Joni Posted August 6, 2017 Posted August 6, 2017 As per the manual: Operational Modes The HSI has four operational modes: INS/VOR Navigation (NAV), TACAN/VOR Navigation (TAC), TACAN Offset Point/VOR Navigation (VAD) and Ground Controlled Interception (TEL). NAV (main INS/VOR navigation mode): In this mode, the HSI connects with the INS and displays waypoint navigation information along with bearing to selected VOR/ILS station. This is the only mode that allows to select between true or magnetic headings, through its two sub modes: Right now, if the airport where Im landing is not a waypoint and has no TACAN or VOR then there is no way to get DME anywhere; nor in the HUD or the HSI. The thin needle should point to the ILS station and provide DME as all ILS do but all it does is stay there and do nothing. The thin needle flag if off so it should work. Intel Core i5-8600k + Cooler Master Hyper 212 EVO | Gigabyte GTX 1070 Aorus 8G | 32GB DDR4 Corsair Vengance LPX Black 3200MHz | Gigabyte Z370 Aorus Gaming 3 | WD Black SN750 NVMe 500GB | Samsung 850 EVO 250GB | WD Green 240GB | WD Caviar Black 1TB SATA 3 | WD Caviar Blue 500GB SATA 3 | EVGA 650 GQ 80+ Gold | Samsung CF391 Curved 32" | Corsair 400C | Steelseries Arctis 5 --- Razer Kraken X Lite | Logitech G305 | Redragon Dyaus 2 K509 | Xbox 360 | Saitek X-52 Pro | Thrustmaster TWCS | TrackIR 5
jojo Posted August 6, 2017 Posted August 6, 2017 As per the manual: Operational Modes The HSI has four operational modes: INS/VOR Navigation (NAV), TACAN/VOR Navigation (TAC), TACAN Offset Point/VOR Navigation (VAD) and Ground Controlled Interception (TEL). NAV (main INS/VOR navigation mode): In this mode, the HSI connects with the INS and displays waypoint navigation information along with bearing to selected VOR/ILS station. This is the only mode that allows to select between true or magnetic headings, through its two sub modes: Right now, if the airport where Im landing is not a waypoint and has no TACAN or VOR then there is no way to get DME anywhere; nor in the HUD or the HSI. The thin needle should point to the ILS station and provide DME as all ILS do but all it does is stay there and do nothing. The thin needle flag if off so it should work. I will try to replicate and check DME. But on ILS you only have deviation needles on ADI, the thin needle doesn't point to the localizer. Mirage fanatic ! I7-7700K/ MSI RTX3080/ RAM 64 Go/ SSD / TM Hornet stick-Virpil WarBRD + Virpil CM3 Throttle + MFG Crosswind + Reverb G2. Flickr gallery: https://www.flickr.com/gp/71068385@N02/728Hbi
Frederf Posted August 6, 2017 Posted August 6, 2017 1. The basic ILS installation does not provide DME services and DME services are not a requirement for a precision approach. The purpose of OM/MM/IM is to gauge provide distance information. There is a very distinct class of instrument approach called "ILS-DME" which is a luxury upgrade over the procedure possible with only the standard installation. The same runway will have a different published "ILS" and "ILS-DME" procedure for when DME is/is-not available. 2. I've never heard of any bearing needle in any airplane system ever which provides direct bearing to LLZ or GS emitters. In cases where simple bearing instrumentation exists it is always to an accompanying NDB/VOR/TACAN beacon instead and not to the ILS system itself. If there is a combined VOR-LOC-GS facility then yes the thin needle will give bearing to the VOR portion of that facility if the VOR radio nav equipment is tuned to it. If there is no VOR service then it won't. The LLZ will not substitute. Basically in the Mirage if you have a VOR tuned you'll get thin needle bearing to station. Fat needle will be to INS destination as will distance readout. ADI will show LLZ and GS signals. If the particular published approach requires DME reception then it the airplane does not meet the requirements and cannot execute that approach.
Joni Posted August 6, 2017 Author Posted August 6, 2017 And Ive never seen an ILS without DME. I have been flying for 13 years and never seen a single one. And I live in a 3rd world country! They are just not constructed without it, its embebed. As for the needle pointing to the ILS, no, it does not exist, it was my mistake. Intel Core i5-8600k + Cooler Master Hyper 212 EVO | Gigabyte GTX 1070 Aorus 8G | 32GB DDR4 Corsair Vengance LPX Black 3200MHz | Gigabyte Z370 Aorus Gaming 3 | WD Black SN750 NVMe 500GB | Samsung 850 EVO 250GB | WD Green 240GB | WD Caviar Black 1TB SATA 3 | WD Caviar Blue 500GB SATA 3 | EVGA 650 GQ 80+ Gold | Samsung CF391 Curved 32" | Corsair 400C | Steelseries Arctis 5 --- Razer Kraken X Lite | Logitech G305 | Redragon Dyaus 2 K509 | Xbox 360 | Saitek X-52 Pro | Thrustmaster TWCS | TrackIR 5
Frederf Posted August 6, 2017 Posted August 6, 2017 Common or uncommon ILS does not spec DME as a strict requirement. In any case for Mirage to receive and display DME distance it must be tuned/mode to the TACAN channel to which that DME frequency is paired. For example if VOR-DME station is 111.7 MHz then TACAN must be tuned to 54X channel such that its DME will show when TACAN HSI mode is selected (although no bearing information will function as the station is not a TACAN). The actual DME frequency in use being 1078 & 1015MHz. The Mirage has no mode to display a DME frequency set paired with the entered VOR frequency. It should be considered a VOR-ILS receiver and not a VOR-DME-ILS transceiver. Theoretically ILS LOC frequencies have paired GS and DME in channelization. The airplane might have been designed to change to paired DME HSI readout based on VOR reception (replacing the INS distance). But since the HSI has only effectively INS or TACAN modes of operation any change to VOR-DME readout would be hazardously confusing.
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