F-18 Deadstick Landing Without Losing FCS possible?

[CommandT]

Hi folks,

 

Can't find any info on this in either the official manual, chuck's guides or any youtube video. I want to find out if there's a way of having both engines shut down/ fail in flight and not loose the hydraulics/ FCS. Does the APU provide any power to some sort of electric driven hydraulic pumps or something of that nature so that you can maintain adequate control trying to do a deadstick landing or is there some specific procedures in the Hornet required to perform a full engine-out landing? 

Cheers! 

Edited April 24, 2021 by CommandT

[Svsmokey]

No hydraulic or electrical on Hornet APU . There is a "mech" control that provides a limited travel to the stabs only , but you'd have to really be desperate (like you don't  want to parachute into an episode of Real Housewives) , Best thing to do if you can't restart is to punch out . Aim the aircraft where they're filming Real Housewives first . Don't know if "mech" is modeled in DCS .

Edited April 25, 2021 by Svsmokey

[Swift.]

5 hours ago, Svsmokey said:

No hydraulic or electrical on Hornet APU . There is a "mech" control that provides a limited travel to the stabs only , but you'd have to really be desperate (like you don't  want to parachute into an episode of Real Housewives) , Best thing to do if you can't restart is to punch out . Aim the aircraft where they're filming Real Housewives first . Don't know if "mech" is modeled in DCS .

 

Either mech or del is modelled in dcs. It's hard to tell because the only case where it would engage in dcs is one where there are no DDIs

[CommandT]

@Swiftwin9s So it's supposed to kick in automatically? Coz in DCS after the engines come offline, you're very quickly left an uncontrollable plane. At least for landing anyway.

 

@Svsmokey Good advice re-Real Housewives but I'm really keen on making this deadstick landing work  

[CommandT]

Also just found this discussion on the topic. Seems a bit bizarre that you are essentially left with an "unlandable" plane if you lose both engines! 
 

 

[Wroblowaty]

If engines flamed out but cores can rotate freely, you can try to turn on APU, and hit engine crank right. This way ATS should rotate right engine core providing some power to hydraulic pump.

[Bunny Clark]

The FCS itself can be powered off the battery, if you loose both generators FCS Ch 1 & 2 will remain operative, which is enough to give you full control (you will loose Autopilot, Auto Throttle, and NWS, not that those are of much concern in that situation). 

 

The bigger problem is the hydraulic system. The 4 hydraulic channels are powered by the L & R AMAD, so if the engine isn't turning you start to loose hydraulic pressure pretty quickly. Once hydraulic pressure is gone, that's it, you have no way of moving the control surfaces at all, regardless of what other systems are still operating.  

 

If you loose both engines simultaneously and you have the altitude, you can attempt either a windmill or APU engine restart. That would be your only real hope of getting the jet back on the ground in one piece. Realistically though, the question is why did you loose both engines? The likelihood of both engines suffering isolated and contained simultaneous failures is vanishingly small, there's no real procedures for it in the Hornet because it's just so unlikely. If both engines quit because of battle damage, or one engine suffers a catastrophic failure that takes out the other engine, the likelihood that other systems have also been catastrophically effected is high. Attempting to land a jet in that condition is far more risky than just pulling the handle. 

 

 

[mongo52]

On 4/24/2021 at 11:44 PM, Swiftwin9s said:

Either mech or del is modelled in dcs. It's hard to tell because the only case where it would engage in dcs is one where there are no DDIs

You could pull 3 of the 4 flight control breakers in the cockpit. Of course that is if the breakers being pulled is modeled. 

[oldcrusty]

13 hours ago, mongo52 said:

You could pull 3 of the 4 flight control breakers in the cockpit. Of course that is if the breakers being pulled is modeled. 

 

It did work when I (with some other folks here) tested the control behavior with some systems disabled.  This was around a year and a half ago and all this 'mech' and electrically driven back up was kinda fuzzy in my head but someone told me that the whole thing was very unfinished at the time. Pulling the breakers did disable the specific systems but the controls were not responding correctly from what I understand.

Well, I think this thread stirred up my NATOPS fever again and get away from blowing things up... for a day or two.   

[CommandT]

Interesting. If I'm honest I just wanted to see how it would feel like to glide down without any engine thrust - pure deadstick. It seems like this is impossible to make happen though. I do find it a bit ridiculous you can't have some sort of back up to power the FCS in dual engine failure. Oh well. Thanks for the responses all

[oldcrusty]

2 minutes ago, CommandT said:

Interesting. If I'm honest I just wanted to see how it would feel like to glide down without any engine thrust - pure deadstick. It seems like this is impossible to make happen though. I do find it a bit ridiculous you can't have some sort of back up to power the FCS in dual engine failure. Oh well. Thanks for the responses all

 

It was possible in the first dozen or so builds of DCS Hornet.  I tried it once.  I was at 20k feet, not far from the runway when I shut the motors down.  I modeled the approach on Viper's power off landing... high key, low key and all that stuff I've been reading about, hehe. I know, Hornet is quite a bit different but hey... it's a sim.

It worked. I was watching my standby instruments, dropped the gear with emergency handle. Touched down hot and of course the NSW and the brakes weren't working and I didn't pull the emergency brake handle, ended up in the grass but in one piece.

As it has been mentioned before, power off landing is not a Hornet thing and dicey for any other jet. 

[oldcrusty]

Realistic or not... it had to be done

 

You can glide down at a very steep angle but not very far. I haven't figured out how to fair out the flaps. Circuit breakers didn't do it. If you pull one or two FCS ch. breakers with engines running you will get the 'FLAPS OFF' fault that can be reset with FCS Reset button. With engines off, once airspeed bleeds off and the flaps drop they stay down no matter what.

You have to be very, very careful with the stick when you glide. Any excessive push or pull will put you out of control. I have no idea what mode is running the controls. I think it's DEL. 

Whatever it is, it seems to be running for more then 5 min. I'll double check NFM000. I think it says if you put the batt. to ORIDE first then ON, you might get 10 min. I'll test the limits later.

 

The first part of my vid shows the air restart using APU (both motors out).  APU is the last choice.  If you're high enough and the engines are spooling down but still above 11%, all you need is the airspeed around 350 knots when diving and as long as the throttles are forward of flt. idle, the motors will start. With both engines down, once you let the RPM drop below 11%, it's hard to bring the RPM up again. With one engine running, it's a piece of cake.

 

Sorry abut the VR FOV when replayed from the track.

 

Edited April 27, 2021 by Gripes323