Fuel consumption
 

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

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.

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

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.

Gear Up or Down?

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

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

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

I believe it was ATC issues not an aircraft one.

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.

What calendar were they using...?

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

https://cimg0.ibsrv.net/gimg/pprune....d70f285d84.jpg

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.

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