Sensor, Magnetic Reed, Normally Closed - With Magnet
You will need at least one 57140-000 Magnetic Actuator to use with this sensor.
This is an inexpensive, small magnetic reed switch that can be used to sense the position of an airbrake or flap actuator or to sense that the landing gear is up or down and locked.  This model is configured for "normally closed" operation which means that there is current flow when the target magnet is out of range and no current flow when it is in range.

Applications
- Airbrake handle in the forward (airbrakes locked) position
- Landing Gear in the down and locked position 
- Flap handle in the cruise region 

Features
-2 part magnetically operated proximity sensor
-Compact size requires only 3.2cm2 (1.26") board space
-Case design allows screw down or adhesive mounting
-Left or right hand side cable exit
-300mm (12") Flying leads
-UL approval

Benefits
-No standby power requirement
-Operates through non-ferrous materials such as wood, plastic or aluminum
-Hermetically sealed, magnetically operated contacts continue to operate long after optical and other technologies fail due to contamination
-Simple installation and adjustment

Terminology

• NO (Normally Open) - current flow when activated, no current flow when not activated
• NC (Normally Closed) - no current flow when activated, current flow when not activated

Applications

• Airbrakes Locked
  The goal is to have current flow when the airbrakes are not closed and locked (fully forward)
  • Use a normally closed sensor at the forward (airbrakes locked) position
• Landing Gear Down and Locked
  The goal is to have current flow when the landing gear is not down and locked.
  • If the sensor is mounted in the gear down and locked position then use a normally closed sensor (recommended).
  • If the sensor is mounted in the gear up position then use a normally open sensor.
• Flap Handle (Cruise/Climb)
  The goal is to have current flow when the flap handle is in the climb range (flaps at +1 or greater) and no current flow when the flap handle is in the cruise region (flaps at -2, -1, 0).  The magnet (or multiple magnets) is mounted on the flap actuator handle and the sensor is mounted on the cockpit sidewall.
  Note: You may need to use several magnets (actuators) to make sure the switch is activated during the full travel of the flap handle in the desired range.
  • If the sensor is mounted in the cruise region of the flap handle's travel (flaps at -2, -1, 0) then use a normally closedsensor. (recommended)
  • If the sensor is mounted in the climb region of the flap handle's travel (flaps at +1 or greater) then use a normally open sensor.

Switch Comparison
Magnetic reed sensors have some advantages and some disadvantages when compared with the mechanical lever switches.  Note that both sensor types have moving parts - reed switches have small internal mechanical switches which have a finite life - just like mechanical lever switches do.

• Magnetic Reed Switch
  • Advantage: Non-contact, no friction
  • Disadvantage: A magnetic target (actuator) must be mounted on the item being sensed.
• Mechanical Roller Switch
  • Advantage: The switch senses the actual item being sensed so no magnet needs to be mounted on the item being sensed.
  • Disadvantage: Mechanical contact is required so there will be some friction in applications where the target is moving relative to the sensor.

Dimensions and Technical Specifications
59140-040 datasheet