164 votes

Why do airplanes use MAYDAY when in danger but ships send SOS?

The difference here isn't between ships and aircraft: it's between Morse code and voice. The SOS signal is only for Morse code. It's short, easy to send, and easy to recognise. But it's not as ...
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  • 12.5k
137 votes
Accepted

What happens if a language other than English is used over the radio?

During the 1990s I flew into countries on every continent except Antarctica. As an American English speaker flying U.S. registered airplanes, I never had a complaint that a controller had trouble ...
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  • 38.7k
116 votes
Accepted

How do civilian pilots and ATC verify that other people on the radio are who they claim to be?

This is a reasonable question, and to an outside the simple answer of We don't / can't might seem a little bit jarring. After-all, we live in a time of hacking, terrorism and so on and I can ...
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  • 8,840
111 votes

Why is "Affirm / Negative" used instead of "Yes / No"?

Why do we say "TANGO" on the radio for the letter "T"? Because "T" could get garbled or misunderstood to be "B", "E", "or "V". "NO" could become "oh?", "YES" could become "us", and so on...the ...
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98 votes

Why do English-speaking pilots and ATC say "Niner" instead of "Nine"?

According to Wikipedia: The pronunciation of the digits 3, 4, 5, and 9 differs from standard English – being pronounced tree, fower, fife, and niner. The digit 3 is specified as tree so that it is ...
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  • 96k
97 votes
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How was I able to just plug in my headphones and listen to ATC and pilot chatter?

This is a feature offered on some United Airlines aircraft and flights. It's an interesting way to hear what's going on in the cockpit. You can find lots of information by searching for United channel ...
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  • 8,823
74 votes
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What are the advantages of squawking 7700?

If you make a radio call, unless you are on 121.5 (or 243 military), then only the station you are talking to will initially know about the emergency. Initial calls should always be with the unit you ...
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  • 30.8k
73 votes
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Who has the higher authority, the pilot in command or ATC?

It isn't a black and white issue of who has higher authority. A pilot in command (PIC) is the ultimate authority for the safe operation of his airplane. An air traffic controller is the authority ...
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  • 34.8k
70 votes
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Why is "Affirm / Negative" used instead of "Yes / No"?

Because it makes you sound cool and very Top Gun! Negative Ghostrider. The pattern is full Seriously though, short words, especially at the end and beginning of transmissions are often clipped. When ...
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  • 30.8k
67 votes
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Is it OK to greet ATC?

It is not part of the standard phraseology by any means, but it is fairly common, as is a very quick pleasantry when changing frequency. [station name], Good morning, G-ABCD, [request] and G-...
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  • 25.4k
62 votes

Why does the ICAO alphabet use "Charlie" for C?

Hard C sounds too much like K. Ch (Charlie) will not be confused with K (Kilo). And soft C sounds too much like S (Sierra).
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  • 8,689
61 votes
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How does an Airbus aircraft connect to the Internet?

There are three different ways that aircraft can give internet access to its passengers, which will most likely be on at around 38,000 feet. First off, to have Inflight wifi, there needs to be a ...
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60 votes
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Why do military pilots report "gear down" during their traffic calls?

In the U.S., military ATC (and civilian controllers working at military fields) are required to: "Remind aircraft to check wheels down on each approach unless the pilot has previously reported ...
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  • 17.8k
55 votes

Why do military pilots report "gear down" during their traffic calls?

Other answers mention "it's the rules" without specifying why the rules are what they are. Civilian airplanes are for the most part assumed to be in proper working order after a flight, ...
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  • 6,197
55 votes

Why do we say certain things three times (e.g., "Mayday, Mayday, Mayday"), rather than two or four?

Yep, the critical commands are repeated 3 times. This ensures there is ABSOLUTELY zero doubt in anyone's mind (especially on a big crew airplane) of what needs to be done in a critical situation. It ...
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  • 511
52 votes
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How are duplicate call signs dealt with?

The scenario you're asking about is common. Let's say that your Delta 158 from South Korea to Detroit is running several hours late, and the decision is made to operate the A320 DTW-BOS on time. ATC ...
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  • 41.9k
51 votes
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Callsign includes the term 'with Kilo' ; What does that signify?

What that probably means is that the pilot is reporting that they have ATIS information kilo. Automatic Terminal Information Service (ATIS) is a radio broadcast on a specific frequency (often a local ...
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  • 49.5k
51 votes
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What does ATC do during "slow" times?

Admin stuff, emails, chat with a colleague if you are not alone on shift, read up on (ever changing) procedures, eat, read a book, make sure the coffee machine works, meditate, watch TV. Anything goes,...
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50 votes

What is your responsibility when a distraught pilot is on frequency?

On frequency, if control is responding to the distressed aircraft you should stay quiet and let them work the problem. This would not be a great time to ask for flight following or traffic advisories ...
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  • 96k
50 votes
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Should I contact ATC if I don't have a transponder?

Every US controller I've ever heard from says they'd prefer to be talking to every aircraft in their airspace, period. This lets them know your intentions and allows them to move you around if needed, ...
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  • 26k
49 votes
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What kind of assistance can another aircraft provide to an incapacitated pilot?

This is speculative and I haven't looked at the links you gave, but I can think of a few things: Having another aircraft there gives ATC a way to gather information that they otherwise couldn't. For ...
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  • 70.2k
47 votes

What happens if a language other than English is used over the radio?

This is much more common than just the countries you list. In Mexico, for example, ATC communications with Mexican carriers are entirely in Spanish and many of the controllers have thick accents. ...
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  • 34.8k
44 votes

Is it OK to greet ATC?

Technically you are not suppose to and for the greatest safety, internationally recognized vocabulary should always be used. However, I have noticed most heavy pilots and many controllers do a ...
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  • 11.2k
43 votes

How often does a pilot ask ATC for a repeat?

How often is hard to quantify, but in general I would suggest the answer is all the time. ATC is there to help you, as a service to you as a pilot. Sometimes out of necessity things are said quickly ...
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  • 25.4k
42 votes
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When should a pilot use the word "takeoff?"

The word "Takeoff" should only be used when clearing somebody for takeoff, acknowledging your takeoff clearance, or cancelling/acknowledging a cancelled takeoff clearance. "Departure" should be used ...
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  • 10.3k
42 votes
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Does air traffic control identify a distress situation when an aircraft flies triangles in the sky?

To my surprise, this does exist, at least in the UK. According to the Manual of Air Traffic Services: 7 Emergency Triangle Procedure 7.1 Pilots lost or uncertain of position and experiencing ...
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  • 70.2k
40 votes
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How would an airplane land if the on-board radio breaks down?

It is important to remember that it is often difficult to diagnose radio malfunction during flight. Therefore it is hard to know whether you have a malfunctioning transmitter, a malfunctioning ...
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  • 25.4k
39 votes
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What does ATC mean when they refer to "company"?

Generally when used in ATC movement instructions the word "company" means "The other aircraft operated by your company". In this context it's a convenient shorthand for controllers and pilots: If two ...
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  • 67.2k
38 votes

What are the advantages of squawking 7700?

Aircraft squawking 7700 are getting a special indication (e.g highlighted, distinct colour, boxed) on Air Traffic Control (ATC) displays. This helps to identify the emergency aircraft not only to the ...
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  • 74.8k
38 votes

How was I able to just plug in my headphones and listen to ATC and pilot chatter?

ATC and aircraft communications (at least in the US) are not restricted for receiving. Anyone can purchase (or make) an "Air band" receiver (or scanner radio) tunable through (roughly) 118-140 MHz and ...
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