What if the projector lamp burns out? Does the entire display go dark?
This tiny halogen projection lamp has a lifespan of at least 400 hours in laboratory torture tests. Sandel instructs that it be replaced every 200 hours or one year, whichever comes first. Yes it does. As you might imagine, this was a significant issue during FAA certification of the SN3308. Projection lamp failure is considered similar to the failure of a compass card servo mechanism of a conventional HSI, or failure of the CRT or power supply in an EFIS system. Consequently, Sandel has taken steps to ensure that lamp failure is an extremely unlikely event. The SN3308 has been life-tested in a lab under worst-case conditions on a shake table under temperature extremes and the halogen projector lamp was shown to last reliably for at least 400 hours. In an abundance of caution, Sandel specifies that the lamp be replaced at 200 hours or after one year, whichever comes first. For most owner-flown aircraft, the one year will be limiting and the bulb will never reach 200 hours; the lamp wil
