Low Fuel Warning

[Dan 300CBI]

Greetings all,

 

I had a low fuel light come on during a long cross country flight the other day with me and another pilot that has been nawing at me. I wanted to get other's opinion on the situation as to what happened and if you would consider the aircraft airworthy or not.

 

The trip was 131nm and after doing all my calculations we needed 20 gallons of fuel. The company with the helicopter has a flight line crew that fuels the aircraft and moves it to a location away from other aircraft for departure. During my preflight I flip on the battery switch and the fuel gauge reads 30 gallons, my weight and balance calc said I could carry up to 31. No problem right? About 3/4 into the flight I was reading back information that we were 24nm's out and the fuel gauge was reading 15 gallons. 2 mins later the low fuel light comes on and we end up setting it down in a wooded / bog area out in the middle of BFE. Once safely on the ground we put the fuel stick in to verify that we were actually out of fuel, we had 1 gallon left. Seeing how it was getting dark and after walking around in the woods for 30mins we got lucky and found a house. We decided to call back to base to have someone drive up 2 hours to get us so we could recover the aircraft during the day (Thanks again Helo08).

 

After talking with the owner he stated that the fuel gauge had been drifting and was off anywhere between 5-10 gallons. In this case it was 10. My question to everyone is this, does the fuel gauge have to be accurate for the aircraft to be airworthy? If he knew that the gauge was off should he have put a placard on the gauge stating it was off and to use the fuel stick? Now, I do take the responsibility for not using the fuel stick to begin with during my pre-flight and only relying on the guage, BUT I would think that a fuel gauge would not be off by 10gallons. Second why should a fuel gauge be off at all, my truck's fuel gauge doesn't drift.

 

Let me know what you think.

 

Thanks

[helidave]

91.205 B (9) fuel gauge for each tank- required

 

required equipment not working = un airworthy aircraft

 

 

 

Seems like the guy could have at least mentioned it to you if he knew it was off 5-10 gallons

Edited September 6, 2007 by helidave

[clay]

the ONLY time a fuel gauge must be accurate is one EMPTY...... so no, there is nothing wrong. thats why YOU should always verify the amount of fuel in the A/C and the amount put in.. not trust some line guy to tell you what he did. your the PIC.

 

but i would like to know if a fuel guage drifted that much..... make sure and always verify your fuel personally before every flight. makes everything easier.

Edited September 6, 2007 by clay

[helidave]

Clay do you have a reference for that?

 

Either way, if he was flying around and it was reading 15 gallons, and then the low fuel light came on 2 minutes later, it wasn't accurately showing that it was empty.

[Dan 300CBI]

Clay,

 

I would agree that I should have verified the fuel with a fuel stick, and I kick my self in the ass for not doing so, but I still argue that if the fuel gauge is off by 10 gallons that it would NOT be considered airworthy.

 

And in this case the fuel tank was empty but still read 15 gallons.

 

To answer your question yes the fuel gauge on this schweizer 300CB did drift. It has drifted before and was re-calabrated one other time but not sure how long ago that was.

 

So now do I start putting a fuel stick in my car to verify I have enough fuel??? lol..

[zemogman]

So now do I start putting a fuel stick in my car to verify I have enough fuel??? lol..

 

Only if you are concerned with your ability to autorotate your car...

 

If I was in your situation I would consider this "not airworthy" or in the least not worthy for me to fly in that condition again. I would consider the fuel guage a VERY important instrument. I visually check the tanks before every training flight....even if the instructor just filled it up in front of my eyes.

 

Not only is the fuel guage important but the LOW FUEL warning light even more...you could have a fuel leak that drains your tanks in flight and a full tank during visual inspection would give you a false sense of security in that case.

 

Airworthiness is not only a book definition...it is a determination that you make before you fly...(don't get me wrong, I understand your question, but I believe this point is very important)...I think that fuel guage problem should have been disclosed to anyone prior to flying that aircraft.

[arismount]

The only regulatory requirement for FAR 23 airplane recip engine fuel gauges is that they must indicate "empty" when no usable fuel is left in the tank. Other calibration, or correspondence between tank contents and tank quantity indication is not required. Turbine engine fuel gauges must indicate fuel quantity in the tank within +/-3%. I'm doing this from memory so don't trust me. You could go to faa.gov and search FAR 23 & FAR 25 for the airplane references, and FAR 27 & 29 for the helicopter references. This would probably be a good learning experience for you as there is a lot of interesting and valuable information in these FAR's, which deal with certification standards.

 

Greetings all,

 

I had a low fuel light come on during a long cross country flight the other day with me and another pilot that has been nawing at me. I wanted to get other's opinion on the situation as to what happened and if you would consider the aircraft airworthy or not.

 

The trip was 131nm and after doing all my calculations we needed 20 gallons of fuel. The company with the helicopter has a flight line crew that fuels the aircraft and moves it to a location away from other aircraft for departure. During my preflight I flip on the battery switch and the fuel gauge reads 30 gallons, my weight and balance calc said I could carry up to 31. No problem right? About 3/4 into the flight I was reading back information that we were 24nm's out and the fuel gauge was reading 15 gallons. 2 mins later the low fuel light comes on and we end up setting it down in a wooded / bog area out in the middle of BFE. Once safely on the ground we put the fuel stick in to verify that we were actually out of fuel, we had 1 gallon left. Seeing how it was getting dark and after walking around in the woods for 30mins we got lucky and found a house. We decided to call back to base to have someone drive up 2 hours to get us so we could recover the aircraft during the day (Thanks again Helo08).

 

After talking with the owner he stated that the fuel gauge had been drifting and was off anywhere between 5-10 gallons. In this case it was 10. My question to everyone is this, does the fuel gauge have to be accurate for the aircraft to be airworthy? If he knew that the gauge was off should he have put a placard on the gauge stating it was off and to use the fuel stick? Now, I do take the responsibility for not using the fuel stick to begin with during my pre-flight and only relying on the guage, BUT I would think that a fuel gauge would not be off by 10gallons. Second why should a fuel gauge be off at all, my truck's fuel gauge doesn't drift.

 

Let me know what you think.

 

Thanks

[volition]

If you don't fill it up yourself, or check the tanks physically, then it's the PIC fault. The gauges could get broken in flight, like asi, altimeter, ect. Like the fuel gauges not properly working is one of them.

[Dan 300CBI]

A Good leason learned and i'll just add that to my personal pre-flight check list to visually check the fuel levels. As a new low time pilot 120+ hours i've never seen it on any checklist that is in an aircraft and I always follow the checklist no matter how comfortable I am with the aircraft. It may take longer to fire it up but I always step thru it so I don't miss anything. I also go thru my personal checklist before and during flight so i'll just add that as a line item to do. But I do think that if an owner knows there is a drift in the fuel sensor that it should be noted in the aircraft whether in a checklist or a placard until the issue is resolved.

 

Thanks for the feedback.

[jet trash]

the ONLY time a fuel gauge must be accurate is one EMPTY...... so no, there is nothing wrong.

 

This is what you are referring to:

 

 

 

§ 23.1337 Powerplant instruments installation.

(a) Instruments and instrument lines. (1) Each powerplant and auxiliary power unit instrument line must meet the requirements of §23.993.

 

(2) Each line carrying flammable fluids under pressure must—

 

(i) Have restricting orifices or other safety devices at the source of pressure to prevent the escape of excessive fluid if the line fails; and

 

(ii) Be installed and located so that the escape of fluids would not create a hazard.

 

(3) Each powerplant and auxiliary power unit instrument that utilizes flammable fluids must be installed and located so that the escape of fluid would not create a hazard.

 

( Fuel quantity indication. There must be a means to indicate to the flightcrew members the quantity of usable fuel in each tank during flight. An indicator calibrated in appropriate units and clearly marked to indicate those units must be used. In addition:

 

(1) Each fuel quantity indicator must be calibrated to read “zero” during level flight when the quantity of fuel remaining in the tank is equal to the unusable fuel supply determined under §23.959(a);

 

(2) Each exposed sight gauge used as a fuel quantity indicator must be protected against damage;

 

However, helicopters are certified under FAR Part 27, NOT Part 23 ( Airplanes)

27.1305 Powerplant instruments.

The following are the required powerplant instruments:

 

 

© A fuel pressure indicator, for each pump-fed engine.

 

(d) A fuel quantity indicator, for each fuel tank.

 

(l) A low fuel warning device for each fuel tank which feeds an engine. This device must—

 

(1) Provide a warning to the flightcrew when approximately 10 minutes of usable fuel remains in the tank; and

 

(2) Be independent of the normal fuel quantity indicating system.

[jet trash]

Only if you are concerned with your ability to autorotate your car...

 

If I was in your situation I would consider this "not airworthy" or in the least not worthy for me to fly in that condition again. I would consider the fuel guage a VERY important instrument. I visually check the tanks before every training flight....even if the instructor just filled it up in front of my eyes.

 

Not only is the fuel guage important but the LOW FUEL warning light even more...you could have a fuel leak that drains your tanks in flight and a full tank during visual inspection would give you a false sense of security in that case.

 

Airworthiness is not only a book definition...it is a determination that you make before you fly...(don't get me wrong, I understand your question, but I believe this point is very important)...I think that fuel guage problem should have been disclosed to anyone prior to flying that aircraft.

 

I always taught the 2 verifiable method of fuel verification. You must verify fuel using two different methods during preflight, such as added fuel against remaining fuel, added fuel against measured fuel, dipstick, or topped off tank. In the airline world we must verify our fuel loads with 2 methods, and each one must be within XXX number of pounds against the other.

 

 

 

As far as the term "airworthiness", I'm always amused at how pilots throw that term around and don't really have a clue as to what it actually means. I'm also an A&P/ IA and get to hear how Joe Pilot tells me an aircraft is "unairworthy" because of one thing or another.

 

In fact, look under FAR 1.1 Definitions and you will not even find the term "airworthy". There's a reason for that.

[Pogue]

I had a low fuel light come on during a long cross country flight the other day with me and another pilot that has been nawing at me. I wanted to get other's opinion on the situation as to what happened and if you would consider the aircraft airworthy or not.

Float gauges have a nasty tendency to stick, so I always check levels visually, myself. Great job on having enough sense to put the A/C down with the fuel warning light. I know everyone says it's a no brainer, but people still seem to be able to run themselves out of fuel after the light comes on.

[clay]

This is what you are referring to:

§ 23.1337 Powerplant instruments installation.

(a) Instruments and instrument lines. (1) Each powerplant and auxiliary power unit instrument line must meet the requirements of §23.993.

 

(2) Each line carrying flammable fluids under pressure must—

 

(i) Have restricting orifices or other safety devices at the source of pressure to prevent the escape of excessive fluid if the line fails; and

 

(ii) Be installed and located so that the escape of fluids would not create a hazard.

 

(3) Each powerplant and auxiliary power unit instrument that utilizes flammable fluids must be installed and located so that the escape of fluid would not create a hazard.

 

( Fuel quantity indication. There must be a means to indicate to the flightcrew members the quantity of usable fuel in each tank during flight. An indicator calibrated in appropriate units and clearly marked to indicate those units must be used. In addition:

 

(1) Each fuel quantity indicator must be calibrated to read “zero” during level flight when the quantity of fuel remaining in the tank is equal to the unusable fuel supply determined under §23.959(a);

 

(2) Each exposed sight gauge used as a fuel quantity indicator must be protected against damage;

 

However, helicopters are certified under FAR Part 27, NOT Part 23 ( Airplanes)

27.1305 Powerplant instruments.

The following are the required powerplant instruments:

© A fuel pressure indicator, for each pump-fed engine.

 

(d) A fuel quantity indicator, for each fuel tank.

 

(l) A low fuel warning device for each fuel tank which feeds an engine. This device must—

 

(1) Provide a warning to the flightcrew when approximately 10 minutes of usable fuel remains in the tank; and

 

(2) Be independent of the normal fuel quantity indicating system.

 

 

that is all fine and dandy, but i am still correct. . . all it has to do is tell you when it is at a certain level. no where does it say it has to be calibrated to show the exact amount all the time. so if i have a full tank, and it shows 3/4...who cares. i did my preflight, i dipped the tank, and i know its full.....

[helidave]

Fuel quantity indication. There must be a means to indicate to the flightcrew members the quantity of usable fuel in each tank during flight. An indicator calibrated in appropriate units and clearly marked to indicate those units must be used

 

 

I would think that would require the gauge to be accurate through the entire range. The key words being "usable fuel".

 

 

As far as the term "airworthiness", I'm always amused at how pilots throw that term around and don't really have a clue as to what it actually means. I'm also an A&P/ IA and get to hear how Joe Pilot tells me an aircraft is "unairworthy" because of one thing or another.

 

I got that speech from our director of maintenance a few weeks ago. He said the aircraft is either airworthy, or is doesn't meet the requirements of it's type certificate. (or something to that effect) Its just a lot easier to type "unairworthy"

Edited September 6, 2007 by helidave

[Goldy]

Dan 300- I dont have this problem in the R22...oops..sorry.

OK< so can we all agree now that its required equipment to have BOTH a fuel gauge and a separate indicator when you have 10 minutes of fuel remaining? With that said, personally I would prefer to have a lil more than 10 minute notice.

 

Glad you had a decent place to set down.

Edited September 7, 2007 by Goldy

[clay]

i'll have to do some more research, the enstrom i flew in doesnt have any kind of low fuel warning...... or 10 minutes till empty light... and on the origional subject, we've all agreed its the PIC's responsibility to check fuel levels personally. so say you fly a S76 or a 412. . . how do you visually verify fuel quantity? or can you dip the tanks? i know on a 206B or L you can look in with a flashlight...

[Gomer Pylot]

In a 412 or S76 you read the gauges. There is no other way. You can look inside, and see that there is fuel, but there is nothing to show the exact amount. You know it's full when it runs out the filler hole. You know it's empty when it gets quiet. If the 412 has the Era aux tanks, you know (or at least suspect) they're full when fuel comes out the filler. Everything else is a wag. The gauges for those tanks are known to be completely unreliable. The gauges for the main tanks are good though, and are required to be calibrated regularly. Transport category aircraft come under different rules.

[jet trash]

In a 412 or S76 you read the gauges. There is no other way. You can look inside, and see that there is fuel, but there is nothing to show the exact amount. You know it's full when it runs out the filler hole. You know it's empty when it gets quiet. If the 412 has the Era aux tanks, you know (or at least suspect) they're full when fuel comes out the filler. Everything else is a wag. The gauges for those tanks are known to be completely unreliable. The gauges for the main tanks are good though, and are required to be calibrated regularly. Transport category aircraft come under different rules.

 

It's doesn't have anything to do with "different rules for Transport category aircraft". Fuel verification works for ANY aircraft. I always use a clock and time rather than rely on a gauge. If you are commercially flying an aircraft, one would assume you would know your hourly fuel consumption. Then it's a simple matter of keeping a fuel score from flight to flight.

 

I own a Cessna 337G Skymaster with notorious unreliable fuel gauges. I installed a Shadin Fuel Flow and calibrated it. In addition, I keep a fuel score of each flight and verify it against the Shadin, and I'm usually within a couple of percent of knowing my fuel remaining.

 

This is not rocket science.

[jet trash]

i'll have to do some more research, the enstrom i flew in doesnt have any kind of low fuel warning...... or 10 minutes till empty light... and on the origional subject, we've all agreed its the PIC's responsibility to check fuel levels personally. so say you fly a S76 or a 412. . . how do you visually verify fuel quantity? or can you dip the tanks? i know on a 206B or L you can look in with a flashlight...

 

I owned a Enstrom 280C, and it had a low fuel warning light. If the one you are flying doesn't have one, it's been removed. All Enstroms were certified under FAR 27, so a low fuel warning device is mandatory for certification.

[jet trash]

that is all fine and dandy, but i am still correct. . .

 

Actually you are not correct. Please go back and read FAR 27. It's very plain.

[Goldy]

"I own a Cessna 337G Skymaster"

 

 

JT- I'm jealous already...Ive always thought the Riley Super Rocket mod was way cool...and I dont even like airplanes.

 

Goldy

Edited September 7, 2007 by Goldy

[clay]

I owned a Enstrom 280C, and it had a low fuel warning light. If the one you are flying doesn't have one, it's been removed. All Enstroms were certified under FAR 27, so a low fuel warning device is mandatory for certification.

 

 

i flew 2 f28A model's, and they sir, do not have a low fuel warning device, as well as other A models i've been in. i cannot speak for every enstrom, its been the norm in the one's i have seen. it has a fuel guage and a PIC that has figured out the fuel burn and amount in the tanks...enstrom a model instrument panel

this isnt the enstrom I fly, just a random one i found off google. but it has no low fuel warning device.

 

 

but i do have to say, i've been looking at other enstrom models, and also other aircraft instrument panels, the f28A model is the only helo i've found without any kind of warning device......

Edited September 7, 2007 by clay

[clay]

Actually you are not correct. Please go back and read FAR 27. It's very plain.

 

can you explain how it is very plain?

 

 

been doing some reading, trying to figure out why were seeing things different on something that should be so plain, i did find out that when the enstrom f28a model was origionally certified, it was certified that ALL fuel was usable, till someone went ahead and tried to run it all the way to empty. now 2 gals is considered un-usable. but im wondering if for some reason when it was origionally certified, because of all fuel being considered usable, they didnt put a low fuel warning device.. all the later enstroms have some kind of light i have noticed though.. so maybe that is why im saying what im saying.

Edited September 7, 2007 by clay

[jet trash]

can you explain how it is very plain?

been doing some reading, trying to figure out why were seeing things different on something that should be so plain, i did find out that when the enstrom f28a model was origionally certified, it was certified that ALL fuel was usable, till someone went ahead and tried to run it all the way to empty. now 2 gals is considered un-usable. but im wondering if for some reason when it was origionally certified, because of all fuel being considered usable, they didnt put a low fuel warning device.. all the later enstroms have some kind of light i have noticed though.. so maybe that is why im saying what im saying.

 

The F28 was certified under CAR6, not FAR 27. When I get some time I'll pull up the CAR6 and read up on it.

 

I have a F28A (in pieces in the shop) I'll look at it when I get home.

[jet trash]

can you explain how it is very plain?

 

Go to FAA.gov, look up Federal Aviation Regulations, then pull up FAR Chapter 27. Then read.