MPA31118 - Textron Aviation OEM Seal

MPA31118 – Textron Aviation OEM Specialized Extruded Seal

Available now through the AirParts Aero marketplace.

Overview Section

The MPA31118 is a genuine Textron Aviation OEM (Original Equipment Manufacturer) seal, specifically engineered for environmental and aerodynamic sealing on high-performance Textron airframes, including the Beechcraft King Air and Cessna Citation series. This part is a specialized "P-profile" or "Bulb-style" extrusion designed to provide a pressurized barrier for airframe apertures, such as emergency exits, baggage doors, or specialized access panels.

Constructed from a high-tier Silicone or Ethylene Propylene (EPDM) elastomer, the MPA31118 is formulated to maintain its elastic memory after thousands of compression cycles. It is critical for maintaining cabin pressure integrity and reducing parasitic drag by ensuring a flush interface between moveable panels and the primary fuselage skin.

Enhanced Technical Data

Advanced Engineering & Structural Application

The engineering value of the MPA31118 lies in its Interference-Fit Capability. Unlike standard automotive seals, this aerospace extrusion is designed with a specific "Wall Thickness to Diameter" ratio. This ensures that even at the extreme pressure differentials found at FL350 (35,000 ft), the seal does not collapse or "extrude" through the door gap.

Aerodynamic and Acoustic Performance

The MPA31118 serves as a primary Acoustic Barrier. By filling the gap between the airframe and the door, it prevents high-velocity airflow from creating "vortex whistling," which significantly reduces cockpit and cabin noise levels. The outer surface is typically treated with a low-friction "slip coat" to prevent the seal from bonding to the door frame during long periods of closure in high-humidity environments.

Aircraft Compatibility

The MPA31118 is a high-utilization seal found in the Illustrated Parts Catalog (IPC) for several Textron pressurized platforms:

• Beechcraft King Air 200/300 Series: Primary seal for specialized utility and emergency exit doors.

• Cessna Citation 500/600 Series: Used in various environmental control system (ECS) access panels.

• Beechcraft 1900C/D: Found in cabin entrance and cargo door perimeter assemblies.

Installation & Maintenance Addendum

1. Adhesive Compatibility: Requires BMS5-95 or 3M 1300L high-performance neoprene adhesive. The mounting surface must be stripped of old adhesive and "scuffed" with a Scotch-Brite pad to ensure a mechanical bond.

2. Corner Radii: During installation, the MPA31118 must be "relaxed" around corners. Stretching the seal during installation leads to "thinning" of the bulb, which causes local pressure leaks.

3. Pressure Testing: After replacement, a Cabin Pressure Leak Test is mandatory per the AMM (Aircraft Maintenance Manual) to verify the "psi per minute" leak rate remains within airworthy tolerances.

The Textron Aviation MPA31118 is the definitive choice for maintaining the pressurization and environmental integrity of your airframe. Engineered to outperform aftermarket "off-the-shelf" extrusions, this OEM seal provides the exact compression rates required for Beechcraft and Cessna closure systems. By utilizing advanced silicone compounds, the MPA31118 prevents the hardening and cracking common in lower-tier seals, ensuring your aircraft remains quiet and pressurized from the ramp to the flight level. Secure your cabin environment with the precision and reliability of Textron OEM hardware.

This part is used on the following aircraft:

• • Textron Aviation Hawker 700
• • Textron Aviation Hawker 800
• • Textron Aviation Hawker 800XP-850XP
• • Textron Aviation Hawker 900XP