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  #1  
Old 12-10-2021, 08:45 AM
PilotjohnS PilotjohnS is offline
 
Join Date: Jan 2016
Location: Southwest
Posts: 2,164
Default Low Fuel Landings

I am about to fly my 9A.
Just curious the procedure for landing with low fuel after a long cross country.
6 gals is still about 45 mins of reserve, so it is possible to be landing with only 6 gals left in one tank.
If I forward slip, or land wing low, due to a cross wind, am I at risk of uncovering the fuel pickup?

Or does a low fuel approach require a different landing technique?
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WARNING! Information presented in this post is my opinion. All users of info have sole responsibility for determining accuracy or suitability for their use.

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  #2  
Old 12-10-2021, 09:05 AM
fixnflyguy fixnflyguy is offline
 
Join Date: Jan 2006
Location: Winston-Salem, N.C.
Posts: 1,531
Default What I did

There has been much talk on this over the years, and though I built a -4, the scenario is the same. Since configurations of pick ups can differ slightly, while your in Phase 1 and have got comfortable with all the "normal" stuff, Plan a flight to fuel starvation on each side, leaving the other near full. Not saying you need to actually make it quit, but get it very low on the fuel quantity and set a hard deck at 3000AGL or so and simulate the landing/slip/skid/ AND go-around configuration. Next flight, do the opposite tank and you will know exactly where it looses fuel pressure, ect. I would not just trust another's opinion and hang your hat on it. Its a simple test flight procedure that will cure most fear of where you become a glider.
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  #3  
Old 12-10-2021, 09:09 AM
mulde35d's Avatar
mulde35d mulde35d is offline
 
Join Date: Dec 2017
Location: Clarksville, TN
Posts: 284
Default

Just some basic thinking through of you're fuel system really should provide your answer. Determine where your fuel pickup is located. If you have an out of balance condition where the normal force on your fuel could cause it to move away from the pickup (think an out of trim condition), then yes you could starve the engine. Also consider how much fuel you burn and the length of the fuel line in regards to how long after the out of balance condition, could result in loss of fuel at the engine.

Generally speaking, a level and in trim flight attitude is best in a low fuel situation. However, so many variations exist in experimental aircraft that you must evaluate your fuel system individually.
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  #4  
Old 12-10-2021, 10:32 AM
A2022 A2022 is offline
 
Join Date: Apr 2011
Posts: 2,425
Default

yep, in trim is the best condition for low fuel condition. do a complete checkout of the fuel system to understand the real fuel exhaustion limit. I always land with at least 1 hr remaining in the tanks.
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  #5  
Old 12-10-2021, 10:49 AM
Avanza Avanza is offline
 
Join Date: Jul 2020
Location: Vastervik Sweden
Posts: 137
Smile Low on fuel

A long trip usually means that tanks are filled up to the top before take off.
What I would do, on the next long trip, keep track of the time and run one of the tanks close to empty. You will hear the engine begin to stumble.
Switch to the other tank and note the flight time for running it to empty.
Then you get a good sense of the time to empty one tank.
The important thing is to keep track of estimated remaining minutes before
engine quits. Running low on fuel is an emergency.
You typically arrive at higher altitude than normal beeing prepared for an
engine out landing. Knowing your plane and what to expect keeps the stress factor lower. It is important to use all fuel you have available.
Running a tank allmost empty is not dangerus at altitude.
Switching tanks at 500 ft is dangerus.

Good Luck.
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  #6  
Old 12-10-2021, 11:30 AM
rocketman1988 rocketman1988 is offline
 
Join Date: Jun 2010
Location: Sunman, IN
Posts: 2,963
Default ...and

"...Switching tanks at 500 ft is dangerus..."

Not as dangerous as running out of fuel at 500 ft!

It is all about risk mitigation.

Oh, and there is NO EXCUSE for running out of gas in an airplane.
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  #7  
Old 12-10-2021, 11:51 AM
DaveO DaveO is offline
 
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Location: Greenfield, IN
Posts: 378
Default

Why run your tanks low to begin with? Fuel exhaustion is without excuse in our country. Why risk it for any reason. Loss of life, or bending of a good airplane.
Do not do it!!!!!
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  #8  
Old 12-10-2021, 11:57 AM
BobTurner BobTurner is offline
 
Join Date: Dec 2011
Location: Livermore, CA
Posts: 8,159
Default

1. These days, with so many having adsb data, you may be able to check the wind at your destination prior to the last tank change. Plan to arrive with most of the gas in what will be the raised wing in a slip.
2. Just fly in a crab until the flare, then transition to a slip. If the engine quits, youíre ready to land anyway.
3.+1 on othersí, donít run out of gas. This all to common occurrence is almost always pilot error.
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  #9  
Old 12-10-2021, 12:17 PM
Low Pass's Avatar
Low Pass Low Pass is offline
 
Join Date: May 2006
Location: Houston
Posts: 2,129
Default

Quote:
Originally Posted by PilotjohnS View Post
I am about to fly my 9A.
Just curious the procedure for landing with low fuel after a long cross country.
6 gals is still about 45 mins of reserve, so it is possible to be landing with only 6 gals left in one tank.
If I forward slip, or land wing low, due to a cross wind, am I at risk of uncovering the fuel pickup?

Or does a low fuel approach require a different landing technique?
All RVs are slightly different from one another. Some more than others. You need to know how yours behaves. Yes, fwd slip may quite likely unport the fuel pickup (if the high tank is selected). The lower the fuel level and more extreme the asymmetry, the more likely the unport. Are both low? No fwd slip, or be prepared for it to quit.


Quote:
Originally Posted by fixnflyguy View Post
There has been much talk on this over the years, and though I built a -4, the scenario is the same. Since configurations of pick ups can differ slightly, while your in Phase 1 and have got comfortable with all the "normal" stuff, Plan a flight to fuel starvation on each side, leaving the other near full. Not saying you need to actually make it quit, but get it very low on the fuel quantity and set a hard deck at 3000AGL or so and simulate the landing/slip/skid/ AND go-around configuration. Next flight, do the opposite tank and you will know exactly where it looses fuel pressure, ect. I would not just trust another's opinion and hang your hat on it. Its a simple test flight procedure that will cure most fear of where you become a glider.
Very good suggestion. But why leave the other side near full?? Enough to assure you can get the plane safely down at the intended airport should be sufficient. All performed over a suitable runway, of course, run one tank empty. See what it takes to get the engine running smoothly again. See what the level and pressure gauges says when it begins to loose fuel flow, and note what the instruments and engine actually do during and just prior. Resistance float type level systems are extremely inaccurate at the low end of the scale. Of course, if you're not at a point with your RV handling skills to safely manage a dead stick landing should it be required, wait until you are. Knowing these things about your plane will allow you to comfortably and more safely enjoy long distance travelling, or those instances where you need to stretch for an unforeseen event.
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Last edited by Low Pass : 12-13-2021 at 11:24 AM.
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  #10  
Old 12-10-2021, 03:06 PM
Flying Canuck Flying Canuck is offline
 
Join Date: Jan 2015
Location: Red Deer, Alberta, Canada
Posts: 614
Default

The 9A fuel tanks (mine at least) are angled to the root such that the fuel reaches underneath the filler in around 5 gallons. Really hard to verify fuel levels below that. If both tanks are at 5 gallons, I have a little better than an hour of flight time left and I usually avoid burning that hour of fuel. My fuel senders are moderately reliable but will fluctuate on the bottom end when wings aren't level. Pretty safe to say that 3-5 gallons won't un-port at any normal flight attitude like +/- 30 degrees bank. Just a question of enough margin of error based on your fuel reporting method.

I've got my fuel system set in litres as that is how I buy it, I have my PFD annunciate tank switches every 15L (~25 minutes). When I fly cross country I count tank switches so I have that situational awareness. If I approach an airport with either of my tanks showing below 15L (4 gal) I'll pick the fullest tank but I don't really give any thought to the direction of turns or slips. I just stay away from stretching legs into that last hour of fuel.

Practically speaking, my personal endurance is only about 3 to 3-1/2 hours, I don't plan longer legs than that. I use 4.25 hours range (less reserve) for trip planning so that works out great. The only time I fly with less than an hour of fuel is if I'm doing the 15 minute hop up to the airport where I buy my fuel. Flying with low fuel is simply too risky and completely unnecessary.

Now IFR fuel planning is a different beast, especially in parts of this country where airports can be 100NM or more apart. Alternates are also mandatory in Canada. Practical range can be as low as 2 hours.
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