Extra 500. Maintenance Manual (2012)

27-00-00

GENERAL

Description

The flight controls consist of the ailerons, rudder and elevators. The right

elevator is equipped with a trim system. All these control surfaces are

constructed of composite material. The primary control system is a

conventional cable-system consisting of a double control wheel (pitch and roll)

with respective coupling systems, hanging control pedals (yaw), tubes, levers,

pulleys and push-pull rods. Between ailerons and rudder controls an

interconnection which is made via springs is installed. However, the coupling

can easily be overpowered (e.g. in side slipping).

27-00-01

Control Cable

Tensions

The control cable systems generally use cable of 3.2 mm diameter. However

the aileron control uses cables of 4 mm diameter in the wing region.

System

Cable Diameter

Cable Tension

Tolerance

Ailerons

3.2 mm/4 mm

220 N/49.5 lbs

 20 N/4.5 lbs

Rudder

3.2 mm

220 N/49.5 lbs

 20 N/4.5 lbs

Elevator

3.2 mm

300 N/67.4 lbs

 20 N/4.5 lbs

27 Page 5

27-00-10

CONTROL SPRINGS

Location

The following springs are incorporated in the control system of the

EXTRA 500:

Application

Location

Down-spring

Cockpit, instrument shelf

Interconnection aileron/rudder

Cockpit, bulkhead

Centering rudder

Tail fairing

Nose gear steering

Nose wheel dome

Nose gear control cable

Cockpit

27-00-11

Down-Spring

Description

Safety spring, affecting the pulley segment of the elevator control, to create a

nose-down pitching control force. The down-spring is located on the LH side,

below the instrument shelf.

In case of down-spring failure the amount of steering force required will rise

when pushing the control yoke. Trimming "nose down" will compensate this

effect. Malfunction of the down-spring will not cause further reductions of

flight performance or any unsafe flight conditions.

27-00-12

Interconnection Aileron/Rudder

Description

To reduce tendency to raise the low wing, esp. during low speed flight (landing

approach), the EXTRA 500 is furnished with an interconnection between the

aileron and the rudder control. When activating the rudder, the coupling

correspondingly actuates the aileron control. When moving the aileron, the

rudder — as long as being free of any control forces — remains in neutral

position.

The coupling is being accomplished by means of a pair of safety springs,

located at the LH foot compartment. The control force is conducted from the

shafts of the rudder control to the safety springs by levers and cables, including

the pulleys.

Once the friction inside the control system has been overcome, a rudder control

input is led to the LH control column by a chain drive.

27 Page 7

Failure of an interconnection spring will cause an additional force in one

direction at the aileron control, which is rated below the tolerated amount.

27-00-13

Centering Rudder

Description

Within the lower rudder bearing a spring-loaded pulley strains a steel plate

attached to the rudder, thus centering the rudder in neutral position and

providing a defined rising of control forces while moving the rudder.

Malfunction of the centering spring will disengage the centering and reduce the

control force rise. Unsafe flight conditions are excluded.

27-00-14

Nose Gear Steering

Description

The pivoting of the nose gear is part of the rudder control system, completing

the control cable arrangement. To de-couple the nose gear steering from the

rudder control, two safety springs are incorporated into the nose gear pivoting.

The springs will transmit the control force forward after having reached a

defined travel.

Malfunction of the nose gear steering springs will abolish pretension of the

control cables. With a 16° play arising inside the nose gear steering, reduction

of max. angular movement from ± 30° to approx. 10° in one direction will

occur, whereas control force at the rudder pedals will slightly increase.

27-00-15

Nose Gear Control Cable

Description

These additional springs will stretch the nose gear control cables, when one of

the springs at the nose gear pivoting has been lengthened due to a rudder

movement against the locked nose wheel.

Malfunction of one or both springs will not affect normal control functions.

Page 8 27

27-10-00

AILERONS

Description

The coupling between the two control wheels of the main control system is

realized by a direct cable-chain coupling. The cables are connected to the

control wheels by means of a longitudinal toothed wheel and run through the

windshield center strut to the wing nose and move outboard. Outside the tank

area they cross the front spar. Then they are connected to a cable segment

which actuates the aileron via lever and push-rod.

Each aileron is attached to the rear spar of the wing by two hinges.

Troubleshooting

Complaint

Possible Cause

Remedy

Lost motion in control wheel.

Loose control cables.

Check cable tension. Adjust

cables to proper tension.

Broken pulley or braket, cable

Check visually. Replace worn

of pulley or worn rod end

or broken parts, install cables

bearings.

correctly.

Resistance to control wheel

Cables too tight.

Check cable tension. Adjust

movement.

cables to proper tension.

Pulleys binding or cable off.

Observe motion of the pulleys.

Check cables visually. Replace

defective pulleys. Install

cables correctly.

Defective quadrant assembly.

Check visually. Replace

defective quadrant.

Clevis bolts in system too

Check connections where

tight.

used. Loosen, then tighten

properly and safety.

Control wheels not level with

Improper adjustment of cables.

Adjust turnbuckle to obtain

ailerons neutral

proper alignment.

Improper adjustment of

Adjust push-pull rods to obtain

aileron push-pull rods.

proper alignment.

Dual control wheels not

Cables improperly adjusted.

Adjust cables.

coordinated.

Chain improperly adjusted.

Adjust chain.

Incorrect aileron travel.

Push-pull rod not adjusted

Adjust rod.

properly.

Incorrect adjustment of travel

Adjust bolts.

stop bolts.

27 Page 9

Removal/Installation

Detail Steps/Work Items

Key Items

Loosen push rod from central part of aileron

Remove cotter pin and bolt from each of the

two hinges

Remove aileron backwards

Install in reverse order of removal

27-10-01

Aileron Cables

Removal/Installation

Detail Steps/Work Items

Key Items

Remove center cover of wing root section

Remove turnbuckle below cover

Perform steps No 3 - 9 at LH and RH side wing each

Remove turnbuckle at outer wing rib

Remove rigging clamps of role servo at

inner wing rib

Remove recognition light at outer wing nose

section

Remove outer side pulley

Push up inner side pulley

Remove teflon guiding bushings at outer

wing rib

Loosen return cable segment at outer wing

Remove bolt and push

rib for removal of 3.6 mm cable

segment sideways

Remove 2 pulleys at windshield center strut

Remove teflon guiding bushings at

windshield center strut

Remove avionic panel

Remove LH and RH side return brackets

Remove LH and RH cable safety brackets

below instrument shelf

Loosen return cable segments at steering

Remove bolts and push

column

segments sideways

Install in reverse order of removal

Page 10 27

27-20-00

RUDDER

Description

The rudder pedals are placed hanging on two tubes which have a lever arm at

the right side of the cabin. From there the cables are led along the cabin right

side armrest panel to the empennage around pulleys positioned in groups. Here

a direct connection to the lever arms of the rudder follows. The connection

points lay inside the tail cone adjacent to the lower rudder bearing.

The rudder is connected to the rear fin spar at three points.

Troubleshooting

Complaint

Possible Cause

Remedy

Play between pedals and

Insufficient cable tension.

Rig the system.

rudder.

Rudder does not respond to

Broken or disconnected

Open armrest panel, access

pedal movement.

cables.

doors and tailcone and check

visually. Connect or replace

cables.

Excessive resistance against

Cables too tight.

Rig the system.

pedal movement, binding or

Cables not running properly

Open armrest panel, access

jumpy movement of pedals.

on pulleys.

doors and tailcone and check

visually. Lay cables correctly

over pulleys.

Binding, broken or defective

Check visually. Replace

pulleys or cable guards.

defective pulleys and install

guards properly.

Pedal torque-tube bearings

Lubricate pedal bearings.

need lubrication.

Defective pedal torque-tube

Check visually. Replace

bearings.

Defective rudder hinge

Check visually. Replace

bearings.

defective bearings.

Clevis bolts too tight.

Check and readjust bolts to

eliminate binding.

Incorrect rudder travel.

Incorrect rigging.

Rig the system.

Excessive resistance against

Worn or defective nosewheel

Check visually. Replace

pedal movement only while

steering bearings

defective bearings.

gear is extended

Nosewheel does not respond

Broken or disconnected

Check visually. Connect or

to pedal movement.

cables.

replace cables.

27 Page 11

Complaint

Possible Cause

Remedy

Reduced nosewheel steering

One steering cable spring

Check visually. Replace spring

travel on one side

broken

Incorrect nosewheel steering

Incorrect rigging.

Rig the system.

travel / aircraft not rolling

straightly with pedals neutral.

Removal/Installation

Detail Steps/Work Items

Key Items

Remove right aft passenger seat

Refer to Chapter 25-20-13

Remove RH side paneling

Refer to Chapter 25-20-22

Loosen two turnbuckles of rudder cables,

located at RH wall adjacent to right aft seat

and baggage compartment

Loosen rudder cables at lower rudder

bearing

Remove bolt at LH side of central rudder

bearing

Remove lower rudder bearing

5 screws M5

Remove cotter pin and nut at lower rudder

bearing

Slightly lift rudder above higher bearing and

remove rudder backwards

Install in reverse order of removal

27-20-01

Rudder Cables

Removal/Installation

Detail Steps/Work Items

Key Items

Remove lower RH side panels in flight,

passenger and baggage compartments

Remove upper rear wall of baggage

compartment

Remove instrument shelf

Remove turnbuckle below RH side of

instrument shelf

Remove 2 turnbuckles at RH side wall in

baggage compartment

Page 12 27

Remove turnbuckle at rear wall of baggage

compartment

Remove 2 pulleys below instrument shelf

Remove safety pin from

smaller pulley

Remove 2 pulleys from RH side wall in

Remove bolts

flight compartment

Remove 2 pulleys from RH side wall in rear

Remove bolts

passenger compartment

Remove teflon guiding bushings at rear wall

of baggage compartment

Remove LH access panel at rear fin

Remove 2 smaller pulleys

Remove 2 pulleys at LH and RH side each

below instrument shelf

Remove teflon guiding bushings to nose

Remove safety sheet

wheel well

Remove nose gear cable control springs

Install in reverse order of removal

27 Page 13

27-30-00

ELEVATOR AND TAB

Description

A lever system transfers elevator control movement from each of the two

steering wheels by a respective carrier bolt bushing to a cable segment. From

this cable segment the elevator cables run horizontally to the right cabin side to

a 90° pulley and parallel to the rudder cables to the empennage. They are led to

the elevator in front of the front fin spar and are attached to a lever positioned

in front of the horizontal stabilizer front spar, which actuates the two elevator

sides separately by means of push pull rods. Each elevator is attached to the

respective horizontal stabilizer by three bearings.

The mechanical pitch trim is actuated through a trim wheel in the pedestal. The

pitch trim tab is located in the right elevator and is linked over a 'redundant'

cable-lever system to the trim wheel. The trim Bowden cables run from the

middle console down crossing the cabin floor and are then directed rearwards

to the empennage following the nose section of the fin to the right side

elevator. Pitch trim can be actuated electrically also by means of switches

located on the pilot's control wheel. The system can be overpowered by pilot's

hand forces in case of system failure.

Troubleshooting

Complaint

Possible Cause

Remedy

Play in control column.

Loose control cables.

Check cable tension. Adjust

cables to proper tension.

Broken pulley or bracket,

Check visually. Replace worn

cable off pulley, or worn rod

or broken parts, install cables

end bearings.

correctly.

Excessive resistance to control

Cables too tight.

Check cable tension. Adjust

column movement.

cables to proper tension.

Pulleys binding or cable off.

Observe motion of the pulleys.

Check cables visually. Replace

defective pulleys. Install

cables correctly.

Defective pulley quadrant

Check visually. Replace

assembly.

defective quadrant.

No nose down force on control

Down-spring disconnected.

Check visually. Attach down-

column.

spring correctly.

Page 14 27

Complaint

Possible Cause

Remedy

Binding or jumpy motion felt

Cables too tight.

Check and adjust tension.

in movement of elevator

Cables not riding correctly on

Check visually. Replace

system.

pulleys.

defective pulleys.

Defective control column

Check visually. Replace

bearings.

defective bearings.

Control guide on aft end of

Loosen screw and tapered plug

control square tube adjusted

in end of control tube enough

too tightly.

to eliminate binding.

Defective elevator hinges.

Disconnect push-pull rods and

move elevators by hand.

Replace defective hinge

bearings.

Elevator fails to attain

Stops set incorrectly.

Rig the system.

prescribed travel.

Cables tightened unevenly.

Rig the system.

Trim control wheel moves

Defective cable or deformed

Check visually and replace

with excessive resistance.

tube.

defective parts.

Trim tab hinge binding.

Disconnect actuator and move

tab up and down to check

hinge resistance. Lubricate or

replace hinge as necessary.

Defective trim tab actuator.

Disconnect cable from

actuator and operate actuator

manually. Replace defective

actuator.

Stick-slip effect between cable

Lubricate all moving parts.

and tube.

Control wheel does not move

Disconnected or broken cable.

Check visually and connect or

trim tab.

replace cable as necessary.

Play between control wheel

Parts worn out

Check visually and replace

and trim tab.

parts as necessary.

False reading on trim position

Indicator incorrectly engaged

Check visually. Adjust

indicator.

on wheel axis.

indicator.

Worn, bent or disconnected

Check visually. Repair or

linkage.

replace parts as necessary.

Incorrect trim tab travel.

Stop blocks loose or

Adjust stop blocks on cables.

incorrectly adjusted.

Incorrect rigging.

Rig the system.

27 Page 15

Removal/Installation

Detail Steps/Work Items

Key Items

RH elevator

Loosen push rod at trimming tab

8 hollow core bolts LN4

Continue as per step 1 to 5, LH elevator

LH elevator

Loosen control lever

Swivel up elevator

Remove socket pins from central and outer

2 socket pins LN6

bearings

Turn elevator horizontally backwards

around inner bearing

Remove elevator

Install in reverse order of removal

27-30-01

Elevator Cables

Removal/Installation

Detail Steps/Work Items

Key Items

Remove lower RH side panels in flight,

passenger and baggage compartments

Remove upper rear wall of baggage

compartment

Remove instrument shelf

Remove turnbuckle below RH side of

instrument shelf

Remove 2 turnbuckles at RH side wall in

baggage compartment

Remove turnbuckle at rear wall of baggage

compartment

Remove 2 pulleys below instrument shelf

Remove safety pin from

smaller pulley

Remove 2 pulleys from RH side wall in

Remove bolts

flight compartment

Remove 2 pulleys from RH side wall in rear

Remove bolts

passenger compartment

Page 16 27

27-50-00

FLAP SYSTEM

Description

The wing flaps are of the Fowler type. Each wing flap (two per side) is

attached to the rear wing spar and guided during its movement by three wing

tracks. Actuation is by means of two spindles, which are connected to the

central electrical flap motor by flexible shafts. The flap motor is located in

front of the rear spar in the fuselage area of the wing and is controlled by the

wing flap position switch in the cockpit. This switch incorporates a preselect

feature which allows the pilot to select the amount of flap extension desired.

When the UP/0°- , 15°- or

30°- position is selected, the flap motor is

electrically actuated and drives the flaps toward the selected position. When the

actual flap position equals the selected position, limit switches located at the

wing tracks respective the outer spindles de-energize the flap motor. The actual

flap position will be indicated by green lights at the left side of the wing flap

position switch. When flaps are moving the yellow light will be illuminated. If

the 0°-position is reached all lights are off.

As the flaps move an electrical circuit compares the movement of the left and

right wing flaps. If the wing flap positions differ by more than 7° ± 3°, the flap

motor will be automatically switched off to prevent asymmetric conditions.

This will be indicated by the flap error warning light located on the warning

light panel. This light indicates also a failure of the complete flap control.

NOTE

In case of the wing flaps being unbalanced, they rest in the position they

have reached when failing and cannot be actuated until airplane has been

in maintenance. However in this case the airplane can be easily balanced

by slight aileron and/or rudder input.

Setting the wing flaps will cause a decrease of airspeed and a moderate nose

down moment.

Bring wing flaps to 0°-position before opening the cabin door

CAUTION

Rigging and Adjustment

This section describes the procedure for correct adjustment of the defined flap

settings as well as the maximum flap asymmetric limits.

Due to the local chord of the flaps (30 % of the wing) and positioning the 15°

and 30° DOWN extension relative to the local chord the travel of the flaps

depends on the lateral station.

All adjustment must be made with the motor power OFF (pulled circuit

CAUTION

breaker FLAP).

NOTE

Rigging of the flap system requires a flap track snap gauge (Extra Part-

No. EA-15182W10). This will be available at EXTRA. See also Chapter

01-00-02.

Page 18 27

Track Adjustment

Perform the following adjustment checks as long as the flaps are not installed.

For flap installation, refer to Chapter 57-50-01:

Check of spanwise adjustment

Check distance between flap tracks at their rear end. Distance between inner

and middle track is 1989 ± 2 mm (78.31 ± 0.08 in.) and between middle and

outer track 1827.5 ± 2 mm (71.95 ± 0.08 in.). If further details of flap track

positioning are required, contact EXTRA.

Check of twist between tracks

Check flap tracks for proper torsional alignment (cord over all three lower

keyways). Max. permissible distance of lower keyway centerline at the middle

flap track is 2mm (0.08 in.), when cord is aligned with outer and inner flap

track keyway.

Guidance Checks and Adjustment

Check the following items after flap installation:

Minimum gap between flap and aileron

While pulling the flaps outboard against the stop, check width of gap between

aileron and outer flap segment. The stop is reached, when one of the sliding

surfaces on the outboard end of the inner or outer flap segment contacts the

middle or outer flap track. Minimum gap width is 8 mm (0.31 in.).

Check the following items after flap installation and after each 100 hours of

operation:

Spanwise flap rigging

Check whether any guidance roller on the inner track protrudes more than

3 mm (0.12 in.) outside the inner track when flaps are pulled outboard against

the stop. The stop is reached, when one of the sliding surfaces on the outboard

end of the inner or outer flap segment contacts the middle or outer flap track.

Repeat the check for the rollers in the outer flap track while pushing the flaps

inboard. Verify visually that stops are definitely reached.

Flap guidance rollers twist rigging

Minimum play in guidance keyways: Check all flap segments for minimum

free play of rollers in keyways. Lift each flap segment manually at trailing edge

and observe for positive free play of flap segment at trailing edge. Check this

for all four flap segments and for flap positions 0° and 30°. The SKF track

rollers (forward roller on inner track and both rollers on outer track) feature an

eccentric bushing to provide a means of adjustment in this respect.

Flap guidance rollers functional check

Check whether the rollers are rolling but not slipping by performing the

following test: Extend flaps to their

30° position and retract them while

manually applying a load of about 200 N (45.0 lbs.) upwards at the trailing

edge of the flaps near the respective track. If a roller is slipping identify cause

and replace roller as necessary.

27 Page 19

Inspection of roller contact areas

Inspect rear side of lower keyway on inner flap tracks for signs of axial contact

with mushroom head of roller. Contact Extra Flugzeugbau GmbH if marks are

found.

Inspect guidance roller tracks for wear and permanent deformation.

For wear and deformation the following service limits are defined:

Max. increase of track width due to deformation: 0.6 mm (0.024 in.) per side.

Width of guidance slot between 16.3 mm and 16.8 mm (0.64 in. and 0.66 in.).

Check with flap track snap gauge (see Chapter 01-00-02).

Actuation Adjustment

Ascertain that both inner flex drive shafts are disconnected from the electric

drive motor and that the flap motor and flap control circuit breakers are pulled.

Make sure for both LH and RH side flap that the respective asymmetry

detection mechanisms are not mounted yet. If they are already mounted, make

sure that the ball joint connection between linkage rod and bracket is

disconnected and the linkage rod is taped to the spar.

If this is not done, parts of the mechanism may be destroyed while

CAUTION

moving the flaps.

Lower both (LH and RH) flaps to their fully extended stop position. This can

be done by turning the hex socket coupling of the RH flex shaft CCW and the

LH flex shaft CW respectively, with view of the coupling. Use a battery hand

held drill with fine speed control and reverse feature, equipped with a 3/16 “

(4.7 mm) Allen key tip.

Do not run flaps to their extreme position (end of trackslots) with electric

CAUTION

drill to avoid damage. Turn flex shafts by hand to reach the end of the

tracks.

If the roller on one flap end rib reaches the outer end of its track slot while the

roller on the other flap end rib is 2 mm or more away from its track slot end,

an adjustment is necessary. This is done at one of the two transmission screw

jacks.

Disconnect the flap bracket from the rod end of its transmission actuator, then

move the rod into the proper direction by rotating it in steps of 180°-turns,

then reconnect. A 180°-turn of the inner transmission’s rod in CCW direction

or of the outer transmission’s rod in CW direction will move the adjacent

roller about 2 mm towards the extended position.

NOTE

The screw of the inboard transmission rod features a RH thread whereas

the outboard one features a LH thread

Raise both (LH and RH) flaps from their extended stop positions by rotating

the hex socket coupling of the flex drive shafts 2.5 turns in reverse direction to

secure a gap between rollers and track slot ends about 1.5 mm (.06"). This will

give the 30° position. Use a 3/16" (4.7 mm) Allen key and turn by hand.

The basic adjustment dimensions at the transmission actuators (measured from

the center of the mounting pin of the screw jack to the center of the rod end)

are:

Page 20 27

Position

0° Retracted

15° Intermediate

30° Extended

Inner actuator

58 + 3/- 0 mm

152 + 3/- 0 mm

270 + 3/- 0 mm

2.28 + .12/-0 inches

5.98 + .12/-0 inches

10.63+ .12/-0 inches

Outer actuator

68 + 3/- 0 mm

135 + 3/- 0 mm

219 + 3/- 0 mm

2.68 + .12/-0 inches

5.31 + .12/-0 inches

8.62 + .12/-0 inches

8 If the rod end at the transmission screw and the respective flap bracket do not

align, disconnect the rod end from the bracket and loosen the two bolts

securing the bracket to the flap. This will allow the bracket to be moved by

tapping. Connect the rod end to the bracket and tap the bracket to achieve a

satisfactory alignment. Disconnect the rod end from the bracket and torque the

bracket attachment bolts. With the transmission screw and flap bracket

aligned, finally connect the rod end to the bracket with the bolt assy.

9 When measuring flap deflection angles, lift the trailing edge of the flap to

eliminate play between rollers and track slots.

27-50-01

Flap Drive Motor

Description

Brush type bidirectional permanent magnet motor, positioned in the wing

center box at the front web of the rear spar

Characteristics:

Hex shafts on both sides

Capability of dynamic braking

Max. ambient temperature: + 40 °C

Voltage: 24 to 30 VDC, 24 VDC nominal

Torque at output shaft: 50.7 Ncm nominal at 24 VDC, 1,600 RPM, 4.5 amps

Power output: 85 W

Ratio RPM/Torque: 5.1 (Ncm ⋅ min) ^-1

Voltage factor: 0.013 V ⋅ min

Efficiency: 78 %

Insulation class IP 54 according DIN 40050 (protected against dirt, dust and

ingressed water)

27 Page 21

27-50-02

Inboard Power Transmission Flexible Shaft

Description

The inboard flexible shaft has a female 3/16" hex drive at motor side and a

DIN 75532 E1 for the screw jack side. LH and RH flex shaft are different in

main rotation due to the musk wire: CW or CCW for main rotation.

Characteristics:

1 Length: 1,400 mm

2 Core: Carbon steel musk wire φ 6 mm

3 Casing and end fittings in CRES

4 Shrink sleeve on casing

5 Minimum installation bend radius: 300 mm

6 Coupling nut 2024-T4 blue anodized or CRES with hole for safety wire

7 Min. static torque : 300 Ncm

27-50-03

Outboard Power Transmission Flexible Shaft

Description

The outboard flexible shaft is a standard type DIN 75532 E1. As for the

inboard shaft LH and RH flex shafts are different in main rotation due to the

musk wire: CW or CCW for main rotation.

Characteristics:

1 Length: 2,000 mm

2 Core: Carbon steel musk wire φ 4 mm

3 Steel casing

4 End fitting in steel zinc - plated galvanically

5 Shrink sleeve on casing

6 Minimum installation bend radius: 55 mm

7 Coupling nut aluminium with hole for safety wire

8 Min. static torque: RH 104 Ncm (CCW)/49 Ncm (CW)

LH 104 Ncm (CW)/49 Ncm (CCW)

Page 22 27

27-50-04

Power Transmission Screw Jacks

Description

The in- an outboard screw jacks consists of a reduction worm gear and

machine screw nut with trapezoid thread (irreversible by choice of pitch). The

inboard screw jacks have right hand threads, the outboard screw jacks left hand

threads. The worm shaft and the screw nut are equipped with ball bearings.

Characteristics:

Worm gear ratio: inboard 5:1

outboard 7:1

Efficiency of worm gear: inboard 0.7

outboard 0.65

Pitch of screw nut: 3 mm stroke per revolution

Number of revolutions for full stroke of screw jack (30° flap setting):

inboard 70 revolutions

outboard 50 revolutions

Stopping accuracy: ± 3 % of full stroke

The unit is sealed

All external parts are protected against corrosion

Periodic lubrication is not required

Output shaft splines: According DIN 75532 E2 for connection to the flexible

drive shafts

27-50-05

Flap Control Box

Description

A Flap Control Box providing the flap control functions is fixed into the

avionic bay with an adapted bracket, using 4 AN bolts with AN washers.

The Flap Control Box performs the following functions:

1 Controlling the motor for the 3 intended flap - positions (retracted, 15° inter-

mediate and 30° fully extended)

2 Activating the flap position signals 15°, 30° or "flaps in transition"

and:

Asymmetry detection by controlling the rheostats fitted at the outboard flaps

on the LH and RH, thus activating:

1 Motor shut-off

2 Signalisation to the warning panel inside the cockpit

Wing flap asymmetric tolerances are adjustable at the trimmer of the watchdog

box. Refer to Subject 27-50-07.

27 Page 23

27-50-06

Flap Limit Switches

Description

The 0° and 30° flap positions are detected by four limit switches, every two of

them attached to a mounting bracket positioned on the LH and RH side wing’s

rear spar web. If one DOWN or UP limit switch related to any of these flap

positions fails, the remaining one on the opposite side will still detect the

desired flap position.

The extended flap position is detected by the DOWN limit switch on the LH

flap (backup switch on the RH side) and the retracted flap position is detected

by the UP limit switch on the RH flap (backup switch on the LH side).

The switches are operated by the same linkage mechanism that is used for

asymmetry detection.

The 15° flap position is detected by two limit switches at the LH outboard

screw jack.

Adjustment

DOWN Limit Switch

Run the flaps to the 30° position determined before. If not present yet, mount

both asymmetry detection potentiometers and put the lever arm on the

potentiometer shafts, but do not tighten their clamping screws yet.

Tightening of the clamping screws may destroy parts of the mechanism

CAUTION

while moving the flaps.

At the LH side wing flap, determine the axial and the angular position of the

arm on the potentiometer shaft so that it contacts the 30° limit switch in the

center of the arm.

With the positions of the potentiometer arm and flap bracket given, adjust the

linkage rod until it fits. The start value is 66 mm (2.6”) between the ball joint

centers. The length adjustment is done by loosening the nuts and rotating the

rod, which features one LH side and one RH side thread. Tighten the rod nuts

and the ball joint nuts after the adjustment is completed, but do not tighten the

potentiometer arm clamping screw.

Manually move the flaps up to the retracted position as described in step 3 of

the Guidance Check and Adjustment Paragraph of Section 27-50-00. With the

flaps on retracted position the gap between the flap and the wing, measured at

the lower side, should be 4 mm (.16”).

Page 24 27

UP Limit Switch

Perform the same way as with the DOWN limit switch, but with the rod

linkage of the RH flap accordingly. Stop the flaps in retracted position just

before any of the flap rollers reach the end of the track slots (approximately

1.5 mm (.06") space should remain between the end of the track slot and the

closer roller of both flaps). Ascertain at least 1.5 mm (.06") clearance bet-

ween the tip of the potentiometer arm and the spar.

NOTE

Flaps must stop prior to rollers making contact with the end of the

trackslots.

Turn one drive shaft coupling (RH or LH side) manually as far as necessary to

give the right flap the same angular setting as the left flap.

Connect and safety-wire the flexible drive shafts to the electric drive motor.

Move the selector switch to position RETRACTED and engage the flap motor

circuit breaker. Run the flaps from the retracted position to the fully extended

position. When the actual flap position reaches the selected position, the

appropriate limit switch must deenergize the flap motor.

Otherwise parts may be destroyed.

CAUTION

15° Limit Switch

Run the flaps by moving the selector to the 15° position. Install the flap

rigging tool, if not previously accomplished. Rigging the flaps to the defined

15° setting max require fine adjustment at the LH outboard screw jack. This

can be accomplished by readjusting the nylon bushing positioned at the end of

the transmission screw that actuates both 15° limit switches.

Run the flaps to the 30° setting for removal of the LH outboard screw jack.

Disconnect the outer flex drive shaft from the LH outboard screw jack.

Disconnect the transmission from the flap bracket. Remove the screw jack

from the rear spar. Loosen the counter stop nut of the nylon bushing. Rotating

the nylon bushing in CW direction will shift the 15° detection to the retracted

position, rotating in CCW direction will shift it to the extended position.

Adjust as required and tighten the counter stop nut. Reinstall transmission unit

to the rear spar. Reinstall the transmission unit to the rear spar. Connect the

flex drive shaft to the transmission actuator.

Check that all bolts and joints are secured where necessary.

Check function of the position indicator. Green lights indicate the 15° and 30°

position and an additional yellow light indicating "flaps in transition". The

retracted position is indicated by the fact that no light is on.

Check the flap operation.

27 Page 25

27-50-07

Flap Asymmetry Senders

Adjustment

This adjustment is required after the flaps have been rigged and checked for

normal operation. The asymmetry senders, one potentiometer at the LH side

and one at the RH side flap, are part of an electric system, the so-called

watchdog. The watchdog shuts off the flap motor when the difference between

the LH and RH side flap angular positions exceeds 7° ± 3°.

Lower the flaps by moving the selector to the 15° position.

Pull the flap motor circuit breaker. Ascertain that the flap control circuit

breaker is engaged. Turn the sensitivity control potentiometer of the

watchdog box towards maximum sensitivity.

Adjust the LH asymmetry detection potentiometer. Make sure that the arm is

loose on the shaft, then rotate the shaft to find out the potentiometer’s center

position between its two internal stops. The angular range of the potentiometer

is ± 170 °. Then tighten the arm’s clamping screw.

Adjust the RH asymmetry detection potentiometer to ensure that the angular

travel to engage the watchdog is the same when retracting as when extending

the flaps. Make sure that the arm is loose on the shaft, then rotate the shaft in

CW direction until the red asymmetry indicator light on the watchdog box

appears (simultaneously the red light on the warning panel in the cockpit

appears). Mark this angular shaft position. Rotate the shaft in CCW direction.

The red indicator light will turn off, then light up again after rotating a few

degrees. Mark this position, too.

Finally rotate the sender shaft to the middle between the two marks and

tighten the arm’s clamping screw.

Now the two potentiometers feature the same resistance value at a given flap

position.

After adjusting, check for correct alignment of asymmetry detection

sensitivity:

With the flaps in 15° position disconnect the RH flex drive shaft from the

electric drive motor. Engage the flap motor circuit breaker and move the

selector switch to the UP position. The LH flap will move up while the RH

flap will stay in the 15° position. After a certain difference in RH and LH flap

angular positions is reached the watchdog shuts off the flap motor.

Measure the flap travel. If it is within the limit of 7° ± 3° , proceed with

step 11. If it is outside that limit, proceed with step 8.

In order to drive the LH flap back to its 15° position, disconnect the watchdog

box from the flap control box, pull the flap motor circuit breaker, move the

selector switch to the 15° position and engage the flap motor circuit breaker.

The flap starts to move back to the 15° position immediately after

CAUTION

engaging the circuit breaker.

Reconnect the watchdog box to the flap control box.

Page 26 27

10 Adjust the sensitivity control potentiometer by turning it in the proper

direction, then repeat steps 6 to 7.

After asymmetry has been adjusted for UP motion repeat this procedure for

DOWN motion:

11 Move the selector switch to the DOWN position. The LH flap will move down

while the RH flap will stay in the 15° position. When a certain difference in RH

and LH flap angular positions is reached the watchdog shuts off the flap motor.

12 Measure the flap travel. If it is within the limit of 7° ± 3° , proceed with step

16. If it is outside that limit, proceed with step 13.

13 In order to drive the LH flap back to its 15° position, disconnect the watchdog

box from the flap control box, pull the flap motor circuit breaker, move the

selector switch to the 15° position and engage the flap motor circuit breaker.

The flap starts to move back to the 15° position immediately after engaging

CAUTION the circuit breaker.

14 Reconnect the watchdog box to the flap control box.

15 Adjust the sensitivity control potentiometer by turning it in the proper direction,

but do not turn it in a way that would compromise the setting found in step 7.

Then repeat steps 11 to 12.

16 Connect and safety-wire the RH flexible drive shaft to the electric drive motor.

27 Page 27

Table of Contents

28-00-00

GENERAL

Description

Figure 28-1, Sheet 1Fuel System Schematic

Figure 28-1, Sheet 2Fuel System Schematic

Troubleshooting

Reduction of Fuel Tank Vapor Hazards

28-10-00

STORAGE

Description

28-10-01

Tank

Sealant Repair

Draining

Leakage Test

28-10-02

Drain (Curtis)

Removal/Installation

28-10-03

Flush Drain Valve

Removal/Installation

28-10-04

Pressure Relief Valve

Removal/Installation

28-10-05

Pressure Relief Valve O-ring

Replacement

28-10-06

Float Valve

Removal/Installation

28-10-07

Fuel Transfer Filter

Removal/Installation

Cleaning

28-10-08

Fuel Transfer Pump

Removal/Installation

28-10-09

Jet Pump

Removal/Installation

28-10-10

Jet Pump Filter Element

Cleaning

28-10-11

Rubber Hose

Removal/Installation

28-10-12

Pressure Switch

Removal/Installation

28-20-00

DISTRIBUTION

Description

Page 2 28

Bleeding Procedure

28-20-01

Check Valves (wing to selector valve)

Removal/Installation

28-20-02

Check Valves (downstream electrical fuel pumps)

Removal/Installation

28-20-03

Fuel Selector Valve

Function Check

Removal/Installation

28-20-04

Fuel Filter Element

Exchange

28-20-05

Electrical Fuel Pump

Removal/Installation

28-20-06

Rubber Hose

Removal/Installation

28-40-00

INDICATION

Description

28-40-01

Fuel Quantity Sensor (collector compartment)

Removal

Installation

28-40-02

Fuel Quantity Sensor (main or auxiliary compartment)

Removal

Installation

28-40-03

Fuel Quantity Gauge

Removal/Installation

Calibration

28-40-04

Fuel Flow Indicator

Removal/Installation

K-Factor Setting

28-40-05

Pressure Transducer

28-40-06

Pressure Gauge

Page Date:9. August 2013

28 Page 3

28-00-00

GENERAL

Description

The next paragraph contains the general description and operation of the fuel

system. The following paragraph contains information about Troubleshooting.

The specified descriptions of the systems, sub-systems and units can be found

in the respective chapters.

The fuel system (refer to Figure 28-01) of the aircraft is a gravity assisted,

pump fed system, supplying fuel to the engine driven fuel pump. The fuel

system consists of:

•

Two integral main tank compartments (one each wing)

•

Two integral collector compartments (one each wing) with strainer, sump,

drain and pick-up point

•

Two integral auxiliary compartments (one each wing)

•

A vent system for each tank

•

Two fuel transfer systems (left and right) for pumping fuel from the auxiliary

tank into the main tank and to keep the collector compartment full (motive

flow electrical pumps with jet pumps).

•

A fuel selector valve (LEFT - BOTH - RIGHT - OFF) located under the cockpit

floor

•

A fuel filter in the engine compartment

•

2 parallel, redundant electrical fuel pumps mounted on the firewall.

•

A fuel quantity indication system with 6 probes in the tanks and 6 indicators in

the cockpit.

•

A fuel flow transducer mounted on the battery mount in the engine

compartment.

•

A total of 12 drains (refer to Chapter 12-10-03 for locations)

28 Page 5

Troubleshooting

Complaint

Possible Cause

Remedy

Fuel tank leakage

Tank sealant damage

Identify and seal

Sump drain leakage

Inspect drain line plumbing

and seal if necessary, or

replace drain

Outer wing flush drain leakage

Replace drain valve.

Relief valve leakage

Replace relief valve/O-ring

Ventline leakage

Inspect float valves, replace if

necessary, seal vent line

connections

Fuel filler leakage

Filler cap O-ring damaged

Replace filler cap O-ring

Fuel line leakage

Line fittings loose

Tighten fittings

Collector compartment not

Fuel transfer filter blocked

Clean filter

full,

Electrical transfer fuel pump

Replace pump

auxiliary tank does not empty

defective

fast enough,

FUEL TRANS LEFT/RIGHT ON

Transfer fuel pick-up blocked

Remove blockage

in flight

Leaking transfer fuel line

Replace fitting or line

Loss of fuel supply

Strainer blocked (tank)

Clean strainer

Check valve (one of four)

Replace check valve

blocked

Selector valve blocked

Replace selector valve

Fuel line blocked

Identify and clean or replace

fuel line

Insufficient fuel supply

Filter blocked

Replace filter element.

pressure reading

Fuel pressure indication

Replace sensor/indicator

defective

Electrical fuel pump failure

Replace fuel pump

Incorrect fuel quantity reading

Float sensor defective

Repair or replace float sensor

Gauge defective

Replace gauge

Incorrect fuel flow indication

Fuel flow sensor defective

Replace sensor

Fuel flow indicator defective

Replace indicator

Wrong K-factor set

Adjust K-factor at indicator

Low fuel warning defective

Fuel low level sensor failure

Replace fuel low level sensor

Page 8 28

Reduction of Fuel Tank Vapor Hazards

General Precautions

During all ventilation or maintenance procedures involving the fuel system,

observe the following general precautions.

•

Defueling should be outdoors with the aircraft at least 100 feet from hangars or

other aircraft.

•

No smoking should be allowed within 100 feet of the aircraft.

•

Suitable fire fighting equipment should be available. Foam or soda type

extinguishing agents are recommended.

•

Ground the aircraft to prevent static electricity from causing sparks. If a ramp

ground is available it should be connected to exhaust stack. If a ramp ground is

not provided, a temporary ground can be obtained by driving a metal rod into

the ground and attaching a ground wire between the rod and the aircraft

exhaust stack.

•

Flame and spark producing equipment should not be operated within 100 feet

of the aircraft.

•

Only personnel working on the aircraft should be allowed in the immediate

area, and no other maintenance should be performed while the tanks are being

worked on.

•

When a fuel tank is opened for repair, air ventilation (refer to Page 7) should be

started immediately to reduce vapor concentrations.

•

When draining fuel, ensure that suitable containers are available and that

drained fuel is stored safely. Do not allow fuel to drip to the ground and form

pools.

•

If it is necessary to ventilate a tank when the aircraft is in hangar, ensure that

vapors do not accumulate to explosive or toxic levels in the hangar.

When fuel is being drained, there is little control over the release of fuel

WARNING

vapor. This vapor should be dissipated as quickly as possible by smoothly

blowing shop air into the tank.

Air Ventilation

•

Completely drain the fuel system per Chapter 12-10-02.

•

Remove inspection doors (refer to Chapter 28-11-03) and tank caps.

•

Use compressed air or an explosion-proof blower to blow air into the tank until

tank interior is dry and free of vapor.

•

Continue ventilation whenever tank is open and being worked on.

If flammable vapors from cleaning solvents are allowed in the tank

WARNING

increase air circulation to dissipate them.

28 Page 9

28-10-00

STORAGE

Description

The aircraft has six integral wing tanks between the wing spars. Each wing side

has a main, auxiliary, and collector compartment. The latter is kept full by a jet

pump driven fuel transfer system in flight.

The collector compartment features a fuel level sensor, a sump with drain, a

strainer and a pick-up tube behind it. The low fuel sensor is also located here.

Three flapper type check valves separate the collector compartment from the

main compartment to make sure fuel cannot flow out, but can flow in, in case

of a fuel transfer system failure. The collector compartment can be inspected

from the main compartment by opening the rib in which these valves are

mounted or from the avionic compartment (center wing) by removing the

inspection door on which the fuel quantity probe is installed.

The main compartment has its own fuel level sensor mounted on the inner

wing inspection door. The vent system has two float valves and an outlet. The

vent systems of the two main tanks are interconnected. Each tank has a 1psi

overpressure relief valve in the aft spar for the case the normal vent system

fails. The main tanks have a Ø 75mm filler cap for JET-A1 with a titanium ring

around it for static bonding.

The auxiliary compartment also has a filler cap, vent system

(including

overpressure relief valve) and fuel level sensor, but is not directly connected to

the fuel distribution system. As long as the auxiliary compartment is filled fuel

is pumped from there into the main compartment by means of the fuel transfer

system.

Observe the safety notes given in Chapter 12-10-01.

DANGER

For all maintenance work on the tanks, drain them completely and

WARNING

appropriate open tank hatches on top of the wing. Be aware of fuel fumes

and fuel stained cloth: highly inflammable!

Power must be off, no external power connected, room well ventilated.

NOTE

If the tank has been opened, a tank leakage test is mandatory. Refer to

Subject 28-10-01 Leakage Test.

Page 10 28

Extra 500. Maintenance Manual (2012) - page 8