Primer for the LASAR electronic ignition system

Primer for the LASAR® Electronic Ignition System

By Jim Melvin, Bryan Quillen, and Harry Fenton

February 1998

When you hear pilots or technicians talk about electronic ignition, electronic engine controllers, or electronic fuel injection and controls, your first thought is that they are talking about their car or that they are discussing the latest in gas turbine control technology. Well, it's time to readjust your thinking because several companies are bringing these types of advanced technologies to today's general aviation market.

The revolution that is going on in the general aviation market today is similar to the revolution that occurred in the automotive industry over the last several decades. Automotive electronic controls for ignition, fuel injection, turbochargers, brakes, and more are now changing from "options" to becoming "standard features" on everything from economy to luxury class automobiles. These changes primarily came about in the auto industry in order to decrease pollution and increase automobile efficiency, performance, safety, reliability, and customer satisfaction.

Similar to the automotive engine revolution, aircraft piston engines are now experiencing major changes and will continue to do so over the next 10 years as new federal regulations for aircraft noise, cleaner burning fuels, and low emissions will be instituted. In addition, the demands of a very large customer base eager for modernization will also continue to drive the aircraft piston engine toward an ever increasing level of electronic controls content.

This contrasts with an industry often resistant to change due to deep rooted conservatism based on a dedication to safety with extremely high certification costs and ever present threats of product liability. As some technicians may ask, "Why put more cost and complexity into an aircraft that works fine just as it is?" The answer to this question is relatively easy. As evidenced in the automotive industry, the new electronic controls provide many benefits which far outweigh their initial costs and which make some current aviation technologies look antiquated.

With the new aircraft piston engine electronic technology comes requirements for aircraft technicians to acquire a whole new set of skills and knowledge in order to enhance their proficiencies and remain marketable. Unison Industries' LASAR® electronic ignition system is one example of a leap in electronic engine control technology which is sure to make a big impact on the general aviation market — making it worthy of a technician's further study.

System Description and Installation
Developed and certified in the early to mid 1990s, the LASAR® electronic ignition system is arguably the first step in a aircraft piston engine revolution. This system digitally processes engine speed (rpm), manifold pressure (MP), cylinder head temperature (CHT), and system health to increase engine performance without compromising safety or reliability.

There are five parts to the LASAR® system. The three main components are the computer controller and two dual mode magnetos. "Dual mode" refers to the mag's two operating modes: automatic and backup. The fourth piece of the system is a low voltage wiring harness used for communication and power distribution between the controller, magnetos, and the airframe. The fifth component is the high voltage wiring harnesses. Slick's high voltage harnesses are the only secondary harnesses currently certified with LASAR®. The controller is the brain of the system.

The controller makes decisions based on manifold pressure, rpm, cylinder head temperature, ignition switch position, and monitors its own health as well as that of the airframes' power source and the magnetos.