DG Flugzeugbau DG-800A, Maintenance Manual, Page: 41 / 163

Maintenance Manual DG-808C
Issued: September 2007 TN800/34 1.28
1.14.15 Proximity switch
The proximity switch at the engine receives the switching pulses by the
steel pins located at the upper drive belt pulley, see drawing 8M110 at
the end of this manual.
The proximity switch effects the following functions:
1.
Activation of the retraction mechanism and indication in the DEI-
NT
2. Pulses for the RPM measurement
3. Electric propeller-brake (Option)
The switch must be adjusted so that the propeller can't hit the engine
doors during retraction. If the switch is moved (distance to the steel
pins reduced) the range will be enlarged.
If the distance is too large, the RPM measurement won’t work
correctly.
Check if the switch switches by watching the control light at the rear
end of the switch or on the DEI-NT display (main switch on).
For a new adjustment start with a distance of 1.8mm (.071 in.).
It is absolutely essential to secure the switch with the 4 counter nuts, as
damage to the switch will stop the RPM measurement and the
retraction-extension control.
With a defective proximity switch (short circuit) the failure message
“RPM Pickup”.will be displayed on the DEI-NT.
1.14.16 Refuelling pump systems
Start the pump by pressing the push button located in the fuselage
main-bulkhead (behind the pilots left shoulder). As soon as the fuselage
tank is full a built in device automatically switches off the pump. If you
want to interrupt or to stop the filling procedure before the tank is full
press the push button again. Starting the pumping again is only possible
by pressing the push button again.
The system is controlled in the control unit.
1.14.17 Connector plugs between fuselage and engine
Except for the starter motor positive and earth wires all wires can be
disconnected by multiple plugs near the hinge of the powerplant (at the
bulkhead in the front upper edge of the engine compartment) to
facilitate the removal of the engine.