Ed Cesnalis Posted September 6, 2013 Report Share Posted September 6, 2013 I was negative on recent arguments on flying CTs heavy. After reading this from a new CT pilot on another forum I would rather see him fly with full tanks. This is a serious flight and fuel starvation at the Vegas end would be really bad. In a flight just completed the sight tubes in the CTLSi appears to show 19 gallons, more than enough for a flight from Carson, Nv to N.LasVegas, Nv... Mogas is not colored so ya gotta look carefully to make sure. Well, guess what? There was only 13 gallons, and we had a fuel emergency just short of the airport. Luckily there is a new header tank in the CTLSi that has 1.1 gallons of useable. We found out that stretched at 4000rpm to get the last 50 mi to the airport and a slipped landing from 3k feet over the runway. The extra height allowed for a possible engine out glide landing. I wonder what happened to the great economy the CTLSi gets? Link to comment Share on other sites More sharing options...
FlyingMonkey Posted September 6, 2013 Report Share Posted September 6, 2013 Seems like 19 gallons should have been enough to make that trip safely...was he running at high RPMs or in a headwind? Link to comment Share on other sites More sharing options...
Ed Cesnalis Posted September 6, 2013 Author Report Share Posted September 6, 2013 He says 19 per sight tubes turned out to be 13. Link to comment Share on other sites More sharing options...
Ian Posted September 6, 2013 Report Share Posted September 6, 2013 What did the fuel dip stick say? Link to comment Share on other sites More sharing options...
Jim Posted September 6, 2013 Report Share Posted September 6, 2013 Ed, do you have a link to the original thread? I missed it. When in doubt, measure fuel by hours flown, not distance or the sight glasses. Link to comment Share on other sites More sharing options...
Ed Cesnalis Posted September 6, 2013 Author Report Share Posted September 6, 2013 dunno, but the owner advised: Not fun. But the lesson is clear. The sight tubes are not enough, and even if you can't get an accurate stick of the tanks due to uneven surface,its stillworth it to push the plane to a place were you can get a stick reading. Link to comment Share on other sites More sharing options...
Ed Cesnalis Posted September 6, 2013 Author Report Share Posted September 6, 2013 Ed, do you have a link to the original thread? I missed it. When in doubt, measure fuel by hours flown, not distance or the sight glasses. http://sportpilottalk.com/viewtopic.php?f=4&t=3191&start=30 Link to comment Share on other sites More sharing options...
Jim Posted September 6, 2013 Report Share Posted September 6, 2013 Found it. See my post. Link to comment Share on other sites More sharing options...
Ed Cesnalis Posted September 6, 2013 Author Report Share Posted September 6, 2013 Sounds like the flight instructor must have declared an emergency at North Las Vegas to get an approach from 3,000' over the runway. Pretty dumb to elect to stretch 1.1 gallons 50miles when they could have landed 50 miles out at Mercury. Maybe I haven't changed my mind? Link to comment Share on other sites More sharing options...
sandpiper Posted September 6, 2013 Report Share Posted September 6, 2013 Never push fuel. Been there. If there is a doubt after airborne, land. Link to comment Share on other sites More sharing options...
N751JM Posted September 6, 2013 Report Share Posted September 6, 2013 Why would anyone trust the sight tubes, or the fuel gauges for that matter? In a light airplane you only know for certain with a calibrated dipstick on a level surface, or watching what is pumped in. I do agree with other comments, if in the air there is any question, stop and get enough fuel to get to your destination for CERTAIN. Link to comment Share on other sites More sharing options...
Jim Meade Posted September 6, 2013 Report Share Posted September 6, 2013 Why would anyone trust the sight tubes, or the fuel gauges for that matter? In a light airplane you only know for certain with a calibrated dipstick on a level surface, or watching what is pumped in. I do agree with other comments, if in the air there is any question, stop and get enough fuel to get to your destination for CERTAIN. Sight tubes and fuel gauges provide some assurance that there is not a fuel leak that causes one to have less fuel then the totalizer or time and use formulas specify. Since some kind of indicator is required it would be nice (though not legally necessary) if they were accurate. Wishful thinking. I need to verify the calibration on my FD dipsticks. They are not consistent. They read 10 and I add 5 gallons measured and they read 17. Hmmm. Fuel management depends in part on good equipment and good procedures. Airlines do not tanker fuel for fun. Many 135 operations land at or very slightly above the minimums. Only small, usually private GA airplanes lack the equipment, training and procedures to manage fuel so that one arrives safely with minimums or more. It's because we don't care enough or plan well enough. Link to comment Share on other sites More sharing options...
FlyingMonkey Posted September 7, 2013 Report Share Posted September 7, 2013 Why would anyone trust the sight tubes, or the fuel gauges for that matter? In a light airplane you only know for certain with a calibrated dipstick on a level surface, or watching what is pumped in. I do agree with other comments, if in the air there is any question, stop and get enough fuel to get to your destination for CERTAIN. I think it depends on what level of trust you are talking about. I don't trust my sight tubes to accurately represent how much fuel is in the tanks, at least not to within +/- 5 gallons or so. However, they are VERY accurate at telling me whether there is fuel in the tank at all, and giving a rough estimate of how much. Sight tubes are great because they show actual fuel in the tank, and about the only way they can fail to show that level accurately is if something big enough (what are the tubes, 3/8"?) to block one end of the tube gets in it. The real problem with sight tubes is calibration. They stickers next to the tubes in my CT are a joke, and the dipstick is not really super accurate either as far as I can tell. I would think the best way to calibrate is to completely drain the tanks, level the airplane in flying attitude, and put a known quantity of fuel in the tank (say 5 gallons), then make a mark on the tube. Add another known quantity and make another mark, etc, until done. This is what I plan to do when my current fuel gets low. I'll probably mark 2.5 gallons, 5 gallons and 10 gallons. The 2.5 gallon mark is really just to give me a "critical fuel" reference, I'd never want to launch without 5 gallons per side. Link to comment Share on other sites More sharing options...
sandpiper Posted September 7, 2013 Report Share Posted September 7, 2013 Next time your sight tubes are replaced is a good time to calibrate. If you want to do it sooner, wait until you are in a low fuel state then drain the tanks. Then fill known quantities and mark. Link to comment Share on other sites More sharing options...
opticsguy Posted September 7, 2013 Report Share Posted September 7, 2013 Rex puts markings on my sight tubes when they are replaced. I found those to be more accurate than the dipstick on level ground. I think the dipstick reads almost 2 gallons high on the left side, one on the right. Link to comment Share on other sites More sharing options...
Jim Meade Posted September 7, 2013 Report Share Posted September 7, 2013 One should try to manipulate the dipstick consistently. On a ladder, able to insert it straight down, is one thing. Reaching up over a wing and not sure if it is straight or seriously canted is something else. See other thread on this. My little experiment showed the dipstick was fairly consistent at various angles except when the bottom was way back and the top way forward it was off about 1.5 gallons. But, I think the markings on mine are, though consistent and repeatable, inaccurate. This is one of those lazy day jobs - to verify calibration. How many of you have calibrated your totalizer and are fully comfortable with it's reading? Link to comment Share on other sites More sharing options...
Runtoeat Posted September 7, 2013 Report Share Posted September 7, 2013 We've argued this almost as much as landing technique. I must totally agree with calibration of the tubes at the time the wings are drained for inspection removal. After adding back in 3 and 5 gallons to each wing, my tubes were marked with red paint at these levels. Even after marking them, I don't ever rely on the 3 gallon mark as an indicator that determines how much longer I can fly. It is an indicator that tells me I need to get on the ground to refuel. We've also discussed dip sticks. My stick has different markings for left and right tanks and the difference is significant. I have not really calibrated this but one could do this during the wing inspection, same as with the sight tubes. The stick is used mainly for guessing how much fuel I need to add when refueling and sighting into the tank is used to verify how full the tanks really are. Link to comment Share on other sites More sharing options...
Ed Cesnalis Posted September 7, 2013 Author Report Share Posted September 7, 2013 I have never looked for precise readings from my sight tubes. I see 2-hour tubes, if both are full I have 4 hours of fuel or more. If I do a 2 hour flight with full tanks I can only see levels on the way home, hours 5 and 6 can't be seen. Note you don't really have 6 hours if you are burning 6gal/hour. If a tube is 1/2 full that is 1 hour. When I have 1/2 of that on both sides I am down to an hour total which is my personal reserve. Left rudder and right rudder is needed to find the middle if you are not sure. This works so well you can calibrate your slip skid ball this way. My useful load is over 600lbs, I never dip my tanks, I just glance at the tubes and think in terms of hours and an hour reserve. With 6 hours of fuel and a 2 hour bladder the only way I get fuel critical is through stupidity and laziness. Link to comment Share on other sites More sharing options...
S3flyer Posted September 7, 2013 Report Share Posted September 7, 2013 My Law of Primacy on this topic was that fuel gauges are always WRONG. I start with a known quantity, calculate the time then track against it. I do reference my fuel gauge but only as a check against my time. Exception would be if the gauge shows materially lower than it should, then I'll take the pessimistic position. Enough deviation and I'll land to see if I have an issue. Link to comment Share on other sites More sharing options...
Jim Meade Posted September 7, 2013 Report Share Posted September 7, 2013 I did some checking on mine today, comparing dipstick, totalizer and sight gauges and it is obvious I need to start from zero. I'm no longer sure which is to be trusted. One thing I totally disagree with is this casual attitude toward fuel. We should be able to know what we started with and how much we use and predict how much we will have (subject to verification through sight guages, etc.). I'm seriously toying with the idea of adding a capacitive gauge setup to the CTSW. Not sure what all would be involved yet. Link to comment Share on other sites More sharing options...
Farmer Posted September 7, 2013 Report Share Posted September 7, 2013 One indicator of fuel is the pump where it is sold to me. Fill the tank fullk and check the Dynon for consumption numbvers, refill at pump and check to compare. After several times you will gain confidence in the Dynon numbers. Now from a full tank you can mark tubes as you wish. Actual use of the site tube for me is to check in route that l am not missing any fuel in flight. When I land there will still be fuel in the tube or I have violated my own rules. If the tank is not full I dip with stick provided by mfgr. So far always right on, side to side with Dynon and pump readings. Farmer Link to comment Share on other sites More sharing options...
Ed Cesnalis Posted September 7, 2013 Author Report Share Posted September 7, 2013 ...One thing I totally disagree with is this casual attitude toward fuel. We should be able to know what we started with and how much we use and predict how much we will have (subject to verification through sight guages, etc.)... Guilty, but its ok I"m old, meaning the CT is my last plane. When I flew the Skyhawk to the same destinations my practice was to top off at every stop. The CT has a long range in time and miles plus it likes car gas from my hangar so my patterns have changed. Its not that I don't calculate I just use round numbers and big reserves. Today I flew for just under 1 hour and saw I had well over 20 gallons from my sight gauges, not precise but not risky, I confirmed via the sight gauges that I have 3 hours remaining. If I go somewhere I'll top it off, If I fly local I might want to video some high terrain so 3 hours might be good. Link to comment Share on other sites More sharing options...
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