Highest Flight Level Actually Flown by a 747
Highest Flight Level Actually Flown by a 747
Just trying to win a bet here.
I'm after the highest Flight Level that 747 (SP Aside) has been flown at. I know they are certified to FL 430, but one of my old Flying (USA) magazines says in one article that a Braniff crew on a ferry flight attained FL 510 in a 747-200 many years ago.
I thinks its not true, more like maybe FL 450. Mate swears 510 is true. A few beers a riding on this.
I'm after the highest Flight Level that 747 (SP Aside) has been flown at. I know they are certified to FL 430, but one of my old Flying (USA) magazines says in one article that a Braniff crew on a ferry flight attained FL 510 in a 747-200 many years ago.
I thinks its not true, more like maybe FL 450. Mate swears 510 is true. A few beers a riding on this.
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The classics are certified to 45,100 feet. Boeing may have done test flights to 510, but the type certificate is to 45,100. I have had a -100 with "A" model Pratts to FL430. It did fine.
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The certification max altitude will determine the programming of the cabin pressure controller (in AUTO).
I wonder what cabin altitude those sorts of cruise altitudes resulted in. not far short of the 'rubber jungle' cabin altitude I bet!
Cheers, FD
I wonder what cabin altitude those sorts of cruise altitudes resulted in. not far short of the 'rubber jungle' cabin altitude I bet!
Cheers, FD
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Whilst I have no doubt that normal operations have never exceeded 45,100 feet, it must be remembered that for every published operating limit, certification and test flying must go beyond the nominated limit to ascertain the margins. This applies in all areas, Vmo, Mmo etc. (To be more exact, testing goes to 'the limit', and a margin then applied to establish a lower 'normal' limit).
Would you fly an aircraft to the published limits, in the knowledge that the test pilots had never evaluated the aircraft one foot of altitude or one knot of speed beyond the limits you're using?
So, whilst 'regular' operations may have never exceeded 45,100 feet, Boeing would have tested the aircraft, both the aerodynamics and the systems, to a Pressure Height somewhat beyond that. 747Focal might be able to shed some light on this.
In some aircraft that I did test flying for in an earlier life, 4,000 feet above was not out of the ordinary.
Regards,
Old Smokey
Would you fly an aircraft to the published limits, in the knowledge that the test pilots had never evaluated the aircraft one foot of altitude or one knot of speed beyond the limits you're using?
So, whilst 'regular' operations may have never exceeded 45,100 feet, Boeing would have tested the aircraft, both the aerodynamics and the systems, to a Pressure Height somewhat beyond that. 747Focal might be able to shed some light on this.
In some aircraft that I did test flying for in an earlier life, 4,000 feet above was not out of the ordinary.
Regards,
Old Smokey
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45,100 is the certified max altitude. It's not really based on the cabin pressure, but the ability of the aircraft to descend to 14,000 in 4 minutes or less.
I have been up to 450 a number of times (delivery flights) and the aircraft does just fine. I can't remember what the cabin pressure was but it was less than 8000'.
I have been up to 450 a number of times (delivery flights) and the aircraft does just fine. I can't remember what the cabin pressure was but it was less than 8000'.
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45,100 feet for the VC-25
http://www.af.mil/factsheets/factsheet.asp?fsID=131
FL450 EDDF - KJFK -100 JT9D-A powered empty freighter. After an hour we descended due to cold fuel.
http://www.af.mil/factsheets/factsheet.asp?fsID=131
FL450 EDDF - KJFK -100 JT9D-A powered empty freighter. After an hour we descended due to cold fuel.
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Hmmm interesting. I thought I remember that 747 could do FL510 (empty of course). I probably read a bad source. Isn't the 747 the highest flying passenger airliner?
I know the Yak-25RV Russian reconaissance jet could do 68,900ft.
What is the highest flyer? Obviously a military jet of some kind...
Edit: Upon further research I found that certain models of the Lockheed U-2R/S can do 90,000ft!!
I know the Yak-25RV Russian reconaissance jet could do 68,900ft.
What is the highest flyer? Obviously a military jet of some kind...
Edit: Upon further research I found that certain models of the Lockheed U-2R/S can do 90,000ft!!
Last edited by sstaurus; 23rd Nov 2005 at 00:52.
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Just interested to know if you can get a 747 to descend from 45,000 to 14,000 in 4 minutes. In the simulators I have used, after the initial 6000 to 8000 fpm as you speed up to just under MMo/VMo, the decent rate sits at about 5000 fpm.
This is with speedbrake fully deployed, gear up, thrus levers closed etc.
This is with speedbrake fully deployed, gear up, thrus levers closed etc.
Somewhere in the US Flying Magazine, they have an article where Grumman was testing the GV in time to hight records and managed level flight at 64,000ft. Its certafied ceiling is FL510. I'll dig it out and ammend the details when I can.
What is the highest flyer? Obviously a military jet of some kind...
The X-15 set some altitude records, but as that's an experimental it doesn't really count I guess.
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Marty-Party,
Our books show a faster overall decent with the gear hanging out. At first clean is good, but overall to 14,000', dirty is mo betta!
This thing will come on down in a hurry if you try! yee-haaa
Our books show a faster overall decent with the gear hanging out. At first clean is good, but overall to 14,000', dirty is mo betta!
This thing will come on down in a hurry if you try! yee-haaa
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Limits
Smokey is right.
I had some questions about Vmo some years back, given I was flying an old aircraft and in decent I always pushed red line.
In this case, VMO testing for this aircraft was to take it 50kts past and do a multiple g pull up, I assume to simuliate the pilot waking up or something and having to avoid the mountain he was descending into.
Another Vmo limitation has nothing to do with excessive drag or engine limitations but like on the Citation X, where it starts to turn left when it flies too fast. Remember the SJ30 crash during testing, pilot didn't reduce power, plane rolled, and that's all she wrote, because he went REALLY fast after that..
The point, the limits you are given are no where close to flight tested capabilities, but the plane might do funny things past the limits that you are given.
Some planes act funny closer to those limits then others. Talk to Falcon pilots and they have no problem taking the wing past mach. Talk to Lear 35 plots, and the wing starts buzzing, maybe even tuck only 10 kts past Vmo.
I suspect, that your 747 could fly to what is known as absolute altitude, and if I remember it's where the plane will not climb more then 100 ft/minute. So if it's cert for 45, another 6k shouldn't be a problem, but what about pressurization, coffin corner, flight characteritics, compressor issues, bleed air, ect.
Food for thought.
SSG
I had some questions about Vmo some years back, given I was flying an old aircraft and in decent I always pushed red line.
In this case, VMO testing for this aircraft was to take it 50kts past and do a multiple g pull up, I assume to simuliate the pilot waking up or something and having to avoid the mountain he was descending into.
Another Vmo limitation has nothing to do with excessive drag or engine limitations but like on the Citation X, where it starts to turn left when it flies too fast. Remember the SJ30 crash during testing, pilot didn't reduce power, plane rolled, and that's all she wrote, because he went REALLY fast after that..
The point, the limits you are given are no where close to flight tested capabilities, but the plane might do funny things past the limits that you are given.
Some planes act funny closer to those limits then others. Talk to Falcon pilots and they have no problem taking the wing past mach. Talk to Lear 35 plots, and the wing starts buzzing, maybe even tuck only 10 kts past Vmo.
I suspect, that your 747 could fly to what is known as absolute altitude, and if I remember it's where the plane will not climb more then 100 ft/minute. So if it's cert for 45, another 6k shouldn't be a problem, but what about pressurization, coffin corner, flight characteritics, compressor issues, bleed air, ect.
Food for thought.
SSG
Read a book on the -sp a few years ago, it had an article about a demo given to the press (prior to airline service) and other airline execs where it flew from New York to Tokyo and reached an altitude of FL 470.
Will try to dig it up.
Will try to dig it up.