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Instrument Scanning and Situational Awareness
Jason Nordby

Course Heading Altitude Traffic Time-Out Systems--CHATTS

Tanks Integrity Meteorology Environment Organize UA Trend--TIME-OUT

I’M Safe No Chain Team Emergency Prep Gyros Riders Icing Theatre Yield--INTEGRITY

Turning Until Rates Next--TURN

CHATTS, TIME-OUT, INTEGRITY, and TURN combine to form a fluid mnemonic set that leads a pilot through a comprehensive instrument scan and awareness check while flying in instrument meteorological conditions. Several years of thought have gone into the development of this system since my early instrument training when I found myself dumbfounded by the instruction to, "Develop a scan and stick with it." I wondered how many structured scans actually took shape from the stumbling of instrument rating candidates. I also wondered if my instructors really had anything specific in mind, but when I queried I most often heard, "Whatever works for you."

The sole intent of this system is example. If you are an instructor, the next time you utter the words, "Develop a scan and stick with it," consider offering this (or a system of your own devise) for the scrutiny of your student. If you are a student, give it a try. More power to you as a pilot if you overhaul or scrap it for something more to your liking; whatever works for you.

In the following pages I will attempt to fully explain the CHATTS system. Perhaps you will think that I’m way off the mark, or that it’s too cumbersome or something is missing. Whatever your thoughts, I invite you to express them directly to me via the e-mail address listed at the end of this article. I am very interested in feedback from other pilots on this.

Any scanning technique should build upon the basic concepts of attitude instrument flying; this concept, after all, did its part in putting men on the moon. In putting these particular mnemonics together I exclusively considered the aspects of the primary/support technique of attitude instrument flying, so I do not know how well it will adapt for those pilots who prefer control and performance, or other techniques I am unaware of.


For ease of understanding, assume straight and level flight is desired, unless otherwise stated. In the cycle examples, words or phrases contained within quotation marks are thought or stated aloud by the pilot. I like to say them out loud to devote more of my attention to the matter at hand. Each time your scan shifts from one instrument to the next be sure to check that each is in agreement with the others. This will aid in quickly identifying a partial panel situation and the culprit(s) responsible.


This cycle begins and ends, as do all the other cycles in the CHATTS mnemonic, with the attitude indicator (AI). Starting there, one should think or say aloud, "Course," to gather mental focus. Then proceed to scan primary and any secondary lateral navigation instruments and, reading those, state your positional orientation relative to your desired course line (on, left of, right of, et cetera.) Return to the AI with your positional awareness and the cycle has ended.

Cycle example: AI, "Course…straight and level." VOR1, "On victor-533," ADF, "approaching BOUND intersection," and return to the AI.


Your lateral situation progresses naturally into the heading cycle. The primary bank instrument is the directional gyro (DG), so the scan moves from the AI to the DG. Assuming you found yourself on-course, you simply want to verify the heading that has been maintaining your course line. If you were off-course, determine whether you have unintentionally relinquished your desired heading, or that perhaps you need to modify the desired value. Either way, the operation of the AI and DG is then crosschecked at the turn coordinator/inclinometer (TCI) and then the scan returns to the AI.

Cycle example: AI, "Heading…straight and level." DG, "270 degrees," TCI, "straight and clean/coordinated," and back to the AI.

Rough corrections to return to the desired course would be made at this point.


The altimeter is the primary pitch instrument so, again starting at the AI to ensure approximate desired attitude, move to the altimeter (ALT) to verify your assigned altitude. Continue to the vertical speed indicator (VSI) to crosscheck or to arrest and correct. Check and correct airspeed at the airspeed indicator (ASI) making necessary corrections in power as well. Return to the AI.

Cycle example: AI, "Altitude…straight and level." ALT, "5,950, seeking 6,000," VSI, "arrest/correct." ASI, "5 knots over 120 cruise." AI, "Shallow climb back to 6."

In the case of small corrections here, remain with this cycle to prevent overshooting, but maintain a general scan of all instruments in the meantime. Avoid cycle fixation just as you should avoid fixation on any one instrument. Also, consider whether or not the altimeter setting is up-to-date.


This element of CHATTS should be quite self-explanatory. It’s in there just to keep those brain cells responsible for see and avoid duties awake and active. Omission of the windscreen from the instrument scan has led to great tragedies. If you are in IMC, hopefully you are in controlled airspace under radar watch. Otherwise it’s up to you.

Time (out)

Okay, so you can’t exactly take time-outs aloft in the IFR system, even if you’re jockeying a fling-wing. But I think ‘time-out’ is a sometimes-magic phrase, the concept of which can cause one to step back for a moment and take a look at the big picture. It may even have the power to lift a little of the mental IMC that forms when the workload gets heavy. For now, though, we will only consider the element of time because it is only intended to be broken down mnemonically at the pilot’s discretion (i.e. fix passage and halfway points of legs.)

The time element has different facets depending upon the phase of flight being conducted. En-route it’s simply a reminder to keep abreast of the flight’s progress and position. While holding, the timer becomes a busy little component. During an instrument letdown we’re timing course reversals and missed approach points. Thus, a glance at a FAA regulation timing device works its way into the scan and correlation is made with the flight plan, approach plate, et cetera.

Systems (or Speed during an approach)

At this point one should give special attention to the very hardworking systems that are part of the airplanes we fly. Oil pressure and temperature, manifold pressure and/or tachometer, fuel mixture settings, alternator…all of the associated systems gauges should be interpreted for potential warning signs. Take a moment to closely listen to your power plant(s). Sometimes an occasionally misfiring cylinder can be hard to detect if conscious effort is not devoted. System failures are exponentially more dangerous when they come as a complete surprise. Early detection and prevention can be your salvation. Develop a systems flow check for each aircraft you fly and touch each instrument as you interpret the information.

An airplane might disappoint any pilot, but it’ll never surprise a good one.

–Len Morgan


As mentioned earlier, this mnemonic is activated at the pilot’s discretion; frequently enough for safe consideration of the aspects contained, but not so frequently as to become a distraction from the primary flight instrument scan. I feel it can easily be done when comfortably reestablished on-course after station passages and, for lengthy legs when the workload is low, at midpoints or whatever suits.


Any guesses? That’s right! Fuel gauges. The one instrument we’re told never to trust still has to be scanned. There is, however, one situation which should prompt us to trust those bouncy little needles with our lives–when they seem to be telling us that we don’t have as much fuel remaining as we thought we should have at a given point. Set minimums here above and beyond the fuel requirement regulations. Designate ‘red flags’ on the quantity indicators, congruous with the burn rates for the aircraft you are flying, below which you refuse to continue operation beyond the next available refueling point. Do not over-fly an airport fuel pump when in doubt about your fuel situation.

After scanning the quantity indicators it’s time to update your flight plan. According to actual times en-route, calculate and record your probable fuel consumption and fuel remaining. I say ‘probable’ because, unless you can rest assured that your rubber band adheres precisely to the figures in the POH and you have set the power and mixture perfectly, you cannot be certain. Always keep in mind that without modifications to your fuel planning figures on the cautious side, you are most certainly carrying less fuel than you think; that is an inherently unhealthy lifestyle to lead in the cockpit.

The only time an aircraft has too much fuel on board is when it is on fire.

– Sir Charles Kingsford Smith


Integrity is another mnemonic in itself. For now simply ask yourself if the flight you have been conducting has demonstrated integrity, according to the definition 1: an unimpaired condition; SOUNDNESS 2: adherence to a code of especially moral or artistic values (adherence to a professional attitude and a thoroughly prepared flight plan) 3: the quality or state of being complete or undivided; COMPLETENESS. If you cannot confidently answer, "Yes," perhaps it’s time to land somewhere and allay your doubts.


There are many ways to get oneself into trouble in the air. One way is to rely solely upon the weather briefing obtained during preflight without any en-route updating. A more direct route to trouble is completely forgoing a weather briefing. Weather is quintessentially dynamic; it is always changing. If the forecast busts and you’re oblivious to the fact until you’ve tripped and fallen right into the hornets’ nest, you could quickly find yourself in past your personal minimums. And this is no way to convince yourself that you’ve been too conservative in setting those criteria, though some pilots follow that path until it leads to disaster.

I heard it best stated thusly, "The really good pilots use their superior JUDGEMENT to avoid situations that might require them to demonstrate their superior skills." Good judgement regarding weather calls for continuously keeping abreast of the changing picture ahead. Keep one of the com-pair busy with AWOS, ASOS, ATIS, or FSS weather chatter when you’re not occupied by ATC. Stay vigilant for PIREP’s made to ATC that could affect your route of flight. PIREP is pilot talk for, "Been there–done that," and is by far the best information that can be made available to flights along affected routes.


Sometimes we become so engrossed in things that we become unaware of our surroundings. Is the cockpit air temperature comfortable? Can you smell any exhaust contamination? Are you physically comfortable and relaxed, or stiff, sore, and rattled by turbulence? If you’re on-edge due to any of these or other factors, perhaps an unscheduled stop for a refreshing stretch is in order. IFR flying is no place for someone who’s on-edge; the slope is steep and slippery if you go over. Assuring your basic comfort eliminates distractions you may not be conscious of when preoccupied by duty.


Pause here and assess the condition of you workspace. Is it neat and orderly? If not, make it so. Is everything you’ll need for the next phase of flight ready at your fingertips? Have you briefed for the expected instrument approach procedure? Are the checklists at hand? Should the aircraft be configured now to lessen the workload in the next phase of flight? The key idea here is preparedness–stay ahead of the aircraft.


It’s your turn to give something back. Prepare a pertinent PIREP and broadcast it into the system for your fellow aviators. Don’t be narrow-minded here either, as I have allowed myself to be in one instance. I was queried one day by ATC for the current conditions in my locale. I was on an IFR flight plan, VFR on top of an overcast. My route was, for all intents and purposes, benign although thunderstorm activity was scattered on both sides of my course and a dark black wall of disturbing proportions dominated the southern horizon. The PIREP I generated was tainted with the optimism I felt regarding my route, stand-alone. When I heard ATC relay this information to a pilot who intended flight through my area southbound, I quickly realized how lacking my PIREP really was and painted the rest of the picture over the frequency. Ensure comprehensiveness in you PIREP’s; you could help someone make a wise no-go decision, save them time, money, and maybe their life.

Another form of PIREP is the position report. Are you in radar contact? If not, you need to report passing each designated and other requested points. While receiving radar service, any points requested by ATC need to be reported upon passing them. Other reports include unforecast weather conditions encountered, malfunction reports, and any other information relating to the safety of flight.


This element is one of a few reminders within the CHATTS system to consider over-all safety of operation. At this point, weigh the actual flight against the flight that was planned (if, indeed, a safe flight was planned) and honestly determine for yourself whether things are going as planned, better than planned, or worse than planned. If things are trending downhill, make a ‘go-no-further’ decision before the trend gathers momentum. Do not lie to yourself. Do not rationalize the negative trend, nor justify it with excuses, nor pepper it with unwarranted optimism. Ignoring that feeling in the pit of your stomach can be unwise.

For those not versed in crew resource management (CRM): Detect the potential problem or change, Estimate its level of threat, Choose a safe alternative outcome, Identify the things necessary to achieve that outcome, Do those things, and Evaluate the new plan as it takes shape. This is the DECIDE model of aeronautical decision making.


Like the time-out mnemonic, this one is activated at pilot’s discretion. Perhaps every-other time-out cycle, perhaps only midpoints. It really depends upon the route structure you are flying. But there are important ideas contained within, so your best effort is needed.


Okay, by now you’re saying, "Enough with the mnemonics, already!" Bear with me. Most of us have heard this one: Illness, Medication, Stress, Attitude, Fatigue, and Eating. I have heard opinions that this is ridiculous. "I’m unfit for flight just because I’m hungry?!" But remember, our ability to perceive is hampered by physiological needs that go unmet. Hunger can be very distracting. Illness can set on rapidly. Medications like aspirin can wear-off (ever wonder why they look for seeming trivialities like acetaminophen in the blood of a deceased flight crewmember?) Hazardous attitudes are just that–hazardous. And stress and fatigue are very detrimental to performance; all of these conditions are.

My opinion is that if you don’t use this mnemonic before leaving the ground you ought to (and you just might be exhibiting a hazardous attitude.) And there’s no good reason to leave it there when you depart. I have changed the ‘a’ from ‘alcohol’ to ‘attitude’ because I don’t think any pilot with common sense–much less good judgement–should have to wonder before flight if they’re too tipsy to act as a flight crewmember. Make that go/no-go decision before cracking open the cold one(s).

No Chain

Failure chain, that is. This element is closely related to ‘trend’ in the time-out mnemonic, and ‘theatre, yield’, which will be covered shortly. How does one detect a failure chain? Quite easily, really. The difficulty comes in trying to break it once you’ve identified it. Any time you are in doubt about some aspect of your flight, it is likely that a failure chain is forming.

Doubt is a small creature, but it consumes many times its weight in safety.

–Jason Nordby

When you feel that doubt, identify the chain and use the DECIDE model to break it. They say that all it takes is to break just one link and disaster can be averted.

The way I see it, every-other link of a failure chain is a Zeigarnik link. What on earth am I talking about, you ask? The Zeigarnik effect is the name given to the strong psychological drive to complete a task once it is started (I’m sure you’ve experienced it.) I would wager it is one of the strongest links in any such chain. It is the only reason wee seem to isolate the go/no-go decision to preflight activities only. I mentioned the ‘go-no-further’ decision earlier–have you ever made that decision? If you identify a failure chain, now may be the time. Don’t let the Zeigarnik link anchor you to impending tragedy.


Is your team efficient and complete? Even if you’re the only crewmember aboard you flight, there exists a team. Passengers can hold things, find things, and write things down, and including them in the loop can eliminate their anxieties. Have you ever flown with an anxious passenger? That anxiety, I have found, can be quite contagious (thus, another element to consider in the preflight decision process.) Do you have an autopilot? There’s another team member. And all of those people on the ground who are a spin-of-the-dial and a mic-click away are all team members, if you include them. Delegate tasks as you can and your job gets easier.

If yours is a multi-pilot crew, you should agree on in-flight duties before leaving the ramp and crosscheck one another from chock to chock. Establish good rapport and use standard phraseology. Agree amongst yourselves that nothing is to be assumed and everything is to be communicated.

Emergency Prep

If something went wrong in the near future, would you be ready for it? Murphy’s Law asserts if something goes wrong, it will happen at the worst possible time. Identify suitable emergency landing points and have the necessary approach plates ready. There’s a product, called the IFR Flight File, which helps you to organize the plates in a quick-flip format and also outlines emergency and other procedures. It’s quite handy. At this stage in CHATTS make sure you’re prepared for the worst-case scenario.


When was the last time you practiced partial-panel? When is the next time you want to apply those rusty skills in the real world? I’ve seen one artificial horizon go belly-up for five or so minutes before mysteriously shaking it off and erecting once again. I was on a VFR training flight, but had I been in IMC I hoped to myself that I would lose all faith in an instrument behaving so and act accordingly. That means treating it as failed, informing ATC of the malfunction, and finding VFR or the best conditions available to set down for inspection. If your instruments exhibit quirks in bad weather, it’s time to backtrack to ‘No Chain’ and DECIDE to play it safe.


You know…those people who might want you to get them there late in this world, rather than early in the next. How are they doing? Let them know you care. If the little voice in you head is telling you that safety cannot be assured without pushing back schedules, inform them of the situation. You might be surprised to find that the people you perceived as relying on you to make them dead before making them late for an appointment are happy to reschedule with clients and the Grim Reaper. Even if they do put up a fuss, don’t forget who is pilot in command.

It's better to miss the lead story at 6 . . . than to become the lead story at 11.

  • Bruce Erion

If safety is assured you still want to check up on them once in a while to make sure they’re not ready to throw a fit if the turbulence doesn’t stop yesterday. If they catch you off-guard with possibly irrational behavior, it could come at a time when you are unable to deal with it in your workload. Use your available time to help them enjoy flying.


This element is meant to prompt you to carefully consider the atmospheric conditions for the potential of icing. Carburetor icing is most likely to occur when the OAT is between approximately 20°F and 70°F with high (80%) humidity. Structural and air intake icing usually requires that the aircraft surfaces be 32°F or colder with visible moisture present. But air intake icing can occur in clear air when the OAT is 50°F or colder and relative humidity is high. Do these conditions exist? If so, you’ve Detected a potential problem; don’t stop there.


This is another look at the big picture. It might sound corny, but it applies to ‘theatre of battle’. Are you winning your battle against poor judgement, weather, fuel exhaustion, system failure, human factors, physiology, workload, et cetera, et cetera? If not, go straight to ‘Yield’. If so, this is where you pass go, but you don’t collect $200…back to the ‘c’ in CHATTS.


Give in, surrender, abandon, abdicate, back down, bend, call it quits, capitulate, cede, come to terms, defer, fold, give up, knuckle under, let go, resign, or throw in the towel. Pilots–by nature–hate such language. But imagine the hangar talk and criticism you will suffer if you choose to continue and disaster strikes. No other pilot who hears of it would ever think of committing such stupid acts. Am I right? We all do it; we hear of an accident or incident, learn a few of the details, and profess how we would have done things ‘a little differently’, business as usual. Yeah, right. Sure it’s rare. But it can happen to me. It can happen to you. You’ve got a conspicuous neon sign hovering above you if you deny that. >PICK ME, MURPHY!<


This one I devised as an add-on to the CHATTS system. It reduces the scan to include only the essentials involved in making a change in heading.


Here, again, one starts with the AI to establish an approximate bank in the desired direction of turn. When the bank is established, the pilot says to him- or herself, "Turning right/left." If a climbing or descending turn is being made, the pitch attitude is also considered.


Moving from the AI to the DG, the pilot notes the current heading relative to the final heading of the turn and says, for example, "Until 090°." If you have a heading bug, set it.


From the DG, shift your attention to the TCI to verify coordinated, standard rate in the proper direction. The pilot says, "Rate of turn…right/left, standard, and coordinated." Now move to the VSI to ensure level flight, or the proper vertical speed. Say to yourself, "Vertical rate…level/500fpm climb/descent," shift to the ALT, "at 2,300," for example. The final rate to examine is the airspeed at the ASI, and then back to the AI.


What’s next? Determine the very next task(s) requiring your attention. These could include course intercept, a change in altitude, reconfiguration of the aircraft, et cetera. Just another effort to stay mentally ahead in the game.

Don’t ever let an airplane take you someplace where your brain hasn’t

arrived at least a couple of minutes earlier.

–Andy Anderson


I will admit, it does seem cumbersome at first. But that’s because you’re sitting here reading and digesting it. And who ever said that your responsibilities as PIC would be few? Every concept contained truly needs attention while flying. Can you rely on yourself to keep all of this in check without some prompting? Probably not. If you think you’ll tire of looking at the big picture so much, just think of it as looking at it from different angles. Often you have to mount several attacks on faulty judgement, omissions, and hazardous attitudes before they are recognized and corrected. If you consistently find no time to perform these checks, then you’re behind the aircraft and should consider discontinuing. Practice on Microsoft or some other flight simulator; I tested it extensively on ELITE while putting it together. Habits take practice and time to form. If at any time you become overwhelmed, start by dropping all but CHATTS. In terminal areas it is the only mnemonic I keep active.

I hope I do not come off as holier than thou. I’m only trying to present IFR flight with all of its sharp edges exposed so that we might avoid getting ‘cut’. Do with it what you will. I only urge that you be comprehensive as a pilot and admit your humanness.

He is most free from danger, who, even when safe, is on his guard.

–Publilius Syrus


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