Boeing 757 & 767 max speed up to 8,000 ft is only 360 mph

[killtown]

(Thanks to malaprop for this)


This is interesting:

Operational Limitations for 767

Please Note: The limitations data contained on these pages is applicable only to the Boeing 767-300 with Rolls Royce RB211 engines, unless otherwise stated.

MAXIMUM SPEEDS

Bird Impact Protection

From Sea Level to 8,000ft restrict airspeed to 313 kts* for Bird Impact Protection. Above 8,000ft, observe Vmo / Mmo pointer and overspeed warning.

*313 kts = 360 mph

Source: 767.org.uk



Operational Limitations for 757

Important Note: The limitations data contained on these pages is applicable only to the Boeing 757-200 with Rolls Royce RB211 engines, unless otherwise stated.

MAXIMUM SPEEDS

Bird Impact Protection

From Sea Level to 8,000ft restrict airspeed to 313 kts* for Bird Impact Protection. Above 8,000ft, observe Vmo / Mmo pointer and overspeed warning.

*313 kts = 360 mph

Source: 757.org.uk

(Knots to Mph converter)

Speeds 9/11 planes flew at when they allegedly crashed:

Flight 11 - 470 mph
Flight 175 - 590 mph
Flight 77 - 530 mph
Flight 93 - 580 mph

[Make7]

1. Bird Impact Protection? Was this truly a concern? ( n/t )

[petgoat]

4. My recollection is that bird impacts are a concern not from EPA-type

issues, but because they can destroy engines. Seems to me I recall something about
frozen chickens being tossed into running jet engines to test impact rtesistance.

[Make7]

6. I believe that these speeds were probably calculated...

... to reduce a plane's exposure to impact damage from birds over some length of time in the service life of the machine. I don't think whoever flew the planes that day were concerned about mitigating possible damage from bird impacts over any statistically significant length of time.

- Make7

[salvorhardin]

2. I hardly think

Terrorists intent on killing a plane load of people by flying into a very tall building full of people are going to reduce speed to 313 knots upon descending below 8,000 feet so they can minimize the risk of killing a few birds. Did you even read what you posted?

From Sea Level to 8,000ft restrict airspeed to 313 kts* for Bird Impact Protection. Above 8,000ft, observe Vmo / Mmo pointer and overspeed warning.

And why go to some site designed to promote conspiracy theories when you can go directly to the manufacturer's site.
http://www.boeing.com/assocproducts/aircompat/757.htm

[killtown]

3. Does Boeing's site say how fast the planes

allegedly flew into their targets???

And do the planes just give off a warning signal, or do they prevent you from breaching that max speed? That's what I'm interested in.

[salvorhardin]

8. Huh?

The site you mentioned posted an operational recommendation that pilots reduced speed below 8000 feet to avoid killing birds. It has nothing to do with the plane's capabilities below 8000 feet.

[killtown]

9. You call THAT site a 'conspiracy site'???

A site that just gives the facts about 757/767's??? I thought you were talking about my site.

Can anyone verify if the plane just sounds off a warning if it breaches 360 mph below 8,000 ft or if it prevents the plane from traveling that fast?

[MercutioATC]

11. Oh, please...

Push the throttles forward and the plane will go faster...at ANY altitude. Why would you think that a low-altitude speed recommendation regarding bird strikes has ANYTHING to do with aircraft capabilities?

"S"-rated automobile tires are defined as having a maximum speed capability of 112mph. What happens if you exceed 112mph on "S"-rated tires? Probably nothing...the rating is just a safety recommendation. The tires don't limit the speed of the car, they just have a maximum recommended speed.

You've cited a great aircrafy safety recommendation...nothing more.

[killtown]

13. So are you a 100% sure it's just a warning signal

and that the software doesn't restrict the flight speed capabilities?

[file83]

14. I understand what you are getting at....

...but I don't think the software acts like a "governor" in cars (you know, like when rental trucks won't drive any faster than 72mph or something?).

The pilots need to have total control over how much thrust the engines have regardless of airspeed.

Of course, I'm not 100% sure. I know a pilot, I'll give him a call tomorrow and see what he knows.

[MercutioATC]

15. Ask a pilot, they'll tell you the same thing.

Hell, you can fly a plane so slow that it falls out of the sky. Sure, the stall warning will sound and the stick shaker will activate (on some planes), but there's nothing physically preventing a pilot from reducing speed until the plane literally falls out of the sky.

Why would you think there would be something that prevented a pilot from flying too fast (especially just to comply with a bird impact recommendation)?

[Kevin Fenton]

5. Maximum safe speeds

They are the maximum safe speeds you can fly them at that level. Flying them at those speeds for a sustained period at that altitude would probably place the aircraft under excessive strain. They can go that fast for a few minutes, no problem.

btw, the real speeds are:
American 11: 430 (see MIT)
United 175: 500 (see MIT)
The other two I don't know, but I really doubt United 93 was doing 580 when it crashed.

[mirandapriestly]

7. Bird damage, fwiw

[killtown]

10. Interesting how before and after 9/11, when a plane hits

an object, the object passes through the plane. However on 9/11, all planes pass through their objects like a knife through warm butter!

[mirandapriestly]

12. I think the Bush Administration

sneaked some physics changes into the Patriot Act while they were at it.