Jerry Wagner, what not to do.

Dan Thomas said:
Most of them will tell you whether the tank is more than half full or less that half full. For many, we can't expect much better than that, but I have fixed some systems with new senders and careful adjustments.

Much inaccuracy is due to neglect. An airplane tied down outside is moving a little if anything more than a light breeze is blowing. That movement disturbs the fuel in the tanks and moves the senders. 40 or 50 years of that and those senders are worn right out, even in an airplane with less than a thousand hours on it. Any moisture in the tank causes corrosion of the sender, affecting its grounding and therefore its accuracy. Even the tank ground straps, often made of aluminum, oxidize and develop resistances.
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True enough. But if the tank is full and the gauge reads 3/4, then the gauge does not indicate the quantity of fuel in the tank.
 
FWIW, the factory gauges on my 45-year-old Cessna are freakishly accurate.
 
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Roger Wilco said:
Not to belabor the issue, but if we apply this literally then a great many light airplanes are unairworthy, as their fuel gauges are intrinsically inaccurate.
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OTOH, even modern fuel totalizers can be inaccurate in terms of how much fuel is left. So while it's literal, it doesn't say anything about some specific number like, "within 2/10ths of a gallon," so we have to think in terms of realistic leeway based on type, age, etc.
 
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Roger Wilco said:
True enough. But if the tank is full and the gauge reads 3/4, then the gauge does not indicate the quantity of fuel in the tank.
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Yes, it does. But it’s the difference between precision and accuracy. Precision is required in a level flight attitude. Accuracy is only required at Empty, which is where the OWT comes from.
 
OneCharlieTango said:
FWIW, the factory gauges on my 5-year-old Cessna are freakishly accurate.
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So are the factory fuel gauges/sending units in my 1980 172N. I have had a sending unit out to replace a fuel tank, put it back in the replacement tank. Both are accurate and reliable so far. 2600 hours on the airframe and hangered inside now, but not for all of it's life.
 
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midlifeflyer said:
OTOH, even modern fuel totalizers can be inaccurate in terms of how much fuel is left. So while it's literal, it doesn't say anything about some specific number like, "within 2/10ths of a gallon," so we have to think in terms of realistic leeway based on type, age, etc.
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Totalizers can be fantastically accurate in calculating fuel burned. But that is not the same as fuel remaining. I learned that the hard way.
 
Ed Haywood said:
Totalizers can be fantastically accurate in calculating fuel burned. But that is not the same as fuel remaining. I learned that the hard way.
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Yep. When I do transitions in to totalizer-equipped airplanes, I point out that while it may be super accurate in terms of fuel usage fuel remaining is subject to to big potential errors. (1) it's GIGO. It's only as good as the staring number when you turn the key. (2) It doesn't account for leakage.
 
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Roger Wilco said:
As Village Idiot (and in the context of my earlier post), I am limited to a mathematical and logical framework in which 3/4 ≠ 1.
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So, when you leave the dining room table when you are "full," what is the fullness number and is it both accurate and repeatable as a measure for the future? :D
 
nauga said:
There is no proportional indicator with zero error in an airplane. ;)

Nauga,
who would rather be approximately correct than precisely wrong
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So much of the real world is analog...
 
This thread about wild bill Wagner has turned a most unexpected direction.
 
Lance F said:
As a twin Cessna owner, CFII, and generally a safety conscious pilot, I consider him and his videos a total embarrassment.
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As a fellow Twin Cessna driver, though not a CFI, I completely agree. I'm honestly more concerned about public perception that these aircraft are somehow dangerous than anything else, just because of a few rotten apples that are in command of way too much plane for their skill level (usually ADM but sometimes stick and rudder as well).:confused:
 
Kitfox43 said:
... His latest video show him landing with the fuel gauges near zero. ...
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My fuel gauges read 0 when each tank has about 5 gallons. If I land in that condition I have more than an hour of fuel.
These fuel gauges do read consistently through the entire range, just on the low side. That's precise if not accurate, conservative, and I'm fine with it.
 
I actually put new EI electronic senders in my tank and measured the sensor count as I added fuel gallon by gallon back into the plane. I also used this to calibrate my main tank dipstick. I have a nice plot of sensitivity curve. It is less sensitive at the top and bottom and more so in the middle, but fairly accurate now.

I always use the most pessimistic of what the fuel gauge says, what my fuel flow meter tells me, and what my watch tells me I should have burned.
 
flyingron said:
... I always use the most pessimistic of what the fuel gauge says, what my fuel flow meter tells me, and what my watch tells me I should have burned.
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Same here, and it saved my bacon once. I was on a long x-country and I knew from experience that the plane burned 8 gph when leaned optimally during high speed cruise at altitude. I always stick the tanks with a calibrated stick and Hobbs meter / timer for fuel and because of this considered the fuel gauges unnecessary. But during this flight the fuel gauges were reading lower than I expected given the time it had been running. Even though I "knew" I was good based on the fuel stick and clock, I made a precautionary fuel stop and discovered the engine was burning fuel at a rate 25% higher than normal for the conditions (10 gph instead of 8 gph). It turned out to be one of the lessons that will stick with me forever, with implications to other areas of aviation.
 
Anyone else notice he starts rolling and crosses the hold short line while the controller is giving him a cloud report?
 
MRC01 said:
Same here, and it saved my bacon once. I was on a long x-country and I knew from experience that the plane burned 8 gph when leaned optimally during high speed cruise at altitude. I always stick the tanks with a calibrated stick and Hobbs meter / timer for fuel and because of this considered the fuel gauges unnecessary. But during this flight the fuel gauges were reading lower than I expected given the time it had been running. Even though I "knew" I was good based on the fuel stick and clock, I made a precautionary fuel stop and discovered the engine was burning fuel at a rate 25% higher than normal for the conditions (10 gph instead of 8 gph). It turned out to be one of the lessons that will stick with me forever, with implications to other areas of aviation.
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We once came out of annual and test flew the plane and opened up the cowl and saw nothing amiss. About 10 minutes into the flight I notice the fuel gauges coming down way down from full. Margy's flying and I point it out to her and I tell her I was pretty sure I topped things off after I test flew it. I continued to stare at them and they are definitely coming down. Margy had just negotiated class B clearance with IAD and I say we gotta land. Looking out we're about half way between FDK and JYO, but closer to JYO so we go there.

Taxi off and I go to find a mechanic. I return with one to find Margy removing the access panel that leads to where the boost pump was (it had been worked on during annual). "How do you get her to do that?" the mechanic asks me. I pointed out she just finished owner-assisting the annual. Anyhow, he has Margy go flip the boost pump on and instantly we see gas spraying out of one of the fuel lines where it ran into the engine driven pumps. Ooops, someone didn't tighten it. Put a wrench on it and it's fixed. Top off the tanks and I figure we were "burning" 60 GPH (normally burn around 12 or 13).
 
Shrug, the smoke video i didn't find horrible.
he purposefully yanks it up to exchange speed for altitude and says he's watching for the stall, he get's close, pushes the nose down and recovers. never actually stalling.
airline flying, heck no.
would i do it, most likely not, esp ifr in clouds but hey his plane.
he executed exactly what he planned, not horrible in my book
 
whitepines said:
I'm honestly more concerned about public perception that these aircraft are somehow dangerous than anything else, just because of a few rotten apples that are in command of way too much plane for their skill level (usually ADM but sometimes stick and rudder as well).
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I think it's time for a review of the Five Hazardous attitudes: https://pilotinstitute.com/aviation-hazardous-attitudes/

Wagner displays several of them, and it does not bode well for him reaching old age.
MRC01 said:
My fuel gauges read 0 when each tank has about 5 gallons. If I land in that condition I have more than an hour of fuel.
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What is the unusable fuel as listed in the TCDS for the airplane? The regulation requires that the gauge read empty when the fuel is down to the unusable level.

And we have to remember that unusable fuel is not just the fuel in the lines or whatever. It's the fuel that will not flow out of the tank in certain attitudes such as a steep climb or descent. In some airplanes it's several gallons.

According to § 23.1337(b)(1), fuel quantity indicators are required to be calibrated to read "zero" during level flight when the quantity of fuel remaining in the tank is equal to the unusable fuel supply. Therefore, fuel quantity indicators should be used as the primary fuel-remaining instruments. Fuel quantity indicators that are inaccurate should be periodically calibrated, repaired, or replaced, as necessary, to ensure reliable readings.

From https://www.faa.gov/documentLibrary/media/Advisory_Circular/AC_23-17C.pdf Page 188.
 
flyingron said:
... he has Margy go flip the boost pump on and instantly we see gas spraying out of one of the fuel lines where it ran into the engine driven pumps. Ooops, someone didn't tighten it. ...
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As I'm sure you know, that (loose fuel lines due to MIF or Maintenance Induced Failure) is the root cause for the crash of N52156 near Grass Valley last year, killing the pilot. The fuel starvation happened on the base leg and the pilot turned away from the airport, which may have contributed to the accident, but I wasn't there and won't second guess his decision.
 
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Dan Thomas said:
What is the unusable fuel as listed in the TCDS for the airplane? The regulation requires that the gauge read empty when the fuel is down to the unusable level.
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The unusable fuel is 1.5 gallons per tank according to the POH (1980 172N). The calibrated fuel sticks I use read "0" when there is still fuel in the tank, but it's unusable (eg. 1.5 gals in the tank is 0 on the stick). These sticks too also read conservatively low overall. With 5 gals remaining in the tanks, the gauges are reading "mostly zero" in that they sit at zero but bounce up a bit. I call that "not quite zero" and compliance with regulation. I've never had the tanks fully empty.
 
MackMooney said:
Shrug, the smoke video i didn't find horrible.
he purposefully yanks it up to exchange speed for altitude and says he's watching for the stall, he get's close, pushes the nose down and recovers. never actually stalling.
airline flying, heck no.
would i do it, most likely not, esp ifr in clouds but hey his plane.
he executed exactly what he planned, not horrible in my book
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Was he IFR at the time, or just VFR in IMC?
 
Roger Wilco said:
As Village Idiot (and in the context of my earlier post), I am limited to a mathematical and logical framework in which 3/4 ≠ 1.
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Again, that’s the difference between precision and accuracy. If it indicates 3/4 when it’s full, you know it’s full when it indicates 3/4. It’s precise (repeatable, and you know where it is) but not accurate (3/4 ≠ 1).
 
MauleSkinner said:
It’s precise (repeatable, and you know where it is) but not accurate (3/4 ≠ 1).
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Simple fractions in and of themselves are generally imprecise. If it reads 0.7500001 capacity at full capacity it is relatively precise, but comparatively inaccurate. If it reads 3/4 at full it is relatively imprecise but accurate to with 1/4 capacity, which is qualitatively inaccurate for some uses but may still be usable as a gross reference for an airplane fuel gauge if it is consistent.

Nauga,
significantly figured
 
nauga said:
Simple fractions in and of themselves are generally imprecise. If it reads 0.7500001 capacity at full capacity it is relatively precise, but comparatively inaccurate. If it reads 3/4 at full it is relatively imprecise but accurate to with 1/4 capacity, which is qualitatively inaccurate for some uses but may still be usable as a gross reference for an airplane fuel gauge if it is consistent.

Nauga,
significantly figured
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Huh?

Mauleskinner
Excessively monosyllabic
 
Lindberg said:
Was he IFR at the time, or just VFR in IMC?
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The radio phraseology made it sound like he was on VFR flight following. It's possible he did have 3SM visibility; a camera (especially one mounted that far back) often doesn't depict exactly what the pilot is seeing.
 
MauleSkinner said:
Again, that’s the difference between precision and accuracy.
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Right. But my point, in #39, was made (tongue-in-cheek) with regard to the FAR that Dan Thomas referenced. If I’m not mistaken, neither Part 23 nor 91 mention anything about precision or accuracy, except when tanks contain no usable fuel.
 
MauleSkinner said:
Again, that’s the difference between precision and accuracy. If it indicates 3/4 when it’s full, you know it’s full when it indicates 3/4.
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Those senders cannot accurately tell you when the tank is full. In wing tanks, they are located near the inboard end of the tank so that they can read empty when they're still floating on the unusable fuel. (You'll note that the gauge drops to less than empty when the master is shut off, too.) If they were located farther out, they'd bottom out when there was still more than unusable. The wing's dihedral does that.

(The float is not supposed to quite contact the tank at either end of its travel, as it can wear a hole in the tank. But modern foam floats are likely less damaging than the old soldered brass floats.)

When the tank is filling, that float will hit its upper stop before that tank is full. It will read full but more fuel still goes into the tank, especially if the filler is farther out in the tank. Those old brass floats that were round, like a miniature barrel, floated about half submerged, and so the upper part of the float was still above the fuel level by a half-inch or so. If it didn't quite touch the tank, there was still considerable room for more fuel. Again, the dihedral affects it.

Wing tanks are shallow (5", maybe 6") and long and wide. The fuel moves around a lot depending on the aircraft's attitude. A car's tank is much deeper, shorter and narrower. The fuel has less area to move around, and the sender float has lots of vertical range. Much easier to have an accurate gauging system.
 
Not that it has anything to do with Jerry but I had to go into my main fuel tank (which is the 50 gallon tip tank on a 414) this weekend for a boost pump issue. My plane has a capacitance type fuel gauge system and I caught a good picture of the fuel level sensor. It’s the blue thing. Once calibrated they’re very accurate.
 

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