This is a human-factors issue that I should best know about myself, but I am still interested in what others here have to say, as most of you have way more practical experience than I have.
As a medical doctor, I have very little time to fly, or for anything else for that matter. But there is a peculiarity in our shift system wherein I get “free” days during the week: About 4 times a month, I am on duty for 24 hrs, either in the hospital or manning an emergency physician response vehicle (Notarzteinsatzfahrzeug). These shifts usually last from about 7.30 am to 7.30 am on the next day, sometimes with slight variations (but never more than 45 mins earlier or later than 7.30 am). Example: Today, my shift started at 08.00 am, and it will conclude tomorrow at 08.00 am.
It is important to know that we’re not working for 24 hrs straight, at least usually. Most of the time is actually Bereitschaftsdienst, which as far as my English goes means “on call” or “stand by” duty. There is a decent chance to get some sleep in, sometimes even more than at home, because there are no kids to wake me up. But of course, sleeping in the hospital or in the ambulance station is not the same quality of sleep as at home. And if you are unlucky, you get one or even several emergencies during the night, keeping you awake.
Once I get off duty, the rest of the day is “free time” for me. Sometimes, I schedule a flight for the morning after such a shift. What do you think about this? How well rested does one have to be to conduct a flight safely? Is it enough to “listen” to your body or is there some “objective” ammount of tiredness that is tolerable (or not)?
Often times, unless I worked all night, I don’t feel tired immediately after such a shift, but rather beginning around noon, when the endorphines from the night shift finally wear off. When I am flying, I am in principle always slightly anxious. I am afraid that I am not able to concentrate properly when necessary without noticing it before getting into a plane. On the flipside, If I automatically disregard these days after a shift for potential flights, I get even less days per month where I could potentially fly, further decreasing my (already meagre) currency…
Actually I have no idea of what could be a 24h shift in your position in terms of awareness, but I had a somehow similar experience during my engineering school, where I had a full 24h work + awake time, followed by a car travel of 10h planned to do Nancy→Marseille (910km). I took it as a “let’s see how it goes and don’t hesitate to stop at first sign of awareness degradation”, as a matter of discovering my own limits. It was not flying but driving, which is a very different awareness pattern, where you need to be more attentive to trajectory and traffic, but less to driving.
Actually I had to take a nap 30m after starting from Nancy because I felt very tired leaving the city in the traffic jam. So basically after a 24hour shift, I discover that I could start and feel good, but after intense moment, my awareness degrades very fast, much more than where you have a normal day.
Now from pilot point of view, I wouldn’t fly in these condition unless I am VFR, flight < 2hours, with a very limited tolerance to change, and not without a good nap before departure.
After a decade flying longhaul I consider myself a fatigue expert (unfortunately), so I dare to analyze this:
Baseline: You can’t be too rested for a flight, only not enough rested.
The issue I see here is
Often times, unless I worked all night, I don’t feel tired immediately after such a shift
If I automatically disregard these days after a shift for potential flights, I get even less days per month where I could potentially fly
If you manage to balance those two out, it can be ok.
F make it bold after such shifts and think twice about it. If you feel like a zombie, scrap it. If you feel good (discounting euphoria of flying), go for it.
These guys got up yesterday morning, around 24 hours ago or earlier (european time). The check in for duty was 22:00 at night european time.
They just passed Gannett Peak in Wyoming, and will be landing in LAX in 2 hours. So around 30 hours later. And they do this multiple times a month.
Fatigue is problematic when it accumulates longterm. No amount of sleep can help, only a longterm recovery of healthy regular sleep patterns.
If you believe your shift causes real fatigue, not just feeling tired once in a while, then I would make it a principle to not fly after 24 hour long night shifts. You are flying for fun. Second thoughts or doubts are not fun. And it’s not worth it.
Keep 8 hours between bottle and throttle
This is a difficult one IMO. One could get all “authoritarian bureaucrat” and say you should rest at least 8 hours before thinking about flying. But it’s also an individual thing. Another aspect is the “condition of your underwear” kind of problem. Let’s say you do have an accident that will be investigated, and the cause was found to be “pilot error”. Most certainly the very fact you have not been sleeping for the last 24h will be attributed to “additional factors”, because quite frankly it is.
What I mean, is that as long as nothing happens, all is good, and you may very well be de facto fit for flight. Only you can know that. But IF something happens, are you willing to take the consequences?
Just don’t fly weather, long distance or tailwheel without enough sleep
It may not matter for “6min PPL student circuit in a C152” but it will kick in as you add more layers of complexity to it and unlike car you can’t just stop nearby and relax…
Depends on how you feel… if it wasn’t a busy night and you actually got some good sleep in, why not? If it was a bad night with multiple emergencies, then probably not. Seems to me, you would be the best judge based on how you feel. I wouldn’t make up a rule and apply each “ morning after” because they can all differ wildly (like many “morning afters” )
Thank you everyone for your replies so far.
Obviously, if I am feeling really tired I will cancel a planned flight immediately upon return home, then go to bed. Sometimes these shifts take quite a toll on you and you literally work for most of the 24 hrs, then you need at least an entire day to regenerate (judging by what older colleagues say, it gets worse the older you are).
I also usually don’t plan for some complicated flight, it is usually either circuit bashing or a simple A-B or even A-A flight.
Dealing with shift work and fatigue is a very individual thing. Every person is different and growing older your habits and personal circumstances also (have to) change.
I used to do very long distance soaring flights after working through most of the night, with only one or two hours of sleep. Likewise, I went to work the night shift after spending 10hrs+ in the glider. It might not have been the smartest thing to do but that was when I was younger and had no kids.
I could easily catch up on sleep the next day or so.
Now in my 40s I don´t plan to go flying until after I got some decent sleep following the night shift. I might fly in the afternoon, but I would definitely not go on a long daytrip.
Not quite the question that you are asking, but on a related note I used to work in emergency medicine and the shifts were gruelling with lots of timeshifting. You would often finish four nights at 08.15 then be back in the next morning at 08.00 for a full 12 hour shift. I used to enjoy the cameraderie of nights and didn’t seem to find them as distressing as other people, but I moved on in part because I could feel my life expectancy shortening with every shift.
In the short term it was clear that the night shifts were affecting my thought patterns. I remember once trying to make a colleague a cup of tea with sugar and no milk in the middle of the night. I drink coffee with milk. It took me 4 goes to make him a cup of tea with sugar but no milk, and a cup of coffee with milk but no sugar for myself. What surprised me though was that a few months after I had finished, my partner observed that my speech had become more distinct and I had lost my habit of starting sentences then losing my train of thought half way through.
I remember one of my classmates telling me about his Dad’s lifestyle as a long-haul captain. Huge amounts of downtime and relatively limited working hours. I think there was a very good reason for that: aviation has historically had a much better handle on human factors than the medical profession. It often struck me as an irony that I would make important decisions about other people’s lives whilst at work, then often feel too fatigued to fly safely on my days off. With my realisation of how they were starting to affect me, I have stopped doing almost any extra shifts – I occasionally will take one when everybody else has said ‘No’.
What you have touched on, which is crucial, is our self-awareness of how our cognition is affected by fatigue. It is something that I feel we are not very good at judging. When I flew r/c helicopters I learned the hard way that if I flew when I was feeling less than 100%, I would have stupid accidents.
Just to be fair
Huge amounts of downtime and relatively limited working hours.
that’s long gone.