ATR 42 Model : 400
SYSTEMS DESCRIPTION
POWER PLANT
P 4
NOV 99
400
1.16
.
20
20.3 LUBRICATION SYSTEM
(See schematic p 11/12)
Synthetic oil specification MIL-L-23699.
A single oil system serves the turbo machinery, the reduction gear box and the
propeller pitch change system.
- Oil tank
Oil is contained in a 9.44 l (10 quarts) tank
1
. A filter cap is provided on the tank. Quantity
indication is checked by sight glass (or by a dipstick) on the side of the tank.
- Pressure system
A gear pump
2
driven by the accessory gear box supplies oil through an air cooler
3
mounted in the nacelle and a filter
4
both fitted with by-passes in case of
clogging.
RGB oil is also cooled in a fuel heater,
5
. An oil temperature sensor is provided.
Oil pressure is controlled by a regulating valve
6
. A low temp. valve
7
is
provided to eliminate damaging pressures surges on cold starts. A pressure
transducer
8
and a low pressure switch
9
are installed.
- Scavenge system
Scavenging is blown down or gravity drained except for N
°
6 and 7 bearing cavity and
the reduction gear box, on which gear pumps are used.
20.4 IGNITION SYSTEM
Each engine is equipped with a high energy ignition system. It consists of two engine
mounted ignition exciters (A and B) powered by the DC ESS BUS and two spark
igniters, one for each ignition exciter. Ignition cycle includes two phases. During 25 sec,
the intensity is 5 to 6 sparks/sec and then, the intensity becomes 1 spark/sec.
The engine ignition system provides ignition for :
- On ground starting using exciter A, exciter B, or exciters A + B (according to ENG
START rotary selector position).
Note : Using exciter A or exciter B may allow to detect an hidden failure.
- In flight starting using exciters A + B regardless of start selection.
In addition, for each engine, in case of NH drop below 60 %, exciters A + B are
automatically activated. This action is inhibited if :
- NH drops below 30 %, or
- EEC is deselected, or
- CL is set on feather or fuel S/O position, or
- On the failed engine in case of ATPCS sequence.
Note : When EEC is deselected, exciters A + B can manually be activated, using the
MAN IGN guarded push-button.
AA
R
R
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