Ever Run a Tank Dry In Flight

[phecksel]

I bet! Next time task the co-pilot to closely monitor the fuel pressure gauge instead of the clock. Lol

Jim

yea, that will work   Don't watch this guage instead of not watching that guage!

 

He was wide eyed as a newly minted pilot involved in his first race.  Funny thing, I had my fuel usage so closely calculated that the time I had planned to switch tanks was only 15 minutes earlier.  I landed with 45 minutes left.  Took 2nd place in that race... my nemisis couldn't be beaten, at least by me.  Funny side to that story, there was a manditory fuel stop, and everybody was waiting for the headwinds in the final leg to die down.  All of a sudden, I see my nemisis get up and walk out the back door to the FBO... hmmm wonder where he's going?  He was sneaking off to his plane.  I told my co-pilot, we're leaving right now and did the same thing   I asked later what caused him to leave, he said they were forcasting the wind speed to actually increase, not decrease... and they did too!

[John Pleisse]

That will serve you well until the unexpected happens. I would feel foolish totalling a plane or injuring passengers because I felt like I had to land a plane early thinking I had a dry tank when in reality I didn't. POH useful fuel vs actual can be very different and knowing the what the actual is can save your bacon.

I had an interiesting thing happen to me and lucky for me it was when I was shutting down my plane and I was on the ground. I turn my fuel selector to the off position when the plane sits. This particular time I turned it and it moved about an 1/8" and got stuck between the 2 tanks. In this position I was able to move it back enough to get it back to the right tank with a lot of force but it would move no further. If this had happen in the air I would be very happy to know my actual fuel available to plan for my safest option to land.

I have a brand new fuel selector valve and when I land and add fuel, I always find my fuel-used computations within a half gallon.....always. But again, this thread is repeating.... I see the same characters, using the same vernacular over and over again... I don't think, in anyone place, on planet earth, do smart grown men, pilots, all stand around and use the term "old wives tales" so much..... OWT......

[sleepingsquirrel]

 No way……last one I did I was hand flying and I gained 100'. I am serious, and if you have done a few you will know why 

 

If the A/P is on you will lose about 5 knots.

 

If you lose 5' maybe OK, but even 50' you are doing it wrong. 

 

KNOW YOUR AEROPLANE!! 

So ,do tell what is it that I did wrong?

[wishboneash]

I have the run tanks try many times. A non-event. 

[David Brown]

So ,do tell what is it that I did wrong?

You lost 500' 

 

I can't be sure exactly, but even if you had it trimmed out and it maintained an airspeed 500' must have been nose down pretty quick, the loss of power should only be sub 5 seconds.

 

Do you remember what you did?

[WardHolbrook]

For what it's worth, I have no qualms about running a tank dry in flight. With fuel injected engines it's simply a matter of watching for the fluctuation in fuel pressure then switching the tanks. I've never had an engine skip a beat doing it that way so no harm, no foul. Not all airplanes have fuel systems as simple as the Mooney. Some single-engine Pipers have 4 tanks and some Cessna twins have six tanks. If you don't run those tanks dry you end up with your reserve fuel spread out over 4 to 6 tanks, Think about it - if you've got an hour's reserve split between 6 tanks and you end up having to dip into your reserves for whatever reason you will have to switch tanks every 10 minutes or so. That's not something I'd be wanting to do while I was in the middle of diverting to an alternate. Do you honestly think that's a good idea? You need to have a fuel burn plan and that plan needs to provide for your reserve fuel to be in one location.

 

I've only run a fuel tank dry inadvertently once. It was in a Beech Sierra so the engine and fuel system was essentially that of a Mooney M-20E/F/J. That time, I did have to run the checklist to get a restart, but it did start. I learned my lesson that day about paying attention. 

[pinerunner]

Couldn't this be used as an argument against switching to the fullest tank for landing? I think if there's a good reason for not trusting that little lever 100% then straight to a good mechanic to check it out. It was standard to check the gascolator in the annual as I recall and I got the impression they're cheap (by GA standards) to rebuild.

[Shadrach]

If one tank has all of the remaining fuel, one can be sure the they are landing on the fullest tank. I'm in the "run dry" camp. However, I became accustomed to it as a kid flying long XCs with my Dad. I can understand how some might be reluctant to do it; for me it's a non-event as I've been in many AC that have burbled and came back to life.

[kmyfm20s]

Did my annual fuel tank check. In my plane (82J) everything was as advertised. 33.5 gals passenger side tank and the light went off at 2.7 remaining. 33 gals pilots side and the light went off with 3.1 gals remaining. The POH say total fuel 66.5 total 64 usable. The tank tabs for the 25 gal usable is the bottom of the hole and the tip of the tab was 25 total remaining(add .5 to passenger side).The guages are accurate on empty:) I took the time to calibrate a Skyhawk fuel dip tube nice to have.

[jetdriven]

Couldn't this be used as an argument against switching to the fullest tank for landing? I think if there's a good reason for not trusting that little lever 100% then straight to a good mechanic to check it out. It was standard to check the gascolator in the annual as I recall and I got the impression they're cheap (by GA standards) to rebuild.

Plan to have a ten gallon fuel imbalance at top of descent. Switch tanks there. Then proceed to destination and you dont have to fool with fuel tanks anymore. If you have to divert, then re-evaluate the fuel imbalance, perhaps run the lower tank a little lower if its not dry then switch at top of descent for the diversion destination.

[fluffysheap]

I run one tank dry occasionally, whenever I need maximum range and to calibrate the fuel gauges and capacity.  I definitely agree that it's better to have all the fuel in one tank, and thereby avoiding ending up with two gallons in each tank and not being able to trust either one.  Frankly, I get itchy with anywhere near the legal fuel minimums - with 70 gallons available and 10 GPH fuel burn, even counting fuel used in the climb I still have 6 hours of flight time with reserves.  And 5 gallons of fuel for reserve is barely a blip in the flight planning.  I usually prefer to land with 10 or more gallons aboard.

 

My procedure is simple.  Switch tank, boost pump on, boost off after the engine restarts.  No need to fiddle with prop, mixture or throttle.  Overspeed has not been a factor, at all (RPM barely changes throughout the whole affair) although I have a 231, so the power comes back a little more slowly as the turbo comes back to life.  The procedure in the POS for air restart is intended to cover a variety of situations and the full procedure isn't needed since you know exactly what is happening.  I find I don't lose much if any altitude although I might lose 10 knots or so for a moment.

 

I believe that LOP makes this procedure safer as the decline in fuel flow will move the combustion away from peak, rather than through peak, as the engine leans out.  But I don't think it matters much.

 

A few things that haven't been mentioned, at least this time around.

 

1) Once you run the tank dry, be sure, during the next runup, to turn the boost pump on and switch to that tank.  Otherwise, you may find there is still air in the fuel line, and when you next switch tanks, the engine will lose power.  It's extra fun if your next flight is a while later, so that you may have forgotten the tank was dry and not immediately realize what's going on.  Out of an abundance of caution, I would still take off on the tank that stayed full the entire time.

 

2) The low fuel lights behave differently in a descent vs. in level flight.  In level flight they come on with about 3-4 gallons remaining, but I find that when descending it's closer to 7-8.  It can make for a little extra entertainment if descending while low on fuel, only to have the light go out when you level out again.

 

3) Fuel tanks have the maximum amount of usable fuel when in level flight, so having one run dry will allow you to get every last drop of the fuel.  If you have two very low tanks, you might find that there's simply no fuel available from either tank in a climb or descent but with all the fuel in one tank you would still have some usable.

[Shadrach]

You bring up the point of fuel tank continuity. I think it's always a good idea to start on the tank opposite to the one you plan on taking off with. I like to start the engine and let all systems come on line, about a minute into taxi, switch to the tank I'll be departing on. Easy way to verify that both tanks are flowing as they should...