WT9 Dynamic LSA. AIRCRAFT MAINTENANCE MANUAL (AS-AMM-01-000, 22. 05. 2017)

GENERAL

POWER PLANT

- GENERAL

71-00

GENERAL

1. INTRODUCTION

This chapter describes:

•

The power plant installed in the aircraft.

•

The components that make the power plant.

•

Maintenance practices concerning the power plant.

The maintenance of engine Rotax 912 ULS2 itself must be performed according
to engine manufacturer

’

s documentation:

•

Maintenance Manual (Line Maintenance) for Rotax Engine Type 912 Series,
Ref. No.: MML-912

•

Maintenance Manual (Heavy Maintenance) for Rotax Engine Types 912
(Ref. No. MMH-912)

NOTE

Refer to the

Pilot´s Operating Handbook WT9 Dynamic LSA / Club

for engine start/stop

procedures.

The power plant has a top and a bottom engine cowling. The two halves are connected
to the airframe with camlock fasteners.

•

Cowling (Chapter 71-10)

The engine is fixed to the airframe through an engine mount. Engine mount is attached
to the engine with four bolts and to the firewall through four rubber silentblocks.

•

Engine attachment (Chapter 71-20)

Holders installed on the engine are used for hoses and wires attachment.

•

Attach fittings (Chapter 71-40)

The engine air induction system receives ram air through an intake tunnel glued
on the left side of lower engine cowling. The air flows through the air hoses, air filter
holder with pre-heating, air filter to airbox. Airbox is connected to two carburettors.

•

Air intakes (Chapter 71-60)

The airbox, drip trays under carburettors and mechanical fuel pump are drained.

•

Engine drains (Chapter 71-70)

Effectivity:

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28. 04. 2021

POWER PLANT
- GENERAL

–

Engine

–

Upper engine cowling

–

Engine mount

–

Lover engine cowling

–

Airbox

Fig. 71-1 Power Plant

Refer to the following chapters for other engine systems:

•

Chapter 28 Fuel system

•

Chapter 75 Engine cooling

•

Chapter 76 Engine controls

•

Chapter 77 Engine indicating

•

Chapter 78 Exhaust system

•

Chapter 79 Oil system

GENERAL

POWER PLANT

- GENERAL

2. ENGINE SPECIFICATION

The  power  plant  includes  engine  ROTAX  912  ULS2.  Rotax  912  ULS2  is  4-stroke,
4-cylinder  horizontally  opposed,  spark  ignition  engine,  with  one  central  camshaft
push-rods-OHV.  Cylinder  heads  are  cooled  with  a  liquid  and  air.  The  engine  is
equipped  with  a  dry  sump  forced  lubrication  system.  The  engine  is  fitted
with an electric starter, AC generator, and mechanical fuel pump. Propeller is driven
via integrated gearbox with mechanical shock absorber and overload clutch.

Engine manufacturer:

BRP-Powertrain GmbH & Co KG

Engine type:

ROTAX 912 ULS2

Bore:

84 mm / 3.31 in

Stroke:

61 mm / 2.40 in

Displacement:

1352 cm

/ 82.5 in

Compression ratio:

10.8 : 1

Power:

Max. takeoff

73.5 kW / 100 hp

Max. continuous

69.0 kW / 93 hp

Engine speed:

Max. takeoff

5800 rpm max. 5 minutes

Max. continuous

5500 rpm

Idle

1400 rpm

Coolant temperature:

Maximum

120 °C

Oil temperature:

Maximum

130 °C

Optimum operation

–

110 °C

Minimum

50 °C

Exhaust gas
temperature:

Maximum

880 °C

Oil pressure:

Maximum

7.0 bar (for short period
admissible at cold start)

Optimum operation

2.0

–

5.0 bar

Minimum

0.8 bar

Fuel pressure:

Maximum

0.50 bar

Minimum

0.15 bar

Engine start, operating temperature

Maximum

°C

(ambient temperature)

Minimum

-25

°C (oil temperature)

Acceleration

Maximum

5 sec. at max. -0.5 g

Effectivity:

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POWER PLANT
- GENERAL

3. TROUBLESHOOTING

TROUBLE

POSSIBLE CAUSE

REMEDY

Engine does not start.

Improper use of starting
procedure.

Refer to Pilot’s Operating

Handbook.

Fuel tanks empty.

Inspect and fill tanks.

Fuel selector valve in

OFF

position.

Place selector valve in on
position to tank contains fuel.

Clogged fuel filter.

Check, clean or renew fuel
filter.

Water in fuel system.

Drain fuel system.

Fuel contamination.

Drain fuel system.

Defective ignition switch.

Check continuity; repair or
replace switch or wires.

Spark plugs fouled.

Remove, clean, and re-gap
(Rotax Maintenance Manual).

Spark plugs wet from fuel
due to excessive
actuation of choke or
overflow of carburettor.

Dry spark plugs, check for
faults in the fuel system.

Unclean or jammed fuel
needle.

Clean or replace.

Clogged carburettor jets.

Clean.

Water in the carburettor.

Drain and clean the
carburettor, fuel lines, and
separator.

Insufficient compression.

Check for pressure leakage,
repair if necessary.

Internal engine damage.

Inspect magnetic plugs and
oil filter for metal particles; in
case of presence, repair
engine (Rotax Maintenance
Manual).

GENERAL

POWER PLANT

- GENERAL

TROUBLE

POSSIBLE CAUSE

REMEDY

Starting speed low.

Faulty or discharged
battery.

Charge or replace battery.

Start problems on cold
engine.

Allow sufficient cooling period
to counter for performance
drop on hot starter; preheat
engine.

Engine idles rough
after warm-up period,
smoky exhaust
emission.

CHOKE

activated.

CHOKE

Carburettors synchronized
inadequately.

Adjust carburettors.

Fuel needle unclean,
jammed, or worn.

Clean or replace.

Intake manifold leaking.

Tighten all connectors,
replace the defective parts.

Engine runs
irregularly or misfires
occasionally.

Spark plugs do not fire.

Check plugs, clean inside
and outside, re-gap.
Replace plugs if necessary.

Spark discharge over
ignition cables.

Dry wet wires.
Replace defective cables.

Defective ignition box.

Box has to be repaired, or
replace.

Clogged fuel filter.

Check, clean or renew fuel
filter.

Engine keeps running
with ignition OFF.

Overheating of engine.

Allow engine to cool down at
1400 rpm.

Defective ignition switch.

Check ground connections,
overhaul switch.

Engine runs too hot,
oil temperature
exceeds 130

°C.

Too much oil remaining in
the crankcase.

Check oil return lines for
clogging, check engine for
fuel mixture leakage.

Insufficient air stream to
oil cooler.

Check for free air passage,
clean.

Insufficient oil supply.

Check oil level, refill if
necessary.

Poor oil quality.

Change oil, use approved oil.

Clogged oil filter.

Replace.

Effectivity:

ALL

28. 04. 2021

POWER PLANT
- GENERAL

TROUBLE

POSSIBLE CAUSE

REMEDY

Knocking under load.

Octane rating of fuel too
low.

Use fuel with higher octane
rating.

Excessive oil
consumption.

Worn, broken, or
improperly installed piston
rings.

Engine overhaul required.

Poor oil quality.

Change oil, use approved oil
type.

Worn valve guides, poor
condition of valve shaft
seal.

Cylinder head repair required.

Oil leaks.

Seal.

Low oil pressure.

Not enough oil in oil tank.

Check oil level, refill if
necessary.

Hot oil.

Cool down oil.

Oil remains in the engine
and does not return to the
tank.

Check oil return line for
clogging.

No oil pressure, air in the
oil line.

Bleed oil line.

High oil pressure.

Too cold oil.

Cover oil cooler surface.

Wrong viscosity of oil.

Change oil to lower viscosity.

Engine hard to start at
low temperature.

Starting speed too low.

Preheat engine.

Faulty or discharged
battery.

Charge or replace battery.

High oil pressure.

At cold start a pressure
reading up to around 7 bar for
short period does not indicate
malfunction.

Oil pressure too low after
cold start.

Too much resistance in the
oil system at low
temperature; stop engine and
preheat oil.

NOTE

Refer to the Operators Manual for Rotax Engine Type 912 Series,
Ref. No.: OM-912 for additional information.

COWLING

POWER PLANT

- GENERAL

71-10

COWLING

1. DESCRIPTION

Engine  compartment  is  covered  by  upper  (4,  Fig.  71-2)  and  lower  (5)  cowlings.
They are made of composite. Near hot areas in the engine compartment the engine
cowling  is  locally  covered  by  heat  protection.  Upper  cowling  is  fitted  with  the  door
for  easy  check  of  oil  level.  There  are  landing  lights  (Chapter  33-40)  installed
in the lower engine cowling.
On  the  front  part  of  both  cowlings,  on  left  and  right  side,  air  intakes  are  located.
On the top of the upper cowling are located two NACA inlets. Lower cowling has one
large  air  intake.  This  air  intake  in  the  towing  version  of  aircraft  is  more  adapted.
On the left part of the lower cowling is glued the ram air tunnel.
Upper  engine  cowling  is  attached  to  the  fuselage  rim  and  lower  engine  cowling
by the quick-closing locks (Camlock); lower engine cowling is attached to the fuselage
rim by means of bolts.

2. MAINTENANCE PRACTICES

A. Engine cowlings

Type of maintenance:

Line

Personnel qualification: Independent certifying staff qualified in accordance

with Part-66 or higher.

Recommended tools, materials, persons and documentation:

ITEM

QUANTITY

Screwdriver 10

1 pc

Hex key 7

1 pc

Persons

Tab. 71-1 Recommended tools, materials, persons and documentation

WARNING

ENGINE IGNITION MUST BE SWITCHED OFF.

(1) Engine cowling removal:

(a) Make sure that the

IGNITION

switches are set to

OFF

(b)  Release all Camlocks (5, Fig. 71-2) and remove upper cowling (1).
(c)  Remove safety pins (9), and unclip the clips (11) on oil cooler holder.
(d)  Release  the  hose  clamps  (7;  8)  and  disconnect  hoses  (12;  13)

from ram air tunnel tubes (10).

(e) Disconnect the landing light connector (Chapter 33-40).
(f)

On lower cowling, unscrew bolts (3; 4) and remove washers (6)
to release water radiator holder and lower cowling.

(g) Direction from bottom to top carefully remove lower cowling (2a, 2b).

Effectivity:

ALL

28. 04. 2021

POWER PLANT
- GENERAL

(2) Engine cowlings installation:

(a) Make sure that the

IGNITION

switches are set to

OFF

(b)  Before installation check engine cowlings for cracks.
(c)  Carefully put lower cowling (2a, 2b, Fig. 71-2) to appropriate position.
(d)  Hold the cowling and attach water radiator holder and lower cowling

using washers (6) and bolts (3; 4).

(e) Connect the landing light connector (Chapter 33-40).
(f)

Connect hoses (12; 13) to the ram air tunnel tubes (10) and secure
them with safety clamps (7; 8).

(g) Attach oil cooler holder by the clips (11) and install safety pins (9).
(h) Check that no foreign objects remain in engine compartment.
(i)

Check that hose clamps, safety pins, clips and bolts are well secured.

(j)

Carefully put upper cowling (1) to appropriate position and fasten it
by camlocks (5).

(k) Check landing light function.

COWLING

POWER PLANT

- GENERAL

–

Upper engine cowling

–

Hose clamp

50 - 70

–

Lover engine cowling

–

Safety pin

1.4 x 20

–

Lover engine cowling (towing version)

–

Ram air tunnel

–

Bolt M5 x 16

For information:

–

Bolt M4 x 12

–

Clip

–

Camlock

–

Air hose ø55 x

370

–

Polyamide washer ø5.3

–

Air hose ø55 x 240

–

Hose clamp ø40

-60

Fig. 71-2 Engine Cowlings Removal / Installation

ENGINE ATTACHMENT

POWER PLANT

- GENERAL

71-20

ENGINE ATTACHMENT

1. DESCRIPTION

The engine is fixed to the airframe through engine mount (1, Fig. 71-3). The engine
mount is a weldment, made mostly of steel tubes. The engine mount is attached
to the engine through four bolts and to the firewall (3) through four rubber
silentblocks (2).

–

Engine mount

For information:

–

Silentblock

–

Firewall

Fig. 71-3 Engine Mount

Effectivity:

ALL

28. 04. 2021

POWER PLANT
- GENERAL

2. MAINTENANCE PRACTICES

A. Engine attachment

Type of maintenance:

Heavy

Personnel qualification:

Independent certifying staff qualified in accordance

with Part-66 or higher.

Recommended tools, materials, persons and documentation:

ITEM

QUANTITY

Hoist, lifting capacity 200 kg

1 pc

Wrench 19

1 pc

Wrench 13

1 pc

Wrench 12

1 pc

Wrench 10

1 pc

Wrench 8

2 pcs

Hex key 10

1 pc

Hex key 4

1 pc

Hex key 2

1 pc

Screwdriver 3

1 pc

Screwdriver 5

1 pc

Screwdriver 10

1 pc

Knife

1 pc

Oetiker pliers

1 pc

Driller

1 pc

Drill ø1

.6 mm

1 pc

Drill ø3 mm

1 pc

Stick ø13

1 pc

Heating gun

1 pc

Multimeter

1 pc

Safety clamp 14.5

1 pc

Cooper gasket ring ø14

2 pcs

Safety clamp 20.7

1 pc

Tab. 71-2 Recommended tools, materials, persons and documentation (page 1 of 2)

ENGINE ATTACHMENT

POWER PLANT

- GENERAL

ITEM

QUANTITY

Spring washer ø10

1 pc

Cable ties 2.6

Cable ties 4.8

Rags

Shrink tube 6.4 x 3.2

Pyrosil tape (fire resistant end sealing tape)

Lockwire ø0

.8 mm

Vaseline

Loctite 243

Loctite 270

Aircraft Wiring Manual (Doc. No. AS-AWM-01-000)

Maintenance Manual (Line Maintenance) for Rotax Engine
Type 912 Series, Ref. No.: MML-912

Persons

Tab. 71-2 Recommended tools, materials, persons and documentation (page 2 of 2)

WARNING

ENGINE  IGNITION  MUST  BE  SWITCHED  OFF.  DISCONNECT
NEGATIVE TERMINAL OF AIRCRAFT BATTERY.
ALWAYS  ALLOW  ENGINE  TO  COOL  DOWN  TO  OUTSIDE  AIR
TEMPERATURE BEFORE START ANY WORK.
ENSURE  THAT  THE  EMERGENCY  PARACHUTE  SYSTEM
HANDLE IS LOCKED.

(1) Engine removal:

(a) Make sure that the

IGNITION

switches are set to

OFF

(b)  Lift the aircraft and secure tail (Chapter 07-10).
(c)  Remove the engine cowlings (Chapter 71-10).
(d)  Disconnect negative terminal of battery (Chapter 24-30).
(e)  Remove the propeller (Chapter 61-10).
(f)

Remove the airbox (Chapter 71-60).

WARNING

DRAINING ALL FUEL FROM THE FUEL SYSTEM IS NOT
POSSIBLE. BE CAREFUL DURING DISASSEMBLING FUEL
SYSTEM!

Effectivity:

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28. 04. 2021

POWER PLANT
- GENERAL

(g) Drain fuel from the fuel system (Chapter 12-10).
(h) Drain oil from the oil system (Chapter 12-10).
(i)

Drain the coolant from the cooling system (Chapter 12-10).

(j)

Remove all cable ties in engine compartment.

(k) Disconnect the electric system.

NOTE

Use Aircraft Wiring Manual (Doc. No. AS-AWM-01-000).

(l)

On charging rectifier located on firewall, disconnect wires
from generator YE-106B, YE-107B (2 pcs).

(m) On firewall disconnect connector of engine rpm indicator B28.
(n) Near engine heads No.2, No.3 and near oil filter, disconnect wires

of temperature sensors M72 and M73.

(o) Near engine fuel pump, disconnect connectors of pressure oil sensor

M101.

(p)  On starter, disconnect wire of starter 101B.
(q)  On generator, disconnect wire of generator 220A.
(r)  On  SMD-Electronic  module,  use  screwdriver  and  pin  to  disconnect

wires B30, WH-113B, WH-114B from connectors.

(s) On engine cylinder head No.2, disconnect the grounding wires 221A

and 222A.

(t)

On engine cylinder head No. 3 disconnect the grounding wire 222A.

(u) On engine mount disconnect ground wire 221A.
Remove following engine systems from engine:
(v) Remove lower exhaust tubes (2, Fig. 78-1) and loosen upper exhaust

tubes (2) from engine (Chapter 78-10).

(w) Disconnect fuel hoses (1; 2; 3; 5, Fig. 28-7) from engine fuel pump

and carburettors (Chapter 28-20).

(x) Disconnect control cables of throttle controller (20, Fig. 76-3)

and choke (22) from carburettors (Chapter 76-10).

(y) Disconnect oil system (13, Fig. 71-4), by removing safety clamps (19)

and disconnecting hoses (14; 15).

(z) Disconnect cooling system by removing air hose (22, Fig. 21-5), hose

clamps (6; 27, Fig. 75-2) and water hoses (14; 17; 19) from engine.
Remove the baffle for cylinders cooling for towing version of aircraft
(Chapter 75-20).

(aa) Disconnect the drain hoses (3; 6, Fig. 71-14) from fuel pump and drip

trays (Chapter 71-70).

(bb) Lift engine with hoist just enough to relieve weight from engine mounts.
(cc) Unscrew the bolts (6; 7; 8, Fig. 71-4), remove the washers (10)

and distance rollers (9). For access to bolts (6; 8) loosen intake
manifolds (2) (see Rotax Maintenance Manual).

ENGINE ATTACHMENT

POWER PLANT

- GENERAL

(dd) Carefully pull out engine from aircraft.
(ee) On engine unscrew the bolt (5, Fig. 71-5), remove the washer (7)

and bracket (9).

–

Carburettor

–

N/A

–

Intake manifold

–

N/A

–

Seal paper

–

Oil system

–

Left drip tray

–

Oil hose

–

Right drip tray

–

Oil hose

–

Bolt M10 x 110

–

Elbow

–

Bolt M10 x 50

–

Adapter

–

Bolt M10 x 46

–

Cooper gasket ring ø14

–

Distance roller

–

Safety clamp 20.7

–

Spring washer ø10

Fig. 71-4 Engine Removal / Installation

WT9 Dynamic LSA. AIRCRAFT MAINTENANCE MANUAL (AS-AMM-01-000, 22. 05. 2017) - page 39