pa28 fuel

[PA28181]

I still think it's a bit rubbish that you can't easily measure what's in the tank. That is assuming the dipsticks on the Cessnas are accurate....!

With unreliable/unusable fuel guages, dodgy dipsticks, I'll have to say it again, once you get used to the aircraft, and know it's fuel burn it's not rocket science to work out how long you have when you know what the previous fuel uplift was, tabs/full. And yes there will be a record of fuel uplift won't there? It isnt that hard to get a good estimate from just looking in the tank anyway. Do you intend to fly to the last drop? Of course not, So don't get too hung up on it.

[A and C]

Jollyrog

There are four rock hard fuel measures on a PA28, the one you forgot is empty !

The engineer removed a measured amount to an approved storage ?.......... I guess that approved storage would be the fuel tank of his racing motorcycle !

[thing]

I find the Cessna dipsticks OK actually. they are always a couple of litres or so pessimistic which is a good thing. I tried the accuracy on a longe range tank 172 with a known amount of fuel and it was remarkably accurate.

My question on the 28 is this; full=182 litres, tabs=133 litres or so but how much fuel have you left when you can just see fuel covering the bottom of the tanks? I've heard two hours to fanstop but obviously you wouldn't want to go on hearsay.

I filled a 161 to the gunnels for a trip to France last year, about two hours each way which I thought would leave me plenty in reserve. When I got back and looked in the tanks I was aghast to see them virtually empty with bare metal showing. I filled up and as I remember put around 130 litres in to brim it, which meant I still had around 50 litres left. Seemed a bit odd to me.

[cockney steve]

May I suggest a simple experiment? Get a large ,shallow dish and fillit with water from a measuring-jug. You will now have a "full tank"
now tilt it.....water will slop over the edge.....continue tilting, until the bottom is exposed on the "high " side HORRORS! - your tank is empty, you can see the bottom.....OK, now level your dish again. SURPRISE!
It wasn't empty, at all. there is now a layer of water across the whole bottom.

Does this sound familiar?
I sometimes wonder just how some people manage to pass their PPL with such a poor grasp of elementary mechanics and physics.

[thing]

Mmm, you may not be aware that most pans are flat and therefore the fuel tank is not 'tilted' in any way. Anyone any serious suggestions?

[A and C]

Cockney Steve

Will you please stop using common sense, don't you know that aircraft run on myth, old wives tails, things that bloke in the bar said....... And worst of all the thing used to explain things people don't understand.... So they call it Airmanship!

Fortunately at the big end of this business Mr Boeing agrees with you, to manually check the fuel level an an airliner they have fitted a roll and a pitch spirit levels, using the attitude information from the two spirit levels and a big set of tables you can turn the inches calibration on the sticks into an accurate fuel volume.

[thing]

See, told you dipsticks were pretty accurate.

[A and C]

Thing

Dipsticks are very accurate but only with the aircraft in the one attitude that the dipstick is calibrated for, hence Mr Boeings use of the two spirt levels & a set of tables the size of the yellow pages.

[foxmoth]

you may not be aware that most pans are flat and therefore the fuel tank is not 'tilted' in any way. Anyone any serious suggestions?

A pan may be flat but most aircraft wing tanks are actually tilted due to the dihedral! The Bulldog tanks for example are over half full if you can see anything in there, can't recall exact figures for Pa28, but certainly IIRC you have an hour plus if you can see fuel in both tanks.

[thing]

Thank you Foxmoth, result.

[tomboo]

This discussion has turned out to be quite interesting and has reaffirmed my original opinion that for something quite important there is only a very vague answer for, both A/C types in fact. I assumed, perhaps naively that a dipstick for a cessna would be accurate:

- Relying on fuel uplift records of a club A/C is potentially silly, mistakes are made and there are many unknowns.
- Why are dipsticks for Cessnas available but not for PA28 - there must be a reason.
- There is no way of knowing how much is in the tank unless empty, tabs or full.

[PA28181]

Relying on fuel uplift records of a club A/C is potentially silly, mistakes are made and there are many unknowns.

Any evidence or hard fact to support that assumption?

Fact: There are dipsticks for PA28's

There is no way of knowing how much is in the tank unless empty, tabs or full.

Now that is silly...............with experience you will know...

[A and C]

PA28181

Evidence to support that.................Try one PA34 landing on a railway line and one very sorry looking pop star !

You sound like your about to play fast and loose with fuel levels......there is only one end to that.

[Big Pistons Forever]

Originally Posted by PA28181

Make sure wings level or readins are u/s

When you are familar with acrft you will soon learn to work on tme flown since last refuel ie: tabs or full. A pretty accurate fuel assesment.

Tabs are a fixed dipstick with one reading. They are also only accurate with the wings level. The advantage of using a dipstick is you get a reading of fuel quantity regardless of what the level is. The caveat of course is having an accurate stick. Calibrating one is not exactly rock science though as you just have to sit the aircraft on a level surface and add measured amounts of fuel.

BTW working fuel gauges are required for Cessna and Piper aircraft in order for them to have the C of A in force. The fuel gauges are admittedly not terribly accurate at high fuel levels but if working properly they will be quite accurate at fuel levels of 1/4 tanks and below and when they indicate zero there is no more fuel left. Low readings on the fuel gauge should always be treated with respect and I refuse to fly an aircraft with fuel gauges that don't work as that aircraft is not legally airworthy.

[Tinstaafl]

Tomboo, what makes you think that a C172 dipstick is any more, or less, accurate than one for a PA28? About the only dipstick in GA that is supplied by the aircraft manufacturer (that comes to mind) is for a Victa Airtourer. All the others you see are made by some company or person unrelated to the aircraft manufacturer.

[piperboy84]

I have a 4 sided length of wood marked as follows, 2 sides for the mains and aux tanks when the plane has the Tundra Tires, and the other 2 sides when I've got the little wheels on, marked up in 10 litre increments starting at the 30 litre level.

After i get done flying, I mentally calculate how much fuel should be left based on the type of flying i was doing i.e. staying low or having a long climb at high power then measure it to see how close I am. Now I know that is may be unnecessary, but the joy i get when the calculations are within 5 litres really puts a smile on my face and makes me feel like a right smarty pants.

Sad b*&tard huh !!!

[PA28181]

You sound like your about to play fast and loose with fuel levels......there is only one end to that.

Absolute codswallop. Know the aircraft and it's fuel burn there is no problem. So when I see a fuel truck load up fuel to tabs to and know the acrft has flown one hour before I use it. Where's the problem? I look in the tank and assess the fuel endurance Cant you?.

I've been about playing with fuel levels for over 36 years now, so have some idea about fuel management by now. This is getting very silly now.

After i get done flying, I mentally calculate how much fuel should be left based on the type of flying i was doing i.e. staying low or having a long climb at high power then measure it to see how close I am. Now I know that is may be unnecessary, but the joy i get when the calculations are within 5 litres really puts a smile on my face and makes me feel like a right smarty pants.

My point entirely...

[tomboo]

So until you're 902 and 'know' the aircraft, you don't know it, if you know what I mean! I don't have 8 million hours on type I have about 3! When I do I will hopefully have a better idea, like riding a bike perhaps, until then, I'll think I'll fill it to the, "known" quantities. It's also unrealistic to think there will always be an instructor/someone about to ask, even if you do trust everyone you meet!

I would definitely say it's silly to rely on other people's paperwork in a club environment, I don't think I've ever seen a tech log/fuel sheet without some sort of correction or mistake on it ! Come to think of it, I always do an A check, even if it's already been out. Maybe I'm just a bit too cautious. Be old not bold - I like that !

Looking at the main pilot shops, only Cessna calibrated dipsticks are sold, I haven't seen any pa-28 ones, just universal ones. That suggests to me that using a dipstick on a Cessna is more acceptable? Is that right do we think, if so, why?

I appreciate that tabs are a form of dipstick, wings level, flat surface this will obviously apply to most fuel system I'd imagine!

So in the highly regulated, safety conscious environment that we operate in, there is quite a lot of suck it and see. Am I right or just a big fat chicken?! Answers on a postcard !!

As I suspected, there is no right answer to the original question and yes it seems to apply to all types, I wasn't being pa-28ist. So I need to work out a my own rule of thumb !!

[malc4d]

BPF
Yes working, but not accurate ....anyway not under FAA rules, There they only have to be accurate when empty ....Now thats really safety in action.

[Big Pistons Forever]

Originally Posted by malc4d

BPF
Yes working, but not accurate ....anyway not under FAA rules, There they only have to be accurate when empty ....Now thats really safety in action.

It is simple, when the fuel gauges are indicating close to zero you are almost out of fuel and you had better do something about it NOW.

Story 1

I have personal knowledge of one accident where the persons instructor had always said, "the fuel gauges are useless just ignore them". He left with one hour out of full tanks ( C 172 40 Gal) on a cross country with a PLOG that said he would land with 45 mins reserve.

Inadequate leaning and shagged out engine made for higher than normal fuel consumption and so when he got to his destination the gauges were showing close to E, but hey the gauges are useless so no worries and so when the tower asks him to hold for 10 mins at a VRP he says sure. On final it gets very quiet and he totals the aircraft landing short of the runway.

The good news is there was no chance of fire as the tanks were bone dry

Story 2

Instructing in a Cessna 150 with standard 22 gal tanks. Left with 1/2 tanks (dipped) gauges show half tanks. 30 mins into the flight gauges show a less than 1/4 so I think "That ain't right" and we head home. When we land the gauges show under 1/8 th, and the belly of the airplane is blue. It turns out the gascolator gasket had failed and we had a pretty good fuel leak happening. By believing the gauge I saved us from a certain off airport forced approach.