course. (TO 1F-4E-1 Fig 1-19 Page 1-49) So off to test with HSI heading set to the same value as the selected course. Edited January 27 by IvanK
IvanK Posted January 27 Author Posted January 27 Tested with setting the HSI bug to the same value as the selected course ... then works just fine.
Snappy Posted January 27 Posted January 27 3 hours ago, AvroLanc said: Yep, you can get bank steering guidance on the ADI to the selected radial, but you also must use the HEADING SET knob to set the command course. Direct quote from HB manual: “The HSI Heading Set knob is used to set a desired TACAN course for bank steering presentation on the ADI. As the bank steering is based on the heading marker position, if it is not set properly, bank steering on the ADI will not be correct to intercept the desired course” Go try it. It works. Interesting, learned something new then today. Thank you for the manual reference too!
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