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kaddyuk
Topic Author
Posts: 3697
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Precautions 2 B Taken On Hydraulic Systems

Sun Jun 13, 2004 6:37 pm

What precautions need to be taken before starting any work on a hydraulic system

This is another question poised to me which yet again isnt covered in my notes. What does need to be done.

What effects can skydrol have on the skin for prolonged exposure...
What saftey equipment is supposed to be worn...

Anything you feel may be of importance.  Smile

Thanx
Kevin
Whoever said "laughter is the best medicine" never had Gonorrhea
 
Jetfixer75
Posts: 29
Joined: Sun May 16, 2004 2:21 pm

RE: Precautions 2 B Taken On Hydraulic Systems

Sun Jun 13, 2004 7:04 pm

Well Kevin,
For starters, is the hydraulic system tagged out? Are there any open hyd lines? Is anything going to inadvertantly move when hyd power is activated? Are all flight control surfaces clear? Are your landing gear pinned? Landing gear handle in the proper position? I have seen too many people get hurt by the disregard for safety when it comes to hyd power, it can kill or maime QUICKLY!!!!
As for the long term effects of Skydrol, a.k.a. Purple Rain......lol, its acts as an irritant to your skin and tends to dry it out quite a bit. I have been working with it almost daily for the better part of a decade and luckily I haven't had any ill effects. When Skydrol was first being developed, the rep for Monsanto, I believe thats the company who first developed it, would drink a Dixi Cup of it to show how safe and non-toxic it really is. I really wouldn't want to do that.
As far as safety equpment, I would suggest wearing gloves whwn handling it, as well as safety glasses. They have saved my eyes mqny times from dripping Skydrol. Most of the mechanic I work with keep a bottle or syringe of mineral oil in their tool boxes in the event of Skydrol getting in your eyes, it takes away the intense burning rather quickly. I have heqrd of people using milk, but I wouldn't advise that because of the bacteria in it.
I hope this helps you out, be safe.......
 
cdfmxtech
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RE: Precautions 2 B Taken On Hydraulic Systems

Sun Jun 13, 2004 7:38 pm

Bleed off and remove source of Head Pressure (pneumatics) from reservoir (If equipped).

[Edited 2004-06-13 12:40:41]
 
kaddyuk
Topic Author
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RE: Precautions 2 B Taken On Hydraulic Systems

Sun Jun 13, 2004 7:47 pm

I didnt know that Skydrol is Non-Toxic...

Very Interesting...

The hydraulic oil we use at college is Red, some weird nasty shit, makes the paint on the hyd trainers bubble on contact.

Wouldnt catch me drinking Skydrol either...
Whoever said "laughter is the best medicine" never had Gonorrhea
 
air2gxs
Posts: 1443
Joined: Mon Jun 18, 2001 1:29 pm

RE: Precautions 2 B Taken On Hydraulic Systems

Sun Jun 13, 2004 8:39 pm

Red hydraulic oil should be MIL spec 5606. I don't remember it bubbling paint though.

The most important thing to remember is: when you open a hydraulic system, secure the pressure source. This includes the head pressure as CdfMX stated.
 
airplay
Posts: 3369
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RE: Precautions 2 B Taken On Hydraulic Systems

Sun Jun 13, 2004 11:53 pm

Here is a link to the MSDS for Skydrol. It's quite irritating to the skin, but it probably won't kill you even with daily exposure:

http://domino.solutia.com/solutia/smsdslib.nsf/0/e8fc447729788fc506256ab200688064/$FILE/English.pdf

One thing I would recommend, is that if you are tasked with helping someone perform a task on a hydraulic system, personally check that the system is safe to work on. Although not an "active" hydraulic system, I was once almost injured helping remove the nose forks on a Twin Otter. Theres a main nut at the top of the oleo that releases the fork and oleo shaft but someone has to hold the fork so it doesn't fall on the floor.

I asked if the oleo air charge was released and was assured it was. When the nut let go, the forks fired out of the oleo, just missing me. The idiot didn't remove the schreider valve pin nor did he remove the enitire air charge.

As far as the "red weird nasty shit" type of mineral hydraulic oil goes, I had one other unpleasant experience and I wasn't even working on the airplane! I was walking by a DC-3 that had the cowlings off. Nobody bothered to cap the hydraulic cowl flap lines and I just happened to be walking by the engine when someone decided to excercise the cowl flap controls. I got showered with the stuff and I can tell you that it stays in your hair for days! Quite irritating too.

One last thing, both Skydrol and MIL-5606 are quite reactive with oxygen. Take the proper precautions to keep the stuff away from pure, ore near pure oxygen or oxidyzing agents such as chlorine..

Almost forgot....the paint bubbling you are seeing on the resevoirs are probably due to the hydraulic fluid interacting with residues of solvents or cleaning compounds that were left behind. There are several compounds are are "sleeper" paint strippers that are just missing a nice organic compound (like mineral oil) to react with.





[Edited 2004-06-13 16:57:16]
 
MD11Engineer
Posts: 13899
Joined: Sun Oct 26, 2003 5:25 am

RE: Precautions 2 B Taken On Hydraulic Systems

Mon Jun 14, 2004 5:45 am

Asides the safety stuff, cleanliness! Get a bucket and a suplly of clean cleaning rags. Get the correct o-rings and seals (check the IPC!). They have to be Teflon or Butyl rubber.

Jan
Je Suis Charlie et je suis Ahmet aussi
 
MD11Engineer
Posts: 13899
Joined: Sun Oct 26, 2003 5:25 am

RE: Precautions 2 B Taken On Hydraulic Systems

Mon Jun 14, 2004 5:46 am

Beside the safety stuff, cleanliness! Get a bucket and a suplly of clean cleaning rags. Get the correct o-rings and seals (check the IPC!). They have to be Teflon or Butyl rubber for Skydrol (Butylphosphateesters) or Neoprene for Mil-H-5606.

Jan
Je Suis Charlie et je suis Ahmet aussi
 
320tech
Posts: 489
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RE: Precautions 2 B Taken On Hydraulic Systems

Mon Jun 14, 2004 1:33 pm

Skydrol has an ingredient that is mutagenic. I don't know how keen I'd be to drink it (doesn't taste all that great, anyway). It causes mild skin irritation, though some people seem to be more sensitive. If you get it in the eye, you will not be looking at anything for a few minutes. Castor oil is the counter-active of choice around here.

What other precautions need to be taken depends on what you're doing. I got a good lungful of skydrol mist from topping up a nitrogen bottle. I'd forgotten to purge the line, and the previous user obviously failed to disconnect the hose properly.

Generally, make sure others around the airplane know that you're going to apply hydraulics - keep your fingers out of moving parts - make sure the flight control (and other items as necessary) paths are clear - make sure pressure has bled off after shutdown and before opening lines (check indication or operate the rudder).

Wearing approved gloves often isn't practical -they're too thick - so wash thoroughly with soap after exposure. Wipe it off painted surfaces, because it will remove paint. Isopropanol removes it well. Try to figure out if the line you're opening will drain a little or a lot - don't want to empty the reservoir!
The primary function of the design engineer is to make things difficult for the manufacturer and impossible for the AME.
 
air2gxs
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RE: Precautions 2 B Taken On Hydraulic Systems

Mon Jun 14, 2004 8:31 pm

We've found that the Nitrile gloves work pretty good with Skydrol.
 
NKP S2
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Joined: Mon Dec 20, 1999 3:16 am

RE: Precautions 2 B Taken On Hydraulic Systems

Mon Jun 14, 2004 11:00 pm

Bleed off and remove source of Head Pressure (pneumatics) from reservoir (If equipped)

Definately...worth repeating again. You'd be surprised how often that's overlooked. Doesn't take barely any pressure at all to get a nasty spewing.

Another one. ( rant mode ON ) DON'T OVERTORQUE ALUMINUM FITTINGS!!! ( rant mode off ) ....and, if one should be so careless to do so and crack it, DON"T tighten it further in order to "fix" the leak you just created.

Don't try to be some parsimounious move-the-metal hero by re-using O-rings on fittings.

More to come as I think some.....................



 
MD11Engineer
Posts: 13899
Joined: Sun Oct 26, 2003 5:25 am

RE: Precautions 2 B Taken On Hydraulic Systems

Mon Jun 14, 2004 11:04 pm

If you are not using gloves... WASH YOUR HANDS BEFORE HAVING A LEAK!  Wink/being sarcastic
(You´ll only forget to do it once)

Jan
Je Suis Charlie et je suis Ahmet aussi
 
NKP S2
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Joined: Mon Dec 20, 1999 3:16 am

RE: Precautions 2 B Taken On Hydraulic Systems

Mon Jun 14, 2004 11:13 pm

Definately one of those vocations that require _before_ and _after_ washings.

As a side note, watch where you sit, and that clothing is but a temporary skydrol barrier. Sometimes that open engine cowling ( on fuselage mounted engines ) or other surfaces seem inviting places to sit while working. It is till you realize in short time what it was like when you had diaper-rash as a baby.

Had to chuckle about another poster referring to 5606 as nasty. For my money, that stuff is 'Kool-Aide'....nectar of the gods...spring water, compared to Skydrol.
 
A/c train
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RE: Precautions 2 B Taken On Hydraulic Systems

Tue Jun 15, 2004 2:07 am

What aircraft is that your working on at college ? uses 585 by the sounds of it ! I trained on a Jet Provost airframe with RR viper engine. Good experience with some crap access wirelocking !!
 
Sinlock
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RE: Precautions 2 B Taken On Hydraulic Systems

Tue Jun 15, 2004 2:57 am

I'll have to second MD11Engineer's statement.

Always wash your hands before you take a leak, even if you are using gloves. You don't want to become the latest hanger joke because someone walked in on you washing your pecker in the sink.

Skydrol can leach through the cheep Latex gloves found in most hangers. Keep a box of Poly gloves in your toolbox and you'll become every Mechanic's best friend.
 
Mender
Posts: 249
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RE: Precautions 2 B Taken On Hydraulic Systems

Tue Jun 15, 2004 3:28 am

Although several people have said more or less the same thing I'll go a little further.

When removing the header pressure on the hydraulic reservoir on proper (large) aircraft you really need to lock open the bleed port so that the tank does not re-pressurize. The occurs because the hydraulic fluid in the fin pushes back down onto the reservoir so it builds up enough pressure to cause leaks in open pipes. When you lock open the port you MUST record this as a defect. You should also record that you have drained the reservoir in the first place. The acurate recording of work on an aircraft is more important than the actual work itself. By this I mean you may not finish the task but someone else will, therefore you need to record what has been done just as much as what needs to be done.
 
kaddyuk
Topic Author
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Joined: Thu Nov 08, 2001 1:04 am

RE: Precautions 2 B Taken On Hydraulic Systems

Tue Jun 15, 2004 3:43 am

Well, we dont actually have much.

The engines we have are Gnome engines from the Westland Wessex and the hydraulic trainers we use are in the back of the room. Covered in BA paint. We have a nose gear leg which doesnt work and A hydraulic elevator. which is being maintained by the guy near the back.



Its pretty crap but we do what we can. We also have a RR Spey and a Lycoming piston engine...

all I know about the hydraulic oil we use is that it is red, very sticky when drying out and is made by castrol.

Whoever said "laughter is the best medicine" never had Gonorrhea
 
saintsman
Posts: 2037
Joined: Fri Mar 15, 2002 12:34 am

RE: Precautions 2 B Taken On Hydraulic Systems

Tue Jun 15, 2004 4:10 am

When checking for leaks on pressurised systems don't wipe pipes and fittings with your finger. 3000 psi does a wonderful job of cutting off fingers!

And as has already been mentioned. Let people know when applying hydraulics (or electrical power come to that). It also pays to walk round the aircraft to make sure that there are no obstructions. Staging does a very good job of making holes in flying controls. Slightly related to staging is undercarriage functionals. Have you ever seen a set of 'A' steps eaten by the undercarriage doors? It gives you a powerful reminder of just how strong hydraulic systems are.
 
Jetfixer75
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Joined: Sun May 16, 2004 2:21 pm

RE: Precautions 2 B Taken On Hydraulic Systems

Tue Jun 15, 2004 11:31 am

I have to whole-heartedly agree with MD-11 Engineer, you'll only do it once!!! Feel the pain of Purple Rain!!!!!OOOOOOWWWWWWW
 
MD11Engineer
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RE: Precautions 2 B Taken On Hydraulic Systems

Tue Jun 15, 2004 2:52 pm

When you are venting the head pressure of a hydraulic (skydrol) reservoir, place a cleaning rag over the vent hole (s). Skydrol vapour acts like teargas.

BTW, the washing your hands before also applies to composite repairs (itch!)

Jan
Je Suis Charlie et je suis Ahmet aussi
 
MD11Engineer
Posts: 13899
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RE: Precautions 2 B Taken On Hydraulic Systems

Tue Jun 15, 2004 3:01 pm

Keep a spare set of overalls and underwear in your locker in case you get drenched (applies to fuel as well, Jet A1 burns the skin just as good).

It happened to me during my apprenticeship. During an engine change on a B737-300 another apprentice and myself were ordered to disconnect the hydraulic lines on the pylon. The qualifieed mechanics told us that they had bled the head pressure, so only few ounces should drip out. When we disconnected thereturn line (actualy my buddy was doing it, I was holding a bucket to catch the spill), there came a fountain of skydrol out under pressure. Both of us got drenched to the skin, only the fact that I´m wearing glasses saved my eyes. The idiots had vented the reservoir alright, but they had pulled the fire handle BEFORE, trapping the pressure between the EDP and the shutoff valve in the wheel well.
Both of us had to take a shower, got issued fuel tank coveralls because we didn´t have any spare clothes and got sent home for the rest of the day.

Jan
Je Suis Charlie et je suis Ahmet aussi
 
kaddyuk
Topic Author
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RE: Precautions 2 B Taken On Hydraulic Systems

Tue Jun 15, 2004 8:09 pm

haha, I know a few fourth years who regulary get covered in allsorts, from chemical blue out of the toilets to fuel to purple rain.

They say its fun but it cant be surley...
Whoever said "laughter is the best medicine" never had Gonorrhea
 
MD11Engineer
Posts: 13899
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RE: Precautions 2 B Taken On Hydraulic Systems

Wed Jun 16, 2004 12:22 am

Blue water.... Fortunately I managed to avoid this until now (touching wood!). I remember a rampy though in SXF doing a big jump backward.
We were replacing a bulk cargo door seal on a DC-10. This guy was supposed to do a toilet service on the aft lav panel. The problem was that he pulled the toggle before he realised that there was a donut installed. So he called us and told us the lav service port was inop. We watched the whole thing, of course, and told him , since he had the proper tool on his truck, to f*ck off and do it himself.
Well, he disconnected the hose again, got the tool, and pulled out the donut while jumping back with a huge leap. He was licky he didn´t get drenched in sh*t!

Jan
Je Suis Charlie et je suis Ahmet aussi
 
RiffedAAMech
Posts: 48
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RE: Precautions 2 B Taken On Hydraulic Systems

Wed Jun 16, 2004 9:08 am

I have been doused with skydrol 2 times. The stuff really burns the skin and washing with water doesn't make it stop. I learned that if you pour milk on the area expose to the skydrol, the enzymes in the milk will stop the burning sensation. Sounds strange but it really works.
 
A/c train
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RE: Precautions 2 B Taken On Hydraulic Systems

Thu Jun 17, 2004 3:20 am

Although ive had some incidents with Skydrol, ''undercarriage changes when nights do the Hyd unions up at the top of the legs'' are interesting, they piss out everywhere. I'd have to say the worst system for smelling and getting covered from my point of view is Fuel, CFM-56's, draining the fuel out of bottom of the filter, comes out at huge pressure and emptys all the fuel in the pipe above, my tip, drop the bloody drain plug in the bucket!! i'll learn  Smile/happy/getting dizzy
But the worst is the Fuel flow governor on the RB211, when you've completely disconnected it, you pull the assy out of the gearbox, "this thing weighs 60 lb dry !!" then you have to lift the back end up and it is like a waterfall of fuel and I cannot think of a way when your doing it on your own which you cannot get soaked through with fuel. Good fun  Smile/happy/getting dizzy
 
MD11Engineer
Posts: 13899
Joined: Sun Oct 26, 2003 5:25 am

RE: Precautions 2 B Taken On Hydraulic Systems

Thu Jun 17, 2004 4:12 am

I had an (at this time inexperienced) colleague, who was sent to check on a loose fuel stick under the wing of a 747 classic. He pulled it out and discovered it was broken off. Now he stood for TWO hours on top of this ladder, sticking his finger into the hole, like the little boy in the Dutch story about the dyke, to prevent the fuel from leaking out and got completely drenched. It was in the middle of the night and he was alone on the ramp. After mentioned two hours another mechanic came to have a look where the f*ck this guy was staying.

You won´t feel Jet A1 on your skin at first, but after about 30 minutes your skin will turn red and start to itch. If you don´t wash off the stuff right away and put some ointment or skin lotion (I usualy nick some of my girlfriends stuff if I need it), your skin will seriously inflame and blister and it will look and feel like a real bad sunburn.

Jan
Je Suis Charlie et je suis Ahmet aussi

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