chapter 27 flight controls - extra aircraft manual and illustrated parts catalogue extra ea-400...

Maintenance Manual and Illustrated Parts Catalogue

Extra EA -400

Page Date: 8. December 1999 27

Chapter 27 Flight Controls


Extra EA -400 Flight Controls

27 Page Date: 27. September 2000

TABLE OF CONTENTS

27-00-00 GENERAL .........................................................................................................4 Description ..........................................................................................................4

27-00-01 Cable Tensions ...................................................................................................4

27-01-00 CONTROL SPRINGS.......................................................................................6 Location...............................................................................................................6

27-01-01 Down-Spring ......................................................................................................6 Description ..........................................................................................................6

27-01-02 Interconnection Aileron / Rudder....................................................................6 Description ..........................................................................................................6

27-01-03 Centering Rudder..............................................................................................7 Description ..........................................................................................................7

27-01-04 Nose Gear Steering ............................................................................................7 Description ..........................................................................................................7

27-01-05 Nose Gear Control Cable ..................................................................................7 Description ..........................................................................................................7

27-10-00 AILERONS ........................................................................................................8 Description ..........................................................................................................8 Troubleshooting...................................................................................................9 Removal / Installation........................................................................................10

27-10-01 Aileron Cables..................................................................................................11 Removal / Installation........................................................................................11

27-20-00 RUDDER..........................................................................................................12 Description ........................................................................................................12 Troubleshooting.................................................................................................13 Removal / Installation........................................................................................14

27-20-01 Rudder Cables .................................................................................................15 Removal / Installation........................................................................................15



Page Date: 27. September 2000 27

27-30-00 ELEVATOR AND TAB ................................................................................. 16 Description........................................................................................................ 16 Troubleshooting ................................................................................................ 17 Elevator Control System ................................................................................... 17 Elevator Trim Tab Control System ................................................................... 18 Removal / Installation....................................................................................... 19

27-30-01 Elevator Cables ............................................................................................... 20 Removal / Installation....................................................................................... 20

27-50-00 FLAP SYSTEM............................................................................................... 21 Description........................................................................................................ 21

27-51-00 FLAP DRIVE SYSTEM ................................................................................. 22 Description........................................................................................................ 22

27-51-01 Drive Unit......................................................................................................... 22

27-51-02 Power Transmission........................................................................................ 22

27-52-00 FLAP CONTROL SYSTEM ......................................................................... 24 Description........................................................................................................ 24

27-53-00 RIGGING AND ADJUSTMENT FLAP SYS TEM ..................................... 25

27-53-01 Flap Track Adjustment .................................................................................. 25

27-53-02 Flap Guidance Checks and Adjustment ....................................................... 25

27-53-03 Flap Actuation Adjustment............................................................................ 26

27-53-04 Adjustment of Flap Limit Switches............................................................... 28

27-53-05 Flap Asymmetry Senders ............................................................................... 30 Adjustment ........................................................................................................ 30




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 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




Figure 27-01 System Surview




27-01-00 CONTROL SPRINGS

Location

The following springs are incorporated in the control system of the EA-400:

Application Location

Down-spring Cockpit, instrument shelf

Interconnection aileron / rudder Cockpit, bulkhead

Centering rudder Tailcone fairing

Nose gear steering Nose wheel dome

Nose gear control cable Cockpit

27-01-01 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.

27-01-02 Interconnection Aileron / Rudder

Description

To reduce tendency to raise the low wing, esp. during low speed flight (landing approach), the EA-400 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. Failure of an interconnection spring will cause an additional force in one direction at the aileron control, which is rated below the tolerated amount.




27-01-03 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.

27-01-04 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.

27-01-05 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.




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

Loose control cables. Check cable tension. Adjust cables to proper tension.

Lost motion in control wheel.

Broken pulley or braket, cable of pulley or worn rod end bearings.

Check visually. Replace worn or broken parts, install cables correctly.

Cables too tight. Check cable tension. Adjust 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 visua lly. Replace defective quadrant.

Resistance to control wheel movement.

Clevis bolts in system too tight.

Check connections where used. Loosen, then tighten properly and safety.

Improper adjustment of cables. Adjust turnbuckle to obtain proper alignment.

Control wheels not level with ailerons neutral

Improper adjustment of aileron push-pull rods.

Adjust push-pull rods to obtain proper alignment.

Cables improperly adjusted. Refer to paragraph XX. Dual control wheels not coordinated.

Chain improperly adjusted. Refer to paragraph XX.

Push-pull rod not adjusted properly.

Refer to paragraph XX. Incorrect aileron travel.

Incorrect adjustment of travel stop bolts.

Refer to paragraph XX.




Removal / Installation

Detail Steps/Work Items Key Items

Removal

1 Loosen push rod from central part of aileron

2 Remove cotter pin and bolt from each of the two hinges

3 Remove aileron backwards

Installation

Install in reverse order of removal




27-10-01 Aileron Cables



Removal

1 Remove center cover of wing root section

2 Remove turnbuckle below cover

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

3 Remove turnbuckle at outer wing rib

4 Remove rigging clamps of role servo at inner wing rib

5 Remove recognition light at outer wing nose section

6 Remove outer side pulley

7 Push up inner side pulley

8 Remove teflon guiding bushings at outer wing rib

9 Loosen return cable segment at outer wing rib for removal of 3.6 mm cable

Remove bolt and push segment sideways

10 Remove 2 pulleys at windshield center strut

11 Remove teflon guiding bushings at windshield center strut

12 Remove avionic panel

13 Remove LH and RH side return brackets

14 Remove LH and RH cable safety brackets below instrument shelf

15 Loosen return cable segments at steering column

Remove bolts and push segments sideways

Installation





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


Rudder does not respond to pedal movement.

Broken or disconnected cables.

Open armrest panel, access plates and check visually. Connect or replace cables.

Cables too tight. Rig the system in accordance with paragraph XX.

Cables not riding properly on pulleys.

Open armrest panel, access plates and check visually. Route cables correctly over pulleys.

Binding, broken or defective pulleys or cable guards.

Open armrest panal, access plates and check visually. Replace defective pulleys and install guards properly.

Pedal bears need lubrication. Lubricate pedal bears.

Defective rudder bar bearings. If lubricate fails to eleminate binding. Replace bearing blocks.

Defective rudder hinge bushings.

Check visually. Replace defective bushings.

Clevis bolts too thight. Check and readjust bolts to eleminate binding.

Binding or jumpy movement of rudder pedals.

Steering rods improperly adjusted.

Rig the system in accordance with paragraph XX.

Lost motion between rudder pedals and rudder.

Insufficient cable tension. Rig the system in accordance with paragraph XX.

Incorrect rudder travel. Incorrect rigging. Rig in accordance XX.






Removal

1 Remove right aft seat Refer to Ch 25-21-02

2 Remove RH side panelling

3 Loosen two turnbuckles of rudder cables, located at RH wall adjacent to right aft seat and baggage compartment

4 Loosen rudder cables at lower rudder bearing

5 Remove bolt at LH side of central rudder bearing

6 Remove lower rudder bearing 5 screws M5

7 Remove cotter pin and nut at lower rudder bearing

8 Slightly lift rudder above higher bearing and remove rudder backwards

Installation





27-20-01 Rudder Cables



Removal

1 Remove lower RH side panels in flight, passenger and baggage compartments

2 Remove upper rear wall of baggage compartment

3 Remove instrument shelf

4 Remove turnbuckle below RH side of instrument shelf

5 Remove 2 turnbuckles at RH side wall in baggage compartment

6 Remove turnbuckle at rear wall of baggage compartment

7 Remove 2 pulleys below instrument shelf Remove safety pin from smaller pulley

8 Remove 2 pulleys from RH side wall in flight compartment

Remove bolts

9 Remove 2 pulleys from RH side wall in rear passenger compartment

Remove bolts

10 Remove teflon guiding bushings at rear wall of baggage compartment

11 Remove LH access panel at rear fin

12 Remove 2 smaller pulleys

13 Remove 2 pulleys at LH and RH side each below instrument shelf

14 Remove teflon guiding bushings to nose wheel well

Remove safety sheet

15 Remove nose gear cable control springs

Installation





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

Elevator Control System


Loose control cables. Check cable tension. Adjust cables to proper tension.

Lost motion in control wheel.

Broken pulley or bracket, cable of pulley or worn rod end bearings.

Check visually. Replace worn or broken parts, install cables correctly.

Cables too tight. Check cable tension. Adjust cables to proper tension.

Pulleys binding or cable off. Observe motion of the pulleyes. Check cables visually. Replace defective pulleys. Install cables correctly.

Defective quadrant assembly. Check visually. Replace defective quadrant.

Resistance to control wheel movement.

Clevis bolts in system too tight.

Check connections where used. Loosen, then tighten properly and safety.

No nose down force on control wheel.

Down-spring disconnected. Check visually. Attach down-spring correctly.

Cables slack. Check and adjust to tens ion specified in paragraph XX.

Cables not riding correctly on pulleys.

Check visually. Replace defective rollers.

Defective control column bearing rollers.

Check visually. Replace defective rollers.

Defective control column torque tube bearings.

Disconnect necessary items and check that bearings rotate freely. Replace defective bearing.

Control guide on aft end of control square tube adjusted too tightly.

Loosen screwand tapered plugin end of control tube enough to eliminate binding.

Binding or jumpy motion felt in movement of elevator system.

Defective elevator hinges. Disconnect push-pull tube and move elevators by hand. Replace defective hinges.





Stops incorrectly set. Rig in accordance with paragraph XX.

Cables tightened unevenly. Rig in accordance with paragraph XX.

Elevators fail to attain prescribed travel.

Interference at instrument panel.

Rig in accordance with paragraph XX.

Elevator Trim Tab Control System


Defective cable or tube. Check visually and replace 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.

Trim control wheel moves with excessive resistance.

Stick-slip effect between cable and tube.

Lubricate all moving parts.

Disconnected or broken cable. Check visually and connect or replace cable as necessary.

Lost motion between control wheel and trim tab.

Unacceptable free play. Reduce free play in accordance with paragraph XX.

Indicator incorrectly engaged on wheel track.

Check visually. Adjust indicator.

False reading on trim position indicator.

Worn, bent or disconnected linkage.

Check visually. Repair or replace parts as necessary.

Stop blocks loose or incorrectly adjusted.

Adjust stop blocks on cables. Incorrect trim tab travel.

Incorrect rigging. Refer to paragraph XX.






Removal

RH elevator

1 Loosen push rod at trimming tab 8 hollow core bolts LN4

2 Continue as per step 1 to 5, LH elevator

LH elevator

1 Loosen control lever

2 Swivel up elevator

3 Remove socket pins from central and outer bearings

2 socket pins LN6

4 Turn elevator horizontally backwards around inner bearing

5 Remove elevator

Installation





27-30-01 Elevator Cables



Removal

1 Remove lower RH side panels in flight, passenger and baggage compartments

2 Remove upper rear wall of baggage compartment

3 Remove instrument shelf

4 Remove turnbuckle below RH side of instrument shelf

5 Remove 2 turnbuckles at RH side wall in baggage compartment

6 Remove turnbuckle at rear wall of baggage compartment

7 Remove 2 pulleys below instrument shelf Remove safety pin from smaller pulley

8 Remove 2 pulleys from RH side wall in flight compartment

Remove bolts

9 Remove 2 pulleys from RH side wall in rear passenger compartment

Remove bolts

10 Remove teflon guiding bushings at rear wall of baggage compartment

11 Remove LH tailcone access panel

12 Remove 2 clamps of pitch servo

13 Remove LH access panel at rear fin

14 Remove 2 larger pulleys

15 Remove linkage between cable and aileron Remove bolt

16 Remove push rod

Installation





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.

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




27-51-00 FLAP DRIVE SYSTEM

Description

27-51-01 Drive Unit Electrical Motor Brush type bidirectional permanent magnet motor (Engel GNM 4175 mod), positioned in the wing center box at the front web of the rear spar

Characteristics: 1 Hex shafts on both sides

2 Capability of dynamic braking

3 Max. ambient temperature: + 40 °C

4 Voltage: 24 to 30 VDC, 24 VDC nominal

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

6 Power output: 85 W

7 Ratio RPM / Torque: 5.1 (Ncm ⋅ min) -1

8 Voltage factor: 0.013 V ⋅ min

9 Efficiency: 78 %

10 Insulation class IP 54 according DIN 40050 (protected against dirt, dust and ingressed water)

27-51-02 Power Transmission

Flexible Shafts Inboard The inboard flex 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




Flexible Shafts Outboard The outboard flex 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)

Screw Jack Inboard & Outboard The screw jack consists of a reduction worm gear and machine screw nut with trapezoid thread (irreversible by choice of pitch). The worm shaft and the screw nut are equipped with all bearings. Characteristics:

1 Worm gear ratio: inboard 5:1 outboard 7:1

2 Efficiency of worm gear: inboard 0.7 outboard 0.65

3 Pitch of screw nut: 3 mm stroke per revolution

4 Number of revolutions for full stroke of screw jack (30° flap setting): inboard 70 revolutions outboard 50 revolutions

5 Stopping accuracy: ± 3 % of full stroke

6 The unit is sealed

7 All external parts are protected against corrosion

8 Periodic lubrication is not required

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




27-52-00 FLAP CONTROL SYSTEM

Description

The two electrical units providing the flap control functions are located in the fuselage area of the wing, in front of the rear spar.

The Flap Control Box (Becker FCB 400-1) 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"

The Watchdog (Becker FZB 400-1) performs the following functions: 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 Ch. 27-53-05.




27-53-00 RIGGING AND ADJUSTMENT FLAP SYSTEM

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.

CAUTION All adjustment must be made with the motor power OFF (pulled circuit 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 Flugzeugbau GmbH. Drawing see also Chapt. 05-00-01.

27-53-01 Flap Track Adjustment Perform the following adjustment checks as long as the flaps are not installed. For flap installation, refer to Ch . 57-50-01.

1 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 Flugzeugbau GmbH.

2 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.

27-53-02 Flap Guidance Checks and Adjustment

Check the following items after flap installation:

1 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.).

Page Date: 5. July 2002




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

2 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.

3 Flap guidance rollers twist rigging Minimum play in guidance keyways: Check all flap segments fo r 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.

4 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.

5 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 Chapt. 05-00-01).

27-53-03 Flap Actuation Adjustment 1 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.

2 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.

CAUTION If this is not done, parts of the mechanism may be destroyed while moving the flaps.





3 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.

CAUTION Do not run flaps to their extreme position (end of trackslots) with electric drill to avoid damage. Turn flex shafts by hand to reach the end of the tracks.

4 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.

5 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

6

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:

Position 0° Retracted 15° Intermediate 30° Extended

7

Inner actuator 58 + 3 / - 0 mm 2.28 + .12/-0 inches

152 + 3 / - 0 mm 5.98 + .12/-0 inches

270 + 3 / - 0 mm 10.63+ .12/-0 inches

Outer actuator 68 + 3 / - 0 mm 2.68 + .12/-0 inches

135 + 3 / - 0 mm 5.31 + .12/-0 inches

219 + 3 / - 0 mm 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.




27-53-04 Adjustment of Flap Limit Switches 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.

DOWN Limit Switch

1 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.

CAUTION Tightening of the clamping screws may destroy parts of the mechanism while moving the flaps.

2 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.

3 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.

4 Manually move the flaps up to the retracted position as described in Chapter 27-53-02, step 3. With the flaps on retracted position the gap between the flap and the wing, measured at the lower side, should be 4 mm (.16”).





UP Limit Switch

1 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.

2 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.

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

4 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.

CAUTION Otherwise parts may be destroyed.

15° Limit Switch

1 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 transmission unit. This can be accomplished by readjusting the nylon bushing positioned at the end of the transmission screw that actuates both 15° limit switches.

2 Run the flaps to the 30° setting for removal of the LH outboard transmission unit. Disconnect the outer flex drive shaft from the LH outboard trans-mission actuator. Disconnect the transmission from the flap bracket. Remove the transmission unit 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.

3 Check that all bolts and joints are secured where necessary.

4 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.

5 Check the flap operation.




27-53-05 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°.

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

2 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.

3 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.

4 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.

5 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:

6 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.

7 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.




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.

CAUTION The flap starts to move back to the 15° position immediately after engaging the circuit breaker.

9 Reconnect the watchdog box to the flap control box.

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.

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

chapter 27 flight controls - extra aircraft manual and illustrated parts catalogue extra ea-400...

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