S2224-1 - Textron Aviation OEM Micro Switch

S2224-1 – Textron Aviation OEM Stall Warning System Micro Switch

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Overview

The S2224-1 is a flight-critical, genuine Textron Aviation Original Equipment Manufacturer (OEM) miniature snap-action switch. This component, commonly known as a micro switch, is the primary sensor for the aerodynamic stall warning system on a vast range of Cessna aircraft. Its function is to provide an electrical signal to the cockpit annunciator (horn or light) when the aircraft is approaching an aerodynamic stall. It achieves this by being mechanically linked to a small vane on the wing's leading edge, which lifts due to the changing airflow at high angles of attack.

This is not a simple switch; it is a high-precision, environmentally sealed device engineered for exceptional reliability and repeatability. Its internal snap-action mechanism ensures a positive, instantaneous electrical contact, which is essential for providing a clear and timely warning of an impending stall. As a genuine Textron OEM part, it is guaranteed to have the precise actuation force and travel characteristics required for this critical safety system.

Key Features

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

• Flight-Critical Safety Component: The primary sensor for the stall warning system, a legally required and life-saving piece of equipment.

• Snap-Action Mechanism: An internal over-center spring mechanism provides a rapid, positive contact transfer that is independent of the actuator's speed, ensuring a clean electrical signal and long contact life.

• High-Precision, Repeatable Actuation: Engineered to actuate at a precise, repeatable force and travel distance, ensuring the stall warning is triggered at the correct angle of attack.

• Environmentally Sealed: The switch housing is sealed to protect the internal contacts from moisture, ice, and contaminants found in the wing leading-edge environment, preventing corrosion and failure.

• Robust Construction: Designed and built to withstand the continuous vibration and temperature extremes of the aerospace environment.

Technical Specifications

• Part Number: S2224-1

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

• OEM Authority: Textron Aviation (Cessna)

• Underlying Manufacturer (Typical): Honeywell Sensing and Control

• Application: Stall Warning System Sensor

• Contact Form: Typically SPDT (Single Pole, Double Throw), providing Common, Normally Open, and Normally Closed terminals.

• Actuator: Plunger or Lever type, per the specific OEM drawing.

• Sealing: Environmentally Sealed.

• Electrical Rating: Per Textron specification (e.g., 5 Amps @ 28 VDC).

• Governing Specification: Textron Aviation Engineering Drawing S2224.

Aircraft Compatibility

This OEM switch is the specified component for the stall warning system on a multitude of Cessna aircraft.

• Primary Textron Aviation Platforms:

  • Cessna Piston Aircraft (100, 200, 300, 400 Series)

  • Cessna Caravan Series

  • Certain applications in Cessna Citation business jets.

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

Applications

• Sole Application: To serve as the electrical switching element in the aerodynamic stall warning system, activated by the stall warning vane on the wing's leading edge.

Why Choose S2224-1?

The stall warning system provides the pilot with the final, critical alert before an aerodynamic stall. Its failure can be catastrophic, particularly during low-altitude, low-speed phases of flight like takeoff and landing. The genuine Textron OEM S2224-1 is the only switch guaranteed to meet the specific actuation force, travel, and environmental sealing requirements of the aircraft's type-certified design. Using a generic, non-certified micro switch would introduce an unacceptable risk of the system providing a late warning, a false warning, or no warning at all.

The high reliability of the S2224-1 is rooted in the engineering principle of its snap-action, over-center mechanism. Inside the switch, a pre-stressed, bistable spring (often made of beryllium copper) is held in one of two stable positions. As the external actuator plunger is depressed, it applies force to the spring, causing it to deform and store energy. When the plunger's travel reaches a precisely defined "trip point," it pushes the spring past its geometric center. At this moment, the stored energy is released almost instantaneously, causing the spring and the attached electrical contact to "snap" to its second stable position with a force and velocity that are completely independent of the speed at which the actuator was moved. This rapid contact transfer minimizes the duration of any electrical arc, dramatically reducing contact wear and ensuring a clean, bounce-free signal, which is critical for the long-term reliability of a safety device.

Note: This is a flight-critical safety component. Installation and any necessary rigging or adjustment must be performed by a certified A&P mechanic in strict accordance with the aircraft maintenance manual. After installation, a full functional test of the stall warning system, including activation of the switch by lifting the vane, is mandatory before the aircraft is returned to service.

Documentation

All technical data, installation procedures, and testing criteria for the S2224-1 switch are proprietary to Textron Aviation. This information is contained within the official Maintenance Manual and Wiring Diagram Manual for the applicable aircraft model. No public-facing documentation is available.