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Dirty / Burnt Airline Engines.  
User currently offlineReverseThrust From United Kingdom, joined Jan 2005, 113 posts, RR: 0
Posted (7 years 10 months 3 weeks 3 days 15 hours ago) and read 2736 times:

I have always wondered why, on some types of aircraft, the rear portion of the engine is sometimes dirty: Airbus A319/20/21 all types of engines. LH, IB, BD and AF are notable examples that I have seen on here.

On MD80's and DC9's the right engine in particular seems burned across the top of the metal part of the reverser.

I am not sure, but have a feeling it may be caused by reverse thrust...

How is this actually caused and why does it only happen sometimes?


Flown MD11/81/82/83/87/90,B732/733/734/735/737W/738/739/742/752/753,F70/100,A300/319/320/321/332/333/343,TU134A/154M,L10
22 replies: All unread, jump to last
 
User currently offlineFlyDeltaJets From United States of America, joined Feb 2006, 1787 posts, RR: 2
Reply 1, posted (7 years 10 months 3 weeks 3 days 15 hours ago) and read 2727 times:

I thinks it is caused by lack of soap and water application for many years

 Wink



The only valid opinions are those based in facts
User currently offlineReverseThrust From United Kingdom, joined Jan 2005, 113 posts, RR: 0
Reply 2, posted (7 years 10 months 3 weeks 3 days 15 hours ago) and read 2727 times:

LOL - Probably in AF's case it is!


Flown MD11/81/82/83/87/90,B732/733/734/735/737W/738/739/742/752/753,F70/100,A300/319/320/321/332/333/343,TU134A/154M,L10
User currently offlineTrent900 From United Kingdom, joined Dec 2003, 516 posts, RR: 0
Reply 3, posted (7 years 10 months 3 weeks 3 days 15 hours ago) and read 2691 times:

Quoting ReverseThrust (Thread starter):
On MD80's and DC9's the right engine in particular seems burned across the top of the metal part of the reverser

I think the deposits you've mentioned on these aircraft is due to the APU exhaust which is situated in the side of the rear fuselage. As for other aircraft I dont know, Im sure a bit of a wash can get the 'dirt' off.

D.


User currently offlineReverseThrust From United Kingdom, joined Jan 2005, 113 posts, RR: 0
Reply 4, posted (7 years 10 months 3 weeks 3 days 15 hours ago) and read 2654 times:

OK, thanks - but on Airbus/Boeing I am a little more curious then. I am quite new to forums and haven't yet worked out how to get pics off of a.net into my posts to provide examples.

Cheers for all relevant advice on the question in hand.

Reverse.



Flown MD11/81/82/83/87/90,B732/733/734/735/737W/738/739/742/752/753,F70/100,A300/319/320/321/332/333/343,TU134A/154M,L10
User currently offlineFlySSC From France, joined Aug 2003, 7379 posts, RR: 57
Reply 5, posted (7 years 10 months 3 weeks 3 days 14 hours ago) and read 2592 times:

In the case of the B737-200, this pic. shows you exactely why the rear part of the fuselage is/was often so dirty :

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Photo © John Farrington - FlightLineImages



Some more :


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Photo © Fabio Laranjeira - Contato Radar
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Photo © Paulo Herren



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Photo © Bruce Leibowitz
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Photo © Kevin Wachter


I guess the reasons are the same on the aircraft types you mentionned, with less impacts on the fuselage itself because of the thrust reverse system's conception

[Edited 2006-06-02 17:01:11]

User currently offlineReverseThrust From United Kingdom, joined Jan 2005, 113 posts, RR: 0
Reply 6, posted (7 years 10 months 3 weeks 3 days 14 hours ago) and read 2558 times:

OK, Thanks again - that one was obvious though, which was why I didn't specifically mention it.

I thought it wouldn't have been a question which was too technical for an answer here. Is the dirt on ther CFM/IAE Engines caused by heat on reverse or by a particularly hard reverse?

KLM's engines on the Boeing 733/734 aircraft are always quite dirty on the aft part of the engine itself too.



Flown MD11/81/82/83/87/90,B732/733/734/735/737W/738/739/742/752/753,F70/100,A300/319/320/321/332/333/343,TU134A/154M,L10
User currently offlineHAWK21M From India, joined Jan 2001, 31576 posts, RR: 57
Reply 7, posted (7 years 10 months 3 weeks 3 days 12 hours ago) and read 2383 times:

Thats why Aircraft should be cleaned regularly. Smile
regds
MEL



Think of the brighter side!
User currently offlineMiamiair From , joined Dec 1969, posts, RR:
Reply 8, posted (7 years 10 months 3 weeks 3 days 11 hours ago) and read 2356 times:

Quoting ReverseThrust (Thread starter):
MD80's and DC9's the right engine in particular

The APU exhaust is on the right side of the fuselage above the rear part of the pylon.


User currently offlineJetstar From United States of America, joined May 2003, 1616 posts, RR: 10
Reply 9, posted (7 years 10 months 3 weeks 3 days 7 hours ago) and read 2188 times:
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On the P&W JT8 powered B-737’s, they use the old style clam shell thrust reversers. To prevent the reversers from blowing any debris on the runway forward into the engine intake when reverse thrust is used, the reversers are installed slightly rotated. Looking from the rear, the #1 engine (left side) reverser is rotated about 30 degrees clockwise and the #2 engine (right side) reverser is rotated the same amount but counter clockwise. The 737-300 and up reverser system is different so they don’t have this problem.

Because of this the exhaust that is deflected from the upper reverser bucket hits the fuselage and leaves its telltale stains in the form of carbon dust. In the late 70’s into the early 80’s the JT8 engines was one of the smokiest engines out there. Watching a 727 or 737 climb out after takeoff all you would see was a black trail of smoke. Because of pressure from the FAA and airline operators, P&W redesigned the combustion chambers to reduce to almost nothing the visible black smoke. Another benefit to this redesign was longer turbine blade life because the carbon exiting the engine eroded the turbine blades.

Before this modification, the 737’s were the filthiest airplanes because of the design of the thrust reverser system left enormous stains on the fuselage. These photos are nothing as to what the airplanes looked like with the old combustion chambers.


User currently offlineBDKLEZ From Ireland, joined Jun 2005, 1735 posts, RR: 10
Reply 10, posted (7 years 10 months 3 weeks 3 days 7 hours ago) and read 2169 times:

Quoting Miamiair (Reply 8):
The APU exhaust is on the right side of the fuselage above the rear part of the pylon.

The APU exhaust is to blame for these dirsty tails as well. The situation is only made worse by the fact that these aircraft tails are painted white.


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Photo © Gary Watt - AirTeamImages


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Photo © Estelle Calleja




Trespassers will be shot; survivors will be shot again!
User currently offlineReverseThrust From United Kingdom, joined Jan 2005, 113 posts, RR: 0
Reply 11, posted (7 years 10 months 3 weeks 3 days 6 hours ago) and read 2137 times:

OK, I'll try and make myself a bit clearer. In the following pictures, all of the aircraft have a stained rear part of the actual engine - nothing to do as far as I'm aware with the APU at all on these particular aircraft. It seems this is not something which always occurs, but what I want to know is HOW this actually happens.... it must get there somehow....


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Photo © Konstantin von Wedelstaedt


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Photo © Stuart Prince


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Photo © Darren Wilson




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Photo © Kevin Murphy



Thanks.



Flown MD11/81/82/83/87/90,B732/733/734/735/737W/738/739/742/752/753,F70/100,A300/319/320/321/332/333/343,TU134A/154M,L10
User currently offlineBR715-A1-30 From , joined Dec 1969, posts, RR:
Reply 12, posted (7 years 10 months 3 weeks 3 days 6 hours ago) and read 2102 times:

Quoting ReverseThrust (Thread starter):
On MD80's and DC9's the right engine in particular seems burned across the top of the metal part of the reverser.

That is correct... The APU Exhaust on the DC9/MD80 is situated right there next to the reverse thrust, so the heat/deposits burn the shell. If you look on some DC9s, the left engine is burnt due to a switch from maintenance.


User currently offlineType-rated From United States of America, joined Sep 1999, 4845 posts, RR: 19
Reply 13, posted (7 years 10 months 3 weeks 3 days 6 hours ago) and read 2067 times:

Quoting Jetstar (Reply 9):
Watching a 727 or 737 climb out after takeoff all you would see was a black trail of smoke

You are so right about that one. Before jet engines went "smokeless" the rear halves of a lot of aircraft were very black. In fact, some were so bad that it looked like the carbon was caked on the fuselage! Some of those engines were so smoky, you'd think they were running on coal!



Fly North Central Airlines..The route of the Northliners!
User currently offlineReverseThrust From United Kingdom, joined Jan 2005, 113 posts, RR: 0
Reply 14, posted (7 years 10 months 3 weeks 3 days 6 hours ago) and read 2057 times:

I'm not referring to the back of the aircraft on my question though, very specifically, the engine itself.

That said however, I am flying the TU134 twice in August... now that is a dirty aircraft which runs on coal if ever there was one.

U only need to view some of the videos on www.flightlevel350.com to bear witness to that.... but make sure u got the volume turned up good and proper!



Flown MD11/81/82/83/87/90,B732/733/734/735/737W/738/739/742/752/753,F70/100,A300/319/320/321/332/333/343,TU134A/154M,L10
User currently offline474218 From United States of America, joined Oct 2005, 6340 posts, RR: 9
Reply 15, posted (7 years 10 months 3 weeks 3 days 5 hours ago) and read 2029 times:

What you see is soot, just like the stuff that comes out of a car exhaust If you cleaned it off every flight it would be right back as soon as the engine is started again.

User currently offlineFlyDeltaJets From United States of America, joined Feb 2006, 1787 posts, RR: 2
Reply 16, posted (7 years 10 months 3 weeks 3 days 5 hours ago) and read 2016 times:

Quoting Type-rated (Reply 13):
You are so right about that one. Before jet engines went "smokeless" the rear halves of a lot of aircraft were very black. In fact, some were so bad that it looked like the carbon was caked on the fuselage! Some of those engines were so smoky, you'd think they were running on coal!

When did jet engines go smokeless. I see smoke trails coming from the back of all types of new aircraft on take-off



The only valid opinions are those based in facts
User currently offlineAndrewUber From United States of America, joined Jul 2003, 2528 posts, RR: 41
Reply 17, posted (7 years 10 months 3 weeks 3 days 5 hours ago) and read 1987 times:

The dark stain you see is not a "burn", it is the soot from the kerosene. I have crews who remove this stuff on a daily basis.

Sometimes the paint will get discolored from turbine oil on the cowlings - especially JT8D powered aircraft (such as DC9, 727, 737-200). The engines will look orange or brown - and that discoloration does not come off.

Drew  wave 



I'd rather shoot BAD_MOTIVE
User currently offlineJetstar From United States of America, joined May 2003, 1616 posts, RR: 10
Reply 18, posted (7 years 10 months 3 weeks 3 days 2 hours ago) and read 1860 times:
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Quoting FlyDeltaJets (Reply 16):
When did jet engines go smokeless. I see smoke trails coming from the back of all types of new aircraft on take-off

The engines never went smokeless, all that was done was to greatly reduce the visible carbon particles in the exhaust. What you see today coming out of a jet engine is nothing like the older and dirtier jet engines.

The same thing was done to diesel engines. Years ago you would see large amounts of black smoke coming out of the exhaust pipes of large trucks and buses. On 18 wheel trucks, the exhaust soot would leave black stains on the trailers.

The diesel engine manufacturers under pressure from the EPA were forced to redesign their engines to meet the lower visible particle requirements, the same thing that the jet engine manufacturers had to do. While truck engines had no requirement to retrofit the change, as the jet engines went through overhaul they were modified to reduce the visible carbon particles so within a few years, all the dirty jet engines were cleaned up or in the case of the real old smokers like the CV-880’s or early B-707’s and DC-8’s were retired.


User currently offlineHAWK21M From India, joined Jan 2001, 31576 posts, RR: 57
Reply 19, posted (7 years 10 months 3 weeks 2 days 17 hours ago) and read 1735 times:

Quoting Jetstar (Reply 9):
To prevent the reversers from blowing any debris on the runway forward into the engine intake when reverse thrust is used, the reversers are installed slightly rotated.

Another Main Reason was that the earlier T/R was lifting the Aircraft off the Ground & reducing Brake Efficiency.Hence the Tilt.
regds
MEL



Think of the brighter side!
User currently offlineType-rated From United States of America, joined Sep 1999, 4845 posts, RR: 19
Reply 20, posted (7 years 10 months 3 weeks 2 days 15 hours ago) and read 1641 times:

Thanks, Jetstar for explaining more of this.

Back in the 60's jets would leave long black streams of very black smoke coming out of each engine. It would trail for miles behind the aircraft. Then in the 70's they redesigned some of the engines as noted in this thread and they became almost smokeless when compared to the previous generation of engines. The jet engines of today put out nothing like the ones in the 60's did, so even though I mentioned them to be smokeless, they still do leave a little bit of smoke.



Fly North Central Airlines..The route of the Northliners!
User currently offline320tech From Turks and Caicos Islands, joined May 2004, 491 posts, RR: 5
Reply 21, posted (7 years 10 months 3 weeks 2 days 9 hours ago) and read 1504 times:

In the following pictures, all of the aircraft have a stained rear part of the actual engine

If you're referring to the streaking that is coming from the gap between the fan cowl and the thrust reverser, that's either an oil or hydraulic leak, or else it's from the oil fill point, where someone missed. Any of those will cause black streaks on the reverser.



The primary function of the design engineer is to make things difficult for the manufacturer and impossible for the AME.
User currently offlineDan2002 From United States of America, joined Dec 2002, 2055 posts, RR: 5
Reply 22, posted (7 years 10 months 3 weeks 2 days 4 hours ago) and read 1379 times:

Woah, check out these stains!


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Photo © Brandon Tseng



 Wink



Dan



A guy asks 'What's Punk?'. I kick over a trash can and its punk. He knocks over a trash can and its trendy.
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