Avionics

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 […]

By “portable” we commonly mean anything which is easily carried, but the FAA adds some things to that definition. According to the FARs, “portable equipment” cannot be permanently attached to the aircraft. Let me give you a few specific examples. If you have one of the new portable GPS units, you can use an external […]

Almost daily I receive calls and questions about avionics master switches. Do I need one? What type should I use? Most of these questions come from owners of aircraft that didn’t have a master switch when originally built, and wonder whether one should be installed now. Prior to about 1970, few aircraft had an avionics […]

“They’re nothing but a crutch,” my friend Saul said over the phonefrom Los Angeles. “Well, you know how I am,” I replied. “I need allthe help I can get.” It was good that he couldn’t see the smile on my face. Or my wife’srolling her eyes to heaven. “Sure,” Saul said sourly. “Help. You didn’t […]

On the Starship Enterprise, when something goes awry, an excitedengineer-type says stuff like, “A warp-core breach is imminent!”This is accompanied by ominous humming and flashing warning lightsto give you the idea that the ship is about to explode. It never does. That’s because the Captain knows to remind theengineer that in case of warp-core breach, […]