Jan asked:
Working of wing valves and engine bleed air valves
03.05.2012 at 07:48:23   Lou and other 707-fans,

According the Boeing 707 operations manual, section pneumatics systems, the engine bleed valve (1, 2, 3, 4.) allows hot bleed air for wing anti-ice.

Is this correct ? Why not using the wing valves for wing anti-ice ?

According the Boeing 707 operations manual, section pneumatics systems, the wing valves (1, 2, 3, 4.) allows hot bleed air for air conditioning and crew and main cabin temp control.

Is this correct ? Why not useing engine bleed air for ACM and temp control ?

According the Boeing 707 operations manual, section pneumatics systems, the engine bleed valve must be closed if the associated air compressor is operating.

Is this correct ? Could you explain this matter. Looks like a controdiciton.

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I have not flown the 707 in 35 years, but I do not remember ever having to use wing anti-ice in the 707.
Each engine was capable of supplying low pressure bleed air to the common wing duct for anti-icing.
There was only one switch that operated all four wing anti-ice valves. If one or more valve did not open
you would use the temp gauge to see the heat going to the wing and if needed, you could increase
the engine RPM to obtain additional heat.



Engine anti-ice was operated by a separate switch for each engine. As you can see, several parts of the engine were anti-iced by this one switch.



No 707 I ever flew used bleed air to pressurize the cabin. Only turbo compressor air was sent into the cabin.
The reason was the danger of the bleed air having some fumes. This of course changed with the 727.




Lou


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