Running a tank dry in flight

[WardHolbrook]

Quote: thinwing

I have noticed that every post on this subject assumes the engine completely quits...that is rarely the case...just run the tank down that you want and as your tank gets close to empty start monitoring fuel pressure.As the fuel level gets close to empty /usable fuel it will unport the fuel pickup but not totally...you will have plenty of warning by monitoring your fuel pressure guage...it will start to flicker and the engine will start to run rough if you wait to long,switch tanks at first fuel pressure fluctuation and with boostpump on the engine never quits completely...kpc

[WardHolbrook]

Quote: DaV8or

Avoid the whole problem and get a fuel totalizer system of some kind. I have one and it is reasonable accurate, therefore no reason to ever run tank dry. Keep some of your researve in each tank.

[jetdriven]

Then you can haveall your usable fuel and some of the unusable too.  In one tank where it can do the most good. Face it, if tyou have 8 gallons onboard, it might be 3 in one side and 5 in the other.  id rather have all 8 in one place.   

For the people who say "I'll never fly into my reserve fuel" it can all change with one missed approach, or holding into your destination.  Especially out west or in Canada, where the nearest airport with a low enough approach might be an hour away or more.

[WardHolbrook]

Quote: jetdriven

For the people who say "I'll never fly into my reserve fuel" it can all change with one missed approach, or holding into your destination.  Especially out west or in Canada, where the nearest airport with a low enough approach might be an hour away or more.

[gregwatts]

Quote: Shadrach

Greg,

While I do have a nice pair , I think you're somewhat overstating the matter... No one that I know of jumps in their plane without sumping the tanks for a 4.5hr Xcountry. Furthermore, no one I know of runs on one tank until it is dry without switching at least once. When I fly long XCs, I typically switch tanks several times befor a tank is run to exhaustion. There are so many other real concerns when flying small airplanes that randomely occuring inflight contamination or sudden blockage of an unopened tank, that I've already used twice in the last 2 hrs, is not near the bottom of the list...it is the bottom of the list.

The fuel system in a Mooney is just not as fragile as some are making it out to be, and I think that the stats reflect that reality.

Now back to our regularly scheduled "run a tank dry and die" narative...

[jlunseth]

George Braley talked about running a tank dry at the GAMI seminar, as no big deal and the best way to insure you get max range.  But he flies an NA aircraft.  As he described it, you will see a wobble in the fuel pressure (as someone else noted), and that is the time to switch.

Friends flew to Canada for a fishing trip some years ago.  Two aircraft, and they flew in formation.  One aircraft (NA) failed to switch tanks.  Pilot in the other aircraft said they reported trying to restart and nothing worked.  That plane is still in the bush somewhere in Can. to the best of my knowledge, if someone wants it, as I recall it is a nice Piper six place of some kind. 

I have an accurate fuel flow meter.  I have run tests on it myself, and when the engine has consumed 50 gal. it will report 50.1 .  I keep a written table of the fuel used out of each tank.  I will typically climb to cruise on a long trip, say FL200, and then switch.  I make a note of fuel used, and fuel remaining in the climb tank, and then switch.  I fly the rest of the trip, or most of it, on the new tank, and on a long trip I will fly that tank down to 0gal. indicated per the tank gauge.  Invariably, the flow meter is telling me there are two or three gallons left in the tank, and that is fine with me.  I then go back to the climb tank and if my fuel planning has been adequate, I have plenty of fuel in that tank to proceed to my destination and land.  In the event of emergency of some kind involving that tank, I have those other two or three gallons before I am toast.  In normal ops we get about 4:30 with a reserve left, and could probably squeeze 5:30 total out of the aircraft, but 4:30 gets you a long long way in a turbo, even if the winds are not friendly, so I have not seen the need to try squeeze every drop out.  Even I need a bladder break at that point, let alone my passengers.

I don't run the tanks dry because of the turbo.  Besides what I said earlier, and Paul said, the other problem with restarting a turbo is that if you are in the Flight Levels when the engine stops and you need to descend below 12k to restart, you are now restarting a very cold engine.  At a minimum you cannot power it up until you have warmed it up, and that will take some more altitude.  If you are over high altitude terrain you have put yourself in very perilous circumstances. 

I do want to try it some day though, just so I know exactly how good the gauges are.  But I think I will be over an airport and under 12k before I do.  I don't think it would be good in normal ops to do in a turbo.

[jetdriven]

Braley talks from experience.   And yes, I dont run it till it quits, I run it until fuel pressure fluctuates.

Perhaps your friends in the Six switched to the other tank which was also empty? I have flown plenty of PA-32 and those have 4 tanks.  Run 3 dry you got all your gas in one tank, instead of 3 gallons in each, you got 12 in one tank.

Excellent comment about turbos.  I wouldnt starve a turbo engine above 12k feet either.

The biggest risk in running a tank dry is overspeeding the prop when it surges to life about 3 seconds after you switch tanks.  Pulling the throttle and prop back prevents this.

Quote: jlunseth

George Braley talked about running a tank dry at the GAMI seminar, as no big deal and the best way to insure you get max range.  But he flies an NA aircraft.  As he described it, you will see a wobble in the fuel pressure (as someone else noted), and that is the time to switch.

Friends flew to Canada for a fishing trip some years ago.  Two aircraft, and they flew in formation.  One aircraft (NA) failed to switch tanks.  Pilot in the other aircraft said they reported trying to restart and nothing worked.  That plane is still in the bush somewhere in Can. to the best of my knowledge, if someone wants it, as I recall it is a nice Piper six place of some kind. 

I have an accurate fuel flow meter.  I have run tests on it myself, and when the engine has consumed 50 gal. it will report 50.1 .  I keep a written table of the fuel used out of each tank.  I will typically climb to cruise on a long trip, say FL200, and then switch.  I make a note of fuel used, and fuel remaining in the climb tank, and then switch.  I fly the rest of the trip, or most of it, on the new tank, and on a long trip I will fly that tank down to 0gal. indicated per the tank gauge.  Invariably, the flow meter is telling me there are two or three gallons left in the tank, and that is fine with me.  I then go back to the climb tank and if my fuel planning has been adequate, I have plenty of fuel in that tank to proceed to my destination and land.  In the event of emergency of some kind involving that tank, I have those other two or three gallons before I am toast.  In normal ops we get about 4:30 with a reserve left, and could probably squeeze 5:30 total out of the aircraft, but 4:30 gets you a long long way in a turbo, even if the winds are not friendly, so I have not seen the need to try squeeze every drop out.  Even I need a bladder break at that point, let alone my passengers.

I don't run the tanks dry because of the turbo.  Besides what I said earlier, and Paul said, the other problem with restarting a turbo is that if you are in the Flight Levels when the engine stops and you need to descend below 12k to restart, you are now restarting a very cold engine.  At a minimum you cannot power it up until you have warmed it up, and that will take some more altitude.  If you are over high altitude terrain you have put yourself in very perilous circumstances. 

I do want to try it some day though, just so I know exactly how good the gauges are.  But I think I will be over an airport and under 12k before I do.  I don't think it would be good in normal ops to do in a turbo.

[Shadrach]

Quote: gregwatts

I think you are assuming that nothing could ever go wrong. Good Luck!

[Shadrach]

Duplex Scribendi...

[Shadrach]

Quote: jlunseth

George Braley talked about running a tank dry at the GAMI seminar, as no big deal and the best way to insure you get max range.  But he flies an NA aircraft.  

[MARZ]

"Braley talks from experience.   And yes, I dont run it till it quits, I run it until fuel pressure fluctuates."

So how long does the pressure fluctuate prior to the engine quitting? 

[Shadrach]

Quote: maropers

"Braley talks from experience.   And yes, I dont run it till it quits, I run it until fuel pressure fluctuates."

So how long does the pressure fluctuate prior to the engine quitting? 

[WardHolbrook]

Quote: Shadrach

The earliest I've caught it is a needle diversion and then another in 10 sec then another in 5 sec soon followed by 2 or 3 needle fluctuations over ~3 second period and then it starts to sputter. When I see a diversion, I get ready to switch tanks, when I see the next diversion I switch tanks and hit the boost pump (it will restart without the boost pump even if the fire's out, but it will take longer). No pucker necessary... 

[thinwing]

And that 15 to 20 seconds is a lifetime!!!I believe the pilot missing all the fuel pressure fluctuations that occur well before any actual engine roughness or shutdown ,has other more serious problems such as whether he is still alive or not,LOLFor me its just good fuel manegement,I cant afford to restrict the range of my aircraft by keeping 45 min (15 gal for the Bravo)in a unused tank just because i am frightened of a sudden fuel selector malfunction.And as others who frequently manage longrange flight have stated...it really is a no brainer..the fuel needle fluctuates...dum de dum de dum..ho hum...reach down and switch the tank...believe me its not like having only 1 second to get the collective down for a heli autorotation after engine failure,...you really practically have all day!!!sinc kp couch

[carusoam]

Anybody see a fuel pressure gage in an Ovation? 

I agree with the ability and proper procedure of allowing one tank to go dry.  Everyone is using the fuel pressure as the final indicator prior to silent ops...

Unfortunately, I can't find my fuel pressure gage.  What choice do I have?  I have a low fuel indicator that comes on with about 6 gals. left, or the FT101 fuel flow gauge may get erratic? or I have silent ops.....

Best regards,

-a-

[Barry]

A NOTE:  ... actually, when switching tanks, I note the fuel consumed on my totalizer and keep a record. I really feel that the money I spent on the totalizer is one of the best investments I've made. As a side note, it is the 1st electrical instrument to fail should I have an electrical failure ... which gives it even more value!!  )

[Barry]

As far as the fuel pressure varying ... I was surprised at how long it will bounce before the engine stops. It is quite a good warning. I watch the totalizer and when I think it is getting close I spend more time watching the fuel pressure guage.

[b65cuda]

I just happened to run a tank dry moments before I was going to switch inbound for landing today. The engine definately lets you know somethng is up, and instantly I switched tanks and all was back to normal. Don't think I'll ever make a habit of it, and I'm sure it would scare the crap out of a passenger, but I'm glad I now have the exerience to know exactly how my plane reacts.

[DaV8or]

Quote: jetdriven

Then you can haveall your usable fuel and some of the unusable too.  In one tank where it can do the most good. Face it, if tyou have 8 gallons onboard, it might be 3 in one side and 5 in the other.

[WardHolbrook]

Quote: DaV8or

So, what's so bad about 3 in one and 5 in the other? If you're truley getting that close to fuel exhaustion, then run the tank with 5 in it dry and then switch to the one with 3. We already established that running a tank dry is a non-event and the fuel system is super reliable, right? IMO, if you're down to the last 3 gallons, that is an emergency. What I like about splitting the gallons up, is it can be a wake up call to when really decide it is an emergency. When the tank with 5 runs dry, that's a strong reminder from the plane that you're about to become a glider. If you drain a tank as a matter of routine, you're not going to get that reminder.

[jetdriven]

You may know you have 8-9 gallons on board, and that is a fine legal VFR reserve.  The average C-J Mooney can run for over an hour on that.  Without an accurate totalizer add a couple more for margin of error. The problem is that you cannot accurately know how many gallons are in each tank. The fuel guages both indicate empty or nearly so. So, you may guess its 3 gallons in the L and 5 gallons in the R.  It might be the opposite, or it might be 2 gallons in the L and 6 in the R.  You are now turning downwind with a tank that has 2 gallons in it rather than the 5. Ask Ross how it feels to run a tank dry on short final.  Better to do it controlled and at a higher altitude than near thge ground where you are dead.  If it was 7 gallons in one tank, then well, you could even make a "prolonged severse sideslip" feeding from the low tank and still be alright.

Its called fuel management. Half of all planes that crash from fuel starvation still have fuel on board.  Procedures.  Training. Proficiency.  Confidence. Knowledge.

[GeorgePerry]

Enclosed is what the MAPA pilot proficiency program has to say about fuel missmanagment.  I submit those who think letting a tank run dry are the future 7 percenters...

[WardHolbrook]

Quote: GeorgePerry

Enclosed is what the MAPA pilot proficiency program has to say about fuel missmanagment.  I submit those who think letting a tank run dry are the future 7 percenters...

[Shadrach]

Quote: GeorgePerry

Enclosed is what the MAPA pilot proficiency program has to say about fuel missmanagment.  I submit those who think letting a tank run dry are the future 7 percenters...

[FAST FLIGHT OPTIONS LLC]

I guess the real issue here is "personal minimums" I don’t like to see the needles go to less then one quarter of a tank on either side.  That's just me and what I feel comfortable with when I'm flying me and my family and friends around. FUEL+ ALTITUDE = OPTIONS so I always like to have plenty of both whenever possible.  I realize this might not be the right answer for everyone but it's what works for me.