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[WIP]FCS BIT problem


duesensegler

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When trying to shut down and restart the Hornet, I noticed that I could Brick the FCS.

 

I go into one of the ready on the ramp mission, no matter what map, and shut down the Hornet according to the Natops manual (Page 340-350) which you can find at this link.

 

 

 

 

I then restart the Hornet according to the Natops manual(Page 321-325). When on step 6 (Page 325) the flaps are raised from the FULL position to the AUTO position you can already see on the FCS DDI page, that the left leading edge flap doesn´t raise up from its 12° down position, but rather stays there while the right one goes up to the 0° position. If I then initiate the flight controls system check by pressing the FCS RESET and the FCS paddle switch at the same time, already only one side of the surfaces are

moving. By then initiating the FCS BIT, like adviced in the NATOPS manual, the plane seems to get stuck in the FCS BIT and none of the surfaces react any more, neither to stick and rudder inputs, nor to flap switch commands.

I know most players are probably not gone encounter this BUG, but it might be a symptom of a bigger FCS issue.

Logs.zip

F-18 FCS BUG.trk

System.zip


Edited by BIGNEWY
1.16
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I have a few questions regarding the checklist steps you mentioned, and will try to replicate the issue.

 

Pg. 324

5. FCS RESET button - PUSH

If the wings are folded, verify aileron Xs are present.

 

Pg. 325

6. FLAP switch - AUTO

 

7. FCS RESET button and paddle switch - ACTUATE SIMULTANEOUSLY (what is the key command for the Paddle Switch?)

 

8. FLAP switch - HALF

 

9. FCS INITIATED BIT - PERFORM (Is this check completed by pressing FCS-MC > FCS on DDI and Y key command - FCS Bit switch simultaneously?)

a. AOA warning tone - VERIFY ANNUNCIATION AT FCS IBIT COMPLETION

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I tested this procedure and found the same problem during start-up, however, it was due to pilot error. I realized that I left NWS steering on.

 

See the following note from the NATOPS Manual -

 

Pg. 243

 

NOTE

• For initiated BIT to start, FCS BIT consent switch must be held for at

least 2 seconds. If not held for the required time, RESTRT is displayed

as the BIT display status message. If RESTRT displayed, repeat

procedure.

 

• Initiated FCS BIT cannot be performed if nosewheel steering is

engaged.

 

• For valid BIT reporting, do not operate switches or controls unless

indicated. Do not rest feet on rudder pedals or hands on control stick.

1. If wings folded, check both ailerons Xd out.

 

Here are the key bindings that I assigned in Control Options -

 

FCS Reset Button (Left Console) – B key

 

FCS Bit Switch (Right Vertical Panel) – Y key

 

Paddle Switch (Control Stick), this is called Autopilot/Nosewheel Steering Disengage (Paddle) Switch in the DCS Control Options – A key

 

I followed the NATOPS checklist as follows and successfully completed the test:

 

Page 324

 

5. FCS RESET button – PUSH Press B key

If the wings are folded, verify aileron Xs are present

 

6. FLAP switch – AUTO

 

7. FCS RESET button and paddle switch - ACTUATE SIMULTANEOUSLY Press B key and A key at the same time

 

If nosewheel steering (NWS) is engaged the following FCS Bit test won’t work properly. Make sure NWS is no longer displayed on the Heads Up Display (HUD)

 

8. FLAP switch – HALF

 

9. FCS INITIATED BIT – PERFORM Press Y key for 2 seconds, continue to hold and press the FCS-MC > FCS OBS button on the right DDI at the same time until you see IN TEST displayed on DDI then release both key presses.

a. AOA warning tone - VERIFY ANNUNCIATION AT FCS IBIT COMPLETION

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Today I experienced this exact issue. It seems to happen when you perform a full shutdown then start up. I've done manual start ups and auto start ups.

 

I've tried Paddle and FCS reset, no joy.

Cycled repeated paddle and FCS reset.

Tried FCS test consent(y) with FCS reset at the same time.

Tried all of above steps, with all 3 flap settings.

Tried all the steps with NWS on and off.

In none of the above attempts could I get the FCS to complete a BIT nor could could I get my flight surfaces to move.

 

Bit annoying that you have to respawn after every landing.

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FCS - RESET on the left panel, is clear the BLIN code on the FCS Page.

 

Now is dosen't work.

 

For information if you perform a electrical reset or pull all FCS circuit breaker more than 10 seconds. The flight computer loose the last status. In fact on the BIT FCS page the FCC A and B come PBIT GO. And you need to press again to the T / O Trim because the STAB comeback at the initial position.

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I realise that this has been explained but just to be clear as there are some contradictory posts:

 

 

  • FCS BIT consent switch (on right cockpit wall): key Y.
  • autopilot/nosewheel steering disengage lever (Paddle switch) (on HOTAS): key A.
  • 2.8.2.2.8 FCS RESET Button. The FCS RESET button on the FCS panel is used to reset the flight control computers after a transient malfunction. (there is no key assignment for this by default, at least on my system).

Looking through the NATOPS one of the steps is explained clearly:

 

2.20.3.5.1 FCS Initiated BIT. For the FCS, the FCS BIT consent switch, on the right essential circuit

breaker panel, must be held ON when initiated BIT is started. This prevents inadvertent initiation of

BIT on the FCS for reasons of flight safety.

However, it is not clear to me what the following action achieves:

 

7. FCS RESET button and paddle switch - ACTUATE SIMULTANEOUSLY

 

All I can find is

 

"Pressing the FCS reset button, simultaneously with the paddle switch, does not correct BIT detected flight

control system failures; it simply clears the BLIN code(s) from the display."

 

So, what is the difference between pressing FCS RESET (alone) and pressing FCS RESET with the paddle switch?

 

 

 

 

 

Also related:

 

2.8.2.4 Actuator Exerciser Mode. An actuator exerciser mode is incorporated to improve cold

weather start-up of the FCS. On the ground, the pilot can initiate the exerciser mode by simultaneously

holding the FCS BIT consent switch ON and pressing the FCS RESET button. When initiated, the

mode cycles the stabilators, flaps, ailerons, and rudders through 20% of full travel for 10 cycles in 20

seconds. The operation can be stopped before 20 seconds have elapsed by pressing the paddle switch.

The mode should be used in cold weather or any time an initial FCS RESET fails.


Edited by Hippo
clarity

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If you continue reading through the checklist procedure, if FCS Reset and BIT Consent do not successfully reset the system, you can pull all 4 FCS Chan breakers to continue resetting the system. I have successfully done this, although one time it did not work. I chalked that up to needing maintenance to look at the plane and just jumped into a different one.

 

Ultimately I believe the root cause of the issue is due to me missing a step in shut down or start up. When I follow procedure to the letter I have never had an issue.

3800X, X570, 32GB 3600, RTX 2080Ti, SSD, Odyssey+ VR

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I've not been able to fix the FCS issue, even when pulling breakers. LEF's will be left at 12 and right at 0. If I start the FCS BIT, then the entire control system becomes unresponsive. I've just resorted to grabbing a new plane after each landing.

 

I will test with a full shutdown then start up checklist. I assume the shutdown checklist is in the NATOPS manual?

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I've not been able to fix the FCS issue, even when pulling breakers. LEF's will be left at 12 and right at 0. If I start the FCS BIT, then the entire control system becomes unresponsive. I've just resorted to grabbing a new plane after each landing.

 

I will test with a full shutdown then start up checklist. I assume the shutdown checklist is in the NATOPS manual?

 

 

I have tried this and confirm that I experience the same or similar issue. But it's the right LEF that stays at 12 on the FCS display, none of the reset attempts from the natops will clear it. Running the FCS initial BIT, it just stays IN TEST and never completes.


Edited by Hippo

System spec: Intel i9 13900KF @ stock,  Gigabyte GeForce RTX 4090 Gaming OC 24GB GDDR6X, Gigabyte Z690 UD DDR4, Corsair Vengeance RGB PRO SL 32GB (2 x 16GB) DDR4 3600MHz C18, Samsung 980 EVO 500 GB NVME M.2 SSD (system drive), Samsung 970 EVO 1 TB NVME M.2 SSD (games drive), Cooler Master ML360 Illusion CPU Cooler, Asus XG43UQ Monitor, Oculus Quest Pro, Thrustmaster Warthog HOTAS, MFG Crosswind Rudder Pedals

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Afirm. Same here. Had to land to escort the E3 home, then I refueled and wanted to head home. Unfortunately FCSA and FCSB tests would not complete. They stay on RESTRT and the left slats appear to be down while right is raised. FCS panels shows no movment when moving the stick. I tried to reset by pushing FCS bit switch together with FCS reset. The surfaces begin to move. But after completition surfaces go back into the same previously stuck position.

 

Any idea?

X-Plane 11.5x / DCS 2.5.6 / P3Dv5 / Aerofly FS 2 / War Thunder

 

Win10-x64 | ASUS Z390 Maximus VI | Intel i7-9700K @3.6GHz | Corsair Vengeance LPX 32 GB DDR4 | 6TB SSD Samsung 850 Pro | 2TB M2 PCI 4x | ASUS GTX 1080 ROG STRIX 8GB DDR5X | TM Hotas Warthog | Saitek Combat Pedals | Oculus Rift S

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  • 4 months later...
  • 3 months later...

Issue that appears to be close to this happening again. AFCS BIT locks up about half way though cycling the LEFs. Left side drives full down and then the entire system dies. Appears repeatable as there are two track attached. I did both of these one right after the other.

 

Not directly the same as this is happening on startup, as opposed to landing/restarting/etc.

 

Edit...only uploaded one .trk file...other one was too large from playing around, resetting breakers, restarting, cycling generators, etc...trying to clear it. None of that worked BTW :)

 

porked1.trk

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  • 1 month later...

FCS BIT FAILS(SOLUTION)

 

Good morning fellas,

I was also experiencing issues with the, after-shutdown, restart FCS-Bit fail. ( FCS-BIT stuck in test and flight controls do not cycle).

I tried the fixes that i read but could not get it to pass.

I have been able to restart with no issues after i did this:

after full shut down: Engines, APU, BATT to off.

 

BATT- ON

APU- ON

ENG CRANK ®

ENG 2 IDLE

Aural Annunciations

Make sure NSW is not engaged

DDI (L) - MENU, FCS

Double stack Master Caution

FCS- RESET

DDI ®- STOP

FCS-MC/GO

Hold "Y" Press FCS OSB

"IN TEST"

Flight Controls cycle (ACTUATOR EXERCISER MODE)

FCSA/B go from "IN TEST" to GO

 

I don't yet understand how exactly...FCC's A/B, CAS,DEL, redundancies compromised?

"Redundancy to the flight control actuators is achieved either by simultaneously pressurizing the actuator from both systems or by supplying pressure to the actuator from 1 system while the other system is in a back-up mode. "

 

My guess would be forcing system 1 into backup mode while pressurizing actuators with system 2 only.

I do not know if this is already a fix by someone else, i just thought i would post it..just in case.

Have a good one!

PS- i am having issues posting a video. i will try and post it :thumbup:

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  • 1 month later...

I am jealous

 

I have struggled with issue since I bought the module in March. I have never been able to restart the f-18 without the FCS-BIT failing. I assumed it was something I was doing wrong shrugging off the notion that if shutdown was so critical a training mission would have been included.

 

I have followed both Grim Reapers and Matt Wagners video shutdowns.

Tried everything suggested on the forums. FCSReset, pulling breakers, restarting computers etc..Hell I even called a buddy, a retired Marine F-18 mechanic, who apologetically said he was on an engine team. FCS issues were addressed by a different team.

Put the mod away in frustration after about 20 game hours of reading,research and experimentation.

 

Been a year since this was first posted about and I will occasionally check the forums and found this one, so its still around and being guessed about. Got back in to see if a fresh mind would help with another pass on this issue and low and behold I found a big clue. I unintentionally shut down on my original starting practice mission in the persion gulf map. It restarted fine, no FCS_BIT fail. Startled, I tried on the caucusus map -fail. Tried on Nevada Map- fail. retried the Persian gulf several more time...all successes.

 

AT this point I can now rule out it isn't bad proceedure. I bought the Persian gulf map with the f-18 mod at same time, dunno if that means anything. I simply do not have enough understanding of the game build to make an educated guess and so I am stuck with having to fly the f-18 on the persion gulf map only, hoping that someone eventually figures it out since other folks are still having this problem. Just not as repeatable as mine. Restarting shouldn't be anymore more problematic than starting. If not true then this info should have been included in the training.

 

Any track I send in would simply show a matt wagner shutdown and restart fail on the caucusus and Nevada maps and a success on Persian gulf. SO regardless of the critique on the procedure it would not explain the success.

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  • 2 months later...

Just a heads up, this is still completely porked...but easily reproduceable. Inadventantly started left engine, disenganged before starting, started right engine, started left as normal. AFCS dead. No response to stick movement, no ability to run AFCS bit. Same result as the other two tracks I posted before. I'm still not sure why this one hasn't been flagged as a bug yet?!?

Dead AFCS.trk

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  • 1 month later...

I still encounter this bug. Just starting up and shutting down hornet at apron does not trigger the bug. But if spawning airborne, landing, shutting down and then starting the hornet up the bug appears. Appers also from cold&dark - airborn - landing - shutdown - restart --> bug.

 

I've attached a track of this bug appearing. Track is saved from stable version.

F18_FCS_restart_bug_2019-09-16.trk

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