WT9 Dynamic LSA. AIRCRAFT MAINTENANCE MANUAL (AS-AMM-01-000, 22. 05. 2017) - page 11

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SERVICING

Engine cleaning

CAUTION

DO NOT USE EASILY FLAMMABLE LIQUIDS OR CAUSTIC
CLEANING AGENT FOR CLEANING THE ENGINE!

Repair leaks if required before cleaning. Always clean engine in cold state.
Usage  of  commercially  available  cold  cleaning  agent  for  the  engine  is
recommended - see Maintenance Manual (Line Maintenance) for Rotax Engine
Type 912 Series (Ref. No. MML-912), Chapter 05-00-00, Chapter 1.5).
Never  clean  the  engine  with  cleaner  under  high  pressure.  This  is  damaging
to electrical  installations and shaft  seals. Oxidation of the various components
and their failure may follow.
Before cleaning, all openings through which cleaning agents and/or dirty water
could enter to the engine have to be closed.
After  each  cleaning  procedure,  dry  all  electrical  components  such  as  battery,
ignition unit,  spark plug connector, clamp connection etc.  with  compressed air
to prevent short circuits.

CAUTION

WHEN  CLEANING  THE  ENGINE,  THE  DISSOLVES  RESIDUES
OF  FUEL,  OIL  AND  OTHER  ENVIRONMENT-CONTAMINATING
AGENTS  ARE  RINSED  OFF.  COLLECT  THE  RESIDUAL  LIQUIDS
AND DISPOSE THEM IN ENVIRONMENT FRIENDLY WAY.

Propeller cleaning
Propeller EVRA PerformanceLine 175/xxx/805.5:

Clean the propeller with water mixed with soap or detergent using a sponge
and finish with the chamois.
The metal shields on leading edge may be re-polished using fine sandpaper,
taking care not to alter the surface of the coating. Lightly coat the metal shields
with liquid paraffin to prevent oxidation. Repeat periodically to keep this protective
oily film.

Propeller KW-31:

For cleaning instruction refer to

“

UM-05 EN - User Manual Aircraft Propeller

Type-Model KW-

31”,

last valid issue.

UNSCHEDULED SERVICING

SERVICING

12-30

UNSCHEDULED SERVICING

1. DESCRIPTION

This chapter contains information regarding unscheduled service which includes
removal of ice and snow from the aircraft.

2. MAINTENANCE PRACTICES

A. Winter maintenance

Type of maintenance:

Line

Personnel qualification:

Pilot/Owner qualified in accordance with M.A.803
or higher

Recommended tools, materials, persons and documentation:

ITEM

QUANTITY

Soft brush

1 pc

De-icing fluid

Soft cloth

Persons

Tab. 12-18 Recommended tools, materials, persons and documentation

Contamination  of  aircraft  surface  by  ice  or  snow  degrades  the  aerodynamic
characteristics of the aircraft and increases its weight. It is therefore important
to get rid of any deposit of ice or snow before flight. If possible, put the aircraft
in a heated hangar to remove ice.

WARNING

ICE OR SNOW MUST BE COMPLETELY REMOVED FROM
THE UPPER AND LOWER SURFACES OF THE AIRCRAFT.

CAUTION

DO NOT USE SHARP OBJECTS TO REMOVE SNOW OR ICE. YOU
CAN DAMAGE THE AIRCRAFT STRUCTURE.

(1) Ice and snow removal:

(a) Use a soft brush and remove snow from the aircraft.
(b) Spray an approved de-icing fluid on ice covered surfaces

with a suitable spray bottle.

removed.

CONTENTS

STANDARD

PRACTICES - AIRFRAME

20 STANDARD

PRACTICES - AIRFRAME

CONTENTS

GENERAL ......................................................................... 3

INTRODUCTION ....................................................................... 3

20-10

TORQUE DATA ................................................................ 5

DESCRIPTION .......................................................................... 5

MAINTENANCE PRACTICES ................................................... 5

Fasteners installation ........................................................ 5

Torque wrenches ............................................................... 6

Torque values .................................................................... 8

20-20

SAFETYING ...................................................................... 9

DESCRIPTION .......................................................................... 9

MAINTENANCE PRACTICES ................................................. 10

Lockwire .......................................................................... 10

Cotter pins ....................................................................... 14

Self-locking nuts .............................................................. 16

Lock washers .................................................................. 16

Loctite .............................................................................. 17

GENERAL

STANDARD

PRACTICES - AIRFRAME

20-00

GENERAL

1. INTRODUCTION

This chapter describes the standard maintenance practices for maintaining items of
the airframe and systems that are typical to more than one area or system, in an
airworthy condition.

Maintenance practices that are unique to a particular system or subject are described
in the appropriate chapter in the maintenance manual.

Maintenance practices in a particular chapter supersede the general information in
this chapter.

The information is broken down into several sections. The following is a list of the
information contained in each chapter.

20-10 Torque Data

This chapter contains general information and provides maintenance practices for
torque of fasteners.

20-20 Safetying

This chapter contains general information and provides maintenance practices for the
installation of lock wire, cotter pins, self-locking nuts, lock washers, and Loctite.

TORQUE DATA

STANDARD

PRACTICES - AIRFRAME

20-10 TORQUE DATA

1. DESCRIPTION

This chapter deals with general torque used to ensure security of installation and
prevent overstressing components.

The torque value tables, listed in this chapter, are standard torque values for the nut
and bolt combinations shown. Special torque values for specific installations are
given in maintenance practices and installation instructions applicable to the various
components.

Torqueing is not required for bolts, nuts, and screws installed in the control systems
or other installations where torque would interfere with proper operation of parts.
On such applications, the assembly shall be firm, but not tight enough to cause
binding.

2. MAINTENANCE PRACTICES

Fasteners installation

(1) Bolts:

(a) When installing bolts, ensure that the threads are free of foreign

material.

(b) Do not use anti-seize compounds or lubricant unless specified in the

specific instructions.

(2) Nuts:

(a) When installing castellated nuts for use with safety wire or cotter pin,

align holes by tightening nut to low torque range and continue to
tighten until holes align. lf holes cannot be aligned without exceeding
the maximum torque value, a washer of different thickness may be
used or another washer added.

(b) When installing self-locking nuts, always use the same type nut as

removed. Self-locking nuts are for one-time use only and must not be
reused. Self-locking nuts should not be substituted for castellated
nuts secured by safety wire or cotter pin. Fiber or nylon self-locking
nuts should not be used in areas subject to high temperature. Do not
use self-locking nuts at joints which are subject to rotation by either
the nut or bolt.

(3) Washers:

(a) When installing a lock washer against aluminum alloy, a cadmium

plated flat washer should be installed between lock washer and
aluminum alloy.

(b) Use of the wrong type or number of washers can result in improper

preloading of the bolts when torqued.

countersunk washer must be used with the countersink next to the
bolt radius, under the bolt head. Reversing a counter- sunk washer or
installing a standard washer can result in bolt failure (Fig. 20-1).

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Fig. 20-1 Washer Installation

– Close Tolerance Bolts

Torque wrenches

Whenever possible, use the torque wrench when tightening of threaded
fasteners.

(1) Use of a torque wrench:

(a) Whenever possible, the nut shall be torqued. When is necessary to

torque the bolt head, the bolt shall be torqued to the high torque
value plus shank friction, if any.

(b) Calibrate torque wrenches periodically to ensure accuracy.

is reached without rotating the nut, the nut must be backed off and
re-torqued.

(d) When torqueing requires the use of an adapter, the torque value

must be computed using Fig. 20-2.

TORQUE DATA

STANDARD

PRACTICES - AIRFRAME

Fig. 20-2 Torque Wrench and Adapter Formulas

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PRACTICES - AIRFRAME

Torque values

The torque values have been calculated on the assumption that no lubrication is
used on the bolted joints and that cadmium plating is a standard surface finish.

STRENGTH CLASS

METRIC

THREAD

10K

12K

MAXIMAL TORQUE VALUE

N.m

kg.m

1.67
0.17

N.m

kg.m

3.45
0.35

N.m

kg.m

4.31
0.44

4.90
0.50

5.39
0.55

5.88
0.60

6.86
0.70

7.84
0.80

8.33
0.85

9.80
1.00

13.72

1.40

16.67

1.70

N.m

kg.m

5.88
0.60

7.84
0.30

8.82
0.90

9.80
1.00

10.78

1.10

11.76

1.20

12.74

1.30

14.70

1.50

20.59

2.10

25.49

2.60

N.m

kg.m

8.33
0.85

10.78

1.10

12.74

1.30

13.72

1.40

15.69

1.60

17.65

1.80

19.61

2.00

22.55

2.30

32.36

3.30

38.24

3.90

M10

N.m

kg.m

16.18

1.65

21.57

2.20

24.51

2.50

27.45

2.80

31.38

3.20

34.32

3.50

37.26

3.80

44.12

4.50

61.78

6.30

73.54

7.50

M12

N.m

kg.m

27.45

2.80

36.28

3.70

42.16

4.30

47.07

4.80

52.95

5.40

58.83

6.00

63.74

6.50

74.53

7.60

104.93

10.70

125.52

12.80

M14

N.m

kg.m

43.14

4.4

58.83

6.00

66.68

6.80

73.54

7.50

78.54

8.00

93.16

9.50

98.06
10.00

117.67

12.00

164.75

16.80

196.13

20.00

M16

N.m

kg.m

60.80

6.20

78.45

8.00

93.13

9.5

98.06
10.00

107.87

11.50

127.48

13.00

131.29

14.00

164.75

16.80

225.55

23.00

274.58

28.00

M18

N.m

kg.m

88.25

9.00

117.67

12.0

137.29

14.00

156.90

16.00

171.61

17.50

196.13

20.00

205.93

21.00

245.16

25.00

343.23

35.00

411.87

42.00

M20

N.m

kg.m

117.67

12.00

156.90

16.00

176.51

18.00

196.13

20.00

225.55

23.00

245.16

25.00

274.58

28.00

313.81

32.00

441.29

45.00

539.36

55.00

M22

N.m

kg.m

147.09

15.00

196.13

20.00

225.55

23.00

245.16

25.00

284.39

29.00

313.81

32.00

33.42
34.00

392.26

40.00

558.97

57.00

676.65

69.00

M24

N.m

kg.m

205.93

21.00

274.58

28.00

313.81

32.00

353.03

36.00

392.26

40.00

441.29

45.00

470.71

48.00

549.17

56.00

755.11

77.00

970.85

99.00

Ultimate strength

100

120

In %

Yield point

108

Tab. 20-1 Recommended Fastener Torque Value

SAFETYING

STANDARD

PRACTICES - AIRFRAME

20-20 SAFETYING

1. DESCRIPTION

The use of safety wire, cotter pins, lock washers, self-locking nuts, and Loctite is to
prevent relative movement of critical components subject to vibration, torque, tension,
etc., which could cause attaching parts to be broken, loosened and or detached.

All attachment points for rotating surfaces should be attached with castellated nuts,
cotter pins or lock wire and drilled bolt shanks. The use of self-locking nuts is not
permitted on rotating joints.

If the locking effect of a component is limited, always replace it with a new
component.

Every non-locked nut or bolt (without cotter pin, self-locking nut, serrated locking
washer…), must be locked using some kind of Loctite.
During assembling, always use the following new parts:



Cotter pin



Roll pin



Tab washer



Serrated locking washer



Rivets



Safety clamps



Cable ties



Sealing adhesive tape



Gasket ring



Lock wire



Pyrosil tape



Shrink cable



Sealing ring

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STANDARD
PRACTICES - AIRFRAME

2. MAINTENANCE PRACTICES

Lockwire

Lock wire comes in two types, which are identified by size:



Zinc plated and Tin-plated steel wire. Used for general lock wiring
procedures.



Corrosion resistant steel wire. This wire is to be used in areas with high
temperature and chemical corrosion.

For general-purpose lock wiring, 0.5 mm diameter wire is used on treads from
M4 to M10, and 0.8 mm diameter wire is used on threads M12 and up.

(1) Method:

The double-twist method of lock wiring should be used as the common
method of lock wiring (Fig. 20-3; 20-4). The single wire method of lock
wiring may be used in closely spaced, closed geometrical pattern (triangle,
square, circle, etc.), on parts in electrical systems, and in places that
would make the single wire method more advisable. Closely spaced
should be considered a maximum of 50 mm between centers.

CAUTION

SCREWS IN CLOSELY SPACED GEOMETRIC PATTERNS WHICH
SECURE HYDRAULLC OR AIR SEALS, HOLD HYDRAULIC
PRESSURE, OR WHERE USED IN CRITICAL AREAS, SHOULD
USE THE DOUBLE-TWIST METHOD OF LOCK WIRING.

(2) Spacing:

(a) When lock wiring is widely spaced in multiple groups using the

double-twist method, three units should be the maximum number in
series.

(b) When lock wiring is closely spaced in multiple groups, the number of

units that can be lock wired by 600 mm length of wire should be the
maximum number in series.

fastenings are from 100 to 150 mm apart. Lock wiring should not be
used to secure fasteners or fittings which are spaced more than
150 mm apart, unless tie points are provided on adjacent parts to
shorten the span of the lock wire to less than 150 mm.

(3) Tension:

(a) Parts should be lock wired in such a manner that the lock wire should

be put in tension when the parts tend to loosen. The lock wire should
always be installed and twisted so the loop around the head stays
down and does not tend to come up over the bolt head and leave a
stacked loop.

SAFETYING

STANDARD

PRACTICES - AIRFRAME

NOTE

This does not necessarily apply to the castellated nuts when the
slot is close to the top of the nut, the wire will be more secure if
it is made to pass along the side of the stud.

(b) Care should be exercised when installing lock wire to ensure it is

tight but not overstressed.

(4) Use of a lock wire:

(a) When removing lock wire ensure that all pieces are removed.

(b) Use only new lock wire of the same type and diameter as that which

was removed. Never reuse lock wire.

pigtail should be bent back or under to prevent it from becoming a
snag.

(d) When castellated nuts are to be secured with lock wire, tighten the

nut to the low side of the selected torque range otherwise specified,
and, if necessary, continue tightening until a slot aligns with the hole.
ln no case should you exceed the high side torque range.

(e) Drain plugs and cocks may be safetied to a bolt, nut or other part

having a free lock hole in accordance with the instruction described
in this chapter.

(f)

When locking is required on electrical connectors (Fig. 20-5) which
use threaded couplings, or on plugs which employ screws or rings to
fasten the individual parts of the plug together, they should be lock
wired with 0,5 mm diameter wire in accordance with the locking
principles as describes and illustrated. lt is preferable to lock wire all
electrical connectors individually. Do not lock wire one connector to
another unless it is necessary to do so.

(g) Lock wire shall not be used on emergency devices that would

depend on fracture of lock wire for operation. However, where
existing structural equipment or safety-of-flight emergency devices
require shear wire to secure equipment while not in use, but which
are dependent upon shearing or breaking the lock wire for successful
emergency operation of equipment, particular care should be
exercised to assure that wiring under these circumstances will not
prevent emergency operations of these devices.

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STANDARD
PRACTICES - AIRFRAME

Fig. 20-3 Lockwire Safetying

SAFETYING

STANDARD

PRACTICES - AIRFRAME

Fig. 20-4 RH Thread Lockwiring Examples

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Fig. 20-5 Electrical Connectors Lockwiring Examples

Cotter pins

(1) Use of cotter pins:

(a) Select cotter pins in accordance with atmosphere and service

limitations.

(b) Use only a new cotter pin of the same type as the one removed.

Never reuse cotter pins.

the nut to the low side of applicable specified or selected torque
range, unless otherwise specified, and if necessary, continue
tightening until the slot aligns with the hole. ln no case should you
exceed the high side torque range.

(d) Castellated nuts mounted on bolts may be safetied with cotter pins or

lock wire. The preferred method is with a cotter pin, bent parallel to
the axis of the bolt (Fig. 20-6). The alternate method, where the
cotter pin is mounted normal to the axis of the bolt, may be used
when the cotter pin in the preferred method may become a snag.

(e) ln the event than the cotter pin diameter is above the nut castellation,

a washer should be used under the nut or a shorter fastener should
be used. A maximum of two washers is per- mitted under the nut.

(f)

Use the largest nominal diameter cotter pin that the hole and slots
will accommodate. No application of cotter pin to any nut or fastener
is permitted if the fastener hole size is less than the required hole
and slot size for the cotter pin.

(g) lnstall the cotter pin with the head firmly in the slot of the nut with the

axis of eye at right angles to the bolt shank. Bend prongs so the head
and upper prong are firmly seated against the bolt.

(h) ln pin applications, install the cotter pin with the axis of eye parallel to

the shank of pin. Bend prongs around the shank of the pin.

SAFETYING

STANDARD

PRACTICES - AIRFRAME

(i)

lnstall the cotter pins (if it is possible):
- from above-downwards
- from the front-backwards.

(j)

Cadmium plated cotter pins should not be used in applications
bringing them in contact with fuel, hydraulic fluid or synthetic
lubricant.

(k) If using a castellated nut and new bolt, screw the castellated nut to

operating position and use diameter 1,6 mm drill to drill a hole for the
cotter pin.

Fig. 20-6 Cotter Pin Safetying

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STANDARD
PRACTICES - AIRFRAME

Self-locking nuts

Self-locking nuts may be used in some applications. The following guidelines
must be followed when using self-locking nuts:

(1) Use of self-locking nuts:

(a) Self-locking nuts must be installed so at least two threads of bolt,

stud or screw are visible.

(b) Self-locking nuts, which are attached to the structure, will be attached

in a positive manner to eliminate the possibility of their rotation or
misalignment when tightening the bolt and screw.

(d) Use only a new self-locking nut of the same type as the one

removed.

Lock washers

Lock washers may be used provided the following conditions are met:

(1) Use of lock washers:

(a) When self-locking feature cannot be provided in externally or

internally threaded parts.

(b) When a cotter pin cannot be used to prevent rotation of internal

threads with respect to external threads.

parts.

(d) When loosening of threaded parts will not endanger the safety of the

aircraft or occupants.

(e) When corrosion is encouraged by the gouging of aluminum by edges

of teeth on tooth locked washers, this will cause malfunction of parts
being fastened together.

(2) The following guidelines must be followed when using lock washers:

(a) Use only new washer for each assembly.

(b) When bending or setting the washer tabs, do not use sharp pointed

tools. Use of such tools can lead to subsequent failure of the locking
tabs that, upon becoming detached, can cause extensive damage.

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