Maintenance Manual STEMME S10-VT
Date of Issue: Jan. 01, 1998
Page 3-41
Amendment Nr. 0
Date: --
A4011121_B23.doc
Doc. No. A40-11-121
Ignition/Starter Switch
with positions "OFF", „RIGHT“, „LEFT“, „BOTH“ and „START“:
The Ignition/Starter Switch, operated by a key, has the positions given above. In position OFF, both
independent electronic ignition systems are cut off. In second, third and fourth position, the ignition system
as marked is active. Spring-loaded position five is for engine start. In this position the control circuit of the
starter relays is switched to ground.
To allow the propeller unfold before engine ignition, a delay switching is combined with the Ignition/Starter
Switch in parallel: A relay contact switches the ignition ground cables to ground during 3 seconds after
switching the Ignition/Starter Switch to "START", thus preventing ignition. The relay is controlled by a
Monoflop switching. The relay picks up when the Monoflop responds on a pulse generated at the
beginning of starter operation. After 3 seconds, the monoflop releases, the relay disconnects the ground
connection of the ignition ground cables and the ignition starts operating. The ignition retarder module is
installed on the electronics / CB plate on the RH side of the instrument panel below the panel cover.
3.7.12 Variable Pitch Propeller
Propeller Pitch Control Switch
with positions T/O and CRUISE
The propeller Pitch Control Switch is installed on the centre console next to the throttle lever. The switch
connects the control circuit of a relay with the generator Bus 5-VV. If the generator is OFF or
malfunctioning, the propeller blades cannot be turned into cruise position, independent on propeller switch
position. The heating elements of the propeller blade actuating system are energised directly from Main
Bus 2VV.
Green
Propeller Pitch Status Light
for T/O position
The green Propeller Pitch Status Light is ON, if the propeller blades are in T/O position within very close limits
(fine pitch), and the light is OFF in any other position. The position signal is generated by a blade position
module, installed on the RH electronic plate. This module only operates if the engine is running.
3.7.13 Main Landing Gear
The landing gear is controlled by the
Landing Gear Lever
, which is a 3-position switch. It is installed in the
switch plate in the centre instrument panel. The switch positions mean:
•
L/G lever DOWN:
The landing gear is extending
•
L/G lever NEUTRAL:
Electric systems of landing gear are de-energised. Gear actuation can be
interrupted at any moment during operation.
•
L/G lever UP:
The landing gear is retracting.
The control of the electric landing gear spiral drive actuators is by a relays-logic, utilising signals of 6 limit
switches (micro switches). Two on each radius rods detect the gear-down position. In gear-up position, a limit
switch is actuated by each gear strut. The signals of the limit switches are analysed by the gear indication and
warning module.
3.7.14 Landing Gear Warning System
The landing gear indication and warning module is installed behind of the RH instrument panel. Integrated in
this panel are the indication lights for the landing gear position and the landing gear warning horn. If the
landing gear is down and locked, the two lights are green. During gear travel, the lights flash red. If the
airbrakes are unlocked with the landing gear not down and locked, the warning horn is activated.
3.7.15 Avionics
See also Fig. 3.2.a
The avionic equipment is installed in the centre instrument panel. The CB´s for avionics are also installed in
this area. The avionic systems are installed in accordance with instructions of the manufacturers and
connected to the electric busses as described. The power supply of avionic equipment is by two separate
busses (refer to section 3.7.11):
Main Avionics Bus 4VV-1
Secondary Avionics Bus 4VV-2
