Training aircraft fuel guages

[Big Pistons Forever]

I recently overheard a discussion between a Instructor (Class 4 ) and his CPL student. I regret to inform the Avcanada reading audience that the contents of this conversation has resulted in an uncontrollable desire on my part to rant on the training forum. So consider yourself warned.

The seminal part of the conversation was the statement from the instructor that he "should always just ignore the inoperative fuel guage as everyone just ignores them anyway and even when they are working they always lie. Fill her up and we will be good to go "

I have a few problems with this statement.

1) Operating fuel guages are mandated by both a specific CAR's regulation (527.1337) and as a "required" item on the aircraft equipment list of all commonly used training aircraft. Therefore flying an aircraft without working fuel guages is illegal as both a violation of the specific CAR on fuel guages and the fact that an aircraft does not have a valid C of A when a "required" item in the equipment list is not present or functioning.

2) Fuel gauges in light aircraft are required to be calibrated to zero or empty every year. That means when the gauge reads "E" it means the tank is indeed empty. If you see this in flight you had better have a plan B.

3) Contrary to urban myth light aircraft gauges are not useless, but as a general rule they are less accurate with fuller tank quantities. My experience is that the gauges are actually quite accurate when indicating around 1/3 or less and any reading of less than 1/4 is something you should respect.

4) The usefulness of fuel gauges can be greatly improved if the gauge reading is compared to the dip stick on every walk around.

5) In the fantasy land of FTU operations all the trips are short and you can just fill the B*itch up. Unfortunately when the CPL gets their first job they will find out that they will almost never get to top off fuel tanks and fuel planning becomes really important because the boss wants you to maximize the payload by carrying the minimum safe fuel load. Figuring out block fuel burns and knowing what the gauges are really telling you and when to believe them matters when you are flying the line.

I teach all my students the following.

A) Snag fuel gauges that do not work.

B) Always compare the dip stick reading with what the gauges say when doing the walk around.

C) The fuel selector and the fuel gauges are connected for checklist purposes. When ever you check the fuel selector position you also check the fuel gauges and vice versa.

D) Respect low fuel gauge readings. You should never be surprised by what the gauge is saying.

E) The vast majority of light aircraft have electrically powered fuel gauges. An unexpected sudden E reading on both gauges probably means that the CB/fuse has blown. Another clue is that in the event of a electrical power interruption fuel gauges will show below E as the needle moves further than the scale. A needle actually sitting on the E or zero likely is indeed showing no fuel.

[robertsailor1]

There is something to be said about the pilot that knows exactly how much fuel he has on board and knows what his engine burns at different power settings and owns a watch and uses it.

[photofly]

See also Denker on the same subject:
http://www.av8n.com/fly/fuel-gauges.htm

[trey kule]

that was a good post bpf

I had a nice rant to add but it disappeared in cyber space.

Nothing is going to change until
1. People have to do more than one 300 mile x-country to get their commercial, and very little more to instruct..Really dont have a clue how to manage fuel, and
2. FTU's stop with the little sayings like the only time you have to much fuel is when the engine is on fire, or one of the most useless things is air in the tanks..CPL's (and pretty much all ex-instructors!!!) as you mentined, get a rude awakening in their first job and have to start, possibly for the first time, to learn how to manage fuel , and
3. Transport and the FTU's stop using contingent fuel without a reason. There should be a reason to add extra fuel, not just blue sky it.,I dont know if it has changed but the old IF rating written had something like 500 pounds of contingency fuel and absolutely no explanatin why you should put it on. this kind of thinking causes problems with new hires as they simply want to always add unneccesary fuel for no reason, and
4. PDM courses should include the psychology of fooling oneself by thinking that the aricraft uses x amt per hour, but I plan to use x plus something..This leads to a false sense of confidence and a delay in decision making if the time comes when fuel is an issue...Proper accurate fuel management is key to making proper decisions. Add a fudge factor, and you suddenly add a psychological factor thinking you are super safe and invulnerable. As a result when action should be taken, it is often delayed as the pilot thinks...all will be well...I added some extra.

Now that is my rant for the day

[crazy_aviator]

Totally agreed with pistons !!
A couple more things, the yearly cal ck ( which many dont do) should entail zeroing the gauges with the transmitters at 0 fuel state (E) AND doing a dip AND noting fuel amounts on a placard at min fuel, 1/4 1/2 3/4 tank. During flight, lower fuel / gauge readings can be collaberated with rolling the A/C and applying adverse yaw, since most A/C have the transmitter on the low/output side, IF the gauge doesnt move from empty with light roll and yaw away from the tank in question, the gauge/txmtr is functioning properly and your pretty much out of fuel. Conversely, If you roll and yaw towards the tank in question, and the gauge goes from say 1/4 to empty and doesnt move with a 20 degree roll,,,then you have reserve fuel available ( determine these by testing and dipping after landing etc. )

[robertsailor1]

New aircraft often have very accurate gauges and no one should disagree on using them as part of your fuel management. Lots of the older aircraft have poor fuel gauges. For example an early Champ or Cub may have nothing more than a wire on a cork bobbing up and down as you fly, fool proof for sure but no one I ever knew could say they knew exactly how much fuel remained without a back up system. If my recall is right the early PA-12's wing tank gauges didn't even start to show fuel used until it was 1/4 gone. Personally out of all the aircraft I've owned over the years I never had an Engineer ever calibrate the fuel gauges as part of any inspection.

[Old Dog Flying]

Unfortunately the "guages" in our Grumman AA1A consists of a menometer..sight tube..on the sidewall of the cockpit where you really cannot see them in flight. And of course the little red bean in the tube bounces all over the place..which can be a bit disconcerting at times. As BPF will testify, you cannot do a dip stick check on the little beast due to the tank design.

I installed a JPI FS450 fuel flow system because of this problem and use it as a backup to the sight guages during my pre-flight.

When I was instructing, I made certain that the quantity showing on the guages were double checked with a dip stick ..ever flight.

[crazy_aviator]

Robert,

Of the 14 ish A/C that ive owned, ive calibrated most of them ,,, peace of mind.. IF there ever is a leak , or other incident which invalidates dip and calculation, the gauges will tell you that you need to land pronto ! I stress that owners get their fuel indicating systems checked for accuracy if they dont have a fuel flow/management system and diligently use it.

[robertsailor1]

I'll never debate someone on not doing their best to double check the fuel, no matter the manner so I applaud anyone who goes out of their way to do what it takes to know how much fuel they have at any given time. Fortunately leaking (large leaks) fuel tanks are very rare so between gauges and your watch you should be good to go. I've owned a lot of aircraft over the years and some have had excellent gauges and others like my current one have a sight gauge that which is mostly unreadable. I dip the tank but for 99% of my flying I always start with the tank topped off.

[Grantmac]

Sight tubes in my PA-16. Horrible things, really only show you the first 2/3s of a tank then they bottom out.
Currently have the tanks out and I'm going to get the floats replaced for hopefully a little more accuracy.

-Grant

[robertsailor1]

Grantmac,
Me thinks a very large majority of this forum are flying current aircraft and their experience is limited to current or recent aircraft. Older aircraft had at best sketchy fuel gauges but running out of fuel was never a big problem because the back up system of knowing the fuel burn and keeping track of your time plus allowing a good safe allowance was just a normal part of flying. I suspect that this might be the reason behind an old timer not trusting fuel gauges. By the way that little Clipper you have is a cool machine. Flown one off and one many years ago. It was the Father of the Piper Pacer which was one of my favorites. Most of those early Pipers had sketchy gauges.

[Grantmac]

Grantmac,
Me thinks a very large majority of this forum are flying current aircraft and their experience is limited to current or recent aircraft. Older aircraft had at best sketchy fuel gauges but running out of fuel was never a big problem because the back up system of knowing the fuel burn and keeping track of your time plus allowing a good safe allowance was just a normal part of flying. I suspect that this might be the reason behind an old timer not trusting fuel gauges. By the way that little Clipper you have is a cool machine. Flown one off and one many years ago. It was the Father of the Piper Pacer which was one of my favorites. Most of those early Pipers had sketchy gauges.

My Clipper has an O-290D and Pacer wing tanks. I alternate every hour, I get about 4.5+30 hours cruise (~6gal/hr and 32gal useful) so if I grossly mismanage my fuel and the first tank runs dry then I know I've got 1/2hr minimum left.
The Clipper is a hell of a fun airplane. Goes like stink with 125HP, currently getting the wing rebuilt, adding 10" a side with Sullivan tips and putting on a 52 pitch prop. I figure 1000-1200fpm at gross is reasonable to expect.

[robertsailor1]

Very cool little bug smasher, the PA-16..pretty on the eyes as well. Reminds me of the aircraft models I built as a kid.
Don't know anything about the addition of 20" of wingspan as when I was flying them the popular wing mod was drooped tips. Instead of the curved wing tip that went from the full cord to the tip bow you added another full rib from the aileron outboard, then added a glass drooped tip. This mod did effectively add more wing area outboard of the aileron but the span only increased by the width of the wing tip which wasn't a great deal. There were a variety of major claims made about this mod but while it did improve the flying and especially the slow flight it never quite lived up to all the claims. I added it on one of the Pacers I owned and liked it. I think it was Madras Super Tips if my memory is correct. Yours has stick controls and of course the Pacers had wheels. I think the PA-15 and 17 morphed into the PA-16 and then into the 20. All were one wing bay short of the cubs which made them very quick in their day.

[AEROBAT]

Good post BPF, however I still use the watch and fuel burn method. If the guage reads low...of course I land.

[Grantmac]

Very cool little bug smasher, the PA-16..pretty on the eyes as well. Reminds me of the aircraft models I built as a kid.
Don't know anything about the addition of 20" of wingspan as when I was flying them the popular wing mod was drooped tips. Instead of the curved wing tip that went from the full cord to the tip bow you added another full rib from the aileron outboard, then added a glass drooped tip. This mod did effectively add more wing area outboard of the aileron but the span only increased by the width of the wing tip which wasn't a great deal. There were a variety of major claims made about this mod but while it did improve the flying and especially the slow flight it never quite lived up to all the claims. I added it on one of the Pacers I owned and liked it. I think it was Madras Super Tips if my memory is correct. Yours has stick controls and of course the Pacers had wheels. I think the PA-15 and 17 morphed into the PA-16 and then into the 20. All were one wing bay short of the cubs which made them very quick in their day.

The Sullivan extension put a glass horner style tip on but it also straightens out the spar caps and adds two ribs. You end-up with wing area approximately half-way to a longwing Piper, plus the tip is much more efficient then the basically ornamental bow.
You do loose the quaint wing shape so some of that "model like" look is gone, but I'll take the increased performance any day of the week; especially when loaded.
I'm hoping that once I move back up to Canada I can take on a few partners and keep her flying over 100 hours a year, because now that I'm throwing money at the plane I want to keep her for a good long time.

Back to fuel gauges.....

[2R]

Small light aircraft certified by the FAA must have fuel guages that are certified to read empty when the tanks are empty.
If you are not planning to be landing soon when the guages are at 1/4 in a school plane or rental you might experience an off airport excursion.
I have seen fuel burns on some airplanes at twice the normal fuel burn and had fuel tanks leak out in flight through leaky fuel caps,corroded fuel tanks,leaking pipes.The only thing that prevented me from harm was what the old school policy was "Plan to land when the tanks are 1/4 on the guage".As below 1/4 to empty they are accurate on most small planes.
To ignore any guage no matter how flawed the seventy year old design may be is bad airmanship and a poor practice.
Sounds like he is strong candidate for tombstone, if tombstone starts hiring more pilots to fly IFR with VFR fuel out of the peg as they seem to have a history of ignoring fuel guages ,flying past airports with fuel and flying on fumes

Strong candidate is one of HR words that means : we can bend this guy over and tell him to do exactly what we want.

[robertsailor1]

I'm going to assume that all these experiences from leaking fuel to engines burning twice their normal were all on other peoples aircraft and not on your own. If your renting aircraft from people who maintain their fleet to this sort of standard then you could visit Tombstone because something else failed.
If these things have been happening to your own aircraft then its time to look into the mirror for the problem. All that aside if your fuel gauges are suddenly reading low only a fool would not be looking for a place to land.

[2R]

You can learn stuff you really should never really need, renting airplanes from some people who rent aircraft.
Out of a fleet of twenty eight airplanes even the best maintenance will have some anomalies ,as most of the mistakes where honest ones i hold no grudge against that particular company.
That said if the guy flying from Daytona had not believed the gauges he would have been landing in a swamp at night ,as it was the double fuel burn was as a result of a faulty carb .Something that you probably benefit from if you fly a carb airplane as the company reported the defect to the FAA and everyone checked their carbs after that.An honest mistake and it was corrected without harm and people learned from the SB that was issued as a result.

[Big Pistons Forever]

Good post BPF, however I still use the watch and fuel burn method. If the guage reads low...of course I land.

The problem is many (most ?) students never look at the gauges because their instructor has told them they are useless so they should just be ignored. A perfect example of this was a C152 that crashed a few years ago after an engine failure right after takeoff. It was rolled up into a ball about 3 miles from the end of the runway with thankfully no injuries. The engine failure was due to fuel starvation. The chain of events ironically started with maintainance draining the fuel in order to conduct the annual fuel gauge accuracy check ( i.e. to prove that the fuel gauges read "E" when the tank is empty of usable fuel). After the verifying the accuracy of the gauges, the aircraft was put back on line and it was ordered to be refueled. Due to some miscommunication the fueling never happened and the next flight was a PPL solo exercise who was told by dispatch that the aircraft had been refueled. Obviously the student was negligent in that he never dipped the tanks to check, but all through the engine start, runup, and pretakeoff checks those fuel gauges would have been clearly showing empty tanks.

However I think it is quite likely either he never noticed them because he had been conditioned to ignore fuel gauges during his training, or he actually saw the gauges but simply assumed that they were wrong because dispatch had told him the aircraft was full and his instructor had told him in the case of a fuel gauge discrepancy/anomaly, to just assume the gauge was wrong. That is the point I was trying to make with my first post.

[Shiny Side Up]

However I think it is quite likely either he never noticed them because he had been conditioned to ignore fuel gauges during his training, or he actually saw the gauges but simply assumed that they were wrong because dispatch had told him the aircraft was full and his instructor had told him in the case of a fuel gauge discrepancy/anomaly, to just assume the gauge was wrong. That is the point I was trying to make with my first post.

While I hear what you're saying and generally agree, there also bears another possibility, and that is the fact that people tend to be incredibly oblivious to their surroundings. Guages I find rarely attract their attention, hence the proliferation of "idiot lights" in automobiles. I don't know how many times I've seen pilots go through checklists, stare right at something that's not ordinary, and it doesn't register. Full stop, back up. Occasionally flashing red lights and large placards fail to get their attention.

[Big Pistons Forever]

However I think it is quite likely either he never noticed them because he had been conditioned to ignore fuel gauges during his training, or he actually saw the gauges but simply assumed that they were wrong because dispatch had told him the aircraft was full and his instructor had told him in the case of a fuel gauge discrepancy/anomaly, to just assume the gauge was wrong. That is the point I was trying to make with my first post.

While I hear what you're saying and generally agree, there also bears another possibility, and that is the fact that people tend to be incredibly oblivious to their surroundings. Guages I find rarely attract their attention, hence the proliferation of "idiot lights" in automobiles. I don't know how many times I've seen pilots go through checklists, stare right at something that's not ordinary, and it doesn't register. Full stop, back up. Occasionally flashing red lights and large placards fail to get their attention.

I like to think my students are not "incredibly oblivious" to their surroundings because I regularly cover the engine/fuel/electrical instruments with my hand and ask what the gauges are registering......and "in the green" is not an acceptable response, I want to know where the needle actually is. Developing the habit of regularly scanning the instruments and noting what they are saying is IMO eminently teachable. Of course if you tell the student to mindlessly ignore what a gauge is saying you are also building habits, just not the good ones......

[Shiny Side Up]

Developing the habit of regularly scanning the instruments and noting what they are saying is IMO eminently teachable.

I'd agree on that, but one also must remember that often with students you're also attempting to undo years - and sometimes decades - of habit formed not registering what the dials are indicating. With that underlying problem at hand one must admit that we also do need to add another layer - the actual checking of physical fluid levels for instance. In my mind with your example the fact that the student didn't take responsibility for checking their own tanks is at least equal to the sin of being complacent/unobservant/educated wrong in the use of the guages.

[Big Pistons Forever]

Developing the habit of regularly scanning the instruments and noting what they are saying is IMO eminently teachable.

In my mind with your example the fact that the student didn't take responsibility for checking their own tanks is at least equal to the sin of being complacent/unobservant/educated wrong in the use of the guages.

Absolutely the student failed in the essential preflight check of dipping the fuel, however the fact remains that if at any point he had registered that the fuel gauges had shown "E" the accident would not have happened. The students owns the fact that he did not dip the tanks during the walk around but I think the fact that the gauges were ignored would be common at many FTU's and this one area where FTU's and instructors could do a better job.

[robertsailor1]

I'm certain that training is different today from what it was 40 plus years ago when I was learning to fly. We were expected to visually check the tanks for fuel, drain off a sample from each tank and then turn on the master to verify the tanks were reading properly. We were authorized to call the fuel truck and top off the tanks when needed. Several times my instructor purposely didn't fuel up prior to me flying just to make sure I was on the ball. The student who jumped into an aircraft that was out of fuel without doing any of the normal precautionary checks is a candidate for wining the Darwinian award and with that type of mindset should not be trying to become a pilot. No system can be set up to overcome stupidity.

[Shiny Side Up]

Absolutely the student failed in the essential preflight check of dipping the fuel, however the fact remains that if at any point he had registered that the fuel gauges had shown "E" the accident would not have happened.

Nor would it have happened should the individual have checked the tanks themselves. Personally I wouldn't assume that someone who would not check their own fuel would also be vigilant to check their fuel guages either.

The students owns the fact that he did not dip the tanks during the walk around but I think the fact that the gauges were ignored would be common at many FTU's and this one area where FTU's and instructors could do a better job.

The point I guess I would debate here is if indeed it is the failure of instructors to emphasize the use of the guages, or whether there is some other factor at play. Personally from what I've seen from a lot of flight schools - and the long checklists they seem to produce - is if anything there's a quadruple redundant checking of all these items before flight which makes it hard to believe that it isn't being emphasized... But this has its own pitfalls. This I feel is where its failing. The system has become so onerus in most cases in the absolute pursuit of percieved safety that people choose to skip around it whenever the opportunity presents itself, or more commonly want for someone to do it for them and abdicate their own responsibility in ensuring their own safety. Compounding this is the policy of most schools to always require the students to have full fuel whenever possible. This idea is what I feel really breeds the complacency which leads people to disregard fuel gauges and fail to check tanks themselves.