Maximum Speed of Airliner At Low Altitude

Airline or Military transport pilots .. I would like to ask you some =
questions about the maximum speed that an airliner like a B-767 or 757 =
can travel at low altitude. Someone claims that the speed at altitude =
is much higher than that at low altitude because the drag of the wide =
body limits the maximum speed at low altitude. Can any of you comment =
on that?

Thank you.

Roger Helbig



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Ian MacLure wrote:
Operationally its irrlevant because the FAA limits speed below 10K
ft to 250Kts IIRC.
As to the actual max speed attainable at low altitude, I believe you
have it correct.


Agreed. Thicker air equals lower speed. FAA equals even lower speed.




--
Mortimer Schnerd, RN


http://www.mortimerschnerd.com

Each aircraft may well have a different low altitude max speed...this will
be given in knots of Indicated Airspeed (IAS)...and typically is about
350-400 knots for passenger aircraft. At low altitude, IAS and True Airspeed
(TAS) are pretty much the same. While the low altitude max speed is
expressed in knots IAS, the high altitude max speed is expressed as a Mach
number. Passenger jet max mach numbers vary from around .8M to close to .9M.

At high altitude, IAS and TAS often are quite different, with TAS being the
larger value.

The low altitude max speed limitation is an airframe limit and not a drag
limit. In most cases, the jet could go faster but for various aerodynamic
reasons, is restricted from doing so.
"Roger Helbig" wrote in message
news:40ccdcd9@hughey...
Airline or Military transport pilots .. I would like to ask you some
questions about the maximum speed that an airliner like a B-767 or 757 can
travel at low altitude. Someone claims that the speed at altitude is much
higher than that at low altitude because the drag of the wide body limits
the maximum speed at low altitude. Can any of you comment on that?

Thank you.

Roger Helbig



-----=osted via Newsfeeds.Com, Uncensored Usenet News =---
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----= Over 100,000 Newsgroups - 19 Different Servers! =---

After an exhausting session with Victoria's Secret Police, "Roger
Helbig" confessed the following:

Airline or Military transport pilots .. I would like to ask you
some questions about the maximum speed that an airliner
like a B-767 or 757 can travel at low altitude.

Since I have a checkride coming up...Vmo is 340 KIAS for the 757 I
fly. "Clackers" start going off if you hit 340...ahem, I have seen
this in an Idle thrust descent.

The 757 is a very "clean" airframe. It does not like to slow down. If
a pilot turned the autothrottles off and simply firewalled the
throttles it would haul ass in the traffic pattern. How fast? Not
supersonic, but it requires surprisingly low thrust to hold the FAA
250 KIAS limit beow 10k'. I should have taken notes today (TIC).

Ramp down from altitude, it would probably scare the islamist ****
terrorist with all the warning noise from an overspeed (340+ KIAS). I
mean scare in terms of, "holy allah will this infidel made machine
hold together?"

Robey

I believe the max for any aircraft is 250 knots.

The restriction is lifted in certain cases, for example: military jets
doing a Missing Man at Arlington National Cemetery.

all the best -- Dan Ford
email: (put Cubdriver in subject line)

The Warbird's Forum www.warbirdforum.com
The Piper Cub Forum www.pipercubforum.com
Viva Bush! www.vivabush.org

Operationally its irrlevant because the FAA limits speed
below 10K ft to 250Kts IIRC.

And Mohamed Atta conveniently ignored this rule. The 9/11 planes went so
fast and so low that they were expected to fall apart in-flight. Boeing
made them too sturdy, however. I wonder if some legal-savvy widows will
sue Boeing for building too good planes and thus causing 2800+ deaths.

After an exhausting session with Victoria's Secret Police, Cub Driver
confessed the following:

I believe the max for any aircraft is 250 knots.

The restriction is lifted in certain cases, for example: military jets
doing a Missing Man at Arlington National Cemetery.

Mil jets are not limited to 250 KIAS "due to operational need," as in
a routine Dash 1 procedure (eg 350 KIAS up Initial for the RF-101, 300
KIAS for the F-4, F-16, F-15). But in the radar traffic pattern we
held it down to 250 KIAS.

But Roger's question has to do with the physical limitation of the 757
not something written in an FAR.

Robey

In article ,
"Mortimer Schnerd, RN" writes:
Ian MacLure wrote:
Operationally its irrlevant because the FAA limits speed below 10K
ft to 250Kts IIRC.
As to the actual max speed attainable at low altitude, I believe you
have it correct.


Agreed. Thicker air equals lower speed. FAA equals even lower speed.

Not necessarily - thicker air also = much more thrust. It's all pretty
much a wash, with a transonic airplane. Usually the TAS in units/time
(mph, kts, km/hr) is higher, but the Mach Number's a bit lower. *The
Speed of Sound is proportional to absolute temperature. It's warmer
near the surface, so there's more mph/Mach Number.

--
Pete Stickney
A strong conviction that something must be done is the parent of many
bad measures. -- Daniel Webster

I wonder if some legal-savvy widows will
sue Boeing for building too good planes

Now you've done it!

all the best -- Dan Ford
email: (put Cubdriver in subject line)

The Warbird's Forum www.warbirdforum.com
The Piper Cub Forum www.pipercubforum.com
Viva Bush! weblog www.vivabush.org

Generally not true. Indicated airspeed top end is usually highest at low
altitude, but true airspeed capability will rise with increased altitude.
This all assumes no airframe structural limit, which is frequently below the
aircraft's capabilities in commercial designs.

R / John

"Peter Stickney" wrote in message
...
In article ,
"Mortimer Schnerd, RN" writes:
Ian MacLure wrote:
Operationally its irrlevant because the FAA limits speed below 10K
ft to 250Kts IIRC.
As to the actual max speed attainable at low altitude, I believe
you
have it correct.


Agreed. Thicker air equals lower speed. FAA equals even lower speed.

Not necessarily - thicker air also = much more thrust. It's all pretty
much a wash, with a transonic airplane. Usually the TAS in units/time
(mph, kts, km/hr) is higher, but the Mach Number's a bit lower. *The
Speed of Sound is proportional to absolute temperature. It's warmer
near the surface, so there's more mph/Mach Number.

--
Pete Stickney
A strong conviction that something must be done is the parent of many
bad measures. -- Daniel Webster