2) Target Pressure Reduction; 1) Target Pressure Reduction At Overspeeding - Rotax 912 Series Maintenance Manual

2.1.2)
00177
Effectivity 912/914 Series
Edition 1 / Rev. 0
BRP-Rotax
Maintenance Manual
Target pressure reduction
Provision for target pressure reduction is made depending on various
effects as a protective measure against overstressing the engine.

2.1.2.1) Target pressure reduction at overspeeding

See Fig. 76-6
It is the responsibility of the pilot to prevent engine speeds in
excess of 5800 rpm, and during fast flight and descent when
using a fixed pitch propeller, the pilot must therefore reduce
the engine performance.
Only if the pilot fails to do this will the TCU lower the target
pressure when engine speed exceeds 5900 rpm and open the
wastegate, thus reducing boost pressure. See relevant dia-
gram.
■ CAUTION:
900
800
700
600
500
400
300
200
100
0
-100
5000 5900 6000
e.g. at take-off performance (throttle valve position 115 %)
- target pressure 1370 hPa (without limitation)
- at an engine speed of 6100 rpm - target pressure reduc-
tion by approx. 265 hPa (according to diagram).
- current target pressure 1105 hPa - corresponds to 70 kW
power instead of 84.5 kW.
The automatic opening of the wastegate by
the TCU is an emergency measure in the
event of a pilot error, but does not release the
pilot from responsibility to reduce the engine
performance.
6100 6200 6300 6400
Fig. 76-6
6500
Motordrehzahl [1/min]
(engine speed)
76-00-00
page 8
May 01/2007