PHX Engine Core Cooling

///AMG said:
That sh** is automatic in the MAXXX with LEAPs. No telling how long you are gonna be staring at "motoring" on the engine display during start. Its a great feature when you are stuck behind one in the alley, that just pushed back. It can be for way more than a minute depending on what the computer thinks.
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The 321NEO had a dual cool feature where it would spin both engines at the same time to cool them. It also had a timer for spinning based on some computation of engine temp, OAT, and how long ago it last ran. Anywhere between 30 seconds and 4+ minutes.
 
BobDDuck said:
The 321NEO had a dual cool feature where it would spin both engines at the same time to cool them. It also had a timer for spinning based on some computation of engine temp, OAT, and how long ago it last ran. Anywhere between 30 seconds and 4+ minutes.
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whats the point of that - yay I beat my best time?
 
Minuteman said:
The current popular mitigation for this is to motor each engine for a minute before attempting a start to remove the bowing. There were designs to have the computer use an electric motor on the accessory gear box to slowly spin the engine like a rotisserie for a while after shutdown, but was not brought to airworthiness.
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The Canadians forgot to put dual cooling on the 220 and now they all must suffer.
 
///AMG said:
That sh** is automatic in the MAXXX with LEAPs. No telling how long you are gonna be staring at "motoring" on the engine display during start. Its a great feature when you are stuck behind one in the alley, that just pushed back. It can be for way more than a minute depending on what the computer thinks.
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A cold engine, for example sitting all night (no idea what the parameters are) is about the same as an NG start +/- a minute. Typically the first flight of the day if the aircraft has sat all night. An NG is about 40 to 50 seconds.

Any other time its about 1:30-1:45 to introduce fuel. At 20% N2, 30 or so seconds in you get the white MOTORING (AKA NIGHTRANGER) prompt on the engine page. So typically 20-30 seconds to spin up the engine then usually about a minute or so to wiggle the bow out and then you can introduce fuel. So a total of about 3 minutes for a warm (bowed) engine.

Party time was in Vegas and it was hot and we had to air start a MAX. That took 5 minutes. We called MX with a sense of dread: "So did we break it?" "Are we OK to fly back to SEA". No you didn't break it. There are tables for the starter and we just couldn't start it again for a specified amount of time.

While we are talking about engines and fun rules of thumb that I have discovered are useful. Try and come up with a fuel flow value for 1 engine taxi and 2 engine taxi. That way when you're captain and you have your ramp fuel - required fuel value = time to F around. You can come up with a minute value for the time you can taxi on one engine, or two engines and you can have some kind of reasoning based on math to ask for singe or two engine taxi.

I had a proud moment when my FO accidentally shut down the APU when we were supposed to do a bleeds off takeoff during shifting winds from passing thunderstorms. He owned his mistake and make a remark about how he had shut down the APU during the after start flow. "Bro run the takeoff performance again. It's not windy anymore." 10 seconds of button mashing and 20 seconds of tense waiting later: No more bleeds off takeoff required! Huzzah!

I made everything easy for once.
 
Stone Cold said:
The G-550 had rotor bow issues. I don’t remember the specifics, as I never flew the 550, but there was a procedure as described above to motor the engines under certain circumstances.

I always thought it was interesting to have to motor engines on a $55 million jet.
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Need to on the 747-8. If it’s been shut down for 30-360 min and the EGT is above 90 it’ll run for 40 extra seconds before introducing fuel.
 
BEEF SUPREME said:
I had a proud moment when my FO accidentally shut down the APU when we were supposed to do a bleeds off takeoff during shifting winds from passing thunderstorms. He owned his mistake and make a remark about how he had shut down the APU during the after start flow. "Bro run the takeoff performance again. It's not windy anymore." 10 seconds of button mashing and 20 seconds of tense waiting later: No more bleeds off takeoff required! Huzzah!

I made everything easy for once.
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For us, APU shutdown is last item on the after takeoff climb check, as opposed to the after start. That way you have it if needed for takeoff for any reason, and if you do a bleed off takeoff, reconfiguring to engine bleeds before shutting it off.
 
MikeD said:
For us, APU shutdown is last item on the after takeoff climb check, as opposed to the after start. That way you have it if needed for takeoff for any reason, and if you do a bleed off takeoff, reconfiguring to engine bleeds before shutting it off.
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I don’t remember if I made the same mistake or not when I was an FO but I think I could easily do it, if I was trying to go fast.

Whenever there is a bleed configuration issue I always remind my FOs to get the checklist out and where to find it on the iPad. I also let them know it doesn’t need to be reconfigured until 17K. So they should be deliberate but not rush and just follow the checklist.


Sent from my iPhone using Tapatalk
 
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