Many of us have experienced momentary lapses in awareness while driving long distances. We have difficulty remembering the past few miles driven, have drifted from the proper lane, hit rumble strips, or completely missed an exit. Or you get ‘the nods’ where your head droops forward for a second, and then you get a sudden body jerk back to full awareness. You turn up the radio or open windows to deal with these warning signs, but to no avail. Hopefully, you pull over and take a rest before something serious happens.
The situation is considerably more fraught with danger when ag flying. A few years ago, I was working a field over 40 miles from my home base, meaning there was a lot of transit time between loads. I remember the day was hot and muggy, and as I was flying an aircraft without an air conditioner, cockpit comfort was an uncomfortable 5 points out of 10. We had started around 4:30 AM, and it was coming to high noon as I headed back to home base.
I clearly remember getting ‘the nods’ en route and desperately fighting the urge to have a quick nap when to my surprise, I had one of those body jerks that brought me back to full awareness just as the airport magically appeared five miles at 12 o’clock. Like the driving scenario, I couldn’t remember the last few minutes and was completely surprised at how close I was to the airfield.
In another incident, I was flying a Brave when the old ‘nods’ again showed up, this time at spray height. Coming up to a small hill, the wheels firmly hit the ground, giving me a good bounce and scaring the daylights out of me. Luckily, I was applying a pre-emergent treatment with little or no crop growth to snag the wheels. Once I arrived safe and sound back at home base, I headed for the crew trailer to get some desperately needed ‘zzz’s.
The Drowsy Flying Problem
The CDC (Centres for Disease Control and Prevention) recognizes drowsy driving as a significant problem in the United States regarding automobile transportation, with the risk, danger, and often tragic results alarming. The CDC characterizes drowsy driving as the dangerous combination of driving and sleepiness or fatigue.
Drowsy flying ups the ante, where drowsiness decreases your ability to pay attention to the task at hand, slows your reaction time and affects your ability to make good decisions, all items that can make for a bad day at the office given the extremely low altitudes that are part and parcel of ag flying.
Warning Signs of Drowsy Flying
The National Sleep Foundation has laid out the following signs of drowsiness:
- Difficulty focusing, frequent blinking, or heavy eyelids
- Daydreaming; wandering/disconnected thoughts
- Trouble remembering the last few minutes
- Yawning repeatedly or rubbing your eyes
- Trouble keeping your head up
- Feeling restless and irritable
If you exhibit any of these symptoms or feel that your flying abilities have been degraded, stop flying and find a quiet place to get some well-needed shuteye. No amount of coffee will get you safely out of the drowsy flying arena.
Preventing Drowsy Flying
Prevent drowsy flying before getting in the cockpit. Get enough sleep – at least 7 hours a day – which is often very difficult given the hectic nature of ag flying with its irregular working hours and often constant demands to get the job done, regardless of weather, fatigue, or other factors. A critically important part is ensuring you have suitable sleeping arrangements to sleep undisturbed. And turn your cell phone off.
Microsleep
One step up (or down, depending on your viewpoint) from drowsy flying is what the National Sleep Foundation terms microsleep, a condition that is quite common among long-distance drivers. It is when you fall asleep for several seconds. Fine when you’re watching your favorite TV program, not so much when you’re treating a field at a boom height of ten feet.
Microsleep occurs so rapidly that the person involved may not even realize they have fallen asleep. Again, many can relate to a similar experience while driving, where you may appear to be awake, even with your eyes open, but the brain is sitting idle, not processing what is going on. I am confident that’s what happened to me when I skipped the wheels of the Brave off the ground I mentioned earlier.
The key risk factor here is that if you are sleep deprived, you are at higher risk for microsleep. It is essential to make sure that you are alert before you climb into the cockpit.
If you feel drowsy, do not fly. One study shows that moderate sleep deprivation produces impairments equivalent to alcohol intoxication. In the study, after 17 to 19 hours without sleep, performance was equal to or worse than that of a blood alcohol concentration (BAC) level of 0.05 percent. After more extended periods without sleep, performance reached levels equivalent to a BAC of 0.1 percent.
A significant part of the problem is that, as a society, we do not recognize sleep deprivation and accompanying drowsiness in the same vein as alcohol consumption. When was the last time you stopped to think about how much sleep deprivation affects your ability to fly safely?
Countering the Effects of Drowsiness
So how do you deal with the dire consequences of drowsiness and microsleep? One of the major difficulties is that, for the most part, ag flying involves single pilot operations where you are self-monitoring, which is not what you would call an objective look at things. The tired person is the last person to realize they are tired.
Because of its insidious nature, having several objective signposts alerting you to the gradual onset of drowsiness is an excellent way to start. As the AAU article from October 2020 discusses fatigue, fly outbound at precisely 300 feet AGL, and fly inbound at exactly 500 feet AGL. On every trip, complete the working logbook detailing times and areas treated. Alternate landings between wheel and three-point. Fly an exact airspeed on final.
Whenever you note you have either missed an item or noted a slide in performance, it’s time to stop flying, take a break, and do whatever is required to get you back into safe and effective operations.
Stay alert. Stay safe. You, and everyone around you, will be glad you did.
AUTHORS NOTE: Several commercial products and apps, such as Fatigue Meter PRO and AlertMeter, also help establish a comprehensive risk management program focused on dealing with fatigue and alertness levels. The products give users the ability to monitor their own fatigue risk. Maybe one day, such products will be incorporated on a large scale within the ag aviation community.
