S1360-5L – Textron Aviation OEM 5 Amp Circuit Breaker (Switch Type)
Available now on the Airparts.aero Marketplace.
Overview Section
The Textron Aviation S1360-5L is an Original Equipment Manufacturer (OEM) Thermal Circuit Breaker designed for essential use in protecting the low-current electrical circuits across the Textron Aviation fleet, including numerous Cessna piston and turbine aircraft. This specific part is a $5\text{ Amp}$ rated breaker, which provides crucial overcurrent and short-circuit protection for sensitive avionics, instruments, or small control loads. The S1360 series typically refers to a manual reset, push-pull type circuit breaker that doubles as an ON/OFF switch for the protected circuit. The -5L suffix denotes 5 Amp trip rating and, critically, the specific body and mounting configuration used by Textron.
As a flight-critical safety component, the circuit breaker’s internal thermal element is calibrated to trip precisely at the specified current rating 5A after a defined delay, preventing dangerous overheating or fire due to electrical faults, while ensuring the circuit remains operational under normal, transient load conditions.
Key Features Section
Thermal Overcurrent Protection: Utilizes a thermally actuated bimetallic strip or equivalent mechanism calibrated to precisely trip at 5 Amps (within tolerance) to protect wiring and components.
Push-Pull Manual Reset: Functions as a discrete ON/OFF switch. Pulling the plunger out manually opens the circuit; pushing it in closes the circuit and resets the breaker after a trip.
5 Amp Rating: Ideal for protecting low-current circuits such as instrument lighting, avionics cooling fans, low-power radios, or warning light circuits.
Trip Indication: The plunger visibly extends (pops out) when the thermal element trips due to an overcurrent condition, providing clear fault indication to the flight crew.
OEM Certified Quality: Guarantees full compliance with the aircraft's electrical load specifications and mechanical interchangeability with the panel cutout.
Standardized Aviation Mounting: Designed for standard panel mounting with a threaded bushing and locking nut.
Technical Specifications Section
Part Number: S1360-5L
Component Type: Thermal Circuit Breaker (Manual Reset, Switch Type)
OEM Manufacturer: Textron Aviation (Cessna)
Trip Rating: 5 Amperes (A)
Voltage Rating: 28 VDC Nominal (Standard aircraft bus voltage)
Function: Circuit Protection (Overcurrent/Short-Circuit) and Manual Switching
Mechanism: Push-Pull (Trip-Free Design is standard for safety)
Mounting: Panel Mount, Threaded Bushing
Governing Specifications: Certified under FAA-PMA/OEM standards; conforms to applicable sections of MIL-PRF-55629 (Reference Standard).
Aircraft Compatibility Section
Cessna Piston Series: Used extensively in the electrical distribution panels of models like the Cessna 172, 182, 206, and 300 series.
Cessna Turbine Series: Used in various panels of Citation Jets (e.g., CJ series, Excel, XLS) and Caravan turboprops for low-amp, non-essential circuit protection.
Note: The correct amperage rating is mandatory for safety. The aircraft’s Wiring Diagram Manual (WDM) and Illustrated Parts Catalog (IPC) are the final authority for verifying the exact part number and its corresponding circuit protection rating.
Applications Section
Avionics Power: Protecting the power input lines to small, sensitive avionics equipment or display cooling fans.
Lighting Circuits: Overcurrent protection for discrete internal or external lighting groups (e.g., panel lights, logo lights).
Warning System Power: Protecting the low-amp power feeds to annunciator panels or warning horns.
Why Choose the S1360-5L?
The S1360-5L is a flight-critical fire safety device. The core danger in an electrical fault is that the wiring harness could overheat and ignite the surrounding insulation or structure.2 Using an incorrect rating (e.g., a 10 A breaker where 5A is required) voids the certified wiring protection and can lead to a fire hazard, as the wiring may overheat before the breaker trips. The OEM-certified S1360-5L guarantees: 1) Precise Thermal Calibration to the 5A trip curve; 2) Trip-Free Design (cannot be held closed during an overload); and 3) Electrical Integrity necessary to protect the aircraft and its occupants from thermal runaway events.
The safety principle behind the S1360-5L is its time-current curve. It is not designed to trip instantaneously at 5A but rather to allow brief, harmless surges (inrush current) while tripping quickly for high-magnitude faults (short circuits). This non-linear response is achieved by calibrating the bimetallic element's thermal inertia. For instance, a short circuit (say, 50A) will cause the breaker to trip almost instantaneously (less than 0.1 second), while a slight overload (say, 6A) might take several minutes to trip. The Trip-Free design is critical; if the pilot holds the breaker in the ON position during an overload, the contacts will still open internally, preventing the fault current from continuing to flow, thus protecting the circuit.
Note: The S1360-5L is a safety-critical component. Never substitute a circuit breaker with a higher amperage rating or attempt to bypass or repair a tripped breaker without first identifying and correcting the underlying electrical fault. Installation must be performed by a certified A&P or avionics technician using the correct terminal lugs and wire connections.
Documentation
Textron Aviation Wiring Diagram Manual (WDM): Essential for verifying the specific circuit protected and the required amperage rating.
MIL-PRF-55629 (Reference): Standard covering the design and performance requirements for aviation circuit breakers.