How often do airline pilots work? (Flight Time Limitations)

I’ll start off with shift patterns. Ultimately the true meaning of a shift at a commercial airline depends on their own internal definition. However, the premise remains the same. Like several other jobs we too work in shifts and the hours of duration and the point they start and end vary just like any other. In commercial flying though there exist restrictions based on the biology of the human body.

Every single one of us posses something called a circadian rhythm. It is this which is responsible for us knowing when we should be awake and when we should sleep. Furthermore, it assists us in appreciating when we should and shouldn’t eat. The list of what our circadian rhythm does goes on and is somewhat beyond the scope of this post but it's effectively what we all call our body clock. Take jet lag for example. When you experience jet lag your rhythm is out of sync. It wants you to sleep but you want to explore your new hotel or perhaps enjoy a swim in the pool. It takes time for it to adjust.

For all of the positives the circadian rhythm brings, aviation somewhat goes against it. For example, the body clock is finely attuned to day light and we naturally wake to the suns rays coming through the blinds which will help you in slowly waking. Another example is the actual wake up time itself. If you've been waking up at 6am for weeks on end you'll likely find any chance of having a lie in rather slim because you'll wake naturally at your usual time. I can certainly hear your frustrations there - there is nothing more irritating than setting a 10am alarm on your day off for your body to go and disregard your wishes and wake you at 6am anyway.

As flight crew we’re often waking up at very early times in the day. Cast your minds to a time you’ve had to trek to an airport to go on holiday at a silly time in the morning. That ‘ergh’ feeling, is what we pilots may feel several mornings in a row. Now for the emphasis of safety here I’ll stress that does not mean we’re unsafe to operate an aircraft as the whole premise of the FTLs exists to protect against that eventually - which I’ll come to later. It does, however, have the potential to impede alertness leading to fatigue. Which again, airlines and FTLs work to avoid through their rostering departments, restrictions on flying hours and the ability of a pilot to refuse to work, with non-jeopardy, if they feel that ultimately the safety of the flight will be impacted.

So to summarise that wall of text: Shift patterns in aviation tend to go against the circadian rhythm on a frequent basis. The negative impacts of this can be handled through understanding and appreciating your body's need for sleep. While we may start our day at 5am, 12pm or on occasion not finish work until very late into the early morning, pilot life is a mix and match and certainly something we have to try to get used to.

Shift Duration Basics

This one is rather employer dependent really, but let’s presume an airline that operates with early and late shift structures for now. An early shift might start anywhere between 4am to 9am and a late can start anywhere from 9am onwards. The actual duration of your shift and therefore the time you finish work, is entirely dependant on the maximum number of hours the FTLs would permit us to to fly. This "maximum hours" figure is usually based on the number of flights the airline would like us to operate in that given period and the time at which we started work.

Allow me to give you an example.

I start work at 6am and fly 2 sectors (flights). The FTLs say I can work for a maximum of 13 hours before running out of hours. This might mean I fly to Larnaca and back whereas if I flew 4 sectors in that same day, I’d only be able to work for 12 hours. If we bring the circadian rhythm back into the picture for a moment a pilots alertness is likely to be a lot less during the earlier hours. This is dubbed the circadian low. As a result, I were start work at 5am the hours I could work may well reduce substantially. 

You might imagine that long days with early starts and late finishes may take their toll. Fortunately these FTLs and other airline specific policies work to reduce the total number of what’s deemed “disruptive” duties from being rostered over consecutive days of flying. Disruption in this sense means a roster which would impede a crew members ability to gain the best possible sleep. With such varying hours sleep is a pilots best friend. I've had to become really disciplined with forcing myself to go to bed earlier and not saying "Oh go on then..." to watching one more episode of the latest box set.

Duty Period Definitions

The actual FTLs I've touched upon so far are incredibly complex and so I won't bore you with the complete ins and outs of the laws associated with it. If you fancy some dense legal reading then just Google it and I'm sure you'll find the dry legal wordings before long. However, what I shall do is provide information on the bits us flight crews work to on a daily basis. The hours we work are split into what's referred to as Flight Duty Periods and Duty Periods. Here's the basic definitions of those:

• Flight Duty Period (FDP)
  A period that commences when a crew member is required to report for duty, which includes a sector or a series of sectors, and finishes when the aircraft finally comes to rest and the engines are shut down at the conclusion of the final sector.
  
  
• Duty Period
  A period which starts when a crew member is required by an operator to report for or to commence a duty and ends when that person is free of all duties, including post-flight duties. Includes flight duty, administrative work, giving or receiving training and checking, positioning, and some elements of standby.

In essence, no matter what type of work I am doing for my employer whenever I am on their time I am considered on duty. Here's a worked example:

A 6 hour flying day consists of one hour prior to the departure for briefing and set the aircraft up, 6 hours of flying and then 30 minutes post-flight period for debrief, admin duties such and checking for rosters changes or work emails. The totals from this day would therefore be 7 hours of FDP - because we factor in the one hour prior to departure - and 7:30 hours of duty overall.

Overall Working Hour Limits

Armed with those definitions and the knowledge that daily limitations are added to our working day, I'll now explain the other limitations imposed. 

Where my Flight Duty Period (FDP) is concerned I cannot exceed:

• 100 hours of flight time in any 28 consecutive days
• 900 hours of flight time in any calendar year
• 1000 hours of flight time in any 12 consecutive calendar months

However, the Duty Period is a lot less restrictive due to the other tasks it permits:

• 60 duty hours in any 7 consecutive days
• 110 duty hours in any 14 consecutive days
• 190 duty hours in any 28 consecutive days
• 1,180 duty hours in any 12 consecutive calendar months 

With all of the above considered when you look to answer the "what hours do you work?" question you soon realise it's not quite so clearcut. An airline pilot is ultimately not allowed to exceed a 60 hour working week of total duty time. It'd be very challenging for that entire 60 hour week to be spent flying as you're not allowed to exceed the daily flight duty limitations imposed and must have the required rest - more on that later. 

If I use another example, during the week of writing I was rostered to fly to Amsterdam, Toulouse, Lanzarote and Corfu. I also had a 8 hour standby to finish off the week. Should every single one of these flights run smoothly with no slot delays, weather delays, etc then the planned Flight Duty Period equalled 20 hours. The overall Duty Period hours though came in at 36 hours - not too dissimilar to the figure your average office worker. What makes it harder than your typical office job though is the fact I started started work at 6am, 5:30am, 5:25am and 4:30am respectively. Add to this it takes me roughly 40 minutes from home to the crew room then that's some pretty early wake up times! 

Now of course there are times when my duty may well exceed the working week of your average office job. We should all by now know aviation is not a straight forward turn up to the airport and go affair. Delays happen. As pilots we dislike delays as much as everyone else. It prevents me getting home as much as it does you and in that sense the odd 10 minute delay here and 5 minute delay there means we might well arrive back to our base and go off duty much later than planned. 

A summary then... it's complicated. There exist several legal protections in terms of the number of hours we can fly and the total number of hours of duty we can perform within rolling time definitive periods. These help to make flying safer, but also (slightly) help us as crew to maintain a normal work life balance. 

Here is an excerpt from my one of my weeks in the height of summer. 

Rest

Rest is defined as the period where we are not working. A gap between two different Duty periods within our working week. In other words, our own time. The time we spend at home eating dinner or bingeing on Netflix. Sadly, unlike my reference to drinking alcohol above I wouldn't be able to crack open a beer during this period because as you might expect, we need effectively zero alcohol in our system in order to be considered fit to operate - unless of course the rest period is over a certain duration (i.e. a full day or more), but I digress.

Our employers must allow us a minimum of 12 hours rest between two periods of duty, or, the length of the previous duty period should that exceed 12 hours. So if we ended up being incredibly delayed the day before and working 13 hours instead of 8, we'd get 13 hours of rest. That rest period starts at the end of the duty period which for me is very often just as i'm getting back to my car in the staff car park. With a 30-40 minute commute home I'm almost down an hour of my rest before i've truly started resting! 

This is a downside to airline flying. The less glamorous bit. Having got up at 4am to report for 13 hours duty of duty at 5am, you might well imagine that by the time I get home I'm not really up for doing much. It can be a real struggle sometimes to go the gym, pre-cook some meals for the week or be bothered to do any house work etc, especially if I've not been managing my sleep well. It's very easy to get into the comfy clothes and watch endless Netflix shows. This is where the real push is needed. When I first started the job I would get home and sleep almost straight away. Over time your body gets rather used to the hours you work and the routines you have but even then it's about looking after yourself. You need to be disciplined and know that if you're showing signs of tiredness you probably shouldn't watch just one more episode despite wanting to. You should probably go to bed! 

If we end up working far beyond the scheduled end time of my day, then airlines will generally change the following day to a days rest, or will shuffle around the schedule such that you get the minimum rest period prior to coming in to fly again the next day. With that in mind, while our working days are set in stone about a month in advance, it's somewhat impossible to predict when you'll finish said working days. It's a fluid environment. I may well have been scheduled a nice and easy Belfast and back on a Tuesday but should Monday's duty mean I don't have the required rest to operate it then I could well be taken off of it and put on a later duty. That later duty could well be a longer four-sector day. It just depends on operational requirements. 

Time Off

I tend to find I get at least three days off on average. In rare cases I've had two days off and in some cases even four days off. I guess it depends on how well the rostering department can utilise you in any given month with your current count of duty hours all considered. If you're running high on duty hours they can't use you as much and you might end up with more time off. 

At my airline a specific structure of days off are more guaranteed with seniority. For example Senior First Officer and Captain ranks can sign up to a fixed pattern. This way they know they'll be working 5 days on, 4 days off, 5 days on, 3 days off. They'll also know their shift pattern too, with a week of early shifts followed by a week of early shifts being common. For us newer crew though we join with fully random rosters which means while they're published a month in advance there's not a huge element of forward life-planning possible. This said, we can still put in our preferences and I tend to get what I request the vast majority of the time. I tend to put a preference in for two-sector early shifts with no changes mid-week to lates. From time to time you can't get what you want as the flying program doesn't allow for it and as such next week is my first full week of late flights in in almost two months which means a few 2/3am finishes.

In my experience three days off should be the minimum at all times really. I find when I have 3 days off it may well take the first of those 3 days to re-join reality. Flying requires concentration a fair amount of the time and so I often find myself sleeping or walking around like a zombie re-acclimatising to life back on the ground as opposed to up at 37,000ft. Day 2 and 3 are then a lot more normal. It's not all doom and gloom though as it's quite nice to have a longer stretch of days off. It's even better if they fall on a weekend too.

As with preferences for working days at my airline you can also put in preferences for certain days off. They're not always guaranteed, but from time to time you'll be lucky! Of course we also get annual leave as any other working person does. 

It's worth noting the rest and days off section of this post is very UK focused. Some countries have vastly different contracts and national annual leave requirements. I suppose it ultimately depends on how strong a union's negotiation powers are. I've heard from many French based pilots that they have amazing contracts over there, across several airlines. 

Given the daily restrictions on the amount of hours we can fly in a given day, what exactly happens if we were to go over that threshold? The simple answer is, we'd not be able to fly. It'd be illegal for us to do so. As the licence holders we are responsible for ensuring we don't breach this restriction as much as the airline is. However, not everything is as simple as it seems on the surface. I'll explain this here.

Reduced Maximum FDP Hours

From the sections further up this post we already know that we as crew have a maximum number of hours that we can work on any given day. So what would happen if we run out of hours down route somewhere? Does the return flight get cancelled? Is it re-crewed? Well... first of all there exists a protection which airlines can implement to safeguard their operation. Quite simply... they take the regulators maximums and make them more restrictive. 

i.e. The FTLs say we can work 13 hours, the airline might reduce elect to make this 11:30 hours. 

You might be questioning what the benefit in doing that is. Surely it makes more sense to allow pilots to fly to the maximum in order to be more efficient? Well while that may be true on one-hand, you also risk planning your operation to the absolute limits and making certain delays irrecoverable subsequently costing the airline thousands in delay recompense. By reducing the maximum FTLs in the above manor - for planning purposes - an airline will be able to build its' roster and flight schedule around their own imposed limitations. This way the airline will, on every good day, switch the crews out for another with a safe period of padding between actual hours flown and the legal limit. This in itself safeguards the operation.

Should a delay happen and the crew end up working beyond the more restrictive limitations of 11:30 hours there exists the padding for the crews to operate up to the legal limitation of 13 hours. That in itself will likely be enough time to recover the operation, without breaking the law. 

Of course, what if any delay was significant and the crew were to approach the full legal limit of 13 hours? Do they simply cancel the flight at that point? The answer is... it depends. Read on. 

Captain's Discretion

Setting the scene

Let's say a crew was to fly a given number of flights and reported at a time which gave them a legal FDP of 12 hours and that the airline had already dropped that to 10:45 hours for planning purposes. During the day the aircraft had developed a slight technical issue which needed looking into by an engineer. The technical issue was discovered by the crew on reaching their third stop of the day. All of the crew onboard were getting close to the airlines own limitations as a result of the aircraft being delayed by an air traffic control slot on its' first flight of the day. After sometime the engineers manage to fix the problem but the crews hours were now standing at 11, which is over the airlines own restriction but below the legal limit. With the flight time back to their base being 2:45hrs they'd end up breaching even the legal limitation!

The problem

As you might tell at this point flying that 2:45hr flight would put the crew well outside of their legal FDP restriction of 12 hours. The crew are subsequently "out of hours". They have no time left in their legal working day to operate the return flight without it being considered illegal. It's a bit similar to a lorry driver and their own driving limits. It's a safety thing ultimately. 

The solution can be "Captain's Discretion"

Of course the aviation authorities were well aware that these types of delays happen and they have the chance to impede an airline operation significantly what with an out of base aircraft, crew being out of base and then a delayed/cancelled flight with all associated complexities that go with that. As a result the aviation authority permits something called Captain's discretion. 

Captain's discretion is an allowance permitted by the authorities to allow an a crew to go beyond the legal maximum FDP hours. This is only possible if the captain can be certain after consultation that his or her crew are considered fit enough to operate the flight in terms of alertness etc. The final decision to operate lies entirely with the captain and not the airline. The captain is ultimately the legal entity responsible for the safety of that aircraft and all passengers onboard during the return flight. If he says no after considering his crew's welfare then the airline operations teams would have to come up with a plan B.

The discretion rules state:

• Duty periods may be extended up to 2 hours (3 in some cases) in order to operate a flight back to home base only.
  
  
• A flight crew can not operate any outbound sector from their home base if at the point of departure or prior to it, it is known that the return flight would be operated into discretion. 
  
  
• The captain can, following the use of discretion, increase the whole crews minimum required rest period as required to ensure adequate rest prior to any further duties the following day.

So there you have it. Should delays cause us to go above our legal hours they can be extended within reason. However, it's not a guarantee to the airline that pilots will always operate into discretion. It's not unheard of for them to feel too tired to operate and reject such a possibility. Being able to reject to operate in this manor is crucial to flight safety. This said, the vast majority of the time discretion isn't needed should airlines plan their operation to an even more restrictive FDP time.