# Did Concorde really fly above 55k feet as mentioned in this report?

Here is a report of the last journey of Concorde from JFK-LHR, which mentions "The highest altitude we reached was 58000 feet." Is this height aerodynamically feasible to reach?

• Sure, why not? You should check out the U-2 or SR-71 ceiling. Jun 18, 2015 at 20:24
• @DavidRicherby I mainly wanted an answer to "Is this height aerodynamically feasible to reach?", which can't be googled. I have been here for more than a month now, and do care to not ask those silly questions! Jun 19, 2015 at 16:55
• @anshabhi You're asking if the height is feasible to be reached by a specific plane. Googling "concorde maximum height" immediately tells you "Concorde had a maximum cruise altitude of 18,300 metres (60,039 ft)" without you even needing to follow a link. Comparing that answer with the value you're asking about (58,000ft) immediately tells you that it is aerodynamically feasible to reach such an altitude. Jun 19, 2015 at 17:19
• Aug 7, 2015 at 9:08
• That answer is a "Peter Kämpf ", the mark of excellence! And ya, if I could I would have marked that as accepted. Aug 7, 2015 at 17:23

Yes. The extra height was necessary in order to reach lower pressure air, and thereby reduce drag, and heating of the airframe from supersonic compression of the air.

Concorde's windows were extra small, so that if a window did blow out, the air compression system could actively compensate by pumping air in faster than it could escape, until the pilot completed his emergency descent.

More details can be heard on this podcast.

• That was a great episode! Definitely recommended for any Concorde (or even aviation) fan. Jun 23, 2015 at 20:04

Yes. According to Wikipedia, Concorde's service ceiling was 60,000ft.

The density will go down a bit at that altitude compared to normal aircraft, but your airspeed is Mach 2, so that's good. Lift is (among others) a factor of both parameters. Be aware that there is a bit more going on though with supersonic stuff as well.

An increasing number of aircraft are approaching this altitude domain. For instance, the subsonic corporate Gulfstream G650 tops at 51,000ft.

• Why do you avoid the term "dynamic pressure"? Adding this should improve the precision of your answer. Jun 19, 2015 at 16:39

As per its service celling that would not have been an issue. It should also be noted that Mach 1 (the speed of sound) is about 90 Knots Slower at that altitude.

• So when Concorde was said to go Mach 2, is that at the altitude it was flying at or at sea level? Jun 19, 2015 at 16:01
• Mach 2 is relative to the exterior pressure. I think it could only reach those speeds at higher altitudes for pressure reduction needs. However at that altitude Mach 2 would be slower (ground speed) than at sea level. FWIW the Mach Number is not actually speed so to speak. Its a dimensionless number that depends on local factors. en.wikipedia.org/wiki/Mach_number
– Dave
Jun 19, 2015 at 17:03
• "Mach 2 is relative to the exterior pressure" -- strictly speaking, relative to the exterior temperature, I think. en.wikipedia.org/wiki/… Dec 26, 2016 at 11:45