How long before water settles to the bottom of the tanks?

Once you're HAPPY, don't get SAD!

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Destruction
 
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OK, so...

Avgas has a density of 690kg/m3, water has a density of 997kg/m3. So, for a given volume water is about 44% heavier than gas. So it would sink fairly quickly, but not like a rock. I was told 15min after fueling when I was in primary training.
 
Since there's been a bit of thread draft from water to check lists, let me add this. My Lear jet mentor taught me to check the "things that can kill you on take off" before crossing the hold short line. In that plane it was flaps, trim, controls, spoilers. I found it good advice to have such a list of any plane I've flown.

By the way IHA.

I hate acronyms.
 
One time I was waiting for a rental cherokee to come back from an instructional flight so I could go wreak some havoc in the skies. I waited for the guys to park and get their stuff, then I started my preflight. I sumped 100% water out of one tank. Couldn’t believe it. Sumped again, 90% water. Sumped again, about 60% water. Took it over to the guys that just brought the plane back, the instructor of 50 years was in shock, he said he was 1000% positive he watched his student sump the tanks. We kind of sort of laughed about it as I dumped the water back in the tank where it belonged and hopped in for my flight of chance. We were all a bit baffled that day.
 
I think I heard 30 minutes somewhere, pretty sure its faster than that. In the military we would fuel the night before and sump in the morning in quart jars, one jar per point. The couple times I saw water, if I shook the jar hard enough the globes of water would break into very small balls almost disappearing. They would separate back out in less than 5 minutes in JP-8. I think water that all of a sudden shows not right after fueling up is stuck on a ridge or some thing in the tank the same way fuel can get trapped if a bladder gets a crease or folded. It could also be water condensing out of any air in the tank if it went from real humid and hot to real cold.
 
teejayevans said:
Do you really need a memory aid to remember how to takeoff?
I never forget that I had to pitch up to get the plane flying, that’s instinctual.
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Considering how many accidents you hear about when professional pilots forget to check that their ailerons are free, take off on the wrong runway, or stall on takeoff, my answer is yes—I’ll take all the help I can get.

I don’t want people reading about my accident and wondering how I could do something so dumb.
 
LongRoadBob said:
Thank you for that information. It was helpful. I wasn't aware of the different types of contaminant water, until now. Good info.
I've thought about doing that. I wasn't sure if it was allowed by the club. I believe I could make a better checklist, as there re definitely mistakes in the club checklist, but I also see that some of them could be be cue of the possibility of a pilot coming from a different place. Such as, the after takeoff checklist includes "check/set flaps up" which makes no sense from takeoff (we don't use flow) but make sense if T&G or short takeoff. I realize I don't know all the circumstances that can happen, and that one can come into a subset of the checklist from another point.
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One of the things I do, and get my students to do, is to make a condensed checklist, using the official flight manual as a guide. I never liked those multi page laminated sheets you find in most airplanes. A single postcard size sheet with the essential elements is far more useful. Even in complex airplanes you can condense the information.
 
sarangan said:
One of the things I do, and get my students to do, is to make a condensed checklist, using the official flight manual as a guide. I never liked those multi page laminated sheets you find in most airplanes. A single postcard size sheet with the essential elements is far more useful. Even in complex airplanes you can condense the information.
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This, I use a 8x11 laminated sheet which I can read without my glasses, has everything including emergency procedures, IFR checklists, speeds, etc. Key things I highlight.
You can customize it, for example my hot start procedure first item is: fuel receipt.
 
sarangan said:
One of the things I do, and get my students to do, is to make a condensed checklist, using the official flight manual as a guide. I never liked those multi page laminated sheets you find in most airplanes. A single postcard size sheet with the essential elements is far more useful. Even in complex airplanes you can condense the information.
Click to expand...

I've taken the advice here, making my "own" checklist, but making sure I include all from the clubs checklist. just in a different order in cases where I KNOW for sure the order is not crucial.

Before engine start checklist for example, made no sense to me, as it "jumped around" with things like mixture, tank selector, fuel "cutoff", etc....I think logically so it makes sense for me to check tank selected-both, fuel cutoff (for me "OFF" since it is not cutting off fuel, fuel is enabled) then mixture and then throttle 1/4" open, then master and check fuel gauges, etc.

So tank (source, through cutoff valve, through mixture to throttle "desitination") "makes sense" to me.

I do wonder about one thing. When we first taxi the checklist just before has us lean the mixture. But on ground check, we set it full, and no item for leaning again, yet we are going to taxi (if the southern facing RWY, for a while too) again, should the mixture be leaned again after ground check? (also is ground check the same as some call "runup"?).
 
teejayevans said:
This, I use a 8x11 laminated sheet which I can read without my glasses, has everything including emergency procedures, IFR checklists, speeds, etc. Key things I highlight.
You can customize it, for example my hot start procedure first item is: fuel receipt.
Click to expand...

Fuel receipt? :)

You mean on engine fail the first item is "check if I bought fuel" ?

I know, I'm missing something (or misunderstanding "hot start") or else it was spell check. I just like the idea of "damn, did they cheat me?? Says here I bought 14 gallons of fuel, boy are THEY in trouble!"
 
LongRoadBob said:
also is ground check the same as some call "runup"?
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Depends. What happens during the ground check? If you're running the RPM's up, doing mag checks, carb heat checks (if equipped) and prop control checks (if equipped), then yes. If ground check is simply checking that the controls are free and control surfaces are moving correctly, or if its some other kind of check, then no.

As for whether or not you lean again after the runup, again it depends. Generally the runup is performed near the take off end of the runway so I probably wouldn't bother to lean again afterward. But some with some runways at some airports, the runup is done further from the take off runway entrance. In that case the answer again depends. If you lean again to continue taxi, are you 100% sure you'll remember to go mixture rich before full throttle? If so, leaning again is probably ok. If not, staying full rich is probably the better bet. Others will surely correct me if I'm wrong but I doubt you're going to foul anything all that bad in a minute or three of full rich taxiing.
 
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LongRoadBob said:
When the CFI is telling me "just follow the checklists!" and yet the list has one setting the parking brake before start, but then before taxi, not releasing it, etc. it bugs the programmer in me.
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I guess I can't be in the club! I never use parking brakes... I saw a Luscombe flip over on landing because he forgot to take off the parking brake. In fact, in a lot of tailwheel airplanes I've flown, the cable has been disconnected!
 
LongRoadBob said:
Fuel receipt? :)

You mean on engine fail the first item is "check if I bought fuel" ?

I know, I'm missing something (or misunderstanding "hot start") or else it was spell check. I just like the idea of "damn, did they cheat me?? Says here I bought 14 gallons of fuel, boy are THEY in trouble!"
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I usually only hot start after refueling, and I would leave the fuel receipt, now I don’t.
 
Lowflynjack said:
I guess I can't be in the club! I never use parking brakes... I saw a Luscombe flip over on landing because he forgot to take off the parking brake. In fact, in a lot of tailwheel airplanes I've flown, the cable has been disconnected!
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How did he takeoff?
I couldn't imagine setting the parking brake in the air...
 
Juliet Hotel said:
Depends. What happens during the ground check? If you're running the RPM's up, doing mag checks, carb heat checks (if equipped) and prop control checks (if equipped), then yes. If ground check is simply checking that the controls are free and control surfaces are moving correctly, or if its some other kind of check, then no.

As for whether or not you lean again after the runup, again it depends. Generally the runup is performed near the take off end of the runway so I probably wouldn't bother to lean again afterward. But some with some runways at some airports, the runup is done further from the take off runway entrance. In that case the answer again depends. If you lean again to continue taxi, are you 100% sure you'll remember to go mixture rich before full throttle? If so, leaning again is probably ok. If not, staying full rich is probably the better bet. Others will surely correct me if I'm wrong but I doubt you're going to foul anything all that bad in a minute or three of full rich taxiing.
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Yes on the first...I was pretty sure but not totally. Yeah, mag check, etc.

On the other, we have it on the before takoff checklist, to full rich on mixture. Then again, if it doesn't make a big difference for engine life, spark plug condition,then I may as well leave it on full rich after runup. Thanks.
 
LongRoadBob said:
On the other, we have it on the before takoff checklist, to full rich on mixture. Then again, if it doesn't make a big difference for engine life, spark plug condition, then I may as well leave it on full rich after runup. Thanks.
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Well I think its important to keep a couple things in mind about checklists. They're not foolproof. They only work when people use them and like it or not, people don't always use them.

So when you consider that fact, you realize that checklists often get into the realm of understanding the divide between the world we would like to exist and the world that actually exists. And its precisely because of that divide that we end up with things of checklists which we don't always understand or which don't always make sense to the computer script/logic programmer in us.

Full rich before runup and not leaning again after for taxi to takeoff is the lessor of two evils. Because even though we put full rich on the pre-takeoff checklist just in case, we're realistic enough to know that often people won't actually use that checklist. And thus in the end its much better and safer to do the final taxi full rich than to try to take off with a too lean mixture. So yeah, lean after runup is fine, but ONLY if you're 100% sure you won't have a brain fart at the threshold and try to firewall the throttle with the mixture knob still back a bit.
 
Juliet Hotel said:
Well I think its important to keep a couple things in mind about checklists. They're not foolproof. They only work when people use them and like it or not, people don't always use them.

So when you consider that fact, you realize that checklists often get into the realm of understanding the divide between the world we would like to exist and the world that actually exists. And its precisely because of that divide that we end up with things of checklists which we don't always understand or which don't always make sense to the computer script/logic programmer in us.

Full rich before runup and not leaning again after for taxi to takeoff is the lessor of two evils. Because even though we put full rich on the pre-takeoff checklist just in case, we're realistic enough to know that often people won't actually use that checklist. And thus in the end its much better and safer to do the final taxi full rich than to try to take off with a too lean mixture. So yeah, lean after runup is fine, but ONLY if you're 100% sure you won't have a brain fart at the threshold and try to firewall the throttle with the mixture knob still back a bit.
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If you lean aggressively, then you can’t forget to go rich on takeoff, because the engine will stall as you try to go full throttle.
 
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