32A Landing gear – Monitoring and indicating

TTP	B1-L3	ATA32A
Beech 90 Series	B2-L3	Landing gear – Monitoring and indicating

 Landing gear warning and indicators 

CBs are on the WARNINGS section of the right CB panel. A landing gear warning horn sounds if the landing gear is not down and locked during flight. The warning horn mode varies, depending on flap position. The horn also sounds if the landing gear control handle is moved out of the DN position while the aircraft is on the ground.

To silence the warning horn, press the GEAR WARN SILENCE button adjacent to the landing gear control handle. On the  C90B and subsequent, silence the warning horn by pressing the silence button on the left power lever. The circuit is protected by a 5-ampere breaker,  placarded  LG WARN  HORN,  on  the right subpanel.

    Power for the intransit and GEAR DOWN lights is drawn from a 5-amp LANDING GEAR/IND circuit breaker on the right CB panel. A circuit to the intransit lights is completed through the drag brace downlock and up-position switches of each landing gear. The up-position switches are in the upper part of each wheel well. 

   A circuit to the GEAR DOWN lights is completed through the drag brace downlock switches of each landing gear. When the landing gear is in the fully retracted position, each landing gear strut actuates  its  respective  up-position  switch  to  open the circuit  to the intransit  lights. The intransit lights remain illuminated until all three landing gears are fully retracted and all three downlock switches are opened. As soon as the landing gear moves from the fully retracted position, each landing gear strut actuates its respective up-posi- tion switch to illuminate the intransit lights. The intransit lights extinguish when the drag brace of each landing gear actuates its respective down- lock switch, opening the circuit to the intransit lights and completing the circuit to the respective GEAR DOWN light. Illumination of the nose geardown light also requires actuation of the nose gear actuator downlock switch.

Landing Gear Position Lights

Visual indication of the landing gear position is provided by two red in-transit lights in the landing gear control switch handle, and a green GEAR DOWN NOSE/L/R indicator  light,  adjacent to the landing gear control  switch on the left inboard subpanel. Illumination of the red in transit lights indicates the landing gear is extending or retracting; the lights extinguish when the gear is up or down. Illumination of the green GEAR DOWN lights indicate the landing gear is down and locked. 

HD LT/TEST pushbutton tests operation of the red intransit indicator lights in the landing gear control handle. Momentarily pressing the pushbutton should illuminate the lights.To check the GEAR DOWN lights, press the light assembly case.

Landing Gear Warning Horn

The landing gear warning and indicators circuit breakers are on the WARNINGS section of the right CB panel.

A landing gear warning horn sounds if the landing gear is not down and locked during flight. The warning horn mode varies, depending on flap position. The horn also sounds if the landing gear control handle is moved out of the DN position while the aircraft is on the ground. 

 To silence the warning horn, press the GEAR WARN SILENCE button adjacent to the landing gear control handle. On the  C90B and subsequent, silence the warning horn by pressing the silence button on the left power lever.

Landing Gear Warning System

 

A landing gear warning system warns the pilot the landing gear is not down and locked during certain flight conditions (refer to the MSM). These conditions vary depending upon the posi- tion of the flaps. With the flaps positioned to up or approach, retarding either or both power levers below 79—81% activates an intermittent landing gear warning horn and the gear handle intransit lights.  Cam  operated  switches  on  brackets  in the pedestal provide power to the warning horn through  the  5-amp  landing  gear  warning  circuit breaker. Advancing the power levers above 79—81%  silences  the  horn.  Additionally,  the horn can, with the power levers below 79—81%, be silenced by momentarily pressing the horn silence button. The intransit lights remain illuminated. The button is on the left inboard subpanel through LJ-1319; starting with LJ-1320, the but- ton is left of the power lever handle.

 If the warning horn is silenced, the landing gear warning system is re-armed if the power levers are advanced above the 79—81%.

 With the landing gear retracted and the flaps extended beyond approach, the warning horn and the intransit lights are actuated regardless of the power lever position, and the horn CANNOT be silenced.

Hydraulic fluid low-level sensor is on the motor end of the powerpack. A HYD FLUID LO annunciator illuminates when a low fluid exists. A yellow HYD FLUID LO annunciator on the glare shield illuminates when the hydraulic fluid in the secondary reservoir becomes low.

An  optical  sensing  unit  on  the  motor end of the power pack contains the light source, sensor,  and  switching  circuitry  to  trigger  the fluid  low  annunciator.  The  unit  also  contains an integral self-test circuit that can be activated by a push-button on the pilot inboard subpanel.

To prevent intermittent or spurious annunciator illumination,  the sensing and test circuitry has incorporated into the circuitry a time delay of up to 5 seconds to illuminate and 15 seconds to extinguish the annunciator light. If a HYD FLUID LOW light is illuminated, the landing gear prob- ably will  not extend with the  powerpack. The King Air C90A/B/GT/GTi has no backup timer mechanism to protect the pump from running dry. Once the up or down cycle has been initiated with a lack of fluid in the system, the only way to stop the powerpack pump from running is to pull the 2-amp circuit breaker adjacent to the landing gear handle.

Landing Gear Control Handle Indicator Lights

The landing gear indications include two red parallel-wired  indicators. These  intransit  lights illuminate when the gear is in transit or unlocked. They also illuminate when the landing gear warning horn sounds. They extinguish when the landing gear is fully extended and locked.

 

Gear Down Indicators

The GEAR DOWN/NOSE/L/R indicators illuminate when the respective landing gear is fully extended  and  locked.  If  the  control  handle  is down  with  indicators  illuminated,  the  landing gear is safe. If the handle is up and the indicators are not illuminated, the landing gear is not down.

 

Gear Warning Silence Pushbutton

Pressing the GEAR WARN/SILENCE pushbutton on the C90B silences the landing gear warning horn if the flaps are at approach or above.

Handle Light Test Switch

The HD LT/TEST pushbutton tests operation of the red intransit indicator lights in the landing gear control handle. Momentarily pressing the pushbutton should illuminate the lights.

 

Downlock Switch

The DOWN LOCK REL  switch  overrides the downlock hook for the landing gear control handle. If either the downlock hook solenoid or a safety squat switch malfunction and the down- lock hook is not pulled back, push the downlock to release tab down to unlock the landing gear control handle.

 

Landing Gear Relay Circuit Breaker

The 2-amp LANDING GEAR/RELAY circuit breaker powers the landing gear control handle downlock hook solenoid and the landing gear remote circuit breaker.

 

Hydraulic Fluid Sensor Test Switch

The HYD FLUID SENSOR-TEST pushbutton verifies the hydraulic fluid level sensor operation. Press and hold this pushbutton to test the sensor. The HYD FLUID LO annunciator warning light should illuminate on the annunciator panel within 5 seconds and, when the pushbutton is released, should extinguish within 15 seconds.

Landing Gear Safety Switches

 

Several aircraft  systems are wired through the landing gear safety switches on the right and left main gear torque knees.

 

Right Safety Switch

•  Landing gear handle downlock hook (solenoid controlled)

•  Landing gear retraction

•  Ground maximum electric heat

•  Hour meter

 

Left Safety Switch

•  Landing gear retraction

•  Stall warning heat (plate only)

•  Door seal solenoid

•  Cabin pressure safety (dump) solenoid

 

•  Cabin  pressure  preset  solenoid  (for  the cabin pressurization controller)

 

•  Right ambient air shutoff solenoid (6-second right pneumostat time delay)

HYD FLUID LO Annunciator

 

The HYD FLUID LO indicator is an amber caution light on the cockpit annunciator panel. It indicates the hydraulic system fluid level is low. It also illuminates when the HYD FLUID SENSOR TEST switch is depressed and held.

LANDING GEAR SYSTEM (LJ-1 THRU LJ-1062,

LW-1 AND AFTER)

Landing Gear Control Switch

Landing gear system operation is controlled by a manually actuated wheel-shaped switch, on the right subpanel.

Landing Gear Position Indication Light

 

Landing gear position is indicated by three green indicator  lights  on the pilot’s  control pedestal, placarded GEAR DOWN. These lights  have  a press-to-test feature. The circuit is protected by 5-ampere fuse, placarded LG IND, on the right subpanel.

 Landing Gear Warning Horn

 

When either power lever is retarded past a warning horn and light  microswitch, with the gear not down and locked, a warning horn behind the instrument panel on the left side will sound intermittently. The circuit is protected by a 5-ampere breaker,  placarded  LG WARN  HORN,  on  the right subpanel.

 Landing Gear Retraction System

 

The landing gear retraction  system consists of an electric motor, gearbox and clutch assembly, torque tube assemblies, main gear actuators, nose gear actuator, and two chains and sprockets. The landing gear retraction system is operated by the landing gear handle located on the subpanel in the pilot’s compartment.

PTP  Beech 90 Series	B1	LOC	FOT		R/I	MEL	TS
	B2	LOC	FOT		R/I	MEL	TS