Boeing 747-400 question?

by Guest57743  |  earlier

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I recently went on a site wherein flights within the US can be tracked. I found this certain B747-400 with a speed of more than 1000kph. Could that be possible (flying at mach 1)? What I know is the 747's cruising speed is within the 900-950kph.





  1. You have to make the distinction between airspeed and ground speed.  The aerodynamic limitations affect airspeed, and cannot be exceeded without turning your airplane into a giant bratwurst in mid air.

    But you can be flying in a jet stream and have a "tailwind" of hundreds of KMpH, resulting in a ground speed in excess of 1000 KMpH, or any other speed that seems to exceed the airframe limitations of the airplane.

    So it has to do with the difference between airspeed and ground speed.  For lots more information, try an internet search on "air navigation."

  2. Of course it's possible. At .85 it would take less than a 100 knot tailwind to exceed a thousand kph. you say yourself 950 kph cruise speed. Fifty knots on the tail and you're there.

  3. with a very strong tailwind you can get those kind of speeds.

  4. You have to understand that various speeds have to be reached at different altitudes to reach mach 1.  You'd have a good strong tailwind to give you an extra 100kph.  But also it could be the landing or descent part which also increases your speed so slightly.

  5. strong tailwinds can make the plane faster.

  6. Yes, with a nice strong taiwind you can achieve 1000KPh 1000kph and Mach 1 are not the same ;)

  7. I'd like to see that web site.


  8. This is not correct.

    The cruise speed for this aircraft is 0.85 Mach 567 mph (913 km/h). This is at normal cruise height of 35000 ft

  9. an extreme tailwind can force the plane into 1000kph however this is still subsonic

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