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D38999/24WC35SN – TE Connectivity Circular MIL Spec Connector 22 Pin Size 13 Jam Nut Receptacle
Available now on the Airparts.aero Marketplace.
The D38999/24WC35SN is a high-reliability, flight-critical circular electrical connector belonging to the MIL-DTL-38999 Series III family. As a Jam Nut Receptacle (Style 24), this component is engineered for bulkhead mounting where a superior environmental seal and EMI/RFI shielding are required. Featuring a Size 13 shell with a high-density "35" insert arrangement, it accommodates 22 Size 22D socket contacts, making it a primary choice for complex avionics suites and data-bus architectures in both pressurized and unpressurized aircraft zones.
This connector utilizes a triple-start threaded coupling mechanism, which provides a robust, anti-decoupling connection capable of withstanding extreme vibration and mechanical shock. The "W" class designation specifies an aluminum shell with Olive Drab Cadmium over Electroless Nickel plating, offering 500 hours of salt spray resistance. The "SN" suffix denotes a normal polarization (N) with socket contacts (S), ensuring precise mating and preventing cross-connection in dense electrical bays.
The D38999/24WC35SN is essential for maintaining signal integrity in mission-critical systems. Its design incorporates a rear-release contact system for ease of maintenance and a fluorosilicone interfacial seal to prevent fluid contamination. For the maintenance professional, this part represents the benchmark in aerospace interconnect technology, balancing weight, durability, and ease of installation.
Key Features
Anti-Decoupling Ratchet Mechanism: Features a self-locking, triple-start thread that eliminates the need for safety wire while providing superior resistance to high-frequency vibration.
360° EMI/RFI Grounding: Integrated grounding fingers within the plug-to-receptacle interface provide exceptional shielding effectiveness across a wide frequency spectrum.
Superior Environmental Resistance: High-grade fluorosilicone seals protect against aviation fuels, Skydrol™ hydraulic fluid, and extreme humidity.
Jam Nut Mounting (Style 24): Optimized for single-hole bulkhead mounting, providing a lower profile and easier installation than square-flange alternatives.
High-Density Contacts: Accommodates 22 gold-plated Size 22D contacts in a compact Size 13 footprint, maximizing space efficiency.
Technical Specifications
Part Number: D38999/24WC35SN
Component Type: Circular MIL-DTL-38999 Series III Receptacle
Manufacturer: TE Connectivity / DEUTSCH
Shell Size: 13
Insert Arrangement: 13-35 (22 Contacts)
Contact Type: Socket (S), Crimp Rear-Release
Contact Size: 22D
Polarization: Normal (N)
Material: Aluminum Alloy Shell
Finish: Olive Drab Cadmium over Electroless Nickel
Operating Temperature: $-65^{\circ}\text{C}$ to $+175^{\circ}\text{C}$
Vibration Resistance: 60g at ambient temperature
Salt Spray Rating: 500 Hours
Governing Specification: MIL-DTL-38999 Series III
Aircraft Compatibility
Fixed Wing: Beechcraft King Air 200/300, Cessna Citation Series, Gulfstream G550/G650, Lockheed C-130.
Rotary Wing: Bell 412/429, Airbus H145, Leonardo AW139.
UAVs/Military: MQ-9 Reaper, Northrop Grumman Global Hawk.
Note: Verification of specific effectivity via the Illustrated Parts Catalog (IPC) or Wiring Diagram Manual (WDM) is mandatory.
Applications
Avionics Bulkhead Penetrations: Providing a sealed interface between the cockpit and unpressurized electronics bays.
FLIR and Sensor Turrets: Handling high-density signal feeds for external sensor pods.
Engine Monitoring Systems: Connecting EGT and CHT probes to digital acquisition units.
Why Choose D38999/24WC35SN?
Selecting a genuine MIL-SPEC D38999/24WC35SN ensures the aircraft's electrical system maintains its original certification basis. Using non-certified alternatives can lead to "wicking" of moisture into the wiring harness or shell-to-shell resistance issues that cause electronic interference. TE Connectivity’s rigorous manufacturing standards guarantee that every connector meets the "fail-safe" requirements necessary for Part 23, 25, 27, and 29 aircraft operations.
The D38999/24WC35SN is a masterclass in materials science and mechanical engineering designed to survive the thermal shock and differential pressure found in aerospace environments. The aluminum shell is precipitation-strengthened to ensure structural integrity while remaining lightweight. The Olive Drab Cadmium plating acts as a sacrificial anode, preventing the aluminum base from oxidizing in saline environments—a critical feature for carrier-based or coastal aircraft. Internally, the contacts are seated in a rigid dielectric header with a resilient face seal. When mated, the socket contacts utilize a closed-entry design to prevent probe damage and ensure a high-normal force connection. The Jam Nut design (Style 24) is particularly effective at maintaining a gas-tight seal at the bulkhead; as the nut is torqued, the interfacial O-ring is compressed into a precision-machined groove, creating a barrier against capillary action of fluids. This design effectively mitigates the risk of dielectric breakdown even when the connector is subjected to rapid decompression cycles.
Note: This is a flight-critical electrical component. Installation must be performed by a certified A&P/Avionics technician. Ensure the use of the correct M22520/2-01 crimp tool and M81969/14-01 insertion/extraction tools to avoid damage to the contact retention clips. Torque the jam nut according to the values specified in the aircraft's Standard Practices Manual (typically Chapter 20).
