Hugh3306 From United States of America, joined Jul 2004, 16 posts, RR: 0 Posted (9 years 4 months 4 weeks 1 day ago) and read 9977 times:
Any experience with commercial jet engine water wash? Especially interested in indicators of when to wash, benefits derived from wash, problems encountered, frequency of wash, how to, etc. Pretty much anything to do with engine washing (good and bad).
Bungle From United Kingdom, joined Nov 2006, 0 posts, RR: 0 Reply 1, posted (9 years 4 months 4 weeks 22 hours ago) and read 9882 times:
I've never had to do an engine wash but I know you should use deminralized water. And you don't have to use water to clean an engine at college we were told that crushed almond shells can be fired down, the intake when the engine is running, as the shells are abrasive enough to remove dirt but do not damage the engine.
Airplay From , joined Dec 1969, posts, RR: Reply 2, posted (9 years 4 months 4 weeks 22 hours ago) and read 9872 times:
There are various methods of cleaning the engine, most using water or a mixture of water and a detergent.
I have seen the use of a water/Magnus solvent (Magnus is a trade name but most of us call this stuff "Magnusol") which is quite a powerful degreaser. The mixture is sprayed into the intake while the engine is dry-motored then pure water is sprayed to rinse. The Magnusol is normally clear but turns white on contact with water, so its quite easy to determine when the engine is completely rinsed.
Magnusol is quite corrosive if you don't rinse thourougly.
The walnut shell method is often called a carbo-blast. It is effective and creates a great light show but the abrasive qualities of the material cause some erosion of the blades so its not used anymore as far as I know. Of course someone out there will come up with proof of someone in darkest Africa still using this method!
The ground-up walnut shells are fed into a hopper that releases them into the running engine.
The benefit of engine cleaning is purely one of maintaining efficient blade shape. Each compressor and turbine blade are tiny airfoils whose shape is ooptinmized for their purpose. Grime and dirt that builds up, modifies the shape of the blades not unlike icing on the leading edge of a wing and spoils the efficiency.
WrenchBender From Canada, joined Feb 2004, 1779 posts, RR: 9 Reply 4, posted (9 years 4 months 4 weeks 19 hours ago) and read 9810 times:
It depends on whether you are talking about Power Recovery Washes (generally what most people above posted about) or a daily De-Salination Wash carried out at the end of the day, on A/C operated on or near Salt Water.
Indications that a power recovery wash is required are higher Ng/N1 or T5 indications for a given Nr/Np/N2 setting. this means the compressor is having to work harder to deliver the same amount of power and therefore requires cleaning.
The de-salination wash is usually a fresh water rinse of the engine (sometimes while running) to remover any salt build up from the compressor and turbines. and is followed by a drying out run after.
MD11Engineer From Germany, joined Oct 2003, 13613 posts, RR: 63 Reply 5, posted (9 years 4 months 4 weeks 19 hours ago) and read 9801 times:
Airplay, LH still does carboblasts on their MD-11s.
During my apprenticeship we did turbine water washs on JT8D engines of B737-200s. We would remove the ignitor plugs and stiock a special probe through each ignitor hole. This probe was connected to a fire hydrant. Then we would dry motor the engine a let the water flow. The main reason was to dissolve sulphurous deposits in the hot section and wash them out.
Mender From United Kingdom, joined Feb 2004, 234 posts, RR: 0 Reply 6, posted (9 years 4 months 4 weeks 17 hours ago) and read 9760 times:
"Does anyone know what "mild abrasive" is sprayed into this engine?"
It's called Jetshot which is form of coke (coal dust) and it's still used today. It's spray dry into the core of the engine at idle power using the compressed air lance you see in the picture. From the flight deck you can barely tell it's being sprayed into the engine, there's a tiny change in EGT. That's it. There will be a bigger effect at high power but the bloke on the Jetwash rig would suffocate because the engine would pull the air out of his lungs!
EMBQA From United States of America, joined Oct 2003, 9352 posts, RR: 12 Reply 8, posted (9 years 4 months 3 weeks 6 days 21 hours ago) and read 9645 times:
Does anyone know what "mild abrasive" is sprayed into this engine?
As said above, in this case it's 'Coke'.....a Steel Production by-product. I've only done it one time on a Saab 340 (GE-CT7). On the down side you can only 'coke' the CT7 one time before your required to send to overhaul as it can actually remove material. On a turboprop it REALLY stinks because you need to stand behind the engine keeping all the hoses out of the way of the prop...and when you inject the coke, you get enveloped in a cloud of coke dust. Coking is only done on an as needed condition and is designed to remove the hard baked on build up.
As for the 'Comp-Wash'... You spool up the engine with the ignition off and inject a heated degreesing fluid into the intake. To me it smells and looks like auto engine degreesing spray and works almost the same way. After you've washed the engine, you then clean it out with several clear water washes, then drag the plane outside and run it to blow out the water and get rid of any bad smells from the washing. If I recall, on the CT7 we did the Comp-Wash every 800hrs or so. As for the cost/benefits......Cost is not that high, just the cost of the Wash Fluid....Benefits include a cooler running engine and thus a longer 'on-wing' time.
Hugh3306 From United States of America, joined Jul 2004, 16 posts, RR: 0 Reply 9, posted (9 years 4 months 3 weeks 6 days ago) and read 9539 times:
Besides engine cooling (I have seen reports of EGT improvements in the 10 - 15 degree range), what about fuel economy gains for the airline? Also, is engine washing something regularly done at a C check or more often than that?
MD-11 forever From , joined Dec 1969, posts, RR: Reply 10, posted (9 years 4 months 3 weeks 5 days 23 hours ago) and read 9536 times:
Well, a reduction of EGT indication usually comes together with a fuelflow reduction. Regarding the interval, there is no such rule as far as I know. It depends largely on the type of operation an airline has got.
LMP737 From , joined Dec 1969, posts, RR: Reply 11, posted (9 years 4 months 3 weeks 3 days 20 hours ago) and read 9422 times:
While I have never done an engine wash on commercial aircraft I have done it on the F-14. Along with keeping EGT temps down it had the added benefit of removing salt from the engines as well.
The engine wash was part of scheduled maintenance. We used a cart specifically desined for washing jet engines. It consisted of tank that held the water/cleaning solvent, a nitrogen tank, and a fitting that attached to the fixed inlet guide vanes. Before you did the actual wash you first had to remove the water traps on the engine so as to prevent water from getting into the engine fuel control system. This can cause the engine to stall.
Once this is done you motor the engine and release the agent into the engine. After all the water/solvent is empteid from the tank you refill it with fresh water only and recharge the nitrogen tank. Then's it's "rinse and repeat".
After the cleaning is finished you reinstall the water traps and run the engine to dry out the motor.
Buzz From United States of America, joined Nov 1999, 697 posts, RR: 23 Reply 12, posted (9 years 4 months 3 weeks 2 days 21 hours ago) and read 9332 times:
Hi Hugh3306, Buzz here. At UAL we used to water wash the JT8D engines in the summer, slight improvement - lower EGT.
I've seen that coke-cleaning of a DC-10 engine - what a mess downwind! It couldn't save the high EGT on that engine, was changed within a week.
Once my partner and i did a DC-10 APU rice-hull cleaning, while standing within touching distance of the APU inlet we sprinkled handfuls of rice hulls which were sucked up and in. OK, so you're supposed to put 'em on a tray and slide the tray toward the inlet... one other guy had the tray "inhaled" and the compressor stall was impressive. The smoke cloud from the burning rice smelled like toasting cereal.
I see that there's a water wash for the CFM56, haven't done it yet.
AirframeAS From United States of America, joined Feb 2004, 14150 posts, RR: 25 Reply 13, posted (9 years 4 months 2 weeks 6 days 22 hours ago) and read 9201 times:
At WN we were not allowed to wash the engines at all. For that reason I dont know why. I got into trouble for doing an engine wash, although I was a new hire and didnt know the procedures. I assumed that WN's procedures were similar to AS's procedures since they both fly B737s.
At AS we were required to do a engine wash before going into a check. After the wash the engines were then turned on for an idle speed check.
A Safe Flight Begins With Quality Maintenance On The Ground.
AirframeAS From United States of America, joined Feb 2004, 14150 posts, RR: 25 Reply 15, posted (9 years 4 months 2 weeks 4 days 20 hours ago) and read 9028 times:
All I was told by my lead that engine wash in PHX prior to the A and B checks that it was strictly not allowed. No one would explain to me why. I think that is probably because DAL appearance technicians were the only ones allowed to do engine wash. Honestly, I dont know why although I found it strange. So yeah, I got busted for it, but didnt count against me during my probation...thank god! Whew!
PS....I dont think its a union issue, I think its a departmental issue. Besides, speaking of the union at WN, they sucked. And when I left they then changed unions and now they are represented by AMFA.
A Safe Flight Begins With Quality Maintenance On The Ground.
NORTHSEATIGER From United Kingdom, joined Sep 2003, 432 posts, RR: 5 Reply 16, posted (9 years 4 months 2 weeks 3 days 19 hours ago) and read 8903 times:
I work on large helicopters that service the oil rigs in the north sea and due to the salt laden atmosphere we wash our engines every night with water, this is done by retarding the engine to ground idle washing for a pre-determined time then drying out at flight idle, Every 50 hrs we do a "Chem" wash wich is venting the engine over and spraying a special fluid into the engine and leaving it to soak for 20 mins then the engine is vented again and water sprayed into to clean out the chemical after that a drying run is carried out. A chem wash may be carried out if the T4 reading is high.
TimT From United States of America, joined Jun 2001, 168 posts, RR: 0 Reply 18, posted (9 years 4 months 2 weeks 1 day 6 hours ago) and read 8606 times:
During my 10 years at TWA we used to wash every engine we ran in the test cell. Used a 2" hose with a small nozzle and lots of pressure. (don't drop the hose) Ran the engine on the starter for 2 minutes (test cell air is cold so you don't have to worry about cooking it) while hosing it down. Then let it blow itself dry and start. Always got lower EGT's. Everytime.
Hugh3306 From United States of America, joined Jul 2004, 16 posts, RR: 0 Reply 19, posted (9 years 4 months 1 week ago) and read 8430 times:
Thanks for all the info. As TimT states "Always got lower EGT's. Everytime." that is what all my additional research has also found. Most interesting was a comment from a Chief Propulsion Engineer at Boeing: "Every 1 degree improvement in EGT margin equates to 1 month additional on-wing time for an engine." Big bucks when you consider what an overhaul costs! Also, at $1.30 or so a gallon for JetA, a 1/2 to 1% fuel savings for a fleet like WN (400 aircraft) would put about $15 million per year to their (already large) bottom line. It amazes me that any union would be that strong; or an airline as savvy as WN would not be doing periodic engine washes.