Question for the Pilots here

[kknudson]

There is the Southwest commercial where they state that their 737s fly at an average speed of 590 mph.
Yet the brochure I just got from a SW flight shows the 737 speed as 544 mph.

So for fun I set them an email questioning that, fun not serious, and got the response that , every claim in this spot has been approved through all proper channels.

So 590 mph seems a bit fast.

Just curious.

[KarTek]

Boeing's specs for the 737 family quote mach .785 or .78 @ 35,000 depending on the model which converts to around 593+ MPH.

Edit:

The calculator I used didn't account for altitude so the 593 MPH would be at sea level.

[Brian Carlton]

Originally Posted by kknudson

There is the Southwest commercial where they state that their 737s fly at an average speed of 590 mph.

EDITED:

The commercial is untruthful. There is no possibility of the 737 averaging 590 mph without a tailwind.

[WVOtoGO]

Cruise speed?
Max speed?
Airspeed?
Ground speed?
What speed, I need?

Most of the newer 737-700s have a max speed of 470ish kts. That’s about 540ish mph.
That’s the max speed the aircraft can fly (certified) through the air.
Their cruise speed is something like 450ish kts. That’s about 515-520ish mph.
That’s all standard day figures for the aircraft itself. No winds. Straight and level.

Now if they go up and catch a 100+ mph tail wind. Their cruising speed over the ground can easily break 590 mph. That number is not too fast.

The brochure is probably giving you the aircrafts max speed.
The commercial is probably giving you their average ground speed.
(At altitude)

Both are accurate numbers. Just a bit confusing when they don’t tell you exactly what speed they are talking about.

[Brian Carlton]

Originally Posted by WVOtoGO

Most of the newer 737-700s have a max speed of 470ish kts. That’s about 540ish mph.

The specs call a cruising speed of .785 Mach. However they also call a cruising speed of only 514 mph. With the speed of sound at 768 mph...........I'm missing something here...........

EDIT: I figured it out.........the speed of sound at 35,000 feet is approx. 690 mph. .785 Mach gives a speed of 541 mph.

So, clearly SWA is untruthful. The aircraft cannot average 590 mph under any circumstances without a tailwind.

[kknudson]

Well thanks guys.

So I guess the definition is air speed or ground speed.

It was just a curiosity.

Thanks

[WVOtoGO]

Originally Posted by kknudson

Well thanks guys.

So I guess the definition is air speed or ground speed.

It was just a curiosity.

Thanks

You're quite welcome.

BTW -
When you hook up with the aviation nuts on this forum...
NOTHING is handled as “just a curiosity.”

[WVOtoGO]

Like missing that the .785 is calculated from CAS and TAS at a specific altitude.
And the 768 is in 68 deg. air.

[WVOtoGO]

Oops...
I see you got it.
Good job.
Never mind.

[WVOtoGO]

Originally Posted by Brian Carlton

The specs call a cruising speed of .785 Mach. However they also call a cruising speed of only 514 mph. With the speed of sound at 768 mph...........I'm missing something here...........

EDIT: I figured it out.........the speed of sound at 35,000 feet is approx. 690 mph. .785 Mach gives a speed of 541 mph.

So, clearly SWA is untruthful. The aircraft cannot average 590 mph under any circumstances without a tailwind.

Why would you say that?
Most of their flights could have one hell of a tail wind.
They will fight for the best winds, tail or head.
Their average speed at altitude could easily average 590.
(Especially for the certain flights they used to make the commercial data from.)

A bit misleading, perhaps. But not clearly untruthful.


Also - Don’t ever mix the aircrafts certified standard operating specs with its actual flight data. They seldom, if ever, jive.

[Brian Carlton]

Originally Posted by WVOtoGO

Why would you say that?
Most of their flights could have one hell of a tail wind.
They will fight for the best winds, tail or head.
Their average speed at altitude could easily average 590.

I'm not believing that they can makeup 50 mph.........on average...........for the entire fleet...........with tailwinds.

They fly all routes in both directions several times in a given day. This tends to minimize any benefits from the wind.

The statement is untruthful.

[Mistress]

Originally Posted by WVOtoGO

Cruise speed?
Max speed?
Airspeed?
Ground speed?
What speed, I need?

Most of the newer 737-700s have a max speed of 470ish kts. That’s about 540ish mph.
That’s the max speed the aircraft can fly (certified) through the air.
Their cruise speed is something like 450ish kts. That’s about 515-520ish mph.
That’s all standard day figures for the aircraft itself. No winds. Straight and level.

Now if they go up and catch a 100+ mph tail wind. Their cruising speed over the ground can easily break 590 mph. That number is not too fast.

The brochure is probably giving you the aircrafts max speed.
The commercial is probably giving you their average ground speed.
(At altitude)

Both are accurate numbers. Just a bit confusing when they don’t tell you exactly what speed they are talking about.

If you can fly faster and jump higher in your PF Flyers Your bound to sell more tickets....

[BamaMB]

The way Southwest pilots fly, I think they are talking about an average speed of 590 MPH crossing the fence on approach to landing.

[Skippy]

Um, well I managed to average 53 mph ground speed in a 240D going from Coronado to Carson City.