Jetliner emitting filthy exhaust trail

[MerchantVenturer]

I was at an English regional airport today when my attention was drawn to a Boeing 737-200 aircraft on approach. It was operated by a well known airline. The aircraft was discharging a dark and thick exhaust trail from both engines, and I mean dark and thick.

I saw the same aircraft take off later and the effect was even more startling. Had the exhaust trail been coloured red, white and blue you would have thought you were at an air display.

I believe that this is not inherently dangerous but it is a public relations disaster in that it is food and drink to those environmentalists and NIMBYs who seek every opportunity to decry air travel. Furthermore, the 737-200 is not the quietest of jetliners either.

Had the aircraft been a bus or lorry I am certain it would have been pulled over by the police for emitting thick and dirty exhaust fumes.

I have seen many 737-200s of this particular company and whilst some of the other aircraft have emitted some noticeable exhaust, others have been 'clean', so I presume it is not down to the engine type. Believe me, this one was bad.

Can anyone please explain:

1. The likely reasons for this unfortunate display from the engine exhausts.
2. Why an aircraft would be allowed ‘to go out in public’ carrying passengers in such an anti social state.

Many thanks.

[Final 3 Greens]

The chemtrailers have reached the UK.

It's the end of the world as we know it.

[timmcat]

Would'nt be our Irish friends would it?
Noticed the same at Leeds yesterday.

Must be something in the bowsers at Dublin.

[Localiser Green]

As they say at Leeds, you always know when the Tupolev 154 charter comes in over the Summer..... it's the only thing louder than Ryanair!! :ooh: :ooh:

[eng1170]

Maybe they've adapted there -200's to use water-meth like you see in those old 'Nam pic's of B-52's!! It'll be carpet bombing next!!

[sky9]

Sure its not Guinness?
I use Redex Diesel addative in my car; its done wonders for the black smoke, could try that :D

[northwing]

Sounds as if the combustion chambers or fuel injectors were in a bad way. However, it would be unusual to have two engines in such a state, so perhaps it had picked up some dodgy fuel. Then again, quality control on fuel is invariably tight so that doesn't seem too likely.

[VS-075]

seen the same at Manchester recently thought it was the TU154 coming in .

[BAe 146-100]

Hi,

If you look at these two pictures you can tell that the engines on the B737-200 and Tu-154 are smoking quite badly.

Ryanair 737-204/Adv (http://www.airliners.net/open.file/309315/M/)

Hemus Air Tu-154 (http://www.airliners.net/open.file/265231/M/)

BAe 146-100

[MikeSamuel]

Didn't we have a post about this kind of thing before? I think it was said that the smoke trails are unburnt fuel as the engines are less efficient than modern equivalents. I don't have any technical expertise so I might be wrong, but maybe the smoke is more visible in particular weather conditions?
Then again I could be talking out of my a**e!

[MerchantVenturer]

BAE 146-100,

Thanks for the photos which I know can sometimes show a distorted image. Anyway the two aircraft in your photos were throwing out a mild exhaust trail compared to what I saw.

The sort of thing depicted in the photos is not uncommon with this airline at my airport, although usually it is more noticeable out of one engine than both. Last Friday's incident was far worse, so much so that it led me to ask the two questions at the start of this thread.

I was hoping that an engineer might comment on both the points I raised at the end of my initial post. Thus far it seems to have raised more of a mild amusement. It was meant to be a serious point.

Perhaps I put the question in the wrong forum but I cannot see a more appropriate one on PPRuNe, unless anyone else can suggest otherwise.

[PlaneTruth]

MerchantVenturer ,

The soot trail you witnessed is indeed unburnt hydrocarbons, just like those emitted by diesel engines.

The 737-200 uses Pratt & Whitney JT-8 turbofan engines of various subcatagories. These engines are far louder than the current generation jet motors and are considerably less tidy. They are, however, a vast improvement to the pure turbojet engines we saw on the first generation of jet liners in the 60's. In calm winds, visibilty use to drop to half a mile on the runway behind a 707 or DC-8 with turbojets. The Convair 990 was horrendous. Remember: The 737 was pressed into service with Lufthansa around 1967. This is old technology.

The reason you see this exhaust trail during landing is that the aircraft is in a high drag configuration during the final stages of approach and the engines have to overcome this drag by operating at a higher power setting. The soot you see is heavy particulate matter and falls to the ground fairly quickly.

Newer engines are not only visibly cleaner, but emit far less CO and CO2 than the older motors. Like modern automobile engines, jet motors have made huge strides in lessening environmental impact.

Rest assured, the 737-200 will not remain in service much longer as it is reaching the end of its economic lifespan. (It's not chronological age that kills aircraft, but rather pressurization cycles which create cracks in the outer skin of the aircraft. At some point, it is no longer economically practical to keep the old birds in the air.) The last 737-200's came off the assembly line in the mid 80's and with an average lifespan of 20-30 years, their time is nigh. Plus, newer generation aircraft are available on the market at fire sale prices. Many airlines are swapping over to the newer aircraft as the opportunity presents itself. My airline has decided to park its fleet of -200's a year ahead of schedule and replace them with state of the art -700's.

Reportedly, a high time -200 is only fetching around $200 K USD on todays used market.

Hope this helps.


PT

[WelshFlyer]

Sounds rarther like my bike! (typical student-pilot transport) it's the same in two-stroke engines as well, but semi-burnt oil createing the hydrocarbons.

WelshFlyer.;)

[MerchantVenturer]

Plane Truth,

Many thanks for your explanation - most interesting and enlightening.

Best wishes.

[Onan the Clumsy]

BAe That's not dirty...

This (http://www.airliners.net/open.file?id=362953&WxsIERv=Qm9laW5nIDcwNy0zMzE%3D&WdsYXMg=VHJhbnMgV29ybGQgQWlybGluZXMgKFRXQSk%3D&QtODMg=TG9uZG9uIC0gSGVhdGhyb3cgKExIUiAvIEVHTEwp&ERDLTkt=VUsgLSBFbmdsYW5k&ktODMp=SnVuZSAxOTcw&WNEb25u=QmlsbCBTaGVyaWRhbg%3D%3D&xsIERvdWdsY=Tjc2NVRX&BP=0&MgTUQtODMgKE=T2xkIEVrdGFjaHJvbWUgc2xpZGUgaW1wcm92ZWQgYXMgZmF yIGFzIHBvc3NpYmxlIC0gYSAnd2V0JyB0YWtlLW9mZiBmcm9tIHIvdyAyOEw gKHdhdGVyIGluamVjdGlvbiBpbnRvIHR1cmJvamV0cyB0byBpbXByb3ZlIHR ydXN0IGNhdXNpbmcgbG90cyBvZiBncmVhdCBzbW9rZSEpIC0gc29tZSBjbGF zc2ljIG9sZCBqZXRzIHZpc2libGUgaW4gdGhlIGhlYXQgaGF6ZSBpbiB0aGU gYmFja2dyb3VuZA%3D%3D&YXMgTUQtODMgKERD=NTQyOQ%3D%3D&NEb25uZWxs=MjAwMy0wNi0wOQ%3D%3D&static=yes&size=M) is dirty. :ugh:

And that's clean compared to the one I was looking for

[411A]

Ah yes, the 707-331, Pratt&Whitney JT4A engines, a lot of thrust, but no fan so airfield performance was ah...rather poor at high weights (over 300,000 pounds).
But a dream at high(er) altitudes.
If you got held down low, the JT4's sucked up an incredible amount of fuel.
Conways were smokier...and noiser.
On final, if you got a bit low/slow, opened the taps and waited...waited...and waited, for the spool-up.
Could be interesting for the unwary.

[reynoldsno1]

Eat my
http://www.airliners.net/open.file/004414/M/
particulates
http://www.airliners.net/open.file/004414/M/

[boeingbus2002]

Its not just the oldies...
Saw a UA 777 last week departing LHR with considerably more black(ish) smoke!!!
:rolleyes:

[wobblyprop]

Can't find the other post but it stated something like

We in europe us a different grade of Jet fuel to the Americans. This means, for example, that BA 777 will have a cleaner trail than a UA 777.

[Bealzebub]

How astonishing !
Does that mean the BA 777 trail will get dirty when it refuels on the other side of the atlantic, and presumably the UA 777 gets cleaner when it fills up this side ? :ooh:

[ramsrc]

boeingbus2002

Here's an example but it's nothing compared to a Convair! :)

Smoky 777 (http://www.airliners.net/open.file/224490/M/)

Convair (http://www.airliners.net/open.file/163732/M/)

[Notso Fantastic]

The more you look along the exhaust trial, the more dense it will appear. The 737-200 is slightly dirtier than modern engines, but not excessively so. You have to allow for your viewpoint.

[boeingbus2002]

Ramsrc..thats the one! And only from one engine too!!
Doubt there is much to it....just wanted to point out that its not always only the oldies that smoke!