SKNA-22-2A

High-voltage discharge from SKNA-22-2A

During start, SKNA-22-2A receives power from the aircraft DC network and charges its internal storage elements. The stored energy is then discharged through the high-voltage output to the spark plug. This creates a surface discharge on the semiconductor plug and ignites the fuel-air mixture in the combustion chamber. The unit is built for short-time operation during start, so continuous energizing outside the specified mode should be avoided. If ignition is unstable, the plug, high-voltage cable, connector and control circuit should be checked together with the unit.

SKNA-22-2A with semiconductor spark plugs

The SKNA-22-2A is intended for ignition systems using semiconductor surface-discharge spark plugs. This type of plug needs a strong pulse across its working surface, rather than a simple low-energy spark. The ignition unit, plug and cable form one working chain. A mismatch between the unit and plug type can cause weak discharge, poor start or accelerated wear of components. For replacement work, the installed plug type and engine documentation should be checked before confirming the SKNA-22-2A as a direct substitute.

Construction of the SKNA-22-2A unit

The unit is built in a metal enclosure and contains induction coils, selenium rectifiers, storage capacitors, activators and arresters. These components form the charging and discharge circuit for the high-voltage pulse. The metal housing protects the internal elements and provides a fixed installation base in the aircraft or engine equipment area. Because the unit operates with high voltage, attention during inspection should go to insulation condition, connector cleanliness, grounding, cable shielding and any signs of overheating or moisture ingress.

Identification and ordering of SKNA-22-2A

Before ordering SKNA-22-2A, the marking should be compared with the aircraft parts catalog, engine ignition documentation or product passport. Similar ignition units may look close externally but differ by discharge frequency, connector arrangement, plug compatibility or approved application. For correct selection, provide the aircraft type, engine type, ignition plug type, existing unit marking and a photo of the data plate if possible. The product is also known under alternative designations SKNA-22-2A and СКНА-22-2А.