Fuel consumption

[airman1900]

JetBlue flight number 285 a A220 flew JFK-RDU on Sat., Nov 11 with a max cruise altitude of 8000. How much different would fuel consumption be?

https://www.flightradar24.com/data/f...b6285#3d048e07

[eckhard]

It would be pretty much same fuel flow at 250 kts indicated at 8,000ft as it would have been at 250 kts indicated at 37,000ft. Probably about 4,500lbs/hr. So, the fuel consumption in pounds per hour would be similar at both altitudes.

The big difference would be in the True Airspeed. 275-ish at 8000ft and about 480kts at 37,000ft. So, the fuel consumption in pounds per mile would be much more at the lower altitude.

[airman1900]

Thanks, I should have thought about it a little more. Of course, you burn much less fuel climbing to 8,000ft vs 37,000ft.

[PENKO]

Yes but you will steadily loose that advantage every second you stay at 8000’. On a 320 you’ll burn about 50-60% more I think, flying that low.

[Deep Throat]

Originally Posted by airman1900

JetBlue flight number 285 a A220 flew JFK-RDU on Sat., Nov 11 with a max cruise altitude of 8000. How much different would fuel consumption be?

https://www.flightradar24.com/data/f...b6285#3d048e07

Gear Up or Down?

[DaveReidUK]

Originally Posted by PENKO

Yes but you will steadily loose that advantage every second you stay at 8000’. On a 320 you’ll burn about 50-60% more I think, flying that low.

Don't be silly - we all know that the real reason planes fly at FL370 is that the view is better from up there.

[dixi188]

This one was didn't go well.
Hapag Lloyd A310.
https://aviation-safety.net/asndb/323474

[TurningFinalRWY36]

Originally Posted by airman1900

Thanks, I should have thought about it a little more. Of course, you burn much less fuel climbing to 8,000ft vs 37,000ft.

but remember you sort of gain that climb fuel back with 30 minutes of almost idle descent time

[airman1900]

Originally Posted by Deep Throat

Gear Up or Down?

I believe it was ATC issues not an aircraft one.

[Noknoipobin]

Everyone already knows which is more fuel-efficient between flying at 8,000 feet and 37,000 feet.So if they were flying at 8,000 feet, there was probably a necessity.

In this case, I’d guess it was likely a pressurization system failure, and it might even have been a ferry flight bringing the aircraft back for maintenance.

[sycamore]

What calendar were they using...?

[DIBO]

Originally Posted by Noknoipobin

In this case, I’d guess it was likely a pressurization system failure, and it might even have been a ferry flight bringing the aircraft back for maintenance.

No, it was reported as ATC capacity / staffing issues forcing them to use the FL80 escape routes.



In fact, the JBU285 flight mentioned by topic starter (Saturday 8th -not 11th-) , was one in a series of lower level 'escape routes':
Nov, 9th: https://www.flightradar24.com/data/f...b6285#3d07d4cb
Nov, 6th: https://www.flightradar24.com/data/f...b6285#3cfd2a7f
Nov, 5th: https://www.flightradar24.com/data/f...b6285#3cf92fa1

Normal flights are around 70-75 minutes, the low level one's were about 90-95 minutes

[Noknoipobin]

Originally Posted by DIBO

No, it was reported as ATC capacity / staffing issues forcing them to use the FL80 escape routes.



In fact, the JBU285 flight mentioned by topic starter (Saturday 8th -not 11th-) , was one in a series of lower level 'escape routes':
Nov, 9th: https://www.flightradar24.com/data/f...b6285#3d07d4cb
Nov, 6th: https://www.flightradar24.com/data/f...b6285#3cfd2a7f
Nov, 5th: https://www.flightradar24.com/data/f...b6285#3cf92fa1

Normal flights are around 70-75 minutes, the low level one's were about 90-95 minutes

Thank you.

[eckhard]

So, to answer the OP’s question, about 30% more?

[AerocatS2A]

Originally Posted by eckhard

So, to answer the OP’s question, about 30% more?

Sounds about right. Using A320 performance calculations, 370 NM, 67T take off, FL370 is 2.1T and 8000’ is 2.7T