investigating engine shut down is impossible, trackfile attached

[Rongor]

Pulling the ECLs back to OFF doesn't stop the engines. They continue running in ground condition. This happened to me in the Cold and Dark Start Up training mission, in the Taxi and Takeoff training mission both engines shut down without issue.

Edited August 9, 2024 by Rongor

[Rongor]

I eventually can shut both engines down by pulling the fire handles, the ECL in OFF detent don't work.

CH-47F_CAUC_TRNG_01_CS.miz_09082024_23-05_ENG dont cut.trk

Edited August 9, 2024 by Rongor

[LuseKofte]

I shut them off with first attempt on first flight by using right click on the mouse on them then throttle

1 hour ago, Rongor said:

I eventually can shut both engines down by pulling the fire handles, the ECL in OFF detent don't work.

CH-47F_CAUC_TRNG_01_CS.miz_09082024_23-05_ENG dont cut.trk 9.87 MB · 0 downloads

 

 

[cw4ogden]

I don't know if it's modeled, but the FADEC back-up power needs to be on to shut down the engines, as the primary system cannot completely stop fuel supply.

[Nealius]

I couldn't shut them off until turning of backup power and turing on the APU+APU Gen. However once off, the rotors took 10 minutes (actually timed it) to come to a complete stop.

[Sarge55]

No rotor brake?

[BeforeBroadband]

15 minutes ago, Sarge55 said:

No rotor brake?

US Army CH-47F model doesn't have one.

[NineLine]

I have set this to investigating, some on the team are having luck, others not so much. Will see if there is a step that breaks the procedure. 

[Nealius]

So far I've found that APU and APU Gen must be on for the turbines to stop. With engine conditions levers in STOP and all fuel switches off, they still run. Upon turning on the APU and APU Gen they immediately shut off. 

[Hawkeye91]

1 hour ago, Nealius said:

So far I've found that APU and APU Gen must be on for the turbines to stop. With engine conditions levers in STOP and all fuel switches off, they still run. Upon turning on the APU and APU Gen they immediately shut off. 

Can confirm, this works

[LuseKofte]

I usualy can stop just by setting the trust levers on off a few times it do not want to switch off. like this time. I went a bit hard on ground and damaged the chopper a little bit while slingloading. 

[Cyborg71]

I've managed to shut it down, but it took 3 days for the rotors to stop spinning....

No brakes. Eeeek 

[Nealius]

10 minutes for the rotors to stop (actually timed it).

[RossC]

Pull some thrust when engines stopped. Increases pitch and creates drag, stop a lot quicker.

Not sure if this is an actually thing IRL but works to slow them down. 

[Slippa]

I’ve been raising the collective slightly as well as pulling the stick aft and left and holding it until the blades stop. When they do stop, they seem to stop abruptly, not sure how they are irl?

Don’t try it too early as, well, you can scratch the paintwork a little bit. Doesn’t take ten minutes anyhow. - Actually, I haven’t timed it and DCS is a bleedin timewarper, I’ll check. 

Edited August 16, 2024 by Slippa

[Mikep821]

On 8/9/2024 at 9:56 PM, Rongor said:

Pulling the ECLs back to OFF doesn't stop the engines. They continue running in ground condition. This happened to me in the Cold and Dark Start Up training mission, in the Taxi and Takeoff training mission both engines shut down without issue.

 

That is not wrong, you need to start the APU and turn APU gen online before shutdown, read procedures and watch some chinook departure and shutoff, they always have APU started after shutting down engines… not a bug… and btw:it is in manual in shut down procedure. Don’t slow down the development just because you lazy to read or investigate please 

[cw4ogden]

1 hour ago, Mikep821 said:

That is not wrong, you need to start the APU and turn APU gen online before shutdown, read procedures and watch some chinook departure and shutoff, they always have APU started after shutting down engines… not a bug… and btw:it is in manual in shut down procedure. Don’t slow down the development just because you lazy to read or investigate please 

It is, in fact wrong.

The NORMAL shutdown procedure does require the APU and APU generator.  But the APU/APU GEN do not need to be running to shut the engines down.  This can be proven with some logic, as the emergency engine shutdown procedure does not task the pilot with starting the APU first. 

The APU is started primarily to maintain electrical power and flight control hydraulics during the shutdown.  The FADEC system uses a built in alternator to power the FADEC in a complete loss of power.  So shutting down with no APU generator the pilot should see a complete loss of electrical power, around 85% rotor rpm, with the battery remaining as the only source of electrical.   The engine shutdown should still proceed normally, as the FADEC powers itself, even without a battery installed ***.  

In real life, the FADEC primary stepper motors can not completely close the fuel valves. The FADEC backup system (reversionary mode) secondary stepper motors are the only way to completely stop fuel during shutdown.   Therefore FADEC backup power MUST be on, or the engines will receive enough residual fuel to damage the engine, and keep the rotors spinning at a low but steady speed. 


This is why with a FADEC primary failure, the procedure to shutdown the engines includes pulling the "fire pull" handle.
I haven't had an opportunity to test it, but ensuring the FADEC backup power is on, would be the obvious fix to the OP, if the system is accurately modeled  Will do some testing and report back.

To the other point raised about rotor coast down time: as is, it is unrealistically long.

*** Anecdotes:

Through a comedy of errors, I watched this FADEC phenomenon unfold twice.  The first was a junior PC who torched an engine on shutdown with a primary FADEC failure.  The command grounded him, and threatened to hold him financially liable for the entire 1.2 million dollar price tag.  Not joking.  At the time we had no procedure for this and assumed the primary system could shut down the engine just fine.  Why wouldn't it?  I dug up the Service Bulletin Boeing had sent the Army detailing the problem, the Army never implemented, and he was off the hook.  Two days later an Army wide pen and ink change to the checklist came down, creating an entirely new emergency procedure - Engine shutdown with a FADEC light.

The other, a neighboring crew chief had "borrowed" his neighbors battery without informing the crew.  Their bird sprung a hydraulic leak, and upon performing an emergency engine shutdown, they lost all power to include the missing battery power, and therefore intercom.  All would have been fine, except they missed turning the FADEC backup power on during runup. 

Both engines glowed red hot for about ten minutes with the rotors continually turning, maybe 5-15 rpm.  We eventually dispatched our crewchief to go pull their manual fuel shutoff handles, as the pilots were baffled up front, and focused why the now inoperative fire pull handles weren't helping.  Their flight engineer almost certainly knew what to do, but without an intercom, he had no idea what was happening.


 

Edited August 17, 2024 by cw4ogden

[cw4ogden]

Looks like in your track file you had backup power on.  Can't speak for the tutorial, but in a cold and dark instant action I was able to shutdown normally.

[Mikep821]

7 hours ago, cw4ogden said:

It is, in fact wrong.

The NORMAL shutdown procedure does require the APU and APU generator.  But the APU/APU GEN do not need to be running to shut the engines down.  This can be proven with some logic, as the emergency engine shutdown procedure does not task the pilot with starting the APU first. 

The APU is started primarily to maintain electrical power and flight control hydraulics during the shutdown.  The FADEC system uses a built in alternator to power the FADEC in a complete loss of power.  So shutting down with no APU generator the pilot should see a complete loss of electrical power, around 85% rotor rpm, with the battery remaining as the only source of electrical.   The engine shutdown should still proceed normally, as the FADEC powers itself, even without a battery installed ***.  

In real life, the FADEC primary stepper motors can not completely close the fuel valves. The FADEC backup system (reversionary mode) secondary stepper motors are the only way to completely stop fuel during shutdown.   Therefore FADEC backup power MUST be on, or the engines will receive enough residual fuel to damage the engine, and keep the rotors spinning at a low but steady speed. 


This is why with a FADEC primary failure, the procedure to shutdown the engines includes pulling the "fire pull" handle.
I haven't had an opportunity to test it, but ensuring the FADEC backup power is on, would be the obvious fix to the OP, if the system is accurately modeled  Will do some testing and report back.

To the other point raised about rotor coast down time: as is, it is unrealistically long.

*** Anecdotes:

Through a comedy of errors, I watched this FADEC phenomenon unfold twice.  The first was a junior PC who torched an engine on shutdown with a primary FADEC failure.  The command grounded him, and threatened to hold him financially liable for the entire 1.2 million dollar price tag.  Not joking.  At the time we had no procedure for this and assumed the primary system could shut down the engine just fine.  Why wouldn't it?  I dug up the Service Bulletin Boeing had sent the Army detailing the problem, the Army never implemented, and he was off the hook.  Two days later an Army wide pen and ink change to the checklist came down, creating an entirely new emergency procedure - Engine shutdown with a FADEC light.

The other, a neighboring crew chief had "borrowed" his neighbors battery without informing the crew.  Their bird sprung a hydraulic leak, and upon performing an emergency engine shutdown, they lost all power to include the missing battery power, and therefore intercom.  All would have been fine, except they missed turning the FADEC backup power on during runup. 

Both engines glowed red hot for about ten minutes with the rotors continually turning, maybe 5-15 rpm.  We eventually dispatched our crewchief to go pull their manual fuel shutoff handles, as the pilots were baffled up front, and focused why the now inoperative fire pull handles weren't helping.  Their flight engineer almost certainly knew what to do, but without an intercom, he had no idea what was happening.


 

 

At least I triggered someone who know I’m engineer on Mi-8/17 and W3A so I was just guessing… I’m glad that somebody legit responded.

[samu]

Hello

To stop the helicopter you have to have the APU activated in RUN position and the APU ON generator and of course the battery On and ENG COND levers OFF This way it stops I hope it works for you.