The Sun Shield Advantage

Here’s what the experts say about heat and avionics:

While cold can play havoc with avionics, heat presents a greater threat. “Heat is by far the worst of the two conditions,” said Bob Hasse, Garmin International ’s manager of avionics product support, “Cold generally rectifies itself in very short order.” Says Richard Hopperstad of Honeywell Commercial Aviation Products, who serves on the RTCA advisory board, “Heat is what kills integrated circuits.” The major sources of heat is the sun and the avionics themselves. Old tube-style amplifiers used in previous generations of avionics generated much more total heat than current units, but the way today’s solid-state avionics and electronics are packed and stacked in aircraft makes keeping the cockpit cool is critical. The vertical stack common to many cockpits can create what’s called a chimney effect, with the rising heat potentially cooking circuitry, so reducing outside heat exposure is very important. Avionic warranties become void if the equipment is operated outside of the parameters it’s certified for. Some of today’s newer avionics have ways to record operational parameters—including the temperatures they’ve been exposed to. If the temperatures are exceeded, the product fails, and it’s returned to the manufacturer as per the warranty, the manufacturer may revoke its warranty coverage.