9387M24P16 - CFM Type 4 Ignition Lead

9387M24P16 – CFM International Type 4 Ignition Lead

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The CFM International 9387M24P16 is a high-performance, Type 4 shielded ignition lead specifically engineered for the CFM56-5B and CFM56-7B turbofan engines. As a critical link in the engine’s starting and combustion-sustaining architecture, this lead is responsible for delivering high-voltage energy from the ignition exciter box to the igniter plug. In the hostile environment of the engine core, the 9387M24P16 must maintain absolute dielectric integrity while being subjected to extreme thermal gradients, high-frequency mechanical vibrations, and exposure to volatile fluids such as jet fuel (Jet-A) and synthetic turbine oil.

Fabricated with a sophisticated multi-layer construction, the 9387M24P16 is designed to mitigate the effects of Electromagnetic Interference (EMI), preventing the high-energy pulses of the ignition cycle from disrupting sensitive FADEC (Full Authority Digital Engine Control) signals and avionics. This lead is characterized by its superior flexibility and robust connector interfaces, which are precision-machined to ensure a moisture-proof, vibration-resistant seal at both the exciter and igniter ends. For operators of Boeing 737 NG and Airbus A320 series aircraft, the 9387M24P16 is an essential component for ensuring rapid engine light-off and reliable "relight" capability during in-flight precipitation or turbulence events.

Key Features

• Type 4 High-Temperature Architecture: Specially formulated to operate continuously in the high-heat zones of the engine fan frame and compressor sections.

• Dual-Layer Braided Shielding: Utilizes a high-coverage nickel or stainless steel braid to provide exceptional EMI/RFI suppression and mechanical abrasion resistance.

• Dielectric Fluoropolymer Insulation: Features high-purity internal insulation to prevent voltage leakage and "arc-over" during high-altitude operations.

• Vibration-Damping Fittings: Engineered with precision-threaded coupling nuts and internal gaskets to maintain a positive electrical connection despite engine-induced harmonic resonance.

• Environmental Sealing: The lead is hermetically sealed at the terminal ends to prevent the ingress of moisture, salt spray, and de-icing fluids, which are the primary causes of ignition system carbon-tracking and failure.

Technical Specifications

• Part Number: 9387M24P16

• Component Type: High-Tension Ignition Lead (Type 4)

• Manufacturer: CFM International (GE/Safran) / Unison Industries

• Application: Ignition System (ATA 74)

• Voltage Rating: Optimized for high-energy exciter outputs (typically 15kV–20kV pulses).

• Conductor Material: Silver-plated copper or specialized high-conductivity alloy.

• Outer Braid: Nickel-plated copper or CRES (Corrosion Resistant Steel).

• Operating Temperature: Rated for continuous service in environments exceeding $500^\circ\text{F}$ ($260^\circ\text{C}$).

• Governing Specifications: CFM56-5B/7B Engine Type Certificate Requirements.

Aircraft Compatibility

• Boeing 737 Next Generation (NG): 737-600, -700, -800, -900 equipped with CFM56-7B.

• Airbus A320 CEO Family: A318, A319, A320, and A321 equipped with CFM56-5B.

• Boeing P-8 Poseidon: Military maritime patrol variants of the 737.

Note: The Engine Illustrated Parts Catalog (EIPC) is the final authority for confirming the 9387M24P16's specific position (Igniter 1 vs. Igniter 2) and length requirement for your engine serial number.

Applications

The 9387M24P16 is a core component of the Engine Ignition System. Its application is to provide a low-impedance path for the high-joule energy required to bridge the gap of the igniter plug. It is utilized during the engine start sequence and is activated by the flight crew or FADEC during "Continuous Ignition" modes to prevent flameouts during heavy rain, icing conditions, or high-alpha maneuvers.

Why Choose 9387M24P16?

Selecting the genuine CFM 9387M24P16 ensures that your ignition system maintains the precise electrical impedance and shielding effectiveness required for modern digital engines. Lower-quality aftermarket leads often suffer from "corona discharge" at high altitudes, which can degrade the lead's internal insulation and lead to erratic engine starts or failed relights. The 9387M24P16 is built to the exact OEM "Type 4" specification, providing the thermal margins and structural robustness necessary for the high-utilization cycles of commercial air transport.

The 9387M24P16 is an advanced transmission line for high-energy electrical pulses, designed to manage the skin effect and dielectric stress associated with microsecond-duration sparks. The core conductor utilizes silver-plated strands to optimize conductivity and prevent oxidation at high operating temperatures. From a physics perspective, the lead must maintain a specific capacitance and inductance profile to ensure the pulse rise-time at the igniter tip is sufficient to ionize the fuel-air mixture. The "Type 4" designation refers to its superior thermal-mechanical stability; the lead utilizes a convoluted PTFE (Polytetrafluoroethylene) core which provides an anisotropic resistance to kinking while maintaining high dielectric strength. The outer shielding is a Faraday cage construction, meticulously engineered to contain the transient electromagnetic fields generated by the 20,000-volt discharge, protecting the engine's low-voltage sensor harness from capacitive coupling and inductive interference.

Note: This is a flight-critical engine component. Installation must be performed by a certified powerplant mechanic in accordance with the Engine Maintenance Manual (EMM). Special care must be taken during installation to avoid exceeding the minimum bend radius of the lead, which can damage the internal dielectric. Ensure that the terminal ends are clean and free of moisture or contaminants before assembly. Proper torque of the coupling nuts is essential to prevent vibration-induced fretting of the electrical contacts.

Documentation

• CFM56-7B Engine Maintenance Manual (Chapter 74 - Ignition) (Access restricted to operators)

• FAA Advisory Circular AC 20-115D - Airborne Software and Airborne Electronic Hardware

• Unison Industries Technical Data for Ignition Leads