-
the change-over valve in the ground check module is in the "ground check" position (there is an unwanted electrical supply to the change-over valve),
-there is hydraulic pressure in the "retract" side of the RAT jack (the jack control module is in the wrong configuration).
To make sure that sufficient inlet pressure for the RAT is available, the air pressure in the Blue system reservoir is monitored. A pressure transmitter is installed on the air manifold of the reservoir. The pressure
R 1EFF : 001-049, 051-061, 101-105, 201-203, 1 29-22-00Page 10 1 1 Config-1 May 01/05 1 1 1CES 1
transmitter sends information to the SDAC/FWC. If the air pressure during
flight decreases to less than 3.1 bar absolute (45 psi A) a class 2 warning
is given when the aircraft lands.
R **ON A/C 062-099,
R In an emergency the Blue auxiliary system supplies hydraulic power to the
R aircraft. Electrical power can also be supplied through the Blue auxiliary
R system by the constant speed motor generator (CSMG). The system supplies
R hydraulic power in less than 4.5 seconds from the time it gets the
R electrical command to extend the RAT. The hydraulic power available from the
R RAT is sufficient to supply the flight controls and the CSMG (for electrical
R power). When the landing gear is extended, the CSMG is automatically
R switched off and electrical power will be supplied from the batteries. The
R RAT is available and will operate through the entire flight envelope. The
R RAT has a stall protection device which prevents a RAT stall below the
R governed speed range. The stall protection device limits the maximum power
R the pump can take from the turbine. When the stall protection device is in
R operation, the pump displacement is adjusted to get a constant RAT speed not
R related to the aircraft speed.
R The RAT has a de-icing device which is installed in the nose of the turbine
R hub. The de-icing device produces heat which keeps the nose temperature to 3
R deg.C (37.40 deg.F) minimum. This temperature prevents icing conditions at
R the turbine hub when the RAT is in operation.
R The de-icing device does not use external power sources. The heat is
R produced by the eddy current heating device. The heating device has two
R basic components, an electrically conductive aluminium plate and an even
R number of samarium cobalt magnets. The magnets are cicumferrentially mounted
R on a stationary magnetic plate. When relative rotation take place, the flux
R field, when it passes through the aluminium plate, produces a current. As
R aluminium has an electrical resistance, power is generated which is than
R dissipated in the form of heat.
R The main components of the Blue auxiliary system are:
R
R - the RAT,
R - the leg assembly with its pivot,
R - the hydraulic pump,
R - the ejection jack,
R - the RAT control panel and
R - selector switches to extend the RAT from the flight compartment.
R
R All the components are in the left belly fairing. This does not include the
R RAT control panel and the selector switches. The RAT control panel is part
R of the ground-service panel of the Blue hydraulic system, and the selector
R switches are in the flight compartment.
R
R 1EFF : 001-049, 051-099, 101-105, 201-203, 1 29-22-00Page 11 1 1 Config-1 May 01/05 1 1 1CES 1 The drain port of the RAT gearbox has a leakage drain line which transfers hydraulic fluid from the internal reservoir of the RAT pump to an external drain tank. The location of the drain tank is behind a cover plate on the left side of the RAT bay.
A pushbutton switch (2805GE) is installed on the hydraulic control panel 40VU in the cockpit. This switch permits the pilot to manually select the deployment of the RAT.
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