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AVIADESIGN INC.

MAINTENANCE MANUAL:

M-8101

HYDRAULIC LANDING GEAR RETRACT SYSTEM. APPLICABLE TO:

ALL KING AIR, QUEEN AIR, BEECH 99, AND MERLIN II AIRCRAFT, MODIFIED IN ACCORDANCE WITH ONE OF THE FOLLOWING S.T.C.'s: SA 4328 WE SA 4013 WE SA 4378 WP SA 1876 NM SA 3217 NM

NOTE: COVERS THE RETRACTION SYSTEM ONLY, UP TO AND INCLUDING THE ACTUATORS. EXTERNAL MECHANICAL DOWNLOCKS AND THE REMAINDER OF THE GEAR MUST BE MAINTAINED IN ACCORDANCE WITH THE ORIGINAL MANTENANCE MANUAL.

DEC. 5,1997

Page 1.

AVIADESIGN INC. M-8101

TABLE OF CONTENTS:

REVISION STATUS

PAGE 3

HYDRAULIC SYSTEM - GENERAL DESCRIPTION

PAGE 4

ROUTINE MAINTENANCE

PAGE 5

RIGGING THE MAIN GEAR

PAGE 7

RIGGING THE NOSE GEAR

PAGE 7

SERVICING THE SYSTEM AFTER AN EMERGENCY EXTENSION

PAGE 8

BLEED VALVE

PAGE 9

LEAKS

PAGE10

LOCATION OF COMPONENTS AND SYSTEM SCHEMATIC

APP.'A'

ELECTRICAL WIRING DIAGRAM

APP. 'B'

MAIN PARTS LIST APPLICABLE TO AIRCRAFT MODEL

APP. 'C'

MAIN ACTUATOR

APP. 'D'

NOSE ACTUATOR

APP. 'E'

DEC. 5,1997

Page 2.

AVIADESIGN INC M-8101 REVISION STATUS: NEW EDITION DATED

DEC. 5,1997

DEC. 5,1997

Page 3.

AVIADESIGN INC. M-8101 HYDRAULIC SYSTEM: GENERAL DESCRIPTION: The nose and main landing gear are retracted and extended by hydraulic actuators which receive fluid under pressure from an electrically driven pump located in the leading edge of the left hand wing. System pressure is maintained between 1500 and 2000 p.s.i.* by a pressure switch, which, via a relay, cycles the electric motor on and off. An amber light, located on the instrument panel, illuminates when power is applied to the motor. The light will remain on during landing gear retraction and extension. The nose actuator has an internal lock that provides a positive downlock for the nosegear. The original mechanical downlocks on the main gear drag braces are retained. The three legs are held in the UP position by system pressure, the extinguishing of the red 'in-transit' light in the gear handle, indicates that the landing gear is fully retracted. During flight, the pressure in the system may slowly bleed down until the pressure switch cuts in and activates the electrically driven pump to build the pressure back up. This pump operation will be indicated by a brief flash of the amber light in the cockpit. A tight system with a fully charged accumulator will hold pressure for an hour before the light flashes. Excessive intermittent operation of the pump is an indication of a leak or other malfunction. The system is designed to operate using hydraulic fluid to Spec. MIL-0-5606. • On 90 and 100 Series aircraft prior to May 1 1985, the system pressure cycles between 1150 and 1500 p.s.i.

DEC. 5,1997

Page 4.

AVIADESIGN INC. M-8101 ROUTINE MAINTENANCE: The components of the system are not life limited. Serviceability is determined on a 'on condition' basis. Every 1000 hrs OR every major inspection, carry out the following routine check: 1.

Place the aircraft on jacks in the approved manner as detailed in the manufacturers maintenance manual.

2.

Interconnect a manual pump (complete with a one gallon reservoir and a 3000 p.s.i. pressure guage) into the system at the service tee fitting. This fitting is located downstream of the pump check valve.

3.

Deactivate the pump and motor by disconnecting the plug on the pressure switch.

4.

Disconnect the pressure relief valve and the thermal relief valve from the system and cap off the lines.

5.

Disconnect the accumulator from the system and cap off the line.

6.

Pressurise the system to 3000 p.s.i.

IMPORTANT:

THE LANDING GEAR CONTROL CIRCUIT BREAKER MUST BE IN AND THE POWER 'ON' FOR THIS TEST TO ENSURE THAT POWER IS APPLIED TO THE SELECTOR VALVE. WITHOUT POWER, THE SELECTOR WILL REMAIN IN THE NEUTRAL POSITION AND EFFECTIVELY BLOCK PRESSURE TO THE ACTUATORS.

7.

When the pressure reaches 3000 p.s.i., the system must remain within 50 p.s.i. of this pressure for one minute without additional pumping.

8.

If this criteria cannot be met, locate and rectify the leak then repeat the test.

8.

Reconnect the THERMAL relief valve and pressurise the system until the valve opens. The cracking pressure of the valve should be 2200 + or - 50 p.s.i.*

9.

With the gear doors disconnected, select 'gear up' and retract using the hand pump. Take the gear up slowly and check the flex lines for clearance and signs of chafing.

NOTE: 10.

EXCESS FLUID MAY VENT FROM THE RESERVOIR OVERFLOW. When the gear reaches the up position, increase the pressure to 3000 p.s.i. The system must again remain within 50 p.s.i. of this pressure for one minute.

* On 90 and 100 Series aircraft prior to May 1985, 1700 + or - 50 p.s.i.

AUG. 5, 1998

Page 5.

AVIADESIGN INC. M-8101 ROUTINE MAINTENANCE ... cont. 11.

Pull the 5 amp L/G control breaker, reconnect the pressure switch plug and reset the 5 amp breaker. Extend the gear with the normal system.

13.

Reconnect the pressure relief valve and pressurise the system until the valve opens. The cracking pressure for this valve is the same as the thermal relief valve, 2200 + or 50 p.s.i.* NOTE: To prevent pressure bleeding off through the thermal relief valve during this test, interrupt power to the selector valve.

14.

Disconnect manual pump from service tee and cap tee.

15.

Check emergency nitrogen bottle is charged to 1500 p.s.i.

16.

With gear in down position and system pressurised, open manual nitrogen valve in the cockpit and check for leaks between the valve and the actuators. Maximum leakage rate, 50 p.s.i. in ten minutes.

17.

Close the manual nitrogen valve and bleed off the pressure in the emergency system by loosening the line at the bleed valve in the nosewheel well. Prior to re-connecting the line, check that the bleed valve is open. Blow air gently into the bleed valve fitting and check the top of the valve for a flow of air. (Refer to Page 9.)

18.

Change the filter element. Part No. AN6235-2A.

19.

Charge the accumulator to 1250 p.s.i. Re-connect to the system. NOTE: To ensure that the accumulator is fully charged, it must be disconnected from the system.

20.

Recharge the emergency nitrogen bottle to 1500 p.s.i. WARNING NEVER, UNDER ANY CIRCUMSTANCES, MANUALLY OPERATE THE SOLENOID BUTTONS ON THE SELECTOR VALVE WHEN THE AIRCRAFT IS SUPPORTED BY THE LANDING GEAR.

On early 90 and 100 series installations, 1700 + or - 50 p.s.i.

AUG. 5, 1998

Page 6

AVIADESIGN INC. M-8101 RIGGING THE MAIN GEAR: 1.

Connect the manual pump to the down side of the actuator and apply 1500 p.s.i.

2.

With the main gear down and locked and the downlock link out of the way, adjust the forkend out until it is just possible to insert the clevis bolt into the slot in the drag link. Assemble the forkend and downlock link to the drag link (with the downlock engaged). Be sure to check that there is no binding. Secure the forkend in this position with the nut and tab lock washer. THE ACTUATOR MUST BE UNDER SUSTAINED SYSTEM PRESSURE WHEN MAKING THIS ADJUSTMENT. NOTE: SIDE LOAD ON THE ACTUATOR FORK END IS NOT PERMISSABLE.

3.

Relieve the pressure and connect the pump to the up side of the actuator.

4.

Disconnect the gear doors. Slowly pump the gear up. Check for minimum clearance to the snubber block. Check for proper rigging of the door. If adjustment is needed the stroke of the actuator may be shortened or lenghtened by loosening the lock ring and rotating the barrel in or out of the trunnion. It is easier to turn the barrel if the forkend is diconnected from the draglink, thus allowing the piston and rod to turn with the cylinder. DO NOT allow the adjustment of the forkend to change. NOTE: A MAXIMUM OF TEN THREADS SHOWING IS PERMISSABLE.

RIGGING THE NOSE GEAR: 1.

Connect the manual pump to the down side of the actuator and apply 1500 p.s.i. With the drag brace in the locked down position, apply a 100 pound load at the drag brace joint, forcing the joint over center. Unscrew the actuator fork end until the attach bolt can be inserted through the drag brace. Remove the 100 pound load. THE ACTUATOR MUST BE UNDER SUSTAINED FULL SYSTEM PRESSURE WHEN MAKING THIS ADJUSTMENT. NOTE: SIDE LOAD ON THE ACTUATOR FORK END IS NOT PERMISSABLE.

2.

Disconnect the pump from the actuator. With both up and down lines disconnected, attempt to retract the gear by applying a 100 pound upward force to the drag brace and a rearward force to the nose wheel. The internal lock must hold.

3.

Connect the manual pump to the up side of the actuator and SLOWLY apply pressure. The mechanical lock must release at 100 to 200 p.s.i.

4.

Slowly retract the gear checking for clearance and chafing problems Adjust the up position by rotating the top cap of the actuator. NOTE: A MAXIMUM OF 10 THREADS SHOWING IS PERMISSIBLE. DO NOT DISASSEMBLE ANY MALFUNCTIONING ACTUATOR, SELECTOR VALVE, PRESSURE SWITCH OR PUMP. CONTACT THE SERVICE DEPT. 208-338-1850

DEC. 5,1997

Page 7.

AVIADESIGN INC. M-81 01 SERVICING THE SYSTEM AFTER AN EMERGENCY EXTENSION: After the emergency system has been used, proceed as follows: 1.

Place the aircraft on jacks in the approved manner outlined in the manufacturers maintenance manual.

2.

Fully close the manual vent and the manual nitrogen valve in the cockpit.

3.

Remove the nose actuator access panel and disconnect the emergency line from the actuator. Bleed off the pressure in the line slowly and listen for three audible clicks as the shuttle valves return to the normal position. The shuttle valves are located in the end caps of the actuators, refer to Appendices 'D' and 'E'.

4.

Disconnect the down line at the nose actuator cap allowing trapped pressure to bleed off. Check the fluid in the reservoir and top up to 2.0 in. below the top of the filler plug.

5.

Retract the landing gear to the up position on the normal system. NOTE:

A SMALL QUANTITY OF FLUID WILL BE EJECTED FROM THE OPEN FITTING OF THE ACTUATOR. IT IS ADVISABLE TO PLACE A RAG OVER THIS AREA UNTIL THE GEAR IS FULLY RETRACTED.

6.

Re-connect the downline of the nose actuator and cycle the gear down and up 6 times. Check that the motor remains cool. Leave the gear in the down position with the power on.

7.

If oil leaks from the open emergency fitting, it indicates that the 'O' ring of the shuttle valve in the nose actuator has been damaged and must be replaced.

8.

If oil leaks from the open emergency line, it indicates the one, or both, of the 'O' rings of the main actuator shuttle valves have been damaged and must be replaced.

9.

Other indications of shuttle valve leakage are: (i) Cycling of the pump with the gear in the down position (ii) Gear will not fully retract.

10.

Recharge the emergency nitrogen bottle to 1500 p.s.i.

11.

Refill the hydraulic reservoir to 2.0 in. below the top of the filler plug.

12.

Cycle the gear 10 times to purge the sytem. Allow sufficient time between each cycle for the bubbles to dissipate in the reservoir.

13.

Prior to re-connecting the emergency nitrogen line, check that the bleed valve is open by blowing gently into the open line. Check the top of the bleed valve for a flow of air.

DEC. 5,1997

Page 8.

AVIADESIGN INC. M-81 01 BLEED VALVE The function of the bleed valve, in the emergency line, is to prevent a buildup of pressure due to minor leakage of the manual nitrogen shut-off valve. The closing pressure may vary between 50 and 150 p.s.i. There should be zero leakage from the valve at 150 p.s.i. and above. After testing, or using, the emergency system, check that the valve has opened, (i.e. the ball has dropped), by blowing air lightly thru one of the connecting lines and checking that there is flow out of the bleed hole at the top of the valve. If this valve is not open and a small leak does occur at the manual nitrogen control valve, pressure will build up in the emergency lines and the shuttle valves will be slowly pushed over. Eventually the shuttle valves will block the flow of fluid out of the actuator and the gear will not retract. Normal down operation is not affected by this malfunction therefore no safety hazard is involved but a trip could be delayed. It is a simple matter to check that the valve is open.

DEC. 5,1997

Page 9.

AVIADESIGN INC. M-8101 LEAKS: A good tight system should not leak, however, an occasional drip along the shaft of an actuator may occur. This type of leak is caused by a small particle of dirt getting past the wiper and unseating the 'O' ring. Continued operation will usually cure this type of leak, but be sure to monitor the level of the fluid in the reservoir. Similarly the pump will occasionally leak a few drops of fluid from the the seal drain. The pump dynamic seal is a 'metal to metal' type and sensitive to small particles. Continued operation could dislodge the particle and reseat the seal. Two indications of how serious a leak may be, are: 1.

How frequently does the system cycle in flight and most important,

2.

How much fluid is being added to the system on a regular basis.

A good system should need only an occasional addition of fluid. To sum up: Occasional drips and seepage, although unsightly, may be acceptable depending on the rate of fluid consumption. The level of the fluid in the reservoir should be checked on preflight and a record of the amount of fluid added to the system should be part of the maintenance records of the aircraft.

DEC. 5,1997

Page 10.

QTY

PART NUMBER

DESCRIPTION

90

A100

B100

200

F90

QA

MLN

99

1

1

ADI-7999-002-1

NOSE ACTUATOR

2

1

ADI-7999-002-1A

NOSE ACTUATOR

3

2

ADI-7999-003-3

MAIN ACTUATOR

4

2

ADI-7999-003-3A

MAIN ACTUATOR

x

5

1

ADI-7999-004-3

HYD.RES.& SCREEN

x

x

x

x

x

x

x

X

6

1

ADI-7999-005-30

EMERGENCY BOTTLE

x

x

x

x

x

x

x

X

7

1

H.P.-300-1

HYDRAULIC PUMP

x

x

x

x

x

x

x

X

8

1

1225P36-3

PRESSURE SWITCH

x

x

x

x

x

x

x

X

9

1

25800/25400

SELECTOR VALVE (incl. Guard)

x

x

x

x

x

x

x

X

10

2

AN6249-6

CHECK VALVE

x

x

x

x

x

x

x

X

11

2

MS28893-C-6

PRESSURE RELIEF VALVE

x

x

x

x

x

x

x

X

12

1

MS28720-6

HTDRAULIC OIL FILTER

x

x

x

x

x

x

x

X

13

2

668123-3

RESTRICTOR VALVE

x

x

x

x

x

x

x

X

14

1

ADI-15VA

BLEED VALVE

x

x

x

x

x

x

x

X

15

1

ADI-7999-002-15

BRIDGE FITTING

16

1

MS28700-1

ACCUMULATOR

x

x

x

x

x

x

x

X

17

1

PDLM-60

CIRCUIT BREAKER

x

x

x

x

x

x

x

X

18

1

MS25041-4

AMBERLIGHT & BRACKET

x

x

x

x

x

x

x

X

19

1

AN3370-1

RELAY (incl. diode)

x

x

x

x

x

x

x

X

20

1

ADI-7999-005-1

BRACKET ASSY. (res.)

x

x

21

1

-2

DOUBLER, RES. DOOR

x

x

x

x

x

x

x

X

22

1

-3

MOUNTING BRACKET

x

x

x

x

x

x

x

X

23

1

-4

MOUNTING BRACKET, SEL.

x

24

1

-5

MOUNTING BRACKET, MAN.

x

x

x

x

x

x

X

25

1

-9

BRACKET, EMER. BOTTLE

x

x

x

x

x

x

x

X

26

1

-10

BRACKET, FILTER

x

x

x

x

x

x

x

X

27

1

-11

CONTROL BOX ASSY.

x

x

x

x

x

x

x

X

28

1

-12

ANGLE SUPPORT, RES.

x

x

29

1

-13

ANGLE SUPPORT, RES.

x

x

30

1

-14

COVER, NOSE ACCT.

31

1

-15

SUPPORT (with phenolic & clamp)

x

x

x

x

x

x

x

X

32

1

-16

BRACKET, ACCUM.

x

x

x

x

x

x

x

X

33

2

-19

MANIFOLD BLOCK

x

x

x

x

x

x

x

X

34

1

-20

TOP HAT; LONG (90,s add 1)

x

x

x

x

x

x

x

X

DEC. 5, 1997

X x

x

x

x

x

x

x

x

x

x

x

x X

x

X

X

APPENDIX 'C'

PACK