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100-121-8815 – Textron Aviation OEM Seal O-Ring
Part Number: 100-121-8815
Manufacturer: Textron Aviation (Hawker Beechcraft)
Common Synonyms: Packing O-Ring, Static Seal, High-Temp Elastomer
Overview Section
The 100-121-8815 is a high-reliability Textron Aviation OEM Seal O-Ring designed for the sophisticated fluid and pressure systems of the Hawker 800/900 and Beechcraft King Air families. This specific part number is frequently identified in the Illustrated Parts Catalog (IPC) as a primary seal for hydraulic manifolds, fuel filter housings, and pneumatic valves.
Fabricated from a specialized elastomer compound—typically Fluorocarbon (Viton/FKM)—the 100-121-8815 is engineered to maintain a hermetic seal under extreme thermal cycling. Unlike standard industrial O-rings, this aviation-grade component is batch-tested for chemical resistance against aggressive synthetic lubricants and hydraulic fluids like Skydrol or MIL-PRF-83282, ensuring it will not degrade or lose elasticity during its service life.
Enhanced Technical Data
| Technical Metric | Specification Data |
| Material Base | Fluorocarbon (FKM / Viton) |
| Durometer (Hardness) | 80 Shore A (Nominal) |
| Inside Diameter (ID) | 0.489 in (Nominal) |
| Cross-Section (CS) | 0.070 in (Nominal) |
| Tensile Strength | 1,600 PSI (Minimum) |
| Operating Temperature | $-40°F$ to $+450°F$ ($-40°C$ to $+232°C$) |
| Fluid Resistance | Synthetic Hydraulic Fluids, Jet A, Engine Oil (MIL-PRF-23699) |
| Max Shelf Life | 84 Months (7 Years) from Cure Date |
| Certification | FAA-PMA / EASA / OEM Certified |
Advanced Engineering & Structural Application
The 100-121-8815 is optimized for Dynamic and Static Seal Glands. In the Hawker 800XP fuel and hydraulic systems, O-rings must survive "Cold Soak" (prolonged exposure to sub-zero temperatures at altitude) followed by rapid heating during system engagement.
Engineering Insight: Resistance to Explosive Decompression
In high-pressure pneumatic or bleed air systems, standard O-rings can suffer from "Explosive Decompression" (ED).1 This occurs when gas molecules migrate into the elastomer under high pressure; if the pressure drops rapidly, the gas expands within the material, causing internal blistering. The 100-121-8815 is manufactured with a high-density molecular structure that resists gas permeation, making it suitable for both liquid and high-pressure air interfaces.
Chemical Compatibility
The FKM (Fluorocarbon) base of this seal provides an inert barrier against the corrosive nature of turbine engine oils and fire-resistant hydraulic fluids. This ensures the seal will not undergo "volumetric swell," which can jam a valve, or "shrinkage," which causes bypass leaks.
Aircraft Compatibility
The 100-121-8815 is a versatile part used across several Textron/Hawker platforms:
Hawker 800XP / 850XP / 900XP: Critical seal for hydraulic pump manifolds and braking system check valves.
Beechcraft King Air 200/300 Series: Utilized in the environmental control system (ECS) and fuel heater assemblies.
Beechcraft 1900D: Found in various engine accessory drive seals and pneumatic regulators.
The Textron Aviation 100-121-8815 is the professional's choice for ensuring leak-free performance in the demanding environment of a business jet or turboprop. When you choose an OEM O-ring, you are not just buying an elastomer; you are buying the assurance of verified material science and dimensional precision. The 100-121-8815 provides superior thermal stability and fluid resistance, protecting your Hawker or King Air from the risks of unscheduled maintenance caused by low-tier seal failure. Maintain your airframe’s integrity with the exact hardware specified by the manufacturer.
Installation & Maintenance Addendum
Cure Date Verification: Always confirm the cure date on the individual sealed package. This part has an 84-month shelf life. Do not install seals that have exceeded their age limit, as the elastomer may have hardened.
Anti-Spiral Lubrication: Apply a thin film of clean system fluid (Hydraulic fluid for hydraulic glands, etc.) to the 100-121-8815 prior to installation. This prevents "spiral failure" or rolling of the O-ring during assembly.
No Metal Tools: Use only plastic or nylon O-ring picks during removal and installation to avoid scratching the precision-machined metal sealing surfaces of the gland.
