RB211 side smoke?

Posted by: crinkles

RB211 side smoke? - 11/22/13 10:09 PM

We took a flight from Johannesburg to Sydney recently on Qantas Flight 64. It is operated by a 747-400 with Rolls-Royce RB211-524G-T engines.

We were sitting on the right outside window, and could see engine #4 (and none other). On taxi we noticed smoke coming from a port on the side of the engine. Swirling, not jetting. This continued during takeoff, and climbout, but obviously became a smoother stream on climbout.

It is disconcerting to see this at the start of a 12 hour flight across the Southern Ocean (Went down to 51 degree south). I assumed they knew what they were doing though...

The smoke was white, probably oil related? As the sun set pretty quick after climbout, didn't pay it a second thought. Taxiing on the ground in Sydney, the swirling smoke was still billowing out.

Was this engine burning oil? does it need a seal replacement?

Here is a good photo, on a different airline though, but same port - just under the Rolls Royce decal.

http://www.airliners.net/photo/Cathay-Pa...732b0b51c77ef00

http://www.gcmap.com/mapui?P=jnb-syd
Posted by: expat

Re: RB211 side smoke? - 11/22/13 10:54 PM

"It is disconcerting to see this at the start of a 12 hour flight across the Southern Ocean (Went down to 51 degree south). I assumed they knew what they were doing though...

The smoke was white, probably oil related?"

It's British, it's supposed to do that.
Posted by: MolaKule

Re: RB211 side smoke? - 11/22/13 11:20 PM

The Rolls-Royce RB211-524G-T is the more fuel efficient version of
the RB211 with a Trent Hot core section and an extra bleed valve.

I suspect the bleed was actually steam.

Or else it needs a serious head gasket replacement. grin2 oilburner
Posted by: JetStar

Re: RB211 side smoke? - 11/23/13 07:08 AM

My first thought was a bearing sump vent, but I don't know RR engines very well.
Posted by: Astro14

Re: RB211 side smoke? - 11/23/13 08:33 AM

Oil vent most likely.

But jet engines hold quite a bit of oil and the pilots have oil pressure, oil temperature and oil quantity gauges. The aircraft monitors those parameters as well...to provide warning if a parameter reaches an alert or critical level. The airline monitors consumption and does analysis on the oil.

So, nothing to worry about, frankly.
Posted by: Cujet

Re: RB211 side smoke? - 11/24/13 09:01 AM

Absolutely normal for rolls engines. They use pressurized labyrinth seals, with no mechanical seal at all. The outboard vent you see is much the same as a crankcase vent going overboard on a car, instead of a PCV system. It will show oil vapor. In cruise flight, it seals very well and little oil is lost.

Other manufacturers do it differently and you don't see the oil mist.

On our company jet, a G550, both Br710 engines have oil vapor swirling about at idle. I think it looks cheap. But, oil consumption is nil, so it must be as effective as any other system.
Posted by: crinkles

Re: RB211 side smoke? - 11/25/13 12:53 AM

Thanks guys. Great Info. Would the amount of venting be different from engine to engine? This is the first time I've seen it. Perhaps that engine was a bit more worn?
Posted by: Astro14

Re: RB211 side smoke? - 11/25/13 01:25 PM

Yes, the venting will vary from engine to engine...these things all have large sumps, scavenge pumps, air/oil coolers, fuel/oil coolers, etc...pretty robust oil systems to feed the bearings oil at a nice, stable temperature and pressure....
Posted by: Propflux01

Re: RB211 side smoke? - 12/08/13 10:57 AM

Originally Posted By: JetStar
My first thought was a bearing sump vent, but I don't know RR engines very well.


My thinking as well (labyrinth seal). I've seen that a lot on T-56, but out the combined bottom drain.
Posted by: john_pifer

Re: RB211 side smoke? - 12/16/13 04:59 AM

The RB-211 bankrupted RR. They'd be outta business today had the Brit govt not bailed them out.