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1SE3-3 - Textron Aviation OEM Micro Switch

1SE3-3 - Textron Aviation OEM Micro Switch

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$ 470.59 $ 470.59

1SE3-3 – Textron Aviation OEM Honeywell Micro Switch

Available now on the Airparts.aero Marketplace.

Overview

The 1SE3-3 is a flight-critical, genuine Textron Aviation Original Equipment Manufacturer (OEM) miniature snap-action switch, manufactured by Honeywell Sensing and Control. This component, part of Honeywell's MICRO SWITCH™ SE Series, is an environmentally sealed switch engineered for high reliability in the demanding conditions of aerospace applications. Its primary function is to serve as a precise limit switch, detecting the position of critical aircraft components such as landing gear, flaps, doors, or flight controls, and providing a corresponding electrical signal to the relevant indication or control system.

Built to exceed MIL-PRF-8805 standards for environmentally sealed switches, the 1SE3-3 features robust sealing to protect its internal mechanism from moisture, dust, and hydraulic fluids. Its snap-action design ensures a rapid and positive transfer of electrical contacts, providing a clean, unambiguous signal that is essential for the reliable operation of automated systems and cockpit indications. As the genuine Textron OEM part, it guarantees the correct actuation characteristics and performance required by the aircraft's type-certified design.

Key Features

  • Genuine Textron Aviation OEM Part: Guarantees the switch is the factory-specified and fully certified component, ensuring correct performance and airworthiness.

  • Environmentally Sealed: Meets or exceeds MIL-PRF-8805 Symbol 3 requirements, providing robust protection against moisture, dust, and contaminants common in airframe environments.

  • Snap-Action Mechanism: An internal over-center spring provides rapid, positive contact transfer independent of actuator speed, ensuring reliable switching and long contact life.

  • High Reliability & Durability: Engineered for demanding aerospace applications with a robust phenolic case and precision internal components for long service life.

  • SPDT Circuitry: Features Single Pole, Double Throw contacts (Common, Normally Open, Normally Closed) for versatile circuit integration.

  • Pin Plunger Actuator: A simple, direct-action pin plunger for precise position sensing.

Technical Specifications

  • Part Number: 1SE3-3

  • Component Type: Miniature Snap-Action Switch (Micro Switch)

  • OEM Authority: Textron Aviation

  • Underlying Manufacturer: Honeywell Sensing and Control

  • Series: MICRO SWITCH™ SE Series

  • Material (Case): Phenolic Plastic

  • Sealing: Environmental Seal per MIL-PRF-8805 Symbol 3 (IP67 Equivalent)

  • Actuator: Pin Plunger

  • Terminals: Turret Solder Type

  • Circuitry: SPDT (Single Pole, Double Throw)

  • Electrical Rating (Typical): 5 A Resistive @ 28 VDC

  • Operating Temperature Range: -65°F to +221°F (-54°C to +105°C)

  • Governing Specification: MIL-PRF-8805/4 (for base switch characteristics); Textron Aviation specific drawing.

Aircraft Compatibility

As a Textron Aviation OEM part based on a standard Honeywell design, this switch is specified for numerous critical position-sensing applications across their diverse fleet.

  • Primary Textron Aviation Platforms:

    • Cessna Citation Series Business Jets

    • Beechcraft King Air Series

    • Hawker Business Jets

    • Cessna Caravan and Piston Aircraft

  • General Aerospace Usage: The underlying Honeywell 1SE3-3 is widely used across the aerospace industry.

Note: Verification of applicability is the absolute responsibility of the installer. The aircraft's current Illustrated Parts Catalog (IPC) and Wiring Diagram Manual (WDM) for its specific serial number are the final authorities for confirming part number eligibility.

Applications

  • Landing Gear Systems: Up-lock and down-lock position sensing, weight-on-wheels (WOW) sensing.

  • Flight Control Systems: Flap, slat, and spoiler position indication.

  • Door Systems: Main entry door, cargo door, and access panel closed-and-locked indication.

  • Thrust Reverser Systems: Deployed and stowed position sensing.

  • Engine Controls: Throttle lever position sensing (e.g., idle, takeoff power).

Why Choose this 1SE3-3?

The failure of a limit switch in a critical system like landing gear or flaps can lead to unsafe operating conditions or prevent dispatch. The genuine Textron OEM 1SE3-3 guarantees that the switch has the correct actuation force, travel parameters, sealing integrity, and electrical characteristics specified by the aircraft's designers. Using a non-certified, generic switch risks incorrect system operation, false indications, or premature failure due to environmental factors, compromising flight safety.

The high reliability of the 1SE3-3 switch is significantly enhanced by its snap-action, over-center mechanism. Inside the sealed phenolic case, a pre-stressed beryllium copper spring is held in one of two stable positions. As the pin plunger actuator is depressed, it applies force to the spring. When the plunger's travel reaches a precisely engineered "trip point," it pushes the spring past its geometric center. This causes the stored mechanical energy to be released almost instantaneously, forcing the movable electrical contact to "snap" to its opposite terminal with high speed and force, independent of how slowly the plunger was moved. This rapid transfer minimizes the duration of any electrical arc between the contacts as they make or break, drastically reducing contact erosion and heat generation. Furthermore, the positive snap provides excellent resistance to contact "teasing" or chatter under vibration, ensuring a clean, reliable electrical signal essential for interfacing with modern digital avionics.

Note: This is a flight-critical component. Installation, adjustment (if applicable), and testing must be performed by a certified A&P or avionics technician in strict accordance with the aircraft maintenance manual and wiring diagrams. Correct wiring polarity and secure mounting are essential. Post-installation functional testing of the associated system is mandatory.

Documentation

The base military specification for this switch type is publicly available. Manufacturer datasheets for the Honeywell 1SE3-3 provide general characteristics. OEM-specific application and installation data is contained within the Textron Aviation maintenance and parts manuals.