INS aligment
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The f-16 has a provision to set true heading while in flight. I guess it’s for heading drift correction or if normal startup alignment fails and pilot needs takeoff in a hurry.
The pilot uses backup magnetic compass and hsi compass rose calibration nob (left of hsi). INS must be attitude mode. Then hud will display the new true heading.
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The f-16 has a provision to set true heading while in flight. I guess it’s for heading drift correction or if normal startup alignment fails and pilot needs takeoff in a hurry.
The pilot uses backup magnetic compass and hsi compass rose calibration nob (left of hsi). INS must be attitude mode. Then hud will display the new true heading.
Something like that is an absolute last resort and is only going to provode basic pitch, roll, and yaw information but all steering information is gone. You would never use ATT mode for drift correction as an in flight alignment (if done correctly) will give you a much better setup than ATT mode.
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Something like that is an absolute last resort and is only going to provode basic pitch, roll, and yaw information but all steering information is gone. You would never use ATT mode for drift correction as an in flight alignment (if done correctly) will give you a much better setup than ATT mode.
I was just talking about heading drift. Position drift is corrected by gps. Attitude drift is nulled by gyro and accelerometers using normal acceleration for refferance. Wouldn’t hurt a thing imo.
I think you can go back to ins normal mode after correcting heading.
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The f-16 has a provision to set true heading while in flight. I guess it’s for heading drift correction or if normal startup alignment fails and pilot needs takeoff in a hurry.
The pilot uses backup magnetic compass and hsi compass rose calibration nob (left of hsi). INS must be attitude mode. Then hud will display the new true heading.
Think that option isn’t in EGI equipped jets anymore.
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Think that option isn’t in EGI equipped jets anymore.
Then the hsi would not be standalone device. …right?
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…didn’t think it was? I thought the EGI equipped jets had the EHSI? Doesnt that link with the MNF?
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EGI jets have en EHSI like the one in the BMS MLU as far as I’m aware of.
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JDAM also gets its accuracy from not being a GPS weapon but an INS weapon with GPS filtered updates. There is software to predict the best satellite conditions over a particular target if you want to schedule the optimized RAIN conditions. I haven’t seen JDAM accuracy quoted at better than 13m CEP with exception of additional optical or radar sensors. A 3m standard JDAM impact is a bit on the lucky side.
Light travels about 30cm in 1ns which is pretty tight timing for most devices (1 GHz).
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I was just talking about heading drift. Position drift is corrected by gps. Attitude drift is nulled by gyro and accelerometers using normal acceleration for refferance. Wouldn’t hurt a thing imo.
I think you can go back to ins normal mode after correcting heading.
Once again the ONLY reason you would ever want to put the INS in ATT mode is for a complete failure of the INS system so you could get back basic pitch, roll, and yaw signals. No you do not go from ATT mode back to NAV. The only reason you are adjusting the HSI to match the whiskey compass at that point is because the INS is so far gone it has no idea which way it is pointed.
If, for whatever reason, some pilot was that desperate to get airborne that he took an aircraft without an INS alignment up he will go for an in flight alignment if the INS is still good. If the INS is bad he can go ATT mode and have P, R, & Y inofrmation but no steering and a rough idea for a heading based on the input from the whiskey compass.
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Then the hsi would not be standalone device. …right?
The HSI never was a stand alone device. It is driven from signals from the INS.
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Once again the ONLY reason you would ever want to put the INS in ATT mode is for a complete failure of the INS system so you could get back basic pitch, roll, and yaw signals. No you do not go from ATT mode back to NAV. The only reason you are adjusting the HSI to match the whiskey compass at that point is because the INS is so far gone it has no idea which way it is pointed.
If, for whatever reason, some pilot was that desperate to get airborne that he took an aircraft without an INS alignment up he will go for an in flight alignment if the INS is still good. If the INS is bad he can go ATT mode and have P, R, & Y inofrmation but no steering and a rough idea for a heading based on the input from the whiskey compass.
FLCS has its own gyros and accellerometers. All ATT mode does is turn off INS for position navigation, only gps is used. INS still drives ADI, HSI etc. I would believe ATT is used if a faulty INS is degrading position data. In this case there is a backup ADI if needed. I guess you don’t get a hsi.
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FLCS has its own gyros and accellerometers.
I know that. What I don’t know is why you are bringing that up as it has nothing to do with the INS.
All ATT mode does is turn off INS for position navigation, only gps is used.
That right there is a fundamental misunderstanding of how GPS is used in the F-16. NO you cannot put the INS into ATT mode and still have position navigation data for use in the aircraft. You will lose ALL steering information and you will lose heading information in the HUD and only have a rough heading from data entered from the whiskey compass on the HSI if you go into INS ATT mode.
INS still drives ADI, HSI etc.
Correct.
I would believe ATT is used if a faulty INS is degrading position data. In this case there is a backup ADI if needed. I guess you don’t get a hsi.
That belief is only half way there. If you are talking about an INS that is drifting too much and your GPS is good then you use an in flight INS align (automatic mode) to bring it back to where it should be. You DO NOT use INS ATT mode unless you basically have a completely failed INS.
I don’t know how to spell this out any clearer. INS fix taking or in flight align manual mode is used to update INS present position when GPS is not tracking or is tracking low accuracy. If you have GPS high accuracy you want to use the in flight alignment automatic mode for the best correction of the INS while airborne. Even for heading errors like you mentioned initially. INS ATT mode is ONLY for a last resort to get you the most basic flight data.
INS in ATT mode will give ADI indications.
Even the HSI will work but only after you have inputted the rough magnetic heading from the whiskey compass. You still won’t have any steering or DME indications just a rough heading.
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NO you cannot put the INS into ATT mode and still have position navigation data for use in the aircraft. You will lose ALL steering information and you will lose heading information in the HUD and only have a rough heading from data entered from the whiskey compass on the HSI if you go into INS ATT mode.
I would have see this in ink. I believe that heading could be lost. However, NAV data is saved somewhere else. HSD, STPT and NAV carrett should fuction with just gps in ATT mode.
As for INS failure, if a gyro fails it’s just about total failure. However, if an accelerometer fails the INS should be able to do attitude data and heading data.
ATT mode is not spiket that limits the flow of INS info to fix a broken INS.
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I would have see this in ink. I believe that heading could be lost. However, NAV data is saved somewhere else. HSD, STPT and NAV carrett should fuction with just gps in ATT mode.
I have it in ink on my CDCs that the USAF issued to me as an avionics maintenance technician. I am not going to go uploading those to straighten you out on this or any other question here though. You will not have any steering data with a dead INS or even with a perfectly serviceable INS that was placed into ATT mode. All of those things you assume you will have with only GPS are wrong.
If you happen to have or see the legit 34-1-1 that is floating out there page 1-153 first paragraph refutes all you state to be true above.
ATT mode is not spiket that limits the flow of INS info to fix a broken INS.
Not even a clue what you are attempting to say there.