PHX Engine Core Cooling

Murdoughnut

Murdoughnut

Well sized member
This is a thing?

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Huh weird. Looks like a regular CFM engine too. We used to have big fans to cool down the brakes on quick turns in LAS, never seen this though.
 
On the newer PW1100G and LEAP engines the compressor exit temperatures are in the range of 550°C-600°C; enough to make weight-optimized rotor shafts bow under gravity after it stops spinning. On the next startup that Boeing can cause severe vibrations.

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.

But yeah, this looks like a plain old CEO engine where it shouldn’t matter.

Let us assume this was a new ramper instructed to hook-up ground air (after they couldn’t find a spool of flight line). And they are apparently good at metal fabrication.
 
The photo makes me laugh. Maybe three years ago I was doing airport standby at DFW for UPS. The A/C went down in the ops building where we hung out. I had noticed it getting toasty in the crew room but I'm pretty tolerant of warmness and didn't think much about it. My F/O comes over and said some of the crews had refused to be in the building and went to the hotel. We were on standby (30 min launch window) and didn't think skeds would be too keen to us going to the hotel but told the F/O he could call skeds if he wanted (major bad on my part as the Capt, I should have made the call on his behalf. He was a pretty senior F/O, though, and soon to upgrade, so it was good for him to make the call in a way, but I've always regretted not being more assertive on this one). Turns out skeds let us go to the hotel. Later we found out it was going to take a few days to get the A/C fixed. We showed up the next day at our usual time to assess the warmness in the crew room and there was an air cart at the doorway to the building with a long hose like in the photo running up the stairwell to the crew area. Some manager thought it would be a good idea to use an air cart to blow cool air up into the crew room during the day when the pilots weren't around and then all would be happy that night. The air cart wasn't on when we saw it. Those things are so loud I can't image how anyone thought having one next to the ops building with a hose through the open doorway was a good idea. Only at UPS...
 
BobDDuck said:
It's possible MX needs to work on the engine, and this is their way of cooling it down so they can get it there quicker.
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Yes. This is commonly seen at my place, where external cooled air blown down the intake of a bird that is awaiting a scheduled 25 hr engine wash and has just returned from a flight. Normally a 3 or so hour wait before the engine temp is in the range where it can have the wash performed, in the latest temps and during alot of summer days, external air is used by Mx to assist in the cooling so the wait doesn’t become an 5+ hour process.
 
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DE727UPS said:
The photo makes me laugh. Maybe three years ago I was doing airport standby at DFW for UPS. The A/C went down in the ops building where we hung out. I had noticed it getting toasty in the crew room but I'm pretty tolerant of warmness and didn't think much about it. My F/O comes over and said some of the crews had refused to be in the building and went to the hotel. We were on standby (30 min launch window) and didn't think skeds would be too keen to us going to the hotel but told the F/O he could call skeds if he wanted (major bad on my part as the Capt, I should have made the call on his behalf. He was a pretty senior F/O, though, and soon to upgrade, so it was good for him to make the call in a way, but I've always regretted not being more assertive on this one). Turns out skeds let us go to the hotel. Later we found out it was going to take a few days to get the A/C fixed. We showed up the next day at our usual time to assess the warmness in the crew room and there was an air cart at the doorway to the building with a long hose like in the photo running up the stairwell to the crew area. Some manager thought it would be a good idea to use an air cart to blow cool air up into the crew room during the day when the pilots weren't around and then all would be happy that night. The air cart wasn't on when we saw it. Those things are so loud I can't image how anyone thought having one next to the ops building with a hose through the open doorway was a good idea. Only at UPS...
Click to expand...
They had to do this last week at Purple. Storms in MEM knocked out power all around town and the AOC was running on backup generators, They had 4 ground air carts running outside with their hoses running to Ops to keep the building cool.
 
We never ran into shaft bow on em but we operated in a pretty mild climate and almost always gave them a pretty good spin after shutdown. Not sure how much of a real issue it was with the later updated versions.
 
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.
 
Minuteman said:
On the newer PW1100G and LEAP engines the compressor exit temperatures are in the range of 550°C-600°C; enough to make weight-optimized rotor shafts bow under gravity after it stops spinning. On the next startup that Boeing can cause severe vibrations.

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.

But yeah, this looks like a plain old CEO engine where it shouldn’t matter.

Let us assume this was a new ramper instructed to hook-up ground air (after they couldn’t find a spool of flight line). And they are apparently good at metal fabrication.
Click to expand...

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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