Over G with F-16 - Avionics and SMS Fault
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Hi All,
I am having an issue which Krause mentioned in a recent video regarding over G causing issues with the F-16’s systems.
I was under the impression with the F16 and even F-18 which I have worked on that when the weapons config was loaded that the flight computer would limiti the G and Flight envelope so damage could not occur. This would adjust as weapons were expended so roll and pitch rates would exand as the aircraft fuel and stores were expended.
I was a weapons loader for 20 years on a number of aircraft and they all seemed to have this feature in the real world.
Is there a reason The aircraft develops these issues if not because of over G.Also I have got avionics Fault soon after takeoff on a couple occasions and I dont know why. I runway started the game so its not something I missed in a Ramp Start. I am just starting to venture into ramp Starts.
AMD FX 8350 4 Gig (Not yet overclocked)
G Force 760
8 Gig Ram -
The F-16 FLCS does not include G protection except the standard 9G limit. The CAT limiter is here to prevent departures, more likely with stores, but G-limit is at the charge of the pilot. The F-18 is more refined and does include some G protection, IIRC… but it is not modeled in BMS mostly because lack of information.
This is where simulation is slightly limited : in the real jet you would feel the G force directly
Some audio feedback is available though : if you turn on the oxygen (panel completely to the right, green switch), then the breathing is modulated with G forces.For your faults, without the fault ID, we cant really help you. Refer to (Install)-> Docs-> Falcon BMS Manuals-> TO-BMS1F-16CM-1.pdf, 3.4.3, to get the list of faults and their signification.
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Your impression is incorrect. The F-16 flight computer limits AoA and roll rate so that the aircraft does not depart from controlled flight. It does this based on a simple two position switch, the STORES CONFIG switch. In CAT I, you get less strict limiters than in CAT III.
Neither CAT I nor CAT III will prevent you from over-Ging the aircraft or stores carried. They can protect you from getting into an out of control situation though. To prevent over G, you need to pay close attention to the force you apply to the stick.
I had heard that the hornet has a more sophisticated stores management system with regards to flight control limiting, but I do not know any details about it. Its possible that what you describe does exist on the F/A-18 - but it does not on the F-16.
EDIT: Sniped by l3!
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If your fault occurs during your last flight, go in the log folder and check the fault log txt file. It list all the aircraft fault during the last flight.
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@Blu3wolf Could you find that info in a NATOPS manual?
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I could look for it in a T.O. but I dont know how likely a Navy manual would be. All my navy manuals relate to training Im afraid, nothing on technical specs or design.
Refer to Figure 1-58. In cruise gains, the AOA/g limiter reduces the positive g available as a function of AOA. The negative g available is a function of airspeed. Below 15 degrees AOA, the maximum positive g available is +9g. As AOA increases, the maximum a,llowable positive g decreases. The positive g limit and maximum AOA depend on the position of the STORES CONFIG switch . In CAT I, positive g decreases to a value of 1g at 25 degrees AOA. Maximum commanded AOA is approximately 25.5 degrees. In CAT III, maximum AOA varies from approximately 16-18 degrees as a function of GW and g. The negative g available above approximately 250 knots is - 3g. Below 250 knots, the available negative g varies between -3g and zero g as a function of airspeed, altitude, and AOA. In takeoff and landing gains, the STORES CONFIG switch has no effect on limiting or gains. Maximum positive g is a function of airspeed and AOA. The negative g command limit is not a function of airspeed. It is a fixed limit. The maximum AOA for 1g is approximately 21 degrees. In inverted or upright departures, the AOA/g limiter will override stick pitch commands if the MPO is not engaged. The MPO can always override the negative g fu nction of the limiter. It can also override the AOA function of the limiter when the AOA exceeds 35 degrees. Refer to MANUAL
PITCH OVERRIDE (MPO) SWITCH, this section.This is taken from page 1-133 of the dash one, under FLCS limiters, specifically AoA/G limiters. The G limiter of the F-16 limits G explicitly to less than 9 positive Gs, and more than 3 negative Gs. It also implicitly limits G further, by imposing an AoA limiter. The purpose of the G limiter is to prevent aircraft damage. The purpose of the AoA limiter is to protect from out of control situations.
Refer to Figure 5-7 this section, and TO IF-16CM-l-2, Figures 5-1 and 5-2 for acceleration limitations. Load factor limits should not be intentionally exceeded. Notify maintenance of a possible over-g if symmetric maneuvering on the g limiter results in a load factor greater than or equal to 9.5g/-3.2g or if symmetric non-g limiter maneuvering or asymmetric maneuvering exceeds a positive or negative g limit specified in this section. Provide details of the occurrence (maximum g indication, airspeed, altitude, description of maneuver, fuel weight and distribution, etc.) and HUD videotape if it is available. NOTE SYM G limits apply to maneuvers resulting
from less than abrupt rol l stick inputs and in which roll rate does not exceed 20 degrees/ second. ROLL G limits apply to maneuvers resulting from abrupt roll stick inputs or maneuvers in which roll rate exceeds 20 degrees/
second. A false maximum g indication may be displayed in the HUD due to INU vibration while the aircraft is at maximum g. G indications above 10 (e.g., 0.2 for I0.2g) have been observed. IDR I Due to the location of the accelerometer, it should not be used to determine maximum g force. For evaluating a possible over-g, determine the allowable CARRIAGE MAX ACCEL G for the actual store configuration at the time of the occurrence. Use of TO I F-16CM-l-2, Figure 5-l , NzW curves (if applicable) is permitted. G’s experienced during a wingtip vortex/wake turbulence encounter should be considered as asymmetrical when determining if a g limit has been exceeded.Also from the dash one, page 5-3. Note that the g limiter is intended to only limit G to less than 9G. Whilst Id like to include Figure 5-2 here for clarification, I am omitting it for space reasons.
I see that NATOPS is specifically training and standards docs anyway, so I am afraid that by definition, I will not be able to find technical details on the F-16 in a NATOPS manual.
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Thanks for the reply - Ill have to be gentle on the stick on titght turns then … I have had the oxygen set on previously so maybe ill do that again - THere is some auto cues with breathing coming on when you pull hard G’s so again take more note of whats going on and the cues supplied …
Thanks again. -
Thanks for the replies guys … -
hanks very much for the reply - Ill try and supply this if I get the fault again. Great Sim - Thanks very much to all the programers for such a fantastic job!
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Your impression is incorrect. The F-16 flight computer limits AoA and roll rate so that the aircraft does not depart from controlled flight. It does this based on a simple two position switch, the STORES CONFIG switch. In CAT I, you get less strict limiters than in CAT III.
Neither CAT I nor CAT III will prevent you from over-Ging the aircraft or stores carried. They can protect you from getting into an out of control situation though. To prevent over G, you need to pay close attention to the force you apply to the stick.
I had heard that the hornet has a more sophisticated stores management system with regards to flight control limiting, but I do not know any details about it. Its possible that what you describe does exist on the F/A-18 - but it does not on the F-16.
EDIT: Sniped by l3!
…the Hornet FCS won’t “save” you from over-G either, but it does do a far more sophisticated job of trying, IMO. I have a feeling the Hornet does a far better job of knowing how much the jet weighs than a Viper does, and it’s control laws are totally different so AOA is less a factor than is in the Viper case. In fact, I’m not sure it factors at all…
