Range of a PA-28?

[venkoj]

Hello,

I currently fly a Pa-28-151. I've read the POH from cover to cover but there seems to be no mention of the aircraft's range. I was told that its endurance is 4 hours on full tanks and 3 hours if on tabs.

So what is the correct way of finding out its range? Is it by calculating the time it takes from A to B and then taking into account the endurance based on how much fuel it has? Any thoughts welcome.

thank you

[PompeyPaul]

I think it works out as full tanks of 50 gallons, with around 45 gallons usable of that. Burn rate of 9 US gallons/hour means an endurance of 5 hours @ 100kts which is around 500NM or 575Miles (not for operational usage)

Although, if it were me, that would be pushing it way more than I'd want to :eek:

[BackPacker]

Even if the POH were to list a maximum range, then this will be the max range under optimal circumstances. High or low as appropriate, power and leaned back for max economy, straight line etc. You'll rarely be able to fly like that in Europe with all the controlled airspace, climb restrictions etc. in the way.

Plus the max range will be assuming nil wind. Hardly likely on a 500+ nm flight.

So better plan your route and altitude and see if the plane can handle this than work the other way around.

[znww5]

I'm assuming this is just an academic exercise to get a ball park idea of theoretical range before the engine stops - nobody in their right mind would try it in reality!

Endurance x IAS = still-air range

The trouble is that endurance figures from the POH are 'showroom' figures based on a new engine in a shiney new aircraft, probably using recommended mixture leaning techniques at the optimum power setting with a test pilot on board.

Personally, I fill it and allow a 1hour reserve - over-cautious perhaps, but fuel exhaustion is a significant cause of GA incidents and I wouldn't like to become a statistic.

[Heliplane]

For very rudimentary flight planning purposes, you could assume the plane has a range of about 500nm, although there are many other factors at play here.

Endurance is the key factor: figure out the speed you want to fly at (if you're going somewhere, you'll probably want to cruise at 70-75% power) and calculate your endurance (48 gallons usable fuel, 8-9 gallons per hour).

Let's say it's about 5 hours (overesimate fuel burn and round down endurance times).

Give yourself at least an hour's buffer of fuel (and possibly more to ensure you can reach a suitable diversion plus have a comfortable buffer on top of that - this will depend on your destination). Add a further 20 mins to deal with startup, taxi and the extra fuel you'll burn during takeoff and climb.

That leaves you with about 3:40 of time to fly. At 75% power (110kts), that should give you a rough figure of about 400nm.

Then factor in the winds and the effect they will have on your groundspeed. Always overestimate a headwind and underestimate a tailwind and remember that crosswinds will have an effect too.

Remember to lean properly as the fuel burns in the POH will almost always assume proper leaning technique (level flight, stabilise airspeed, set power, slowly reduce mixture until you sense engine roughness and then push the mixture lever forward about an inch - remember to enrichen for climbs and re-lean every time you change height).

You'll also want to think about yourself and your passengers - I find that anything much about 2-2.5 hours in a light single in one go starts to get uncomfortable. If you have passengers, will weight and balance allow you to take full fuel?

Few things to think about, a lot of variables, but that's why pilots are special.

The legal bit: everything I have written is qualified entirely by the aircraft's POH.

[IO540]

The half tongue in cheek answer is that the range of a PA-28 is an unknown quantity, because

- nobody taught you how to lean the engine

- the fuel gauges are useless

- there is no fuel totaliser

- the tachometer is probably knackered so setting an accurate RPM, hoping to get the fuel flow in the manual, cannot be relied on

The only way is to find a way to lean for peak EGT, or some nearby operating point, in cruise. With no instrumentation, the way to do this is to set a power setting of say 65% (use the manual to find the RPM) and then lean until the power suddenly drops off, then advance the mixture back until the power is just restored.

Then do two identical flights which differ only in the length of the cruise segment. Top off before/after each flight, and then by subtracting the fuel usage on the two flights you get an accurate figure for the cruise fuel flow at that power setting. This will be specific to that aircraft.

Then, you can fly reasonable distances with some confidence.

Otherwise, the range is about 200 miles.

[englishal]

Don't all POH's have graphs in them detailing either fuel burn or endurance or boh? Certainly all the ones I have looked at have, and they show endurance / range / fuel burn for various altitudes when properly leaned .....Are you sure there is nothing in the POH? Mine has a tabular format which lists pressure altitude, power setting, fuel flow etc.....

[smarthawke]

I was filling in the log books for one of the aircraft in my charge the other night - Piper PA28-181 Archer II and found 5.1 hours on the Hobbs in one flight. It was then refilled to full with 169 litres with a total useable capacity of 181 litres (same tanks as a Warrior 151 and 161). Me thinks someone was pushing their luck....

[A and C]

With only 12 lts left that is just over 18 min at 75% power!

[UV]

around 500NM or 575Miles
figure of about 400nm.
the range is about 200 miles

Which, once again, shows that when you ask 10 pilots the same question, you always get 11 different answers!.
UV

[Mark1234]

The trouble is that endurance figures from the POH are 'showroom' figures based on a new engine in a shiney new aircraft, probably using recommended mixture leaning techniques at the optimum power setting with a test pilot on board.

First up, we always say something like this, and it's not a bad attitude to have, however, I'm pretty sure I recall reading somewhere that the aus (where I'm flying) standards for the POH reauire that the takeoff / landing data is required to have a percentage 'fudge factor' - i.e. there's a margin built in that makes things realistic for the 'average' pilot, and aircraft. I'm not suggesting you use that margin, and a 'personal limits' buffer on top isn't a bad thing, but don't be too hasty to dismiss the POH.

Secondly, while not as comprehensive as IO540's method, I generally dip the tanks before *and after* each flight. That gives me a pretty good idea of fuel burn for the aircraft on an 'average' flight (though it lumps climb, descent etc all together). Longer flights will always do better, but guess what.. if anything the POH figures come out *pessimistic* - so I can plan the POH figures with confidence. Your mileage may vary!

@UV, I think you'll find IO540's '200 miles' was a little tounge in cheek! Otherwise, 500+ miles to dry, 400 with sensible reserves would seem ballpark.

@venkoj (original poster), I don't wish to be unkind - I suspect you're in training: the POH has all you need to know, you should probably have a chat with your instructor. If you're a 'fully fledged' pilot, some revision would be suggested.

[Tinstaafl]

12L (presuming all is useable) might only equate to 18 mins at 75% but at 45% it's significantly more than that. As a minimum, in the US for example, VFR by day requires a 30 min reserve (45 min at night), Oz requires 45 min day or night.

Without the POH I'm only surmising but 12 L useable would be pretty close to a required reserve at 45%. If there are a reasonable number of airfields in the last few enroute sectors *and* the pilot has a good record of his past achieved fuel consumption in that aeroplane then its not such a big deal.

No argument about the benefit of fuel totalisers though! The aircraft I'm on has those and the owner has just installed a JPI EDM-760 on my recommendation. It's just sooooo easy and comforting to be able to run lean-of-peak for excellent economy AND know exactly what's happening to the fuel flow, remaining endurance and what each cylinder is doing. As far as I'm concerned a totaliser & EDM should be mandatory.

[IO540]

Problems with using the POH might include

- a different prop has been fitted

- prop overhauls, removing metal (overhauling a fixed prop means a higher RPM is needed for the same thrust)

- the engine might be knackered (the fatal IOW one last year had so much metal missing off the camshaft that the valve lift was reduced by 40%)

- the engine control end stops might be set wrongly

- the RPM gauge might be off (power is proportional to RPM cubed, I think, so a 5% error means a 15% error in setting the power (=thrust) figure)

- the 30 year old POH might have been hacked around, bits replaced, etc.

etc.

500+ miles to dry, 400 with sensible reserves

is not good! What if the destination is closed due to say fog? You have to fly say half an hour to an alternate, and then you have almost nothing in the tanks. And fog tends to be widespread. A 1hr reserve is not enough. With my 1% accurate flowmeter I can do this (but wouldn't).

[Johnm]

The POH will give you fuel consumption and capacities, but you'll be lucky if you get book figures. As it happens I do, but I've got a new engine and lean religiously with the help of a EGT.

A good rule of thumb for VFR that I was taught while training for typical trips below 5000ft is:

2 gals taxi and climb, 2 gals descent and land and 10 gals per hour in the cruise and 5 gals (half an hour) reserve. This should be checked against the POH to make sure it's more conservative. You have a maximum of 48 gals usable so at a typical Archer 2 cruise of about 110 kts my arithmetic says that'll take you about 430nm in nil wind conditions.

Oops, just seen that we're talking about a 151 not 181 in which case cruise is going to about 90kts and so range is nearer 350 nm

Personally I always plan around 2 hour legs just for my own comfort.

[eugegall]

Just to keep think a little more simple here.

I flew from Fairoaks to Carlisle on full tanks with 3 people inc me. on the way i had near nil wind conditions. When i got there i had an inch above tabs on both wings. I was shocked to say the least. I could have easily flown all the way back and then done 20 circuits

[FREDAcheck]

Oops, just seen that we're talking about a 151 not 181 in which case cruise is going to about 90kts and so range is nearer 350 nmI think Johnm makes an important point. Every PA28 is different. Which engine? Which model? Warrior or Hershey Bar wing? New or clapped-out engine? And of course, what power setting? Leaned or not? Head/tail wind? Take-off weight? Which prop, and in what condition?

As a result, there really is no general answer to range, but you can get an approximate answer to duration. The one I fly (a 180) does 38 litres/hr at 75% power (2560 rpm) giving a theoretical endurance of 4 hours 45 minutes, and 32 l/hr at 60% (2350 rpm) giving an endurance of 5 hours 40 minutes. Personally I would never assume more than 5 hours, even though I were flying at around 60-65% power, and I always allow a reserve of an hour on a long trip.

If I'm taking passengers I find the main limitation is that they get bored / want a coffee / want the loo every two hours or so - 3 hours max - especially if it's bumpy.

[venkoj]

I'm assuming this is just an academic exercise to get a ball park idea of theoretical range before the engine stops - nobody in their right mind would try it in reality

it is indeed, I have no intention of pushing it to the limits

@Mark1234: yup, still in training. have chatted to 2 instructors about it but got different answers... I now have even more :)

[IO540]

have chatted to 2 instructors about it but got different answersThat's because they haven't got a clue. Most PPL training in the UK is done with the mysterious red lever all the way forward (wasting about 30% of the avgas) and the flights are kept short.

That's why I suggested doing those two flights, etc.

One should never push fuel planning to the limits, but accurate data enables you to plan the reserves with confidence. Let's say you have established that your range to dry tanks is 630nm, then (at say 100kt) you can do a 400nm flight, 100nm to alternate, and still have 1hr in the tanks (the FAA IFR reserve rule, FWIW in this case). My own planning is destination, alternate, then 2hrs in cruise, but then I fly a TB20 with a dry-tanks range of 1300nm.

The stuff I was taught in the PPL, like "3 hrs in an Archer" is just crap, and dangerous once some pilot discovers that he can stretch it quite a bit.

[englishal]

I learned about fuel flow from flying a PA28-236 for about 4.7 hours from TABS!!! (and the subsequent misfire on the ILS....) But that was a long time ago and something I NEVER repeated.

Anyway I know that my current plane does 31L per hour average....by experimentation and lots of flights, which matches the book figures. Still because we never really know how much fuel is onboard, other than our calcs (fuel is not visible after an hour per tank, even with over 100L onboard - 170L tanks) I'm going to get me one of these:

http://gps.co.uk/newhtm/instruments/fs450.jpg

[Tinstaafl]

You don't need to do two flights to get accurate fuel consumption data. The PA28 series has a L - R - OFF fuel selector. Start with the tanks filled to a known, easily seen point eg the tabs or the filler neck or a convenient scratch or whereever. Start, taxi, take off & climb to your typical cruise altitude (better slightly higher than lower) then set *leaned* cruise power on one tank. Note the time and change to the other tank and cruise for an hour or, better, two. Note the time & change back to the start tank for descent & landing.

Refuel to the original level & note what each tank used. You now have the data to calculate fuel consumption from start to landing excluding cruise and, separately, leaned cruise. If you apply the calculated leaned fuel rate to the entire flight duration you will have a figure that represents how much fuel would be used if the aircraft had started above the airfield at cruise altitude/configuration/power setting, and arrived above the destination the same way. Compare that extrapolated fuel burn with the total fuel burn for the flight to find the additional amount of fuel that is used from start to top of climb and top of descent to landing.

If you have multiple tanks eg mains and auxillaries and are without an accurate fuel flow system it's possible to compensate - slightly - and have at least two points where the amount of fuel on board is known accurately. First point is prior to departure with full tanks or filled to a known level. The second point is running the alternate tank dry or very nearly dry. The principle is that if you have two or more containers (instead of a single large container) you will have a known quantity remaining in the remaining, unused containers if consumption is confined to a single container at a time until it is empty.

Provided the time from start to when you switch to the alternate tank is relatively short then what's left in the mains will be very close to the calculated amount after subtracting estimated fuel burn. Over such a short period of time the margin of error is small.

If you have a good idea of cruise fuel flow eg the proving fuel consumption flight discussed above, then the time to empty on the Aux can be anticipated to within a few minutes. At the point where the Aux runs dry or you decide it's as close to empty as you're willing to go, you have a pretty accurately known quantity of fuel on board in the remaining tank(s). If not run dry there will be a margin of error but it doesn't affect the accuracy of the known fuel in the other tanks.

If you have to switch between pairs of aux's to maintain lateral balance then for this purpose you would consider the pair to be a 'single' tank and known fuel on board accuracy will be when both aux. tanks are empty.

[IO540]

Very clever, Tinstaafl :ok:

Incidentally, I have a variant of the Microflo-L (http://www.shadin.com/products/ff_mgt/microflo/index.html).

The transducer for all of these products (Shadin or JPI, etc) is a Floscan 201B (http://www.floscan.com/html/blue/aviation.php) or similar.

I'd never fly anywhere half serious without this kind of kit.

[Mark1234]

IO540, good points all - I did say your mileage may vary. All I can say is for the fleet I'm hiring from, I'm getting marginally better than the suggested fuel burn. I generally plan 36ltrs/hr. None of them are at all close to brand spanking new. They are however well maintained, and I do use the spiky red knob. The point I intended to make was to compare actuals and know what to expect at worst.

As for the POH/conventional wisdom, it seems to suggest we're all flying knackered old pieces of cr*p that don't come anywhere near to doing what the book says. I don't believe it. Not suggesting one should push the numbers however.

I'm also reasonably confident we'd all agree that fuel planning is done on time, not distance, distance being rather more of an outcome than an input.

What constitutes a reasonable reserve, over and above the legal minimums is up to you, the pilot. I'd hazzard a guess that I'm blessed with better weather, and more convenient alternates than IO540, am not IFR, and last but not least when the forecast gets frightening I stay on the ground. I always plan on landing with *at least* an hour in the tanks, though I'll frequently plan more, especially if there are other factors. Based on that, given a good VFR day with the right conditions 400nm is about ballpark for the PA28-161's I fly, and theoretically they'd hit a bit more than 500 before falling out the sky - all in still air. Of course, it also depends how high you fly.

[A and C]

12 Lts is no doubt IRO the required reserve fuel if you are at 45% Power at best lean mixture, but is this wise?

When the guy ahead of you blocks the runway and you go around at full power, full rich mixture will eat into this at an "interesting" rate, next you are off to another airfield and during this (most likley high workload) diversion you dont have 45% power set at best lean mixture then the fuel gets burnt at a much higer rate, at the same time the aircraft is flying at a much slower speed than the usual cruise speed.

I would suggest that what is in theory OK might not be quite so wise in the real world.

[Pugilistic Animus]

And sometimes with an operation you have to just get out the POH and get to figgerin'---only to find out after the Wx check you've got to have fuel stop anyway:}

PA

[Rishy]

Mark1234, you have PM.

[Brooklands]

eugegall,
I flew from Fairoaks to Carlisle on full tanks with 3 people inc me. on the way i had near nil wind conditions. When i got there i had an inch above tabs on both wings.

?? Did you mean 1" below tabs on arriaval? From what I remember of the PA28-180 I flew full tanks was 48 USG and tabs was 36 USG. I can't see how you could get from Fairoaks to Carlisle using less than 12 USG.

Brooklands

[Blinkz]

Why is there such confusion going on?? The simple reason why endurance is given as the main fuel burn as opposed to range is because the range will ALWAYS change with the wind, endurance given the correct procedures will be relatively accurate. Its all very well saying the Pa28 has a range of 500 miles, but this is not correct. It has a range of 500 miles in nil wind, or a range of 0 miles if the is a headwind of 120knots!

or have I missed the point of the original post??