Denver

In my meager time flying King Air 200's but my long time flying lots of other aircraft I cant for the life of me figure out why so many different pilots and operators refuse to sump their tanks on the first flight. The saying allways goes: "Maintenance always does this because the drains get stuck and you will spill fuel all over the ramp". Like us pilots are to stupid to figure out how to get the drain unstuck. I have had this happen lots on piston aircraft and by gently ramming the drain in a rythmatic fashion with the plastic stickie uppie thinghie comming out of the fuel capturing device while singing the alphabet I have always been able to get it to close.

So whats the deal with this superstition like its going to summon the 4 horsemen of the apocalypse or something. Oh and I never seem to see this mythical maintenance man show up before each flight to drain the tanks either. Perhaps it gets done during the phases if they remember it? Are we all above "sumping" now that we have moved up from those meager piston bangers? Don't want to get any Jet A on our shiny black shoes?

I seem to recall a fatal King Air 200 crash out of KLGB because of water in the tanks and a cry of the surviving pilot that said "Maintenance is supposed to do that" to the NTSB. I wonder if he sumps his King Air tanks now?

Dufur2003

If you have never had a sump not close off on you that is very surprising. I have had gallons of 100ll pour out on me and the ground before I finally found a new sump plug to put in and stop the leak. Also, Jet A mixes more with water than 100ll does with water. So say you sumped right after fueling then you would probably see that no water was present but in reality there might be.

Thedude

How often does your airplane fly?

If it flies at least one day a week, I do not recommend sumping the tanks on a turbine aircraft. You are just asking for one of the drains to stick open.

If you suspect fuel contamination, then sump it.
If it makes you feel better, then sump it.



Next up, engine covers and 135.

bbrunton

Unless the aircraft has been sitting motionless for several hours you will not get any water out even if it is in there. It takes several hours for the water to settle.

Pulling the aircraft out of the hangar, or letting it sit on the ramp with a breeze blowing will jostle the aircraft enough to redistribute the water into the tank and you will not be able to drain any water.

If you let the aircraft sit motionless overnight in the hangar, then you will be able to drain the tanks and get the water out. But don't open the door and go up the airstairs to get the drain tool. That will be enough movement to redistribute the water.

When you drain, be sure to start with the highest tank in the system and work your way down to the lowest tank drain.

Any way, for small amounts of water the engine will not notice. Ice is not really a problem either as the King Airs have an oil to fuel heat exchanger to raise the temperature of the fuel to about 70 to 90 degrees so it always has the same density and that will melt any ice.

For other contaminates be sure to drain the strainer at least before every flight.

That is what I have always been told, and I have told others over the years.

Bill

FlyerJosh

I once thought this. Then I saw a demonstration with Jet A and water in a mason jar at FSI Wichita. Although water doesn't "fall out" as quickly as it does with 100LL, it does separate about as quickly as vegetable oil and water. Less than 5 min after shaking the jar, you could see a definable line of separation.

Denver

I agree, Jet A weights 6.7 lbs per gallon, 100LL weighs 5.8. Water weighs about 9 lbs per gallon. Jet A and 100LL are much closer in density than any fuel is to water. I will need to do this experiment myself but I am willing to bet pulling the airplane out or walking up the air stair would not disturb the water in the slightest. Refueling however most definitely would but probably would come out of solution much quicker than we think.

Beechcraft says drain the sumps before first flight each day.

NTSB Releases This Grim, Detailed History Of Fatal Flight That Killed Tom Dean, Mark Bixby & Jeff Berger & Two Others

The King Air that crashed at Long Beach may or may not have been caused by water in the fuel tank. One interesting note in this article is that witnesses heard some "popping" accompanied by white smoke puffs from the engines. This would be indicative of a power interruption and subsequent attempt for the autoignition in trying to relight the engines. It is suspected that water could have caused the power interruption. The accident airplane flew allot in the months before the crash and the pilot never drained the sumps. It was said that maintenance was in charge of that.

JohnBurke

Entrained water can stay suspended in turbine fuel for a long time, especially after fueling. This, despite what you think you saw in the mason jar.

When was the last time any of us in a 747 or 737 walked around the airplane with a little plastic cup, sumping something? Never?

If one has never had a fuel drain stick open and refuse to close, one hasn't been flying or sumping very long, and doesn't understand the construction of the drain valve very well. It's very possible for a drain to stick open and not close at all. This, despite the "expert" pilot who keeps stabbing it with his Jr. Fuel Tester.

Checking fuel is a pilot job, not a mechanic job. A turbine airplane is not the same as a piston airplane, however, and if you're carrying your piston habits and know-all with you, you may yet have a few things to learn.

FlyerJosh

Eh. YMMV.

Yes. it can stay suspended, but some will also fall out within 10-15 minutes. That which accumulates overnight, isn't likely to be resuspended through a smooth push/tow or boarding the plane.

Comparing a 747 or 737 engine to a smaller turbine (such as those on the Citation Mustang, King Air, or other smaller turbine aircraft) isn't exactly a fair representation. A 1/4 cup of water per gallon in a PT-6 burning a gallon a minute is a lot more likely to cause issues than in a larger turbine burning 5-10 times more per minute.

For the record, we regularly sump fuel at our operation- at least once a trip (initial mx preflight before leaving home). Fuel is also sampled on the road either from the aircraft or the fuel truck as necessary when on the road, but with the exception of longer flights, we often tanker enough fuel from home to make the round trip.

727gm

I know that many pilots don't want any smell of Jet A in the airplane from the fuel sampler or rags, as it doesn't evaporate away as fast as avgas, consequently will use any excuse not to sump. Letting passenger "comfort" dictate over safety.

I remember having the fuel gauge indication on one 727 fuel tank in Hawaii keep jumping up and down by 1000 lbs..... the lead mechanic told the other mechs "have you guys been sumping this thing? Go do it now"... sure enough, 15 or 20 gallons of water.

8ballfreight

We don't sump our 99s.