S1891-6S – Textron Aviation OEM Stainless Steel Hose Clamp
Available now through the AirParts Aero marketplace.
Overview Section
The Textron Aviation S1891-6S is a high-performance Worm-Gear Hose Clamp manufactured from 300-series stainless steel. Designed specifically for the rigorous demands of aircraft fluid and air systems, this clamp provides a uniform, high-torque seal for rubber and silicone hoses used in fuel, oil, and environmental control systems (ECS).
The "-6S" designation indicates the sizing and material specification. Sourced as an authentic Textron part, the S1891 series is engineered to maintain its clamping force under the extreme vibration and thermal cycling common in engine compartments and pressurized airframe sections. Unlike standard automotive clamps, the S1891 features a shielded or lined band (depending on the revision) to prevent the hose material from extruding through the worm-gear slots.
Key Features Section
All-Stainless Steel Construction: Both the band and the screw are fabricated from corrosion-resistant steel, ensuring the clamp remains serviceable in salt-air environments and resistant to chemical degradation.
High-Torque Worm Drive: Features a precision-cut screw thread that provides smooth, incremental tightening, allowing for an airtight seal without the risk of the screw "slipping."
Hose-Friendly Band Design: The inner surface of the band is engineered to be smooth or includes a protective liner to prevent "ribbing" or cutting into soft silicone or rubber hoses.
Vibration-Resistant Locking: The screw housing is designed to maintain tension under high-frequency engine harmonics, preventing the clamp from loosening over time.
Compact Housing Profile: Optimized for tight clearances within the engine nacelle or behind instrument panels where space for tools is limited.
Standardized Sizing: Specifically sized for the -6 diameter range (typically fitting hoses with an Outside Diameter around 1/2" to 3/4", verify per IPC).
Technical Specifications Section
| Specification | Detail |
| Part Number | S1891-6S |
| Manufacturer | Textron Aviation (Cessna / Beechcraft) |
| Material | 300-Series Stainless Steel |
| Clamp Type | Worm-Gear Drive |
| Nominal Size | -6 (Verify OD range per Textron Standard) |
| Band Width | Standard Aerospace Width (Typically 1/2") |
| Screw Drive | Hex Head with Slotted Drive |
| Finish | Passivated Stainless |
Aircraft Compatibility Section
The S1891-6S is a "fleet-wide" hardware staple for Textron aircraft in the AirParts Aero inventory:
Cessna Single-Engine: Used for fuel line connections and scat-tubing for cabin heat on the 172, 182, and 206.
Beechcraft King Air: Found in the engine compartment for oil cooler lines and air induction systems on the 90, 200, and 300 series.
Beechcraft Baron/Bonanza: Essential for securing vacuum system hoses and engine baffle seals.
Textron Jets: Utilized in secondary fluid drainage and environmental system ducting on the Cessna Citation line.
Technical Applications & Safety
While a hose clamp seems simple, it is a primary failure point in fluid systems. The S1891-6S is designed to provide 360-degree radial pressure. If a clamp is over-tightened, it can crush the internal reinforcement of the hose; if under-tightened, the hose may "blow off" under pressure or develop a slow leak that could lead to an engine fire.
Safety Warning: Do not use "slotted" clamps on soft silicone hoses. Standard worm-gear clamps have slots that allow the soft silicone to "ooze" through, creating a leak path and damaging the hose. Ensure the S1891-6S variant you are using is either the lined version or being used on reinforced rubber as per the Aircraft Maintenance Manual (AMM).
Technical Engineering Insight
The engineering value of the S1891-6S lies in its Slotted-to-Solid Band Ratio. In aerospace engineering, the clamp must provide enough "bite" to hold the hose against the barb of a fitting under pressure, but enough surface area to avoid localized stress on the hose. The S1891 series is manufactured with rolled edges on the band to prevent the sharp stainless steel from "sawing" into the hose during vibration cycles.
By choosing the genuine Textron hardware through AirParts Aero, you ensure the screw is made from a compatible stainless alloy that won't cause galvanic corrosion when in contact with the band. This prevents the clamp from "freezing" in place, allowing for easy removal during the next scheduled inspection.
Installation & Maintenance Addendum
Torque Calibration: While often tightened by "feel," many AMMs specify a torque in inch-pounds for hose clamps (typically 15-25 in-lbs). Over-tightening is a leading cause of premature hose failure.
Orientation: Install the screw housing in a location that is easily accessible for a screwdriver or nut driver, but ensures it does not rub against moving parts like throttle linkages or control cables.
Visual Inspection: During every 100-hour or annual inspection, check for "cold flow" (where the hose has compressed over time) and re-snug the S1891-6S if necessary.