Can pilots sleep when they are flying?

This is a question that I have been asked a lot of time on my youtube page .

The answer to this is YES, but only if the company have a approved procedure for it and it is done in a controlled way. Hence the official name of it: Controlled rest.

So, how is it actually done? Can a pilot just sleep for a while when he or she feels tired?

No, the way the procedure is normally done, and this varies between different airlines, is that in case a flight-crew member feels like he/she would like to take a nap it has to be discussed with the other flight-crew member. The flight have to be long enough to safely accommodate the rest and the Cabin-crew have to be informed.

The minimum flight time needed to do controlled rest is normally 145 minutes. The reason it is that long is that controlled rest cannot be used during critical phases of flight. This means that during climb and descend, both pilots needs to be alert and ready. After top of climb, the Captain can decide on a timeframe of maximum 45 minutes when one pilot can take a rest. This timeframe is selected when there is a period of relative calmness without any complex operation like multiple FIR crossings or anticipated level changes. When this is decided the Cabin Crew have to be informed since they normally call in to check on the alertness of the pilots every 20 minutes. During the time of controlled rest the roles will be reversed so that the operating pilot will call the cabin-crew every 20 minutes instead to allow the resting pilot not to be disturbed. If this call is not made, the cabin-crew will call anyway.

45 minutes of rest is chosen to allow a maximum of 30 minutes of sleep, this is to avoid that the resting pilot goes into “deep-sleep”. 

After the rest is finished the resting pilot needs a minimum of 20 minutes of “recovery” time during which he/she is not allowed to take controls of the aircraft. The recovery have to be finished at least 30 minutes prior to Top of descend in order for the crew to be properly prepared for the descend and approach phase of the flight.

In most cases it has to be recorded on the travel documents when if and when the rest have been done as well.

As you can see, there are very robust rules surrounding the use of controlled rest and the purpose of this procedure is to make sure that the crew avoid microsleep etc during very long flights. It is considered better to have a controlled procedure rather than having pilots dose off on their own.

There are alos other procedures that include Augumented flightcrew. That is when there are more than 2 pilots forming part of the flightcrew but that is normally only used on very long, long-haul routes.

I hope that makes sense to you all. And I want to stress that not all airlines utilise this kind of procedure. It has to be pre-approaved by the local CAA before used.

Have a fantastic day !