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PAE An-124 Spoolup

Posted: Thu Feb 07, 2019 3:36 am
by RTNOBLE
I was out at PAE today and noticed an AN124 holding for Takeoff.

A new Fedex 763 was inbound, it came in to land, did a go around and took a nice long lap around Snohomish before coming back,

In the meantime, this AN124 rolled onto the runway, held for a second, then spooled up engines - and then sat there with engines at what sounded like takeoff thrust for what must have been 10 minutes. Flightaware said the Fedex bird would come at 12:22 (it then went around) and flightaware says the AN124 departed at 12:32. It was 10 minutes of screaming AN124 engines. Is this common? Why would this have happened? How much fuel would have been burned off?

I spend a reasonable amount of time at PAE, I don't see the Ruslan very often on the ground but I am sure I've never seen such a protracted start up. What was going on here?

Re: PAE An-124 Spoolup

Posted: Thu Feb 07, 2019 4:02 am
by akiss20
Maybe taxi out/delays were shorter than expected and they needed to get down to MTOW? If you need to burn fuel fast, TO power is your best bet and probably not too many places you can throttle up near a runway besides the runway itself.

Re: PAE An-124 Spoolup

Posted: Thu Feb 07, 2019 4:13 am
by portcolumbus
They're in-and-out of IAH all the time and ALWAYS require around 4-6 minutes on the runway for spool-up.

Re: PAE An-124 Spoolup

Posted: Thu Feb 07, 2019 4:15 am
by crownvic
Most AN-124 take offs I have ever seen do this. Maybe not 10 minutes, but a full throttle spool up for several minutes is not uncommon at all.

Re: PAE An-124 Spoolup

Posted: Thu Feb 07, 2019 4:28 am
by GalaxyFlyer
It was a procedure in the early days of the TF-39 powered C-5 and, I suspect, was done here. The problem was stabilizing temps and internal clearances to achieve full thrust required what old engineer’s called “cooking the engines”. The Russians had difficulty finding advanced metallurgy and the fuel burn on that thing is pretty high.

GF

Re: PAE An-124 Spoolup

Posted: Thu Feb 07, 2019 5:03 am
by Max Q
Pretty amazing their engine technology is still at this level


I read an article recently that said they are looking at re-engining the -124 with the GE - CF6-80


Seems like a solid plan

Re: PAE An-124 Spoolup

Posted: Thu Feb 07, 2019 5:25 am
by CATIIIevery5yrs
I remember seeing an An-124 perform the same run up on ATL’s 27R with a long line of departures. They then held subsequent departures because the An-124 was reported as barely climbing and real slow across the ground.

Re: PAE An-124 Spoolup

Posted: Thu Feb 07, 2019 6:33 am
by iamlucky13
Yes, I have also noticed the An-124's at PAE sit for several minutes spooled up. I suppose the relatively cold weather may have led to a longer warm up today.

I found some further discussion here:
https://www.pprune.org/tech-log/273290- ... e-t-o.html

Re: PAE An-124 Spoolup

Posted: Thu Feb 07, 2019 1:10 pm
by slcguy
All An-124s I've seen in SLC have done the same thing, power up for awhile before rolling. Usually only for a minute or so, never seen one do it for 10 minutes. I have no idea what the reason for this procedure is.

Re: PAE An-124 Spoolup

Posted: Mon Feb 11, 2019 1:59 pm
by mach144
At runway line-up point just before take-off roll An-124 warms-up all four engines at 70% nominal (max. cruising) power for two, four or six minutes (depending on take-off weight, outside temperature and aerodrome location).
One minute before start high-lift devices are set in take-off position and one of the engines is set to 80% for a while and then set back to 70%.
3 seconds after brake release initiating take-off roll all four engines are set to calculated take-off power and this regime is maintained up to reaching height of 120 m, when throttles are set to nominal power.
Engines warming-up procedure is used to prevent possible engine-surge at take-off.

Re: PAE An-124 Spoolup

Posted: Tue Feb 12, 2019 4:24 am
by acjbbj
Max Q wrote:
Pretty amazing their engine technology is still at this level


I read an article recently that said they are looking at re-engining the -124 with the GE - CF6-80


Seems like a solid plan


They should do the Trent 560. Either way, they should do it for both the 124 and the 225