My experience running a tank dry.

[pa38112]

Originally Posted by togaflyer

Question...let say you were flying somewhere in a commercial airliner and all the engines went silent for a short perior of time. Then the Captain announces, "don't worry folks, we just ran our fuel dry in one tank. This is our normal operational procedure". Would you ever fly that airline again. Lots of things G.A. pilots can do that working professional pilots would never consider doing. Even though the risk appears minimal, aren't you creating the potential of a real emergency where one did not exist?

I have been on several commercial flights where the pilot came on the radio and announced that we were diverting to a different airport because we do not have enough fuel - the passenger response is the same as what you are questioning. There were people on those flights who will tell that story for the rest of their life - about how they almost ran out of fuel and that the airline should have put more fuel onboard before the flight.
How the general public reacts to aviation is really irrelevant. There is nothing unsafe with running a tank dry as long as you do not let the engine quit or the fuel system become air-bound. Given the reliability of fuel gauges in the GA fleet I think it is adding safety to keep your last fuel quantity in one tank rather than split between two tanks. Here is why:
A 45 minute reserve is 6 gallons. That means 3 gallons per tank, which is in the red on my fuel gauge. That makes my passenger and me more nervous than anything to see both tanks in the red. I would much rather land with 6 gallons in one tank than assuming I have 3 in each but not really knowing for sure. It is less likely to un-port, and if I have to go-around and get distracted there is a good chance of running the one tank out while low & slow and not focused on the fuel gauges. When I go to fuel power on a go-around and fuel consumption goes up to 16gph, that 3 gallons turns into a 10 minute fuel supply (assuming it is exactly 3 gallons to start with). What if I really have 2 gallons in the tank I am using and 4 in the tank I am not?

Many will argue that a 45 min reserve is not adequate, and I do agree; however there are times when you are racing weather and darkness and other factors where it is much safer to land with a 45 minute reserve than to land short for fuel and add an hour to your trip. In those cases I choose to have all of the remaining fuel in one tank.

[RogerG]

I was once right seat in a Bonanza over central CA when PIC ran tank dry. He switched tanks, and went to work on the wobble pump, we lost maybe 1500-2000', and got down to a few hundred feet over flooded rice fields, all aboard was tightening seat belts, when finally he got a restart. His comment was "I don't know why that happened, it has always restarted easy for me".

Note to Self - Avoid running tank dry.

[rv8ch]

Originally Posted by Sam Buchanan

It would be my luck that the only tank with gas left in it would have a plugged vent......

I don't run a tank dry.

That would be exactly my concern - or a bit of proseal clogs something, or whatever. While the risk of running one tank dry seems low, the reward seems lower.

[FORANE]

Put in a header tank and you can run both tanks dry routinely.
Seriously folks, you will never regret being too conservative with fuel planning.

[Ed_Wischmeyer]

If you've been switching tanks during the flight, why would you suspect that one tank suddenly would not feed? If that were a legitimate concern, then the only safe course would be to fly the entire flight on just one tank.

And as for the airline analogy... Jets have all kinds of automation in the fuel systems. By the way, back in DC-6/7 days, on very long range flights, they did indeed run the tanks dry in flight.

[RVbySDI]

Originally Posted by Ed_Wischmeyer

And let's face it, precise fuel management in an RV is more optimism than practice. Probably the best fuel burn numbers come from factory built airplanes with the same engine/prop combination, and that will give fuel burn per hour, but those numbers will need adjustment for climb, etc. And although RV tanks are relatively easy to fill completely, the wing ribs can act as air traps, so you may not get them exactly full.

Well, I am sure each RV is going to be different. Given that, I most certainly cannot agree with this as a blanket statement about all RVs. I have been flying my 9A since 2010. I have been religious about measuring and calculating the fuel quantity and fuel burn of every tank full of gas in those 7+ years (as a side note, I do this with all my ground vehicles as well). I have put thousands of gallons of fuel through the engine. Without question I can say that my GRT fuel totalizer is 100% reliable and valid down to the .1 gallon level. There has never been a moment in time when I did not know exactly how much fuel I have in the tanks, how much I had burned, how much was left to burn, and how much time was left before I needed to be on the ground. Thus, I have great confidence in relying on my fuel instruments to tell me what my fuel situation is at any given time.

Originally Posted by rightrudder

I'm a proponent of always having an hour's worth of reserve fuel!! Just simpler, with less that could potentially go wrong that way. My typical longer stints are about 3 hours, which leaves closer to 1.5 hours reserve.

Originally Posted by togaflyer

Question...let say you were flying somewhere in a commercial airliner and all the engines went silent for a short perior of time. Then the Captain announces, "don't worry folks, we just ran our fuel dry in one tank. This is our normal operational procedure". Would you ever fly that airline again. Lots of things G.A. pilots can do that working professional pilots would never consider doing. Even though the risk appears minimal, aren't you creating the potential of a real emergency where one did not exist?

Originally Posted by Flienlow

I only have 250hrs as a PP, but I fail to see the logic in A. having an engine stop mid flight and B.unbalancing the airplane. It makes no sense to me.

Originally Posted by RV8iator

In these United States of America, there is never a reason to run out of gas. Bad planning or bad decision making will lead to it. If you get into your last hour of flight and actually worry about making it home, that?s bad planning or decisions.
I?m not saying don?t run a tank dry but if you feel you have to to make it home safely, land and get gas.

My thoughts are reflected above. With full tanks I plan for an average fuel burn of 8 gph. with 36 gallons that equates to 4 hours. This is a conservative expectation but one that I believe will always allow me to land with fuel in the tanks. In the real world I average more like 7 - 7.5 gph. So even using the conservative choice of 7.5 gph, real world, that gives 4.8 hours of flight time. So planning for 8 gph should always provide for any deviation in climb or descent or other unforeseen issues.

The other issue that has been brought up by Flienlow is the balance of the airplane. With my 9A, if I allow one tank to burn down while the other remains full I have to deal with a noticeable imbalance of the airplane. By switching tanks every 30 minutes I keep the plane in trim at all times.

One last issue, I must always be cognizant of my passenger's needs and desires. She rarely will tolerate a flight leg longer than 3 hours. The longest she has endured has been 3.5 hours. At the speeds of our RVs, 3 hours flight time puts us about 500 statute miles away from our starting point. I don't know about where you live but for us, that places us in an entirely different world from our home world.

I do believe it of value to run a tank dry to examine the performance of the airplane. I do not believe it a prudent thing to do after testing as it only increases the risk factors of that flight whenever it is done. Once one knows the performance of the plane at its extreme limit, is it really necessary to always fly to that extreme?

Oh yes, one last thing, LIVE LONG AND PROSPER!

[RVbySDI]

Originally Posted by pa38112

I have been on several commercial flights where the pilot came on the radio and announced that we were diverting to a different airport because we do not have enough fuel - the passenger response is the same as what you are questioning. There were people on those flights who will tell that story for the rest of their life - about how they almost ran out of fuel and that the airline should have put more fuel onboard before the flight.
How the general public reacts to aviation is really irrelevant. There is nothing unsafe with running a tank dry as long as you do not let the engine quit or the fuel system become air-bound. Given the reliability of fuel gauges in the GA fleet I think it is adding safety to keep your last fuel quantity in one tank rather than split between two tanks. Here is why:
A 45 minute reserve is 6 gallons. That means 3 gallons per tank, which is in the red on my fuel gauge. That makes my passenger and me more nervous than anything to see both tanks in the red. I would much rather land with 6 gallons in one tank than assuming I have 3 in each but not really knowing for sure. It is less likely to un-port, and if I have to go-around and get distracted there is a good chance of running the one tank out while low & slow and not focused on the fuel gauges. When I go to fuel power on a go-around and fuel consumption goes up to 16gph, that 3 gallons turns into a 10 minute fuel supply (assuming it is exactly 3 gallons to start with). What if I really have 2 gallons in the tank I am using and 4 in the tank I am not?

Many will argue that a 45 min reserve is not adequate, and I do agree; however there are times when you are racing weather and darkness and other factors where it is much safer to land with a 45 minute reserve than to land short for fuel and add an hour to your trip. In those cases I choose to have all of the remaining fuel in one tank.

I understand what you are saying. However, I would contend that rather than using this philosophy of fuel consumption protocol in order to prevent such a precarious situation at the end of a long flight with little fuel left, I believe one should never plan a flight, or continue a flight, even unplanned, into that environment. In my world 6 gallons of fuel is way below my personal minimums. As stated in my comments in my previous post, anything below an hour reserve is going beyond the minimums allowed for a flight in my plane. There are more reasons to avoid the risks of running a tank dry than there are in running balanced fuel tanks within a planned fuel burn protocol.

[pvalovich]

I regularly fly my -8A from California to Pennsylvania and back normally with two fuel stops going east and three flying west.. Have spent a lot of time considering optimum fuel management based on my knowledge/experience with fuel burn and accuracy of fuel level readings (running on left tank, engine quits almost immediately at zero; right tank gives a few more minutes).

I'll burn the left tank dry (at altitude) and finish the flight on the right tank. I do not want to have to worry about fuel tank management in case of a problem/divert.

Not for everyone - but works for me.

[Sam Buchanan]

Originally Posted by Ed_Wischmeyer

If you've been switching tanks during the flight, why would you suspect that one tank suddenly would not feed? If that were a legitimate concern, then the only safe course would be to fly the entire flight on just one tank.

The reason it might not feed is the same reason the pitot got clogged with a bug wing while descending through a hole in the clouds.

Yeah, I know, it is a very small risk, but I can't figure out why I should ever run a tank dry. We do so much hand-wringing over how double and triple redundant our panels and electrical systems should be and then some want to remove all fuel redundancy by only having fuel in one tank. I don't get it.

Two hours is pretty much my personal endurance/comfort zone so fuel range just isn't an issue and the fuel computer and gauge on my plane have proven to be very accurate. But I realize there are some iron-butts out there that like to see how many hours they can sit in a small airplane....

[pa38112]

Originally Posted by pvalovich

I regularly fly my -8A from California to Pennsylvania and back normally with two fuel stops going east and three flying west.. Have spent a lot of time considering optimum fuel management based on my knowledge/experience with fuel burn and accuracy of fuel level readings (running on left tank, engine quits almost immediately at zero; right tank gives a few more minutes).

I'll burn the left tank dry (at altitude) and finish the flight on the right tank. I do not want to have to worry about fuel tank management in case of a problem/divert.

Not for everyone - but works for me.

What is different between left and right? Could you explain more about your procedure and your fuel system : carbureted/injected? How do you know when the tank is empty, ect.