Air traffic controllers operate on a simple premise: “No two airplanes should ever occupy the same airspace at the same moment in time.”

To make that work, controllers need pilots to follow ATC instructions closely. But the FAA's massive Aeronautical Information Manual, pilots written link to good communications, offers just eight pages of pilot/controller lingo.

And because it’s contained in the AIM, it’s not even regulatory in nature. At the same time, controllers use the Air Traffic Control manual, 7110.65Z, as their operational guide because it details nearly every single air traffic control procedure, as well as the phraseology that most efficiently communicates the intended message. Making the ATC system work smoothly lies somewhere between these two books, and of course how pilots interpret them. 

We asked several air traffic controllers at a couple of the most popular pilot/controller online forums to share examples of the radio communications that make their jobs tougher and slow the entire ATC system, especially when there’s a considerable amount of traffic. The responses were evenly split among control tower, en route center and TRACON controllers.

Listen First

One of the top problems relates to those pilots who switch from a previous frequency and immediately key the microphone and begin talking. This makes it nearly impossible for other pilots already on the frequency to acknowledge an ATC instruction they had just been given. It also often completely blocks other aircraft waiting their turn.  Always, always, listen on the frequency for 5-10 sec. before punching the transmit button. 

Think Before Talking

Pilots can often be heard trying to figure out what they want to say to a controller after they’ve keyed the microphone rather than before. This translates into a pilot taking up 30-sec. of precious radio airtime to say what other pilots might say in only five. Case in point: During a busy traffic period when an instructor allows an inexperienced pilot to attempt to learn radio communications on a busy arrival, departure, or overflight frequency, please figure out the words before you begin speaking to ATC.

Tell The Truth

Controllers often speak quickly when they’re busy and that intimidates some pilots into simply acknowledging an instruction before they realize they don’t completely understand what’s being asked of them.

Controllers ask pilots to, “Please Speak Up,” if they don’t really understand the instructions. It’s dangerous to all when a pilot accepts an ATC instruction but wanders around the sky only thinking they understand. “I don’t care how busy I am," one controller said. "Confirming is better than guessing any day.”

'Immediate' Means Get Moving

When a tower controller says “Falcon 123, cleared for immediate takeoff,” the crew is expected to bring the throttle up smartly and get that airplane moving down the runway. This can be a bit tougher if the waiting airplane wasn’t on the runway yet.

Pilots must understand that a controller bases meeting the required separation minimum on the pilot getting that airplane moving right away. Some tower controllers will make it a bit easier on pilots by saying, “Falcon 123, cleared for immediate takeoff runway 16 or hold short. Traffic is a King Air on a three-mile final." The same emphasis on speed applies while airborne. “Gulfstream 788 turn right immediately. Traffic 12 o’clock and less than a mile.” A failure to comply can be disastrous.

Acknowledging Traffic

Controllers say they become annoyed when they call traffic only to hear a response like, “We’re looking for him on the fish finder,” or “We see him on TCAS,” That doesn’t work for ATC. The best response is either “King Air 766 looking for traffic,” “King Air 766 has traffic in sight,” or ‘King Air 766 negative contact.” It’s important that pilots tell ATC when they lose sight of traffic they previously reported in sight.

Controller Attitude

A TRACON controller said, “Sometimes we might sound upset when we really aren’t. A lot of ATC facilities are understaffed and overworked, so please bear with us. Then too, there are a few controllers who are just jerks. Sorry about that.”

Just like pilots, remember that controllers are often in training as well. That’s when everyone must add some patience to their flight plan.

Stick To The Speed Assigned

In most busy terminal areas, controllers are extremely fussy about airspeeds. When ATC assigns a speed of 160 kts, for example, they expect pilots to fly that speed precisely, right up to the outer marker. Don’t ever slow the aircraft early without asking first. If ATC ever asks a pilot for something the aviator can’t handle, for whatever reason, a simple “Unable,” works best. Controllers will quickly create an alternate plan.

'Blocked '

Using this phrase often makes everyone on a frequency crazy because no one knows for sure who should speak next. Three or four pilots jumping on to tell ATC an unknown transmission was “blocked,” simply makes a difficult situation worse. Give the person on the ground a few seconds to sort things out.

Checking In 

The AIM offers a few non-regulatory examples of how pilots can check in between ATC facilities while en route, but controllers mentioned one that isn’t helpful at all: “Malibu 788, 6,000 climbing 9.”

Instead, this is preferred: “Cleveland Center, Falcon 915RB, leaving Flight Level Two Zero Seven, climbing to Flight Level 350.” If an aircraft is inbound on a STAR, mentioning the procedure on the initial call-up helps.

A Word About Training

Despite the search for communications perfection, there are times when training or letting the new person learn the ropes should be put on hold.

When new controllers are training, they’re plugged into their sector alongside a more experienced controller who can override them if safety is threatened. As one controller and pilot mentioned, “There have been times when I’m flying that I find myself praying the ATC instructor will step in and fix a traffic mess a new controller has created." Instructors must always weigh the benefit of a trainee digging their own way out of a situation versus the cost to the overall operation.

It’s a balance on both sides of the microphone.