Just Say It: Unable

This one word can make the difference between complying with an instruction that really shouldnt be attempted, and a nice, safe, comfortable flight.


How often has ATC asked or maybe even told you to do something that was just not inside your capabilities or safety limits? A few times? Maybe you are an airline pilot and it happens somewhat often. What about when you requested a short cut or something other than normal?

There are many cases on both sides of the mic where saying, “Unable” is the best thing to do.

Yes? No? Maybe?

“Unable” is pretty easy to understand. One is simply not able to comply. This word is one that every controller, pilot, and student pilot must know and be willing to use. It is a game changer in every instance of its use. It isn’t just something you can pull out and use at your convenience, but rather that last resort that you know will always work.

This most helps the student pilot who, ironically, is probably most reluctant to play the unable card. It’s interesting how I have not heard “Student Pilot” very much anymore, but by the way they talk on the radios I can tell.

ATC will often ask pilots if they can do something somewhat out of the ordinary for the purpose of granting a shortcut or maybe to gain that extra slice of airspace. This subtle word works on both sides of the coin. In the pattern, Tower might ask a pilot to fly a short approach that—if the pilot is unprepared and accepts it—requires a steep and fast dive. Perhaps you’ve been offered that so they can fit you inside of other traffic, to avoid vectoring you 10 miles out to get behind everyone. Or, perhaps they just need you to cross the approach end of the runway so they can start getting other airplanes out. Regardless, if you don’t think you can safely and properly comply, bring on the PIC authority and just say it, “Unable.”

Of course, don’t frivolously decline an instruction just because you don’t want it. If you can comply safely and properly, do so, even if you’d rather not. Also, if you can’t, it’s helpful if you tell the controller why. For example, on that short approach, “Unable this close. It’s a bit too steep.” This tells the controller what s/he must do to make things work for you.

As you’ve likely experienced, getting an “Unable” from the controller is also common. Perhaps you’ve requested a short approach, and you hear, “Unable, traffic on final.” We all want shortcuts, just to shave a few minutes—and perhaps thousands of dollars—off the trip. Instead of having to fly around a MOA or other restricted airspace, you can ask. “Request direct DAFIX,” is evaluated on a case-by-case basis. In the worst-case scenario, you get an “Unable” and you’re no worse off than before you asked. Asking for shortcuts (at least in the air) doesn’t hurt. Pilots fly for a reason, they have places to go.

Other Uses of Unable

In the ATC book (7110.65), “Unable” has many uses. Maybe you need to deviate for something, or I can’t give you a landing clearance. Growing up in ATC, this word was taught to me early so I would not draw out a situation. My first lesson was while I was in ground control (first position working live traffic), and a pilot asked for a certain route along the taxiways, and I had a long story to explain why not. My monitor cut me off and said, “If you can’t give ’em what they want, say ‘Unable!'” This is why I believe it needs to be taught to student pilots well before they solo. Imagine a student pilot’s first solo and ATC is asking for some Top Gun maneuvers? I can’t imagine a more stressful situation.

Another frequent use of the word “Unable” is around weather. This is one of the few instances when an “unable” becomes a “make it happen.” Say you’re approaching a buildup and you ask for a deviation. You might be hemmed in by traffic and the controller says, “Unable.” However, it’s common to say why in your initial request, “Request 20 right to avoid a buildup.” So, the controller will likely offer you an alternative—perhaps a deviation to the left, a different altitude, or a delay approving a right deviation. Consider these and pick the best one.

Sometimes ATC might give you a heading or an altitude that doesn’t make sense. While we normally comply with these simple instructions, asking for a clarification or verification is reasonable and better than a simple “Unable.” You might be descending to land and get a climb-and-maintain instruction. So, you verify the instruction, and you either get a very good reason, or the morning coffee kicks in and the instruction is corrected. Don’t be afraid to “Verify” an instruction.

Needs vs. Wants

What does ATC want when asking pilots to take shortcuts or do something slightly out of the ordinary? What do pilots want when asking ATC for something? The short answer to both questions is simple: It doesn’t matter. Getting a shortcut is a small bonus but is never guaranteed … even if the airplane 10 miles ahead got the shortcut, you can’t expect it. Airspace or other traffic might be in your way, but was such that the airplane in front could get through. Again, don’t expect to win every time.

Now how do those wants compare to the needs? A pilot may want to take a shortcut or descent early through a random airspace, so on his side of things, it’s relatively simple. On the ATC side of that same request, and depending on your altitude, the controller may be able to approve it easily, or in some cases controllers working in one facility (center or TRACON) might have to coordinate with other facilities to approve that request. Based on workload, it could just be a simple matter. But, if traffic is heavy this request could take up to a full minute or longer to accomplish. ATC may also look at this request as, “How much can it help me? Does my workload permit? Does it help the pilot move on through while not drastically increasing workload?” All of this can happen within the span of a few seconds.

Now let’s imagine the reverse. You’re at cruise, approaching descent for your destination, and ATC would like to speed you on your journey with a shortcut. “N12345, cleared direct DAFAF. Descend and maintain 7000 feet. Expedite through 9000.” You pause for a few seconds to assimilate that and make sure it passes your safety margin. If it doesn’t—perhaps the shortcut doesn’t give you sufficient distance to descend—so you reply, “Unable. That doesn’t give us enough distance for descent. Request original routing.”

While the pilot is evaluating this request, ATC was already thinking of all the coordination (if any) to be done to help them, help you, help them. Maybe this was a little too much to ask of the pilot. If a controller asks enough pilots to do something, and they all decline, the controller might stop asking or might look at each case more carefully. That request might be a challenge for a Skyhawk, but a no-brainer for a Lear.

Pilot in Command

I want to wrap it up by citing two instances where “Unable” was and should have been used. The first instance is when Capt. Sully had to put Cactus 1549 down in the Hudson River. His aviating and navigating priorities required his communications to be short and simple. It’s interesting that after this event, pilots’ use of the word “Unable” jumped up noticeably. The realization of what the word meant likely clicked for a few pilots. Completely unintended I’m sure, however not the worst thing to come out of that event.

The next event happened on Thursday, June 9th, 2016, at Houston Hobby (KHOU) Airport. This may have already clicked for you, but if not, a Cirrus pilot with low time was attempting to land at the busy airport but was sent around several times so that “IFR jets” could land. She ended up crashing the airplane and all three souls were lost.

Without going into the full report, ATC messed up, and she should have called them out. To cite the report, “During this extended period of maneuvering the pilot did not assert the responsibilities that accompany being a pilot-in-command and did not offload the workload by either requesting to be re-sequenced, telling the controller to standby, or stating ‘unable.'”

She was ultimately responsible for the safe operation of the flight that, instead, resulted in a stall-spin to the ground. However, the other two probable causes on the report included ATC’s instructions and “the pilot’s lack of assertiveness.”(NTSB.gov,. 2017) One word could well have saved three lives.

Here’s your simple takeaway: Trust your gut. Lacking certain circumstances, we won’t intentionally go into a situation with a high probability of a bad outcome. Assert when you need to, and have no fear. No external stress or hazardous attitudes can stop you when you put your foot down, not the company you work for, not your passengers, no one else. That is why there is only one left seat. Fly safe.

Unable Means No!

I was working Tower recently with pretty standard traffic—nothing fancy, just a few arrivals/departures on one side and pattern traffic on the other side. In total I believe it was perhaps five aircraft doing touch and goes. All of these were from the same flight school, so I’m thinking, they wouldn’t intentionally cut each other off, plus they called each other in sight.

About 30 minutes into these touch and goes, one requested a “stop and go.” I could not have five aircraft doing touch and goes with one doing a stop and go; it would mess up the pattern and I’d be making student pilots do a lot they didn’t need to. So, I come back with, “Unable. I have five of y’all.” He came back with, “Well we need to do stop and goes for training.” I thought about putting that one airplane on the other runway, but I had started to have a line of departures and arrivals. “Unable,” I repeated. I thought the matter was closed, as it should have been.

I then went back to all of my pattern traffic individually with, “(callsign), cleared touch and go only.” Then over the numbers was the pilot with that request, and another one right behind him, probably about a mile behind. He does a stop and go. I suspected it, and immediately called him out, “I said unable stop and go, you need to roll immediately. Traffic short final.”

I ended up having to send the guy on final around, right around the time the one on the ground started to roll and rotate. Now this was not cool. I had two planes fairly close to each other on the go from a single runway. I had the stop-and-go guy extend upwind while I put the guy behind him in front. With that sorted out, I tried to impress on the stop-and-go guy how serious this was. “Sir, you were cleared touch and go only. Having two planes in my pattern that close is no good.” They came back with a bland, “Oh sorry.”

Was it over? Nope. Luckily for me, I anticipated it the second time and built a few miles space for him. He comes in to touch and go, and stops, again. I calmly told him to “start your roll, expedite.” He got up safe and for the last time, “Sir, make left traffic for the east runway.” He acknowledged. Mid-field downwind, I told him, “You are cleared to land.” He replied confused, “Um Tower, request option.” I quickly said, “Unable. Cleared to land.” No reply. He landed and exited the runway, and with a quick point out to Ground I taxied him to parking. He was confused to say the least. It’s not my normal custom to deny traffic pattern operations, but when something becomes unsafe, I have no choice.

No, I didn’t bust him. I considered it but thought the paperwork wasn’t worth it to me and I hoped he’d already had his learning experience.

Elim Hawkins not only uses “Unable” for aviation, but for life outside as well. He is often puzzled when people stare at him after asking for something and getting a simple “Unable.”


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