You’re ten miles away from your home airport, inbound for landing, and you switch over to the AWOS for a weather check. Nothing. Must not be working. You get closer to the airport and dial up the control tower to inform them of your intentions. No response. After some troubleshooting, you determine that your radio is dead. What do you do? When was the last time you really walked yourself through different aircraft radio communication problems, or “chair-flew” it, as they say?
Aircraft Radio Communication Problem – Uncontrolled Airport
You just took your parents for their first flight since you got your license. You’re ten miles north of the airport, day VFR, setting yourself up for a straight-in to runway 18 at an uncontrolled airport. You haven’t heard anyone on CTAF even though you can see planes in the pattern, and after checking other frequencies you’ve come to the conclusion that your radio is inoperative. What are you going to do?
Walk yourself through the procedures now.
- It’s a good habit to set your transponder to 7600 whenever you realize you have a radio malfunction, even if you’re not in controlled airspace. Build those habit patterns!
- Stay clear of all traffic until you determine which runway everyone is landing on, and which direction traffic is in. If you fly at this airport routinely, it probably hasn’t changed. If you were setting yourself up for the straight-in, stay clear by holding your altitude (at least 500’ higher than the traffic pattern) and offset the runway laterally so that you can make a big circle around and figure out which aircraft are where.
- When you determine that it’s safe to enter the traffic pattern, do so and stay predictable. Fly the same direction and speed as you normally do so, and don’t forget your landing checks.
- Continue to key the microphone and announce your position just in case it starts working again.
- After landing, clear the runway immediately. Survey the taxiways between you and your destination and taxi when it’s clear.
Aircraft Radio Communication Problem – Class D Airspace
You’re returning home from a weekend at a cabin in the mountains. The time is 2030 local time and the skies are clear. Your home airport is in Class D airspace; the control tower stays open until 2200. You’re ten miles east of the airport, just wrote down the ATIS information, and switched over to tower frequency. ATIS says winds are out of the north and landing traffic is using runway 34. The tower isn’t answering any of your radio calls but they’re talking with other traffic; when you transmit, you can’t hear sidetones (clicks) in your headset like you normally do. No one is answering your radio checks and you realize your transmitter is broken.
What are you going to do?
- As in the previous example, set your transponder to 7600.
- You must stay clear of the Class D airspace boundaries until you determine the flow of traffic. This can be done horizontally or vertically, and at night, it may be easier to get a picture of the traffic by looking down on it from above.
- Enter the traffic pattern when safe to do so – entering on the upwind gives you maximum time to prepare yourself.
- From here, just fly your normal night traffic pattern and continue to key the microphone with your position just in case your radio starts working again.
- Tower won’t know you have an operable receiver so they’ll give you light gun signals (they may also transmit your clearances in the blind, but they don’t on this night).
- Which color are you looking for?
- What if tower gives you a steady red light, what do you do?
- How do you acknowledge these signals at night?
- A solid green light means you’re cleared to land, and you may only land after receiving this signal. Acknowledge this signal at night by flashing your landing light. A steady red light means you must give way to other aircraft in the pattern. Continue to circle and wait for a steady green light.
- After landing, continue to look for light signals – you’re looking for either a flashing red (taxi clear of runway) and or flashing green (cleared to taxi). The tower will most likely freeze ground traffic until they determine where you’re headed.
Aircraft Radio Communication Problem – Class B Airspace
It’s a beautiful day and you’re returning to land at a Class D airport underneath San Francisco’s Class B shelf. You notice smoke coming from your radio so you immediately turn it off; the smoke goes away and you elect to keep your master battery and alternator on for the meantime. You’re 15 miles away at 3,000’ AGL, and it’s your closest runway.
What are you going to do?
- Change your transponder. Here, you could set either 7600 or 7700. This is an age-old debate amongst instructors. Some say that in this case you can just set 7600 to indicate you’re NORDO. Other instructors will say that if you did any emergency checklist actions (like turning off a smoking radio), then you set 7700. In this case, that might be a good idea, in case the fire is smoldering at least fire trucks will be waiting for you on the ground. And this could always develop into something worse. No one will fault you for setting 7700.
- Remain clear of the Class B airspace if you can (by going underneath). This is how most VFR pilots will operate anyways. If you can’t, ATC will see your transponder and keep other traffic clear of you – that’s their job in Class B airspace.
- From here, it’s the same basic procedures as the previous Class D example. Stay clear until you determine traffic flow, enter the pattern, and look for light gun signals from the control tower. The fact that you might be in Class B is irrelevant at this point. How do you acknowledge a light gun signal during the daytime?
- Acknowledge by rocking your wings.
Troubleshooting Aircraft Radios
Any number of things can cause a transmitter failure, a receiver failure, or both.
Indicators that your radio may be malfunctioning:
- Lack of sidetones (clicks/feedback) in your headset when you transmit (at least a transmitter failure).
- Not hearing any transmissions on automated frequencies like AWOS & ATIS (at least a receiver failure).
- No answers to “radio checks” you transmit (could be a transmitter or receiver failure).
- And, of course, the thing won’t turn on.
Steps to troubleshoot a radio in the air:
- Start with the most basic things first, and that’s usually cycling the power on the radio unit itself.
- Check the volume knob – did it somehow get turned all the way down? Do you hear any static when you turn it up? If not, you probably have at least a receiver failure.
- Toggle the squelch settings – again, are you hearing any static when you do this?
- Check your headset cord – is it still plugged in? Does your headset have a volume knob as well?
- If your circuit breakers are accessible (and most are) check that it’s still in. If it’s popped, reset it. If it pops again, there’s probably a really good reason it’s popping and you should leave it off.
- Don’t become so engrossed in troubleshooting your radio that you forget to fly your aircraft!
Remember at all times that you must maintain basic VFR weather minimums and visual contact with the control tower, if there is one. Further references can be found in the FARs parts 91.125-131, and in the AIM Chapters 4-2-13 & 4-3-13.
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