Switch Tanks, Switch Tanks, Switch Tanks!

[eman1200]

After reading about everyone’s techniques, I must be one of the most conservative pilots on the planet.  I’ve always just noted that for most flights, roughly 95% are taken solo (and this stat holds true for many pilots).  Thus, W&B is not really an issue.  So, what, require for flight, variable can I affect the most to give myself the greatest odds of being able to use my options—fuel.  Outside of remembering the old saying “the only time you can have too much fuel is when you’re on fire,” I fly on the top half of the tanks (another old saying) and manage fuel based on time and flow.  If a person wants to experience what it feels like to starve an engine in flight, just turn the valve to the off position.  A tank doesn’t need to be dry to still learn how to respond to an otherwise startling moment.

I agree. While I wouldn’t fault someone for circling an airport and running a tank dry strictly as a test/practice, to strive to run tanks dry regularly is just not good advice, period. I urge new mooney owners/members not to listen to this advice, even if it comes from an “A-list” mooneyspace member. Don’t plan to do it. Plan to just barely not have to do it. Know your fuel capacity (this is where you ‘might’ consider initially running a tank dry but there’s still no need to do it), known your fuel burn under different scenarios (longer climb, unexpected headwinds, etc) and have a good tank switching plan and you’ll never have to run a tank dry. Don’t do it because SGOTI told you to do it. It’s a non event until it isn’t. Then you have to explain how you heard it on the internet and thought it was OK.

Be prepared for it and know how to do it but jeez, don’t make it part of your flight plan.

BTW I’m not going back and forth trying to justify my opinion. You go ahead and run your tanks dry, this is my stance and that’s all there is to it.

[gsxrpilot]

1 hour ago, eman1200 said:

I agree. While I wouldn’t fault someone for circling an airport and running a tank dry strictly as a test/practice, to strive to run tanks dry regularly is just not good advice, period. I urge new mooney owners/members not to listen to this advice, even if it comes from an “A-list” mooneyspace member.

Obviously the advice to run a tank dry at altitude periodically, isn't original with me. I was persuaded by many other much more experienced pilots/owners/instructors than I. And was finally convinced/persuaded/educated to the benefits and increased safety of this procedure by the gentlemen teaching the APS class in Ada, OK. Braly, Deakin, and Atkinson are all proponents of this procedure as well and some of the most knowledgeable piston single guys on the planet.

[Greg Ellis]

31 minutes ago, gsxrpilot said:

Obviously the advice to run a tank dry at altitude periodically, isn't original with me. I was persuaded by many other much more experienced pilots/owners/instructors than I. And was finally convinced/persuaded/educated to the benefits and increased safety of this procedure by the gentlemen teaching the APS class in Ada, OK. Braly, Deakin, and Atkinson are all proponents of this procedure as well and some of the most knowledgeable piston single guys on the planet.

And I am not saying that this is absolute but the recommendation for my C model to run the tank dry comes directly from the POH page 21 under fuel management.  Now I agree that this was from the 1960's and we don't do a lot of things like we did back then but I do follow this.  I also took the Advanced Engine management course from Braly, Deakin and Atkinson and their recommendation reinforced this procedure as well.  And there are many others that have given me this advice.  I am not saying it is right for everyone and people have their own level of comfort on how to manage their fuel but it works for me for what that's worth.  

[Skates97]

Just now, Greg Ellis said:

And I am not saying that this is absolute but the recommendation for my C model to run the tank dry comes directly from the POH page 21 under fuel management.  Now I agree that this was from the 1960's and we don't do a lot of things like we did back then but I do follow this.  I also took the Advanced Engine management course from Braly, Deakin and Atkinson and their recommendation reinforced this procedure as well.  And there are many others that have given me this advice.  I am not saying it is right for everyone and people have their own level of comfort on how to manage their fuel but it works for me for what that's worth.  

I agree, and it is right in the POH, and with the O-360 it is an absolute non-event. I'm not saying (nor the POH) take off on one tank, run it dry and then switch. In that case I don't know what the situation is in the other tank.

However, I start, taxi, run-up and take off all on the same tank. I fly on that tank for an hour and switch. If there's a problem when I switch I knew I can switch back and I have another hour and a half to get on the ground somewhere before running out of fuel. If all is good when I switch (it has been so far) I will fly on that tank until it's empty (if a long flight) or until on descent. I know when I switch back the fuel is good and will flow (at least that's the assumption having been using it for an hour on that flight) and I am going to be landing on the tank with most/all of my fuel in it. My personal minimum is to land with 10 gallons  on board. So far with 350 hours in my plane and 300 of that falling in the 50+nm cross country category I've always landed with at least 10 gallons on board. 

[Ibra]

48 minutes ago, Skates97 said:

I am going to be landing on the tank with most/all of my fuel in it. My personal minimum is to land with 10 gallons  on board

Whatever fuel management framework you use as long as you have more than 10USG in the current tank and 0USG in the other then you are doing it the right way, got caught once and found that flying with (8USG left, 8USG right) is worse than (10USG, 0USG) 

POH practice of running dry was in the days where fuel totalisers were not available but getting one tank empty to zero USG while there is plenty in the other is still a sensible thing to do... 

Edited March 11, 2020 by Ibra

[Skates97]

1 hour ago, Ibra said:

Whatever fuel management framework you use as long as you have more than 10USG in the current tank and 0USG in the other then you are doing it the right way, got caught once and found that flying with (8USG left, 8USG right) is worse than (10USG, 0USG) 

POH practice of running dry was in the days where fuel totalisers were not available but getting one tank empty to zero USG while there is plenty in the other is still a sensible thing to do... 

The EDM-830 I have is accurate enough to know within about 5 minutes when the tank is going to run dry. It is soon to be replaced by an EDM-900 along with the CIES senders which will provide even more accuracy. I will still plan to run a tank dry on long cross countries, not to know what is available as was the purpose the POH was addressing in 1965, but to have the most fuel in one tank when landing rather than split between tanks. As you said, having 10 in one and none in the other is much better than having your fuel split between two tanks.

[gsxrpilot]

My EDM900 and CiES senders are accurate to about 1 minute till empty. But things happen over a couple of hundred hours of flight time, so I like to verify them occasionally by running it dry in flight.

[carusoam]

Both logic and comfort prevail...

But...

1) Don’t leave a few gallons in one tank, then need it later...

2) Having old float sensors won’t allow you to know if that is five gallons left in both sides...

3) When you have a couple of gallons in one tank.... you will find that it is not enough to keep the fire burning when you point the nose downhill...

4) pointing the nose down hill... makes the fuel run away from the pick-up.

5) Short final silence... the sound of oops... 

6) switching tanks... the sound of hope this works...

7) a few seconds later... the sound of power returns...

8) it is a land now moment... you already proved to yourself how little you know about the fuel status for the rest of the flight...

9) I thought it was the most full tank... it wasn’t.

PP thoughts about a simple short series of maintenance flights in an M20C...

Best regards,

-a-

[EricJ]

Eons ago when I was learning to fly in Cessnas, it was pretty common practice, and taught, that if you were running tight on fuel and were uncertain of how much was left (since this was in the days before engine monitors and fuel flow gauges for GA), run it on BOTH for long enough to equalize the levels, which doesn't take very long, then switch to either L or R and start a timer.   When that tank is run dry, you know by the timer how much you have left in the other tank.

Can't do that in a Mooney, but in many high-wing airplanes it's a nice technique when needed.

[jetdriven]

Certain ones like the 177 and 172 had a equalizer tube between them.  So 3hr on the first tank wouldn’t equal 3hr on the second... because some fuel was transferred without the pilot’s knowledge.  But that a systems thing the pilot should know. It’s a good practice in general. 

[Shadrach]

On 3/10/2020 at 11:10 AM, Gagarin said:

There is floating debris that never get drained and can be ingested by the fuel pick up at low fuel levels. To avoid this at every annual remove the fuel tank drain valves and empty the tanks completely. 

Floating debris? Have you ever witnessed these debris? I have never seen floating debris in a fuel tank.  I  have seen sediment in the bottom but the pickup is more than an inch off of the bottom. There are three fuel screens between the tank and the injectors. I don’t see how much of anything in the way of debris makes it from the tank to the injectors. I’m sure it has happened, but the odds are very slim...

Edited March 12, 2020 by Shadrach

[Gagarin]

6 minutes ago, Shadrach said:

Floating debris? Have you ever witnessed these debris? I have never seen floating debris in a fuel tank.  I  have seen sediment andin the bottom but the pickup is more than an inch off of the bottom. There are three fuel screens between the tank and the injectors. I don’t see how much of anything in the way of debris makes it from the tank to the injectors. I’m sure it has happened, but the odds are very slim...

Flying bugs get inside the tank through the vent and die once inside, this happens when the plane is parked on grass.

[jetdriven]

1 hour ago, Shadrach said:

Floating debris? Have you ever witnessed these debris? I have never seen floating debris in a fuel tank.  I  have seen sediment andin the bottom but the pickup is more than an inch off of the bottom. There are three fuel screens between the tank and the injectors. I don’t see how much of anything in the way of debris makes it from the tank to the injectors. I’m sure it has happened, but the odds are very slim...

Don’t even bother debating factual info with him.  

Here’s some more factual info, we opened up Mooney 201 to reseal the right inner and middle fuel tank, no floating debris, no trash no water no anything really. Also, yes, the pick up is an inch off the bottom so you have to have a gallon of water in there before you start picking up something....I regularly run my cars down to a half a gallon of gas remaining as well, and it’s the same old story that running your tank low picks up stuff off the bottom when it’s a complete fabrication. It’s not even relevant.

[Shadrach]

12 hours ago, Gagarin said:

Flying bugs get inside the tank through the vent and die once inside, this happens when the plane is parked on grass.

Can you link a single incident of this ever happening....?

[Hank]

12 hours ago, Gagarin said:

Flying bugs get inside the tank through the vent and die once inside, this happens when the plane is parked on grass.

And bugs never fly above paved ramps, they stop at the edge of the asphalt . . . .

[Gagarin]

8 hours ago, Shadrach said:

Can you link a single incident of this ever happening....?

https://www.aircraftspruce.com/catalog/eppages/fuelscreen.php

Fuel flow to your aircraft's engine can be compromised by insects or debris entering fuel tank vents. This remove-before-flight Fuel Vent Screen prevents contaminants from obstructing or contaminating the fuel system. The attached foot-long, florescent, and weather-resistant reflective streamer stands out equally well in daylight or darkness under all weather conditions, so it won't be forgotten during your pre-flight.

 

Edited March 12, 2020 by Gagarin

[gsxrpilot]

12 minutes ago, Gagarin said:

https://www.aircraftspruce.com/catalog/eppages/fuelscreen.php

Fuel flow to your aircraft's engine can be compromised by insects or debris entering fuel tank vents. This remove-before-flight Fuel Vent Screen prevents contaminants from obstructing or contaminating the fuel system. The attached foot-long, florescent, and weather-resistant reflective streamer stands out equally well in daylight or darkness under all weather conditions, so it won't be forgotten during your pre-flight.

 

A solution looking for a problem... it's what marketing departments do.

[Shadrach]

11 hours ago, Gagarin said:

https://www.aircraftspruce.com/catalog/eppages/fuelscreen.php

Fuel flow to your aircraft's engine can be compromised by insects or debris entering fuel tank vents. This remove-before-flight Fuel Vent Screen prevents contaminants from obstructing or contaminating the fuel system. The attached foot-long, florescent, and weather-resistant reflective streamer stands out equally well in daylight or darkness under all weather conditions, so it won't be forgotten during your pre-flight.

 

Incident as in crash or engine stoppage.  A newgadget to solve a problem I don’t have is not really a convincing argument. I pulled and cleaned the gascolator screen over the weekend during annual. Nothing that makes it through that screen is getting lodged in an injector. It’s like fine steel panty hose. 

Edited March 13, 2020 by Shadrach

[MooneyMitch]

"It’s like fine steel panty hose."

That's kinda scary................. do those really exist ? 

[carusoam]

Matter of fact...

Parked outside @39N in NJ... a bug decided to take refuge in my co-pilot side tank vent...

Part of the pre-flight was to check it... nothing visible.

There was one hint though... when opening the fuel cap... there was a slight relief of pressure... sitting out in the sun, in a new to me plane... that was an oddity that should have scrubbed the flight (or found the bug)... it went unrecognized...

There is a very visible oil canning effect if the vent isn’t open....and a pretty strong vacuum to match...

The fuel pump keeps drawing fuel...

 

Briefly... it is a good idea to not have a clogged vent...

Once in 20 years isn’t terrible.

PP thoughts only, not a mechanic...

Best regards,

-a- 

 

[Shadrach]

7 hours ago, carusoam said:

Matter of fact...

Parked outside @39N in NJ... a bug decided to take refuge in my co-pilot side tank vent...

Part of the pre-flight was to check it... nothing visible.

There was one hint though... when opening the fuel cap... there was a slight relief of pressure... sitting out in the sun, in a new to me plane... that was an oddity that should have scrubbed the flight (or found the bug)... it went unrecognized...

There is a very visible oil canning effect if the vent isn’t open....and a pretty strong vacuum to match...

The fuel pump keeps drawing fuel...

 

Briefly... it is a good idea to not have a clogged vent...

Once in 20 years isn’t terrible.

PP thoughts only, not a mechanic...

Best regards,

-a- 

 

I don’t think you’ll get any disagreement that vents must be kept clear.

[kmyfm20s]

On 3/11/2020 at 9:57 AM, gsxrpilot said:

My EDM900 and CiES senders are accurate to about 1 minute till empty. But things happen over a couple of hundred hours of flight time, so I like to verify them occasionally by running it dry in flight.

I have the MVP-50 and the EI fuel senders which I have found to be very accurate as well. When calibrating your senders didn’t you have to put the 3 unusable gallons in first and start your calibration from there? When my gauge says zero I need to take note of the fuel quantity from the fuel totalizer to know when the tanks going to run dry. After 3 more gallons is burned off and when the fuel pressure starts getting erratic then I know I’m only a few drops of fuel from being dry. Most of the time I don’t want to stare at the monitor that long so I  just listen to the engine. This is the bonus 3 gallon or 15 minute benefit of running a tank dry.

[gsxrpilot]

8 hours ago, kmyfm20s said:

I have the MVP-50 and the EI fuel senders which I have found to be very accurate as well. When calibrating your senders didn’t you have to put the 3 unusable gallons in first and start your calibration from there? When my gauge says zero I need to take note of the fuel quantity from the fuel totalizer to know when the tanks going to run dry. After 3 more gallons is burned off and when the fuel pressure starts getting erratic then I know I’m only a few drops of fuel from being dry. Most of the time I don’t want to stare at the monitor that long so I  just listen to the engine. This is the bonus 3 gallon or 15 minute benefit of running a tank dry.

Yes, the calibration on the ground is one thing. And you do that by the book, including measuring and adding unusable fuel. But then I verify it in flight to know the actual numbers.

With the EDM900 as calibrated in my airplane, the gauge will X out when I have 1.5 gal of useable fuel remaining. This picture was prior to connecting them. I'll obviously never run both tanks dry at the same time .

 

The other fuel indicators such as USD, REM, and T to E, continue to count down/up.

But when I get the X on the nearly empty tank, I can watch the USD count reliably go up by 1.5 and then the engine will stumble.

[jetdriven]

On 3/11/2020 at 11:10 AM, Ibra said:

Whatever fuel management framework you use as long as you have more than 10USG in the current tank and 0USG in the other then you are doing it the right way, got caught once and found that flying with (8USG left, 8USG right) is worse than (10USG, 0USG) 

POH practice of running dry was in the days where fuel totalisers were not available but getting one tank empty to zero USG while there is plenty in the other is still a sensible thing to do... 

I don’t runa tank out of gas all the time, in fact very rarely. But I do like to land with the minimum of 10 gallons and that is in the tank that I’m using to land on. So, 15 gallons I may have a couple in the light side and 12 on the other, but the real safety factor here is having at least 10 gallons in one place. Yes, running a tank right now switching it is a slightly  elevated risk profile then running on on one tank forever, but it’s a lot less risk profile than landing with either 7 gallons in the tank you’re feeding from, or  three, you can’t really tell. A fuel starvation event near the ground, there’s a lot of risk. Much more than all those cumulative little times running  a tank empty In a controlled fashion.
Now here comes the naysayers, it’s dangerous, people have died,. (I can’t find one where someone deliberately ran a tank empty and crashed).  That’s their opinion and they’re sticking to it. But not based on fact, it’s based on feelings. 
I think it was George Braly at Oshkosh a few years ago. He had a heated discussion with a Baron friend about how running tanks dry kills people. He refused to do it. Absolutely refused. He was dead the next day. Pushed the range and ran a tank dry accidentally, crashed with fuel in the aux tanks. Some 421s have six tanks. So you leave 5 gallons in each aux and each locker tank  that’s 20 gallons of fuel not used. 20 gallons  not in the mains at landing   How is that safer? 
people say, well my bladder only lasts two hours, I never fly that far, all of that   And for some who depart and fly only on Gin-clear days and full 62-gallon tanks for a hamburger that’s 75nm away, carry on.  But a lot of use use the airplane to travel. Some of us only have 54 gallons, five hours at cruise, about ~750nm of range plus reserves. Skipping a fuel stop lowers risk too..2 landings and takeoffs instead of 3. But add an IFR alternate, the range gets short pretty quick. Unexpected headwinds. The destination gets bad, you go missed to your alternate. Now you’re flying an hour longer than planned, perhaps. Maybe your alternate is poor and you want another one. Planning the fuel quantity you want by speed management and  having it all in one place is good practice.  It’s a tool, a strategy. Like many other things   

 

 

 

 

 

[aaronk25]

Agree with all you said! I would like to know if you ever ran out one of the 747 engines .....I run one out frequently as well. Min 10 in a side after landing is my goal also.


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