Backup Tacan
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Hello Everyone -
Little issue last night, flight of two in hardcore low level strike. Lead gets shot down by a manpad, I get some triple A action and get hit.
Little cockpit tour, engine is doing OK, some fault lights, HUD still working, DED and left MFD dead.
Great, lets get out of here, jettisson the A/G munition, and turn south at low level.
Getting organized to find my way back, I set up my backup UHF radio, and since I don’t have any navigation anymore, try to set my backup TACAN. Good thing is I still have one MFD left, bad this is that the backup TACAN page says “MMC OFF” and I can’t do anything.So my two questions are :
- Is it normal that the backup TACAN page says “MMC OFF” and I cannot set anything ?
- What happens if both MFDs are down ? No backup TACAN of any sort ?
Thank you
Flow.
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So my two questions are :
- Is it normal that the backup TACAN page says “MMC OFF” and I cannot set anything ?
- What happens if both MFDs are down ? No backup TACAN of any sort ?
Thank you
Flow.
Yes and yes. Limitation of the RL backup system.
The true reason is that on aircrafts equipped with MIDS, the TACAN is done with MIDS. But the MIDS LRU only communicate with the MMC and has no connection to analog digits like the old TACAN LRU. EHSI is similar: it was introduced to have numerical interfaces with the MIDS bay, and not the analog signals from the old TACAN LRU.
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Yes and yes. Limitation of the RL backup system.
Thank you for your answer. Sound like a wonky backup system
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Thank you for your answer. Sound like a wonky backup system
See my edited post
It works only for UFC failures, that’s it.
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Yes and yes. Limitation of the RL backup system.
The true reason is that on aircrafts equipped with MIDS, the TACAN is done with MIDS. But the MIDS LRU only communicate with the MMC and has no connection to analog digits like the old TACAN LRU. EHSI is similar: it was introduced to have numerical interfaces with the MIDS bay, and not the analog signals from the old TACAN LRU.
Thats promising to hear!
My aircraft has the MIDS LRU, but most of the MIDS specific functionality is broken. Can I get a new Line Replaceable Unit, please?
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All clear, thank you. Very complicated to find my way back without HSD and without TACAN
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dead reckoning and pilotage remain valid VFR navigation methods… In the weather, it starts getting a bit more interesting.
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All clear, thank you. Very complicated to find my way back without HSD and without TACAN
Chart, Compass, Watch, … Radar may help if working.
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Well visibility was close to zero, so a chart is not super useful in that case
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5km visibility is enough (and 5km is not much). I guess if you have no tacan, and no INS, you dont have much options other than ejection - or some dead reckoning.
Fly towards home plate with the compass, at a known airspeed. Check the watch at intervals to establish rough position. Look for positive fixes from whatever ground objects you can establish. If you know where you are, work from the clock to the map, and the map to the ground. If you are totally lost, work from the ground to the map to fix your position, then work from the clock to the map, and the map to the ground.
If you get to the area where home plate or a divert field is, and you cant find it due weather, your options are holding in the hopes the weather will improve, or diverting elsewhere in the hopes they have better weather. When you get fuel critical, ditch into the sea and eject beforehand. Over land if possible.
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Well visibility was close to zero, so a chart is not super useful in that case
So got to catch one of you win on radar, go in close form on him, send him the RTB order and do your best to stay in close.
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So got to catch one of you win on radar, go in close form on him, send him the RTB order and do your best to stay in close.
I wish I wish, but as I said in the first post, flight of two in a TE, I was the wingman and the lead got shot down.
Anyways, I have my answer Thank you all !
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How about calling AWACs asking for home plate or divert field ?, then if you dont have HUD course information use the magnetic compass
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Yeah it was kinda odd to move backup tacan to mfd page , since, let’s face it, it’s not even close to reality., no backup instrument is on something digital multi-functional., it should rely on its own hw circuitry.
But, doh, I understand , there was nowhere to implement it in bms without messing too much. So bear with this.There is a switch in sim/acdata for backup tacan on mfd or old <4.33 behavior., but it will mess with server MP in that theater, if for SP then you can revert that setting to 0 , then you’ll be able to use backup tacan without mfd, provided that airplane in question has backup tacan controls switches.
Cheers
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Yeah it was kinda odd to move backup tacan to mfd page , since, let’s face it, it’s not even close to reality., no backup instrument is on something digital multi-functional., it should rely on its own hw circuitry.
But, doh, I understand , there was nowhere to implement it in bms without messing too much. So bear with this.Cheers
Do I understand you correctly ? Your saying that the MFD TACAN is something BMS cooked up ?
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Partially, YES, … can’t say 100% , never been in contact with real F16 / F18 MFD , … but it seems like that. It is a hack.
eg, primary tacan is on UFC / DED . BUT! , BACKUP instrument is NEVER on any kind of MFD , which can die in more ways, makes sense ?
So BACKUP controls are always on separate circuitry , and their own minimal hardware …, there’s no sense if they work on primary circuit so if it dies , secondary backup control dies too…
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Partially, YES, … can’t say 100% , never been in contact with real F16 / F18 MFD , … but it seems like that. It is a hack.
eg, primary tacan is on UFC / DED . BUT! , BACKUP instrument is NEVER on any kind of MFD , which can die in more ways, makes sense ?
So BACKUP controls are always on separate circuitry , and their own minimal hardware …, there’s no sense if they work on primary circuit so if it dies , secondary backup control dies too…
So you are guessing.
I on the other hand am 100% sure Backup TACAN control through the MFD is a real thing. -
Well , its your call, I don’t buy it.
You have every right to believe what’s good for you. I, otoh, will patiently wait for confirmation anyway, you know, the proof.
BACKUP Tacan controls on MFD is certainly critical error in systems design , well it is an electrical jet anyway, but with ‘electricity’ gone … there goes your backup too.
So, that certainly sounds as NO backup to me… …or I live in the stone age and the Tacan is a relic that doesn’t deserve respect as before
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Well , its your call, I don’t buy it.
You have every right to believe what’s good for you. I, otoh, will patiently wait for confirmation anyway, you know, the proof.
BACKUP Tacan controls on MFD is certainly critical error in systems design , well it is an electrical jet anyway, but with ‘electricity’ gone … there goes your backup too.
So, that certainly sounds as NO backup to me… …or I live in the stone age and the Tacan is a relic that doesn’t deserve respect as before
Sure…
I just hope you don’t also question that upcoming second confirmation. -
There are no stupid questions , just stupid answers.
Look , F16 in 80’s tacan was … you know where it was… in today’s block’s , there is a possibility that it was moved to where is referred to, but that only means they are 99% sure that it wont fail, or they don’t give a *** if it fails…
Only that I can say with 100% … is that IT WILL FAIL in one way or the another.
BACKUP instruments shouldn’t fail as a result of a secondary, collateral (damage?) process… So if you break your mfd with a fist , or you’ve lost lcd/touch controller(s) with no redundancy , that means that you’ve lost a BACKUP instrument too ?? … Thin ICE.