UA839 from Los Angeles to Sydney has diverted to Pago Pago in American Samoa (not verified)

GON

GON

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United Airlines Boeing 787-9 operating flight UA839 from Los Angeles to Sydney has diverted to Pago Pago in American Samoa. The aircraft has a potential engine oil leak and landed at Pago Pago.

United has scheduled a rescue operation as follows - The 787-9 N24979 currently flying from Houston to Sydney as UA101 will land in Sydney and turn around and return to Pago Pago to collect the passengers stranded by the diversion of UA839. The rescue flight will be trackable as UA2795. https://www.flightradar24.com/data/flights/ua2795

Passengers are likely to have a wait in Pago Pago of 12 hours. The 31 Dec 2022 Sydney to Los Angeles UA842 service is now Cancelled
The diverted A/C on the ground is BOEING 787 - MSN 37814 N38955
Serial number 37814 LN:297
Type 787-9
First flight date 30/04/2015
Test registration
Plane age 7.7 years
Seat configuration C48 Y204 Seat
Hex code A47FDE
Engines 2 x GEnx-1B
322880736_734529324901735_1633910917586759423_n.jpg
 
Rescue plan already being executed. Good to see.

Hard to know what’s going on, too soon to tell, but landing with two engines running in Pago Pago sure beats having one of them quit while trying to continue on to Sydney.
 
I had no idea where Pago Pago was. 9000' runway. Looks like the plane is still there. Did they end up picking up those passengers?
 
SevenBizzos said:
I had no idea where Pago Pago was. 9000' runway. Looks like the plane is still there. Did they end up picking up those passengers?
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United has scheduled a rescue operation as follows - The 787-9 N24979 currently flying from Houston to Sydney as UA101 will land in Sydney and turn around and return to Pago Pago to collect the passengers stranded by the diversion of UA839. The rescue flight will be trackable as UA2795. https://www.flightradar24.com/data/flights/ua2795
 
I believe this altitude profile shows that an engine was shut down at about 7hrs 15 minutes into the flight. The flight continued for about 2.5 hours to PPG on one engine.

@Astro14 @lurker does this make sense?

uaengineshutdown.JPG
 
wwillson said:
I believe this altitude profile shows that an engine was shut down at about 7hrs 15 minutes into the flight. The flight continued for about 2.5 hours to PPG on one engine.

@Astro14 @lurker does this make sense?

View attachment 133176
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It's impossible to maintain high altitude cruise after an engine failure or in-flight shutdown if thats what happened.

If I am reading that graph properly, it looks like it went down to FL 250/200 which makes sense.

For illustration purposes, if you had an engine shutdown in the Airbus at FL350 at a heavy weight ( 35,000 feet ), you would need to descend to 18,000 feet.

Just looking at the Airbus manual......would be unable to maintain cruise at FL350 but have enough power for a gradual descent which could take 400 NM and over 1 hour if ATC allowed. That's at min speed to preserve altitude loss which isn't how we would normally fly once the engine is secured.

In oceanic/Non-radar environments, all airlines have to comply with contingency procedures until an ATC clearance is obtained.
 
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lurker said:
If I am reading that graph properly, it looks like it went down to FL 250/200 which makes sense.
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Correct, it took about 1 hour to descend from 38,000' to 20,000'

Is my assumption correct that they shut down one engine and flew the rest of the flight on one engine?
 
GON said:
engine oil leak
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How do jet engines lubricate?

I presume there is no sump and the oil just gets circulated through bearings, a filter, maybe a cooler, and then through the races again?
 
All jet engines have their own self-contained oil system.

18 quarts of oil per engine on the Airbus. Consumes 1/2 quart per hour.

Each engine ( Airbus ) has its own oil "tank" which gets pumped through an oil filter to the bearings and gearbox. After that, it gets pumped ( scavenger pumps ) through a fuel oil heat exchanger back to the tank and the cycle repeats.

Time for bed. Goodnight.

Before I go....

3 oil related cockpit ( airbus ) warnings/cautions regarding oil problems:

1. Lo oil pressure

2. High oil pressure

3. Oil filter clogged

We can get some flashing “ advisories” for other oil related issues


Now I am going to bed.
 
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lurker said:
All jet engines have their own self-contained oil system.

18 quarts of oil per engine on the Airbus. Consumes 1/2 quart per hour.

Each engine ( Airbus ) has its own oil "tank" which gets pumped through an oil filter to the bearings and gearbox. After that, it gets pumped ( scavenger pumps ) through a fuel oil heat exchanger back to the tank and the cycle repeats.
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So the oil gets burned right out the back of the engine, interesting! I guess you have to top off the oil tank after every few fuel ups?
 
Owen Lucas said:
So the oil gets burned right out the back of the engine, interesting! I guess you have to top off the oil tank after every few fuel ups?
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Jet engines leak like crazy. Nearly all oil is lost through operation by leaking past the no. 6 bearing in the turbine rear frame. This is the location of incredibly high heat and high difficulty in sealing. They don't use seals like on a car engine but rather they use a labyrinth seal that uses internal air pressure to literally blow the oil back into the scavenge sump.

There are three gearboxes that are potential oil leakers: inlet, transfer, and accessory drive module. Each of these gearboxes have shafts that can wear. They use carbon seals which do a great job of sealing but are very picky about being perfectly smooth. As wear creates gaps, oil leaks begin and increase exponentially over time.

And of course, the system is a dry sump design that mounts the oil tank on the side of the fan frame. The potential exists for servicing errors by ground support and the fact that this plane had a failure at this time duration makes it's quite possible that something was not done correctly back in Los Angeles.

I am curious to see if any information is brought forward on the cause of this problem. Rarely do companies share such data because it's bad for business but maybe someone with internal information can share when it's made available. All the speculation and it could turn out to be a faulty sensor.
 
Owen Lucas said:
How do jet engines lubricate?

I presume there is no sump and the oil just gets circulated through bearings, a filter, maybe a cooler, and then through the races again?
Click to expand...
LOL…

Seriously? You presume a $15 million engine has no sump and maybe a cooler?

Large sump, usually 15-20 quarts, multiple scavenge pumps, primary pump, filters, oil coolers, oil fuel heat exchanger.

Here is the engine in question.

en.wikipedia.org

General Electric GEnx - Wikipedia

en.wikipedia.org en.wikipedia.org

Cockpit instrumentation includes oil quantity, oil pressure, oil temperature. Oil quantity varies on my airplane, as cold oil isn’t scavenged back to the sump as quickly as warm oil. So, typically after start, there is an initial sump level drop, of several quarts, then, as the oil reaches operating temperature, sump quantity rises back up and stays steady for he next several hours. Even on a 10 hour flight, there is no appreciable drop in sump quantity.

They’re not leaking oil everywhere, as was stated, they’re pretty tight, and I’m flying 20+ year old engines, not brand new ones like this flight. Consumption happens, sure, but it’s more like a quart every ten hours, or every 6,000 miles, if you would like to look at it that way.

The engines are checked and serviced every flight. ETOPS flights require a more rigorous inspection, particularly oil and hydraulic fluid levels.

By the way, the air/oil cooler is used to cool the oil when the airplane is on the ground, or low altitude. Fuel is used to cool the oil when at altitude, which has the benefit of warming the fuel prior to the high pressure fuel pump and fuel control. When the airplane spends several hours at altitude (where the air is often -60C), the fuel gets cold. Warming it helps prevent problems like fuel freezing.
 
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