I chanced on this article which raises the titled question: Why aren't two pilots mandated for all planes esp. military? What happens if the lone pilot becomes incapacitated, esp. if the plane has passengers who aren't pilots?

Two captains of Cathay Pacific Airways lost sight during two separate flights, according to the Hong Kong Civil Aviation Department. In both cases, the first officer managed to land the aircraft safely.


On January 28, 2016, a pilot of the British Royal Air Force had lost sight during a training flight in a Hawk jet in North Yorkshire. Another jet had been scrambled with an instructor on board that helped the impaired pilot to land at RAF Leeming air base. Sources quoted by the Telegraph had said at the time that his vision was affected by the sudden deterioration of an eye infection.

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    $\begingroup$ The wording "first officer managed to land the aircraft safely" is possibly misleading to people who don't understand the role of the first officer. The first officer is absolutely capable of flying and landing the aircraft in all phases of flight. They have to be, they are trained and qualified to do so. -- I know this doesn't address your actual question, but I wanted to point out the misleading wording there. $\endgroup$ – Greg Hewgill Sep 11 '19 at 3:16
  • $\begingroup$ @GregHewgill I did know that, but thanks for clarifying! $\endgroup$ – Accounting Sep 11 '19 at 5:06
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    $\begingroup$ I don't understand your question, why do you think that only one pilot was on board? The article explains that one pilot (the captain) became unable to fly and the second pilot (the first officer) took over. This question might help to explain the titles. $\endgroup$ – Pondlife Sep 11 '19 at 6:59
  • $\begingroup$ @Pondlife: Yes, it makes much more sense to call the second pilot the co-pilot, rather than "first officer". $\endgroup$ – jamesqf Sep 11 '19 at 17:47
  • $\begingroup$ @Pondlife 'why do you think that only one pilot was on board?' I don't. I was referring to other flights with one pilot, not the ones cited. $\endgroup$ – Accounting Sep 12 '19 at 2:37

Well I guess there are multiple angles to this. Perhaps someone can chime in with reference to regulations, but I can offer a more pragmatic answer.

Like it or not, aviation, like many other things, is a trade-off between risk and cost and I think that's what it boils down to. So what is the risk of single-pilot incapacitation and what is the potential consequences versus what is the cost to have all aircraft have at least two pilots aboard (not withstanding the impracticability of fitting two people in most single-seater aircraft.

So, I guess, we as a society have accepted the risk of single-pilot incapacitation and it seems that mostly the consequences are acceptable compared to the cost. It would be unlikely that we would mandate against single-pilot cockpits, but where to draw the line between single-pilot and multi-crew aircraft is certainly an on-going and active regulatory discourse.

In the end, I could ask you why don't we mandate two people with two steering wheels in cars? It would certainly prevent some accidents (hell, maybe many!), but it could also cause some too. And, practically, it just isn't going to happen is it?

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  • $\begingroup$ Additionally, I would say the expansion of single-pilot cockpits is probably more likely as automation continues to pervade aircraft systems. For example, it's technologically possible to have aircraft land themselves already, so it's not a stretch to imagine a aircraft protection system that, without a valid pilot response will automatically select the nearest appropriate runway and land there automatically. In events such as hypoxia, lives could have been saved by such a system already.... but as I already mentioned ... risk/cost. $\endgroup$ – Simon Opit Sep 11 '19 at 4:27
  • $\begingroup$ 'In the end, I could ask you why don't we mandate two people with two steering wheels in cars?': This analogy doesn't account for the differences between cars and airplanes? E.g., car speed is much lower, and someone starting to feel sick can pull over and stop. $\endgroup$ – Accounting Sep 13 '19 at 2:12
  • $\begingroup$ It's not the speed that kills you, it's the stop. Of course there are differences between cars and aeroplanes, but the point being made was that you could feasibly save lives of drivers by mandating dual-driving cars, but we don't, because it's deemed unnecessary. Added to that, distraction is a key killer in driving cars and two drivers could reduce the chance that both drivers are distracted and finding a place to pull over isn't always that easy on long motorways or country roads. $\endgroup$ – Simon Opit Sep 13 '19 at 3:43

Why isn't a second driver (and dual controls) required for automobiles, or commercial vehicles like trucks and buses? There are far more auto crashes caused by incapacitated drivers than there are plane crashes caused by incapacitated pilots.


1) Most (maybe all) commercial passenger flights DO require two pilots.

2) For military fighters, having two crew adds weight, which decreases performance.

3) For general aviation, imagine the hassle if every time you wanted to take your Cessna or Piper up for a spin*, you'd have to find a second pilot to ride with you. Not to mention what it does to the idea of soloing.

*Well, perhaps not the most felicitous choice of word there :-)

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  • $\begingroup$ In addition to point 2, many military jets only have a single seat $\endgroup$ – expeditedescent Sep 11 '19 at 5:54
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    $\begingroup$ @J. Hougaard: Yes, though I see that as circular logic. Single place military planes (and high performance sailplanes, aerobatic planes, &c) are single place because that allows for a performance increase. $\endgroup$ – jamesqf Sep 11 '19 at 16:49
  • $\begingroup$ @jamesqf and more often because there's no need for a second crew member to perform the aircraft's primary mission $\endgroup$ – jwenting Sep 12 '19 at 4:40
  • $\begingroup$ And in the case of military fighters, it's not obvious that adding a second crew member would reduce overall risk. With redundant flight controls, there may be some risk reduction in the case of pilot incapacitation or some types of error, but there would also now be a second crew member on board, which means a second person at risk if something does go wrong. Is the new risk of losing two people worth the risk reduction provided by the second pilot? $\endgroup$ – Zach Lipton Sep 12 '19 at 7:14

As others have said, it's about risk vs cost.

More specifically, the requirement for two (or more) pilots is roughly linked to the size (i.e. number of seats) on an aircraft, which balances the cost of a second pilot (which has to be paid by the passengers) with the number of passengers at risk. Light aircraft are frequently flown with zero passengers, so it just doesn't make sense to require a second pilot. And some very light planes only have one seat anyway!

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  • $\begingroup$ not just risk and cost, but performance. A smaller, nimbler, aircraft can typically outperform a larger, bulkier, competitor on turning radius, speed, range, etc. for the same fuel load and engine. $\endgroup$ – jwenting Sep 12 '19 at 4:42

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