Unblocking a drain mast
 

How do you guys unblock a grey water drain mast?Which aircraft (Boeing,Airbus,Embraer) is the worst for clogging?What's your worst experience in dealing with drain masts?Love to hear your storys,also please include some pics

Boeing experience only
 

One of the most important tools is a 2 liter bottle of Coke. I also keep a 10' length of plastic-coated 1/8 inch cable to snake out the drain mast from the outside. Don't stand in line with the mast, last time I got a geyser of brownish cottage cheese.

Don't talk while you are clearing it either.

I have heard of the famous cottage cheese,was it in a 747 by any chance?The guys were almost sick when they smelt the cottage cheese.I can imagine that the smell of these masts must be absolutly awful.Amazing,there is a snake small enough to fit in the tiny holes of a drain mast.Do you get blocked masts mainly on bigger jets like the 747 or 777 or do the smaller ones like the Embraer E-Jets also suffer this?Sorry about all the questions but I find it all very interesting.Which jets out of Airbus,Boeing,Embraer,get the most problems with blocked masts?Worst story I've heard,a guy was working on a mast and someone up in the lav had a pee in the sink,;)

3000psi from an n2 rig attached to the mast normally clears it!:ok:
Mind you it'll take a few hours to clean all the galleys out.
If only the CC didn't put milk and red wine and coffee grains down the sinks in the first place.
Worst I've seen recently on a 744 was a total blockage of around 10 feet of drain line in the fwd cargo bay, ceiling panels down, lots of pipes out and half in dia steel rod, just about cleared it!

Boeing introduced the GWDU on B777 which has helped tremendously to prevent blocked drains.

Interesting stuff,are these masts hot on the ground as well as in the air?Hope they are not too hot,otherwise you guys get burned or do you wear special gloves?Have all aircraft got the same size holes in the mast or is there a difference?Love to see some photos of them.

'Boeing introduced the GWDU on B777 which has helped tremendously to prevent blocked drains'


Thank god they did that, er what is a GWDU :confused:

Galley Waste Disposal Unit.

Full Disclosure, I had to look it up in the Aircraft Maintenance Manual.

The toilet in the galley, connected to the toilet tank system

found a cap off the free tooth paste blocking the waste pipe once took couple of hours to clear with hold panels down and pipes out.
orange juice the type with the bits left in blocks pipes a treat.
a coat hanger wire up the drain mast often cured blockages

On the Boeings the masts are heated on the ground, but with a lower voltage than in the air, therefore they are hot they are not HOT. Don't know about Airbuses.

The incident I referred to was a 777. I took a pic of the resulting mess on the ramp, but it doesn't do it justice. 744s are also fun, in that there are about 9 different drains that lead to the forward mast.

Reminds me of something I saw in the 80s. CO had just gotten 4 A300s from Eastern, and I watched as some of their techs tried to deal with a blocked rear lav. Apparently they thought it would be a good idea to hook up an airstarter to the dump chute and give it a blast. They had a guy in the lav holding a blanket over the toilet (must have been junior). Long story short, I don't know what happened to him, but these aircraft had lav walls made of vinyl with holes about every 1/4 inch (for acoustic suppression?) and most of the holes were filled!

That sounds like fun!So the Trippie can be a messy baby too,:)I was enjoying a nice cottage cheese sandwich,whilst reading this but suddenly lost my appetite :yuk:
Any chance of that pic,cheers,now back to my sandwich!

ah.. you mean that over-engineered waste disposal unit which tends to break down a lot? Instead of coffee grinds, I'm sure the flight attendants are finding more solid things to dispose of, like coffee sachets and tea bags, which lead to even more serious blockages :}

http://t3.gstatic.com/images?q=tbn:A...l2wqAwh0Pj8M5A

http://t0.gstatic.com/images?q=tbn:A...c6miAttMsK6m-g

What's the diameter of the openings of these masts?The Airbus one looks tiny.The Boeing one looks so big in comparison.

The waste drain lines in Boeings are 1/2" ID, I believe, and you wouldn't want the outlet to be much smaller.

How about the Embraer E-Jets,are they prone to clog as well?Also why do some masts have two holes and others only have one?I had a look on a E-195 and I saw 2 openings in the mast,does she pee in stereo,:D

The answer is simple, big jets have more pax, more ditzy flight attendants, they serve much more food and drink & longer stretches of drain hose. On most e-jets you would be lucky to get a bag with a bottle of water and a packet of salty nuts in it.