11
$\begingroup$

I recently read this article that talks about 747s taking off from Princess Juliana International Airport in Sint Maarten.

The Princess Juliana runway is only 7,546 ft, but according to Wikipedia, the 747 needs more than 10,000 ft of runway for take-off.

Wikipedia 747 takeoff distance specs

How can the 747 take off from Princess Juliana?

Improve this question
$\endgroup$
5
  • $\begingroup$ Accelerate in ground effect over the ocean? $\endgroup$
    – jamesqf
    Commented Jul 13, 2017 at 19:08
  • $\begingroup$ Corsair has (had?) scheduled flights to TNCM, with B747-400. Youtube. $\endgroup$
    – mins
    Commented Jul 13, 2017 at 19:29
  • 1
    $\begingroup$ Landing and takeoff distance depends on weight, winds, temperature and runway surface. Boeing for a while flew 747s into Renton's 5000 foot runway. $\endgroup$
    – Steve Kuo
    Commented Jul 14, 2017 at 21:07
  • $\begingroup$ I guess that is for a safe takeoff, e.g. if the pilot want to give up he/she can stop within the runway. The actual lift off distance should be much shorter. $\endgroup$
    – user3528438
    Commented Jan 31, 2018 at 0:45
  • 1
    $\begingroup$ A completely empty 747 Dreamlifter took of from a 6100 ft runway, after some Atlas pilots mistakenly landed at the wrong airport - en.wikipedia.org/wiki/Boeing_Dreamlifter#Incidents $\endgroup$
    – selectstriker2
    Commented Jan 31, 2018 at 1:48

2 Answers 2

Reset to default
12
$\begingroup$

enter image description here
(Source: Boeing)

The approx. 10,700 feet Wikipedia figure is for a fully loaded 747 at sea-level. The lighter the plane, the less runway it needs. The 7,500-foot runway at TNCM allows a takeoff at 84% of the maximum takeoff weight. (Not taking into account any climb restrictions, such as the big hill over there.)

And as Terry pointed out, "ambient temperature also enters in. The cooler the air is, the more you can lift." And vice versa for a hot day.

Improve this answer
$\endgroup$
5
  • 1
    $\begingroup$ So in other words, the aircraft has to be carrying fewer people, less fuel or both $\endgroup$
    – cph2117
    Commented Jul 13, 2017 at 17:29
  • $\begingroup$ @cph2117 Yes, and the ambient temperature also enters in. The cooler the air is, the more you can lift. $\endgroup$
    – Terry
    Commented Jul 13, 2017 at 18:29
  • $\begingroup$ It's never cool in St Martin, always a balmy 30 C $\endgroup$
    – Koyovis
    Commented Jul 14, 2017 at 10:37
  • 1
    $\begingroup$ @Koyovis - it's always cool 😎 $\endgroup$
    – user14897
    Commented Jul 14, 2017 at 12:25
  • $\begingroup$ @ymb1 I know man, Marigot has the best bbq lobster. $\endgroup$
    – Koyovis
    Commented Jul 14, 2017 at 15:53
8
$\begingroup$

You would have to go the the manufacturer approved performance charts for this as opposed to Wikipedia as I don't really know where the author obtained that.

But Boeing published the following airport planning data for the 747:

enter image description here

This chart would be representative of a worst case scenario on a hot summer day (90°F) and calm winds. Even under these conditions, the airplane can still depart using a 7000 ft takeoff roll with an GTOW of 700,000 lbs. Practically speaking, this would allow for a full passenger and cargo complement plus 200,000lbs of fuel, which should enable it to fly 3000+ miles with IFR reserves, clearly enough to reach a suitable airport in the Americas, Europe or Africa.

And it really does work, albeit a little hairraising for the tourists on Maho Beach!

This guy is rotates and gets airborne just shy of the aimpoint markers for runway 9, giving him about a 6000 ft takeoff roll. Ambient conditions and GTOW of this particular flight are unknown.

Improve this answer
$\endgroup$

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .