The 10-821414-4 dual ignition harness is an aircraft engine ignition lead assembly used on Continental piston engines. It routes high-voltage output from both magnetos to all engine spark plugs, providing full dual-redundant ignition for all cylinders.

It is designed for 3/4-20 magneto connectors, commonly used in D4/D6 ignition system configurations depending on engine model. The harness is pre-terminated and routed to match specific cylinder firing order and engine installation geometry.

Key features include:

Dual magneto ignition harness (complete engine coverage)
3/4-20 magneto connector interface
High-voltage insulated ignition leads
Pre-terminated spark plug terminals
Designed for Continental D4/D6 ignition system configurations
Heat, oil, and vibration resistant construction
Maintains redundant ignition for engine safety
Routed for correct cylinder firing order
Compatible with specific Continental piston engine models (IPC-dependent)
Used in certified aircraft engine maintenance and overhaul procedures