757 TQ wiring

[jackpilot]

Precious info even if this logic is of limited use in our simulation softs.
Just one (more) question, which will help interfacing:
The reversers levers are
1) Full forward (no action) switch closed
2) Pulled backwards to mid position (cam lock) (switch opens)
3) Can be pulled full backwards (switch still open)

What's happening on the real plane ?
1) Stowed
2) Deployed
3) proportional thrust ?

[tomenglish2000]

Hi Jack,

Thats right.

The reverse levers fully down and the forward levers fully back is forward idle.

The reverse levers up to the first detent is reverse idle. This activates the switch which if all the conditions are met tells the reverse doors to open. The engine remains at idle thrust. The reverse lever is prevented from raising past reverse idle until both reverser halves reach at least 60% of full travel, the interlock then releases the lever. The reverse lever can now be raised up to full reverse, this just controls how much thrust the engine produces.

Then the process is reversed. Moving the levers to reverse idle from full reverse (or an intermediate position) does nothing. Moving the levers to fwd idle commands the reverser halves to stow.

There is no interlock to prevent the fwd levers being applied while the reverser halves are still deployed.

Figures above quoted for CFM engine with EEC.

Thanks.
Tom.

[bernard S]

as in the pm i sent you ?  if you are wanting full interoperability per the aircraft you will require the thrust reverser interlocking actuators and some sort of clutch try to source the P box for such it may make it easier .. I do not know if your software supports such beasts in my 74 I have full TQ function so you may have to write some sort of add on wish i could be of more help but my 73 75 76 knowledge is strictly limited  to basics  those basics being  push fwd  it goes faster pull back it goes slower

[Garys]

"Then the process is reversed. Moving the levers to reverse idle from full reverse (or an intermediate position) does nothing. Moving the levers to fwd idle commands the reverser halves to stow.

There is no interlock to prevent the fwd levers being applied while the reverser halves are still deployed"


Actually there in an interlock that will inhibit the fwd motion of the levers until the reverser sleeves are completely stowed.  That means the reverse thrust levers have to be fully down and the amber REV on the Engine display must be out before the system will allow you to move the throttles fwd. Also the same when applying reverse thrust. When you move the reverse handles to the idle position the reverser sleeves must be in fully deployed position and you must wait until the REV goes from amber to green on the engine display before the interlock will allow you to move the handles up to full reverse position.

[tomenglish2000]

Hi Gary,

Thanks for that. I was in two minds about posting that about the lack of a forward interlock, I couldn't find it in the books so thought it didn't exist. Maybe I was looking in the wrong section. It didn't make sense to me though.

Do you know how "closed" the reverser sleeves have to be to remove the interlock? On the CFMs with EEC the reverse interlock is removed at 60% of reverser sleeves movement.

Thanks.
Tom.

[Garys]

They need to be fully stowed. If the translating sleeves are in transit the interlocks are engaged.

What model CFM engine do you have the notes on?

[tomenglish2000]

Hi Gary,

It's a CF6-80C Series. The AMM says that once the sleeves are open 60% of full travel the reverse interlock disengages. Thats for EEC controlled engines. The EEC will then (proportionally?) limit the reverse thrust until open. For non-EEC controlled engines (doubt there are many around these days) the interlock disengages proportionally between 76% to 95% of the full travel.

I don't have any information on other engine types.

Tom.

[Garys]

That makes sense for the CF6 as the Central Drive Unit is air driven by aircraft pneumatics. On PMC (Cables) CF6 engines the interlocks are in the pylons. Fadec version of the CF6 has the interlocks in the throttle quadrant. Both types have EEC but on the PMC type the EEC is supervisory only.

[jackpilot]

Are you Guys talking about the 757 or the 737 ?   

[Garys]

I was originally talking of the 757. The GE CF6 engine that Tom was talking about is the for the 767.  The throttle quadrant is pretty much identical including the switches that you wanted info on and how it worked on the aircraft. There are slight differences between the aircraft when the interlocks engage/disengage but the thrust reverse sleeves move so fast that you don't really see much of a delay unless your specifically looking for one.

Cheers
Gary