14

Which commercial aircraft, when fully loaded with fuel (and passengers and luggage up to its max takeoff weight), could stay in the air the longest without landing, and how long could it stay in the air? What conditions would it need to have maximum possible endurance if the plane had no intended destination to land or particular flight path? (This is for a fictional story.)

Note: I was thinking commercial jetliners when I wrote that, and I still am, but I was accidentally unclear about it. That's preferably what I'm looking for, though.

Jason C
  • 383
  • 4
  • 14
  • 5
    You just wait until the start making commercial Solar Impulses. – Gallifreyan Apr 30 '17 at 20:41
  • 4
    A bit of a side note: These guys are a civilian commercial outfit that does refueling (on contract to the military mostly) but still counts as a commercial aircraft. Im not sure if the refueling tank is connected to the main system but if it is I assume it can stay aloft for some time more than a regular aircraft. – Dave May 01 '17 at 00:28
  • 1
    The Goodyear blimp? – Tyler Durden May 01 '17 at 01:21
  • 6
    Is a space shuttle considered an aircraft? – user3528438 May 01 '17 at 04:52
  • 1
    @user3528438 - When it's in the atmosphere, yes. Though it's hard to make the case for it being a commercial aircraft. I don't think anyone has ever paid to put something on a space shuttle because of its atmospheric capabilities. – aroth May 01 '17 at 08:24
  • 2
    Having recently read some novels in which the aircraft operations descriptions were rather sketchy (I'm looking at you, Clive Cussler), I appreciate that you're attempting to get some reality into your story! – FreeMan May 01 '17 at 11:46

2 Answers2

18

A commercial airship, like the 'Zeppelin NT' can stay airborne for 24 hours.

The record (for a military US-Navy blimp in the 1950s) is 264 hours, 12 min. It covered more than 13,000 km.

Record flight of 8,216 miles in 264 hours. Lakehurst NJ to west Africa to Key West FL non-stop. (Source)

xxavier
  • 11,071
  • 3
  • 29
  • 72
18

If you mean a jetliner, then it's easy.

Airliners more or less fly at the same speed, so the longest range ones would typically have the longest endurance.

The longest range airliners currently are the Boeing 777-200LR and the Airbus A340-500.

Airplane     Range       Payload          Speed      Duration est.

777-200LR    15,840 km   317 passengers   892 km/h   17.8 hours
A340-500     16,670 km   293 passengers   871 km/h   19.1 hours

The Wikipedia article Longest flights may be of interest.

This may or may not assist in your story, but there are two ways to increase the endurance:

  1. Fly slower, and/or
  2. Shut down one engine and increase the power of the other(s)1.

Both 1 and 2 may require flying lower, and both will hurt the range.

1 Explained in the last part of this answer, but in short it's because jet engines have the lowest fuel flow per unit thrust when they are running at near their maximum continuous thrust setting.

  • 7
    But an airliner will presumably fly slower than that if the aim is to maximise the time in the air. – TonyK Apr 30 '17 at 15:34
  • @TonyK, the aircraft is optimized in such a way that it cruise speed is also the most optimal speed. – Brilsmurfffje Apr 30 '17 at 18:26
  • @ymb1, you can also reduce the payload and then fly further as your graph indicates as well. – Brilsmurfffje Apr 30 '17 at 18:26
  • 8
    @Brilsmurfffje: cruise speed is the most economical speed for a given distance. If you throttle down from cruise speed, you go slower but you use less fuel per second. – TonyK Apr 30 '17 at 19:13
  • Did Airbus choose a cruising altitude of 39,000 ft in that document because that's the A340-500's most efficient cruising altitude, or because of regulations, or some combination of both? – Jason C Apr 30 '17 at 20:49
  • Given that the question is explicitly asking for which single commercial aircraft model can stay in the air longest, this answer would be significantly improved by providing some comparable numbers for the 777-200LR (It doesn't need to go into as much detail, just something like: "for the 777-200LR the range is X, with a similar true airspeed, equating to an endurance of Y hours". As it is, the answer is just stating the numbers for the A340-500 without actually asserting that it is the longer of the two, just that those two models are the ones which would be the longest range. – Makyen Apr 30 '17 at 20:51
  • 3
    @JasonC - it's not easy to fully explain in a comment, but on an actual long range flight, the plane will keep climbing the more it burns fuel and gets lighter. –  Apr 30 '17 at 21:16
  • If anybody is curious, as an aside, a previous revision of this answer had a link to a nice document about the A340, that document is here. – Jason C May 01 '17 at 00:13
  • 1
    @JasonC - sorry, wanted it to be concise, but if you liked that chart, check this post ;) –  May 01 '17 at 00:54
  • Oh, question: Is it always the case, in commercial aviation, that the amount of fuel loaded is precisely what's needed for the trip? So, in the case where the aircraft was initially scheduled for a normal, actual flight, only e.g. flights like QR 921 would be able to approach that amount of time in the air, right? – Jason C May 01 '17 at 13:51
  • 1
    @JasonC - in most cases they load what they need + some for contingencies, check here. It's very rarely full tanks. –  May 01 '17 at 14:04