Frequently Asked Questions
about our
Altitude Alerters



Which Model do I need? That depends on how high you fly. The AirSport IFR is the most popular model, it offers the features most pilots need. If you fly above 18,000 ft (or if you fly in parts of the world that use Millibars) then you need the AirSport PRO. The PRO and the IFR are supplied with all accessories, in a protective carrying case.

Are AirSport Alerters different than the competition?Our competitors make fine equipment, and strictly as alerters they are all good investments. But they are wired to the altitude encoder. What if something happens to your altitude data after it leaves the encoder? Other alerters don't monitor health or status of the transponder. Only AirSport Altitude Alerters monitor actual transponder data, both Mode A (squawk code) and Mode C (altitude). We see the same data being sent to ATC. Your transponder signal is what the controller sees, you should know what your equipment is actually reporting.

Where do I put it? Most pilots place their Alerter on the glareshield. Depending on the aircraft, you may prefer to locate it under the instrument panel or elsewhere. Since it's portable, pilots find a variety of locations. It comes with Velcro strong enough to hold during turbulence. Some AirSport Alerters have been permanently installed and FAA approved via 337s. (For installation notes, Click Here) This equipment is really intended to be portable, and is legal per FAR 92.21(b)&(c).

How long does the Battery last before recharging? The general answer is about 8 hours, enough for an average day's flying. If backlighting is not used, much more time is available before recharging is needed. It can be recharged overnight with the 110 volt charger supplied. Or, if you operate your Alerter from aircraft power, then there is no time limit, and the battery is recharged automatically.

Does it work with 28 volt systems? Yes. Either 14 or 28, just plug it in.

What about pressurized aircraft? It doesn't matter. Your alerter is a receiver, not an air pressure instrument. It receives the transponder signal and displays the same altitude that ATC is seeing.

Does it really work without connection to the plane? Yes. These Altitude Alerters will even work in an airliner. (You should have a window seat, and it's up to you to smuggle it aboard!) It needs no connection to aircraft systems because it picks up the transponder signal and decodes all the data. To hear the altitude alerting tones, you should connect the unit to your headset or intercom with the supplied cable. AirSport Altitude Alerters are compatible with all audio panels, regular and stereo intercoms, and all types of regular and noise-cancelling headsets.

Do I have to enter my squawk code? No. Your squawk code is being received from your transponder, and is displayed to let you know your transponder is operating correctly.

What about barometric pressure? Each time you reset pressure on your altimeter, you should reset your alerter. Your encoder puts out pressure altitude. (Pressure altitude is what you would read if your altimeter were set to 29.92"). On the ground, ATC equipment automatically adds barometric correction before the controller sees your altitude. AirSport Alerters do the same, so everyone is working with the same numbers.

Does it work at Flight Levels? Flight Levels are handled by the AirSport PRO, but not by the IFR models. On the PRO, any assigned altitude can be chosen up to 17,900 ft, plus FL180 to FL555. The PRO changes to standard pressure automatically when entering Flight Levels, and a tone reminds you to change your altimeter. Prior to descent, you can set the new barometric pressure, and the PRO will switch back to altitudes at the legally correct point in accordance with FAR 91.81, and will again remind you to put the new setting in your altimeter.

How does it know which transponder is mine? It's a matter of signal strength, yours is the strongest! If your transponder is not on, it may receive another transponder within about a half mile. Otherwise, it will receive only yours.

Is it easy to use? Yes. The outer knob selects functions, they are shown in the function window. The inner knob adjusts a value. For instance, in the Set Target function, the small knob sets your assigned altitude. Plus, every unit contains a demonstration mode which allows you to learn before you take it flying. You can practice setting cruise altitudes, become familiar with the many tones, and so on. The User's Manual is written from a pilot's perspective, we're proud of the many compliments it has received.

In cruise, how much altitude tolerance do I have? It's your choice, you can select a band with a total thickness of 100 ft or more. ATC violation can occur if you deviate 300 ft from your assigned altitude, so it's a good idea to set the tolerance less than that. You will receive audible and visual warning if you fly outside of your selected tolerance. The tones indicate how far you are off, and which way you need to go to return to assigned altitude.

How big is it? Two inches high, 5-1/4 inches wide, and 5-1/4 inches deep. It weighs 28 ounces. The battery and antenna are inside.

How long has it been on the market? The first AirSport PRO's were delivered to customers in April 1991. The IFR model was introduced in 1993. They have been protecting pilots worldwide since.

What about reliability? AirSport Alerters have demonstrated excellent reliability. All components are high quality, and we take pride in our workmanship. Unlike many units on the market, our equipment is 100% designed and built in the USA. The design team members are all pilots, so we understand why reliability is important. And we back it up with a 26 month warranty on parts and labor.

As always, we appreciate any additional questions or comments you may have.

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