Avionics

A good place to start is with one of the most-asked questions that we receive from pilots: Don’t all active headsets work the same way…or do the same thing? The answer is a simple “yes”…and a much more detailed “no.” It’s yes because the principles of additive cancellation with out-of-phase sound is several decades old […]

According to my computer database, Cessna/ARC nav-comms fail 83% more often than theKing KX-155. Think about that next time you’re plowing through a cloud on approach. Sureyou have two radios, a hand-held, and perhaps a Gideon Bible you stole from the hotel. Butthat still might not be enough to keep you out of the rocks. […]

There are two FARs that dictate the biennial checks for most general aviation aircraft:FAR 91.413 for the transponder and encoder, and FAR 91.411 for the static system andaltimeter. First, notice that I didn’t mention the pitot system. While any sane pilot would liketo know that his airspeed indicator is reasonably accurate, the FARs do not […]

If you walk out across just about any aviation ramp, you’ll notice few noticeablechanges in the aircraft in the last decade or two. If you open a cowl or two, you alsonotice the powerplants haven’t changed much, either. But look at a few radio stacks andyou’ll see a dramatic progress. In the last couple of […]

VHF Comm Many years ago it was decided that civil aircraft communications radios would use the118-137 MHz band, and would use amplitude modulation (“AM”). Like many otherthings in aviation, this has remained unchanged for many decades. It’s a pity, because ourair-ground communications would have much better audio quality if we could switch tofrequency modulation (“FM”) […]

“ADF” stands forAutomatic Direction Finder. “Direction finder”because it’s job is to point in the direction of whatever station you tune in.”Automatic” because many years ago airplanes used manual direction finders (or”DFs”) which required manually rotating a loop antenna looking for a null on asignal-strength meter. The purpose of the ADF is to point to a […]

It’s getting to be almost impossible to fly anywhere without aMode C transponder. This equipment is now required in all Class A, B, and C airspace,within 30 miles of primary Class B airspace airports, and anytime you’re above 10,000feet. And if the FAA has its way, that altitude will soon drop to 6,000 feet. ATC […]

Distance measuring equipment—often called DME—is one of the most valuable pieces ofavionics in the aircraft. The main purpose of the DME is to display your distance from aVORTAC, VOR-DME, or localizer. (Some NDB stations have colocated DME, but not many.) DMEreduces pilot workload by continuously showing your distance from the station, accurate towithin a half-mile […]

“ELT” stands forEmergency Locator Transmitter. It’s the little “blackbox” (actually, most are orange) mounted in the tailcone and connected to a flexiblewhip antenna. The purpose of the ELT is to transmit a distress signal if the aircraftimpacts something with high “G” force. This little jewel is probably the leastappreciated and the most priceless piece of […]

Without doubt, GPS has been the greatest advance in aviation navigation since the invention of railroad tracks. It operates in just about any weather, uses a small antenna, and doesn’t necessarily have to be panel-mounted. In fact, some of the portable GPSs have more features than the panel mounts (because they aren’t hamstrung by the […]