Abnormal Nr/Nf Readings; Hydraulic System Failures - Eurocopter AS 350 83 Flight Manual

FLIGHT MANUAL
.4 ABNORMAL NR/NF READINGS
4.1 Rotor RPM Indicator Failure
In the event of cOll1Jlete loss of NR indication:
-Maintain engine torque above 10 % : NR reading is then given by the
Nf pointer.
-Land as soon as possible.
4.2 Free Turbine RPM Indicator Failure
Check that NR reading remains within governed range when collective
pitch is slowly IIKJdified with engine torque above 0 %.
Continue flight.
.
Hill : The NF value can be read on the VEMD screen. Press "SCROLL", then
"+" as many times as required to display the parameter in the
rectangular window at the bottom of the FLI or 3-parameter screen.
5 HYDRAULIC SYSTEM FAILURES
5.1 Yaw Servo-control Slide-valve Seizure
-In hover : If no IIKJvement about the yaw axis, land normally;
if rotation about the yaw axis, cut off hydraulic
pressure by actuating the switch situated on the
collective pitch control lever.
-In cruising flight: Reduce speed, entering into a side-slip if
necessary, then cut off hydraulic pressure by
actuating the switch situated on the collective
pitch control lever.
5.2 Main Servo-control Slide-valve Seizure
-Actuate the switch, situated on the collective pitch control lever,
to cut off hydraulic pressure.
Load feedback will be felt inmediately ; load feedback may be heavy
if the helicopter is flying at high speed:
collective pitch: 20 kgf pitch increase load
.
.cycl ic : 7 to 12 kgf left-hand cycl ic load
.cyclic : 2 to 4 kgf forward cyclic load
.yaw pedals: practically no load in cruising flight.
-Reduce speed to 60 kt (111 kin/h) and proceed as in the case of
illLlnination of the "HYD" light.
.
DGAC Approved: 350 B3 3.2
I A I B I C I F I 97-40 Page 5