LY777
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Recap About Airliners Cruising Speed

Wed Sep 30, 2009 9:19 pm

Hi all,

I would like to make a recap about airliners cruising speed according to the type:

Boeing:
707: ?
717: ?
727: ?
737 Classic: ?
737NG: mach 0.785
747Classic: Mach 0.84
744: Mach 0.85
757: mach 0.80
767: mach 0.80
777: mach 0.84

Airbus:
A300: ?
A310: ?
A32X: mach 0.79
A330: mach 0.82
A340: mach 0.82
A380: mach 0.86 (IIRC)

MDD:
DC8: ?
DC9: ?
DC10: ?
MD80s: ?
MD90: ?
MD11: ?

Lockheed:
L1011: ?

Avro:
Bae 146: ?

Il:
Il86:?
Il 96:?

Tu:
Tu 154:?
Tu 204:?


If you could fill the ? with the speed in mach only!!! It could be a nice recap (and if you have more airliners that come to your mind...)

Regards

Sacha

PS: this is the continuation of this older thread: Official Cruising Speed Of Each Airliner (by LY777 Nov 27 2007 in Tech Ops)
but it woul be better if we have a list.
Flown:A3B2,A320,A321,A332,A343,A388,717,727,732,734,735,738,73W,742/744/748,752,762/2ER/763/3ER,772/77E/773/77W,D8,D10,L
 
411A
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RE: Recap About Airliners Cruising Speed

Thu Oct 01, 2009 1:51 am

Boeing 707....M.82

L1011.... M.85
 
Max Q
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RE: Recap About Airliners Cruising Speed

Thu Oct 01, 2009 5:14 am

When the 727 was initially flying in the early days with cheap fuel .84-.86 Mach cruising was common and quite comfortable with a maximum of .92.



Later on as fuel prices rose most operators would cruise at .8 Mach.
The best contribution to safety is a competent Pilot.
 
wilco737
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RE: Recap About Airliners Cruising Speed

Thu Oct 01, 2009 10:11 am

MD11: normally 0.82. Up to 0.85 possible

wilco737
 
CX Flyboy
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RE: Recap About Airliners Cruising Speed

Thu Oct 01, 2009 11:24 am

It is very hard to just pick a speed, especially of a 777. In a lightly loaded 777-200 on a short flight at relatively low altitude, the FMC might recommend only 0.79 as a cruising speed. A heavy 777-300 near it's maximum altitude might cruise at 0.85 so it does depend on the day. The fastest I have been is 0.88 on a medical diversion.
 
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747classic
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RE: Recap About Airliners Cruising Speed

Thu Oct 01, 2009 12:32 pm

There are different CRZ figures, even for one aircraft/engine combination.
CRZ econ, CRZ long range, high speed CRZ.
These CRZ settings are calculated by the FMC/FMS/PMS installed, and are a function of aircraft weight, altitude, wind speed and direction, air temperature.
In the early jet age (with low fuel prizes) high speed crz was often used and was a fixed mach number at high altitude or a speed value on lower altitudes..
As an example : For the 747-100/200, high speed crz speed was M.860. This was also done to get speed stability, because on early jet aircraft no auto throttle was used during cruise.
Later on, with increasing fuel prizes, all kinds of graphs were used during flight to calculate optimum cruising speeds, until the computers took over.
Operating a twin over the ocean, you're always one engine failure from a total emergency.
 
AAR90
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RE: Recap About Airliners Cruising Speed

Thu Oct 01, 2009 2:55 pm



Quoting LY777 (Thread starter):
737NG: mach 0.785

I've operated in cruise anywhere between 0.72m - 0.815m. Most commonly seen on transcons today: 0.795m.
*NO CARRIER* -- A Naval Aviator's worst nightmare!
 
Alias1024
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RE: Recap About Airliners Cruising Speed

Thu Oct 01, 2009 5:41 pm

Though not on the list, typical at my airline for the CRJ-200 is .74. The airplane is a real dog above 20,000 ft.

Quoting LY777 (Thread starter):
Avro:
Bae 146: ?

I don't know the exact number, but I'd wager it has a minus sign at the front of it.  Big grin
It is a mistake to think you can solve any major problems with just potatoes.
 
LY777
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RE: Recap About Airliners Cruising Speed

Thu Oct 01, 2009 9:20 pm



Quoting Alias1024 (Reply 7):
I don't know the exact number, but I'd wager it has a minus sign at the front of it.

lol
on Air France magazine, they say 0.70 mach: why such a low cuising speed?!
Flown:A3B2,A320,A321,A332,A343,A388,717,727,732,734,735,738,73W,742/744/748,752,762/2ER/763/3ER,772/77E/773/77W,D8,D10,L
 
XXXX10
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RE: Recap About Airliners Cruising Speed

Sun Oct 04, 2009 11:02 am

I have the BAE 146 brochure, it claims that because of the short sector length the M 0.70 had little effect on flight times and I presume it allows them to design a wing for very slow take-offs and landings.

I thought that the 747-400 was the fastest pax a/c and could cruise at M0.88
 
saab2000
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RE: Recap About Airliners Cruising Speed

Sun Oct 04, 2009 11:26 am



Quoting Alias1024 (Reply 7):
Though not on the list, typical at my airline for the CRJ-200 is .74. The airplane is a real dog above 20,000 ft.

This is all correct. But I have seen, in winter on a cold ISA day, .82 in level flight at FL320. Still a pig.... but not quite as bad.
smrtrthnu
 
brains
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RE: Recap About Airliners Cruising Speed

Mon Oct 05, 2009 5:03 am

I jumpseat fairly regularly on the A300, and if I recall they cruise around M.80
Brains
 
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calpsafltskeds
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RE: Recap About Airliners Cruising Speed

Mon Oct 05, 2009 5:24 am



Quoting XXXX10 (Reply 9):
I have the BAE 146 brochure, it claims that because of the short sector length the M 0.70 had little effect on flight times and I presume it allows them to design a wing for very slow take-offs and landings.

The BAE146 has a lower cruising altitude, which probably cuts down on the speed as friction would be greater at FL240. IIRC, the aircraft has window seals that don't allow higher altitudes.
sites.google.com/site/unitedfleetsite/
 
B777LRF
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RE: Recap About Airliners Cruising Speed

Mon Oct 05, 2009 7:22 pm

This discussion will never be able to yield a single number applicable for each of the types you have listed. There are simply too many variables, some of which have already been mentioned.

We drive the aircraft at the speed our lords and masters (the beancounters) tell our Chief Pilot to tell us.

We comply by punching the required Cost Index* into the box, and the electronic brain will do the rest. Updates always tell us to put a lower number in the box, I've never seen them increase it. So we're generally going slower and slower, and most of us are now flying at the very low end of Cost Index numbers.

But that's for OPS normal. There are literally thousands of different scenarios that may result in a correction of the cruising speed. And just like the beancounters always revise downwards, pilots always tend to revise upwards; any excuse to go faster

B757 Short-/medium haul: .78
Nowadays, B757 short-medium is more like .78, but the autothrottle is not the best so in reality it's .78-.81 (it rarely seems to go below set speed, only above). Well, that's what the bean-counters in one outfit I'm familiar with has dictated anyway. They're flying on a Cost Index of 10 or thereabouts.

In my days on a Roller powered 75 we used to drive them at a CI of 40-50, which was around .80-.81 depending on weight, height, temp, wind etc.

A300: .78
B717: .74-.76
B737Cl: .74-.76
E-jet: .74-76
MD80: .76-.78
Tu204: .78

I'm sure there's got to be some sort of aerodynamic sweet-spot, for a short- to medium-haul aircraft/wing combination, right around the .76 mark, give or take a .02 Mach. Not only taking into consideration fuel-burn, but the total operating costs. But I'm neither a beancounter nor an aerodynamicist, so I'll just have to take my own word for it - unless someone can prove me wrong of course.

A306: .80
B707: .84

* Cost Index is Boeing speak, not sure if Msrs Airbus, Bombardier et al use the same expression.

[Edited 2009-10-05 12:25:03]

[Edited 2009-10-05 12:27:22]
From receips and radials over straight pipes to big fans - been there, done that, got the hearing defects to prove
 
411A
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RE: Recap About Airliners Cruising Speed

Tue Oct 06, 2009 2:10 am



Quoting B777LRF (Reply 13):
We drive the aircraft at the speed our lords and masters (the beancounters) tell our Chief Pilot to tell us.

Not at my company they don't.
I am the Chief Pilot, and I mention to my line Captains that the speed that they desire to cruise at is their business...most use M.84....which, as it happens, is the LRC mach number for most weights.
Type, L1011.
 
B777LRF
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RE: Recap About Airliners Cruising Speed

Tue Oct 06, 2009 7:15 am

... but at least we agree line skippers fly the speed they're told, or told to decide for ourselves in your case. Which must be nice, but that sort of freedom has forever been eroded with the vast majority of operators.
From receips and radials over straight pipes to big fans - been there, done that, got the hearing defects to prove
 
CX Flyboy
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RE: Recap About Airliners Cruising Speed

Tue Oct 06, 2009 10:25 am

We input the Cost Index which is of course decided by the company and changes with regards to fuel price and maintenance costs etc.. Having said that, there are times when we input a speed manually into the FMC is we see the need to beat someone to a certain waypoint if we know that being number 2 to them is going to delay us further down route.
 
pilotpip
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RE: Recap About Airliners Cruising Speed

Tue Oct 06, 2009 5:20 pm



Quoting B777LRF (Reply 13):
E-jet: .74-76

Vmo on the 170/175 is .82

I've only done it a couple times because it burns a lot more fuel than it does at .78 (where we file) and doesn't have much of an effect on any of the legs we fly, even the longer ones. If we push off early going to a hub and show that we're way early I'll pull it back as far as .68 to try avoiding waiting for a gate in the penalty box. This will save a few hundred pounds per hour over .78.

Going fast is fun and all, but we're paid by the minute  Smile
DMI
 
Curiousflyer
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RE: Recap About Airliners Cruising Speed

Tue Oct 06, 2009 10:14 pm

Dont forget:

Aérospatiale Concorde: M 2.
 
413X3
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RE: Recap About Airliners Cruising Speed

Wed Oct 07, 2009 4:29 am

what cost indexes are 747-400Fs using these days?
 
Max Q
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RE: Recap About Airliners Cruising Speed

Thu Oct 08, 2009 7:06 am



Quoting B777LRF (Reply 15):



... but at least we agree line skippers fly the speed they're told, or told to decide for ourselves in your case. Which must be nice, but that sort of freedom has forever been eroded with the vast majority of operators.

I don't think so, my outfit tells us to use the lowest cost index that will allow an on time arrival (or in the case of pushing the extreme limits of the Aircraft, cost index 0 ! )


However if we are running late or have a good operational reason to go fast it is entirely up to us Captains to do so with no criticism from management.



I would think most operators would still leave this decision to the Captain.
The best contribution to safety is a competent Pilot.
 
CX Flyboy
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RE: Recap About Airliners Cruising Speed

Thu Oct 08, 2009 2:09 pm



Quoting Max Q (Reply 20):
I don't think so, my outfit tells us to use the lowest cost index that will allow an on time arrival (or in the case of pushing the extreme limits of the Aircraft, cost index 0 ! )

We used to be told to reduce the CI zero, ETA permitting. However they worked out that the fuel it saved was offset by the cost of having the engines work for longer so they now tell us to reduce to 20 instead of zero. To be honest it doesn't make much difference!
 
saab2000
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RE: Recap About Airliners Cruising Speed

Thu Oct 08, 2009 2:35 pm



Quoting CX flyboy (Reply 21):
We used to be told to reduce the CI zero, ETA permitting. However they worked out that the fuel it saved was offset by the cost of having the engines work for longer so they now tell us to reduce to 20 instead of zero. To be honest it doesn't make much difference!



That's similar to what we had when I flew the SAAB2000 at LX. Company figured out it was cheaper, all things added up, to run the airplane at max speed. Fuel burn was not enough less at slower speeds to offset additional run time on maintenance items. But like you say, it doesn't make much difference, especially on the short flights I normally operate. Even our longest route of MCI-PHL probably only makes a few minutes difference between running slow or running at MMO. Things like tailwind, or vectors coming in to PHL, etc. can make a much greater difference.
smrtrthnu
 
Max Q
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RE: Recap About Airliners Cruising Speed

Thu Oct 08, 2009 8:43 pm



Quoting CX flyboy (Reply 21):

We used to be told to reduce the CI zero, ETA permitting. However they worked out that the fuel it saved was offset by the cost of having the engines work for longer so they now tell us to reduce to 20 instead of zero. To be honest it doesn't make much difference!

Point well made CX, however we have some routes that we operate the 757 on westbound across the Atlantic in the winter that are at the extreme range limit of the Aircraft. On these routes literally every drop counts in order to make it back non stop so engine hours really don't matter.

Quoting Saab2000 (Reply 22):
That's similar to what we had when I flew the SAAB2000 at LX.

How fast was the -2000, nice flying Aircraft ?


I flew the old A model a lifetime ago and always admired the look of the -2000.
The best contribution to safety is a competent Pilot.
 
SQ325
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RE: Recap About Airliners Cruising Speed

Fri Oct 09, 2009 8:06 pm

We used to fly the RJ85 with .70!
.72 is max butr i know quite a few operators are flying .68 as cruising speed!

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