Hawker 800 pressure Venturi Q

[Douglas825]

Hello all,

I am a newb, I don't know much about the 800 and have a question.

I understand the concept of outflow/safety valves in terms of pressurization.

But what exactly does the Venturi on the right side of the hawkers fuselage do? What is its purpose and how does it fit into the pressurization system? A simplified explanation would be great.


Thanks! :)

[HS125]

Hi Douglas,

Welcome to the forums and the Hawker! I hope it gives you many happy years of flying. I'm not sure I completely understand the question (although I do know to which components you're referring), but I'll try….

Outflow/Safety Valves
Basically they have two functions, normally they are controlled by the pressure controller and maintain the cabin altitude according to the selected flight regime by providing a means for the controller to increase the rate at which air can leave the cabin.

They can also operate as Safety Valves and can be forced open to prevent the cabin differential pressure from becoming too high or closed to prevent it from becoming too low [sic. negative].

Right Cabin Side mounted Venturi
This device provides power in the form of a vacuum to operate components of the pressurization system.

Durning normal operation it provides the vacuum to the Cabin Controller. Alternatively, via the Manual Control Valve [located under flap on the sidewall panel to the copilot's right] it can be used to provide it's vacuum to one of the Outflow/Safety valves, in that case you have manual control of that valve to determine the cabin altitude and therefore differential pressure.

I hope this helps.