Cockpit Considerations--Making the Case for Avionics Upgrades
Produced by Aviation Week, written by Paul Seidenman
Today, the decision to bring a cockpit into the 21st century is more than just a matter of considering front-end acquisition and installation costs for the new equipment. Also factored into the mix is maintainability, which is becoming increasingly dependent on the availability of parts.
“Within the next 10 years, the cathode ray tube (CRT) displays used on the first-generation EFIS cockpits will run into parts-obsolescence issues,” reports Chad Ostertag, an avionics sales representative at Duncan Aviation in Battle Creek, MI. “About 10-15 years ago, there were hundreds of CRT suppliers, but today there are just two, as the world has moved on to light emitting diode (LED) and liquid crystal display (LCD) technology products. That means that the CRTs and their accompanying high-voltage power supply units are becoming scarce.”
Part of the reason for this has its origin in the consumer electronics market. Mark Wilken, director of avionics sales for Elliott Aviation in Moline, IL, explains, “The color CRT was originally developed for color television sets, but it wasn’t long before that technology was applied to the cockpit as a first-generation EFIS component. Now CRT technology has been supplanted by LCD technology, and as a result CRTs are no longer being manufactured for consumer electronics,” he says. “Since the avionics OEMs rely on third-party vendors to supply the CRT units, they are noticing a reduced ability to buy replacement CRTs and their parts. However, they have taken advantage of LED and LCD technology developed for the consumer market and adapted it for aviation.”
Wilken says that ”based on information from the avionics OEMs, the manufacturers have made their final purchases of new CRTs within the past 1-2 years, and it is projected that this inventory will be depleted by the 2017/2018 time frame. By then, procuring a replacement display will mean having to go to the used, overhauled-components market, since new CRTs will no longer be available from the avionics OEMs.”
“Even now,” Wilken says, “supplies of serviceable CRTs are drying up. One reason for this is that the CRT is prone to phosphor burn a permanent ghost image burned into the screen by a prolonged display of non-moving images. In a good 50% of the cases, they are beyond any economical repair.”
Delmar Fadden, a technical consultant and board member of Sandel Avionics in Vista, CA, also reports that for those who are considering retaining a 20th century era electro-mechanical avionics system the repair service base is disappearing. To illustrate why, he cites a typical electro-mechanical system, specifically the Rockwell Collins FD108 series of flight instruments, manufactured throughout the last half of the past century.
“These precision instruments were constructed of complex mechanical pointers and dials, which were servo-driven and made even more complex by the need for dual-axis motion. Due to their cost, they were limited to commercial airliners and high-end business jets. These instruments and their competitors went out of production between the 1990s and the early 2000s, and now the only flight instruments available for this class of airplanes are computer-driven flat-panel electronic displays,” he says. “Simplified versions of electro-mechanical ADIs and HSIs were still being produced for smaller, general aviation airplanes into the early 2000s, but by 2008, the transition to electronic displays had swept through this segment as well.”
What this means, Fadden points out, is that the OEMs of the older avionics may no longer have the tooling in-house to support the equipment—or the people with the knowledge to use it. “If the tooling is no longer available at the OEM, it is impossible to build the assembly again. This means that the repair work would have to be subcontracted to a specialty shop, or a surplus or overhauled system would have to be located.”
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