Changing fuel tanks on PA-28-161

[Pilot16]

Hi,

Im wondering how often do you change the fuel tanks on the
PA-28?

As far as my understanding goes, the PA-28 aircraft will take fuel from the tank selected (unlike C152 where it is taken at the same rate from both tanks)...

My instructor said that tank should be switched every twenty minutes in flight in the PA-28-161

How do you do it? What if the fuel gauge indicator is showing one tank has more fuel then the other? Then the obvious instinct is to keep the tank with more fuel turned on hence it may not be the best of ideas to stick to the twenty minute routine!

[TonyR]

On a long flight I change tanks every 30 minutes, in the 161 you are only going to use about 16 litres every 30 minutes and that wont affect the aircraft in any way.

Fuel gauges on ALL light aircraft are USELESS, Know before you take off how much fuel you have and make a note of, take off time ,and the time you change tanks.

I have a simple system.

If I take off when my watch is between 6 & 12 ie. the left side of the "clock, I take off on the left and next change at a "quarter past" to the right tank, then at a "quarter too" I go back to the left.

It may not work for everyone but it has worked for me for many years in various aircraft.

Tony

[Final 3 Greens]

At the risk of stating the obvious, you need to switch on the electric fuel pump before changing tanks, then switch it off after.... but monitor the fuel pressure gauge for a few seconds afterwards to ensure that all is okay.

[foxmoth]

20-30 mins is fine UNLESS there is a large imbalance for some reason (i.e. the last person to fly it did not balance the tanks).
Idealy fill to a balanced state before flying, but if not possible for C of G reasons or fueling not available for example, then fly on the fullest side until that side indicates just below the other side, THEN go to the 20-30 mins system. (Making sure VISUALLY before flight of course that the fuel state agrees with the guages). Also make sure that the reason for any imbalance is not a fuel leak. :ok:

[tmmorris]

Mind you, if flying solo I find the PA28 needs constant gentle right aileron to balance my weight, so you could always burn asymmetrically to offset this...

My instructor in a PA38 (same system) taught me to pick a field to land in before changing tanks...

Tim

[WestWind1950]

I like your system TonyR... sounds simple enough.

basically, as already said, it depends on fuel amounts, etc. Weighing only around 110 pounds myself, if I have both tanks full but a passenger weighing 2-3 times my weight :uhoh: I would obviously use up the right tank a lot longer before changing. :cool: and, as already said, don't forget to put on the fuel pump before changing and letting it run a few minutes afterwards before turning it off.

Westy

[IO540]

If planes had usable fuel gauges, this question would not arise :O

I would say every half hour. Some people use a cooking timer for it.

[A and C]

If you want to change the fuel tanks on a PA-28 you will need a good philips screwdriver , a drill with a number of bitts and an E-Z out.

The chances are that the screw heads will be in such poor condition that most of them will require the E-Z out to remove them.

I would recomend that CRS screws are fitted as the tanks now have to be removed for a five yearly AD on the spar.

[Microheavy]

Hahaha......................Classic.......

A and C, You made me wake the baby I laughed so loud so suddenly !

[FlyingForFun]

Yep - me too! No baby to wake here, but I think the neigbours heard laughing over the sound of their stereo (and to hear anything over the sound of the neigbour's stereo is an achievement!)

A&C, how long do you think it would take to change a fuel tank on a PA28? I'm a little concerned about the suggestions to change tanks every 20 minutes - if it takes more than 20 minutes to change a tank, the second one will need changing before I've finished changing the first, and things will start getting very difficult..... :D :D :D

FFF
---------------------

[18greens]

How about when you land?

I've never noticed a serious fuel imbalance affecting flight and I'm always more concerned about having enough fuel to get back.

If you arrive at the destination with both tanks balanced but below tabs I always feel compelled to fill up because I am never quite certain how much fuel there is in the tank. Obviously it depends on the journey but it would be just my luck for that to be the day it decides to burn 15gph instead of 8.

I read an ILAFFT about a piper that leaked fuel from the left tank while the right was selected and vice versa. The pilot was on a run dry strategy and was also trying to eke out economy by flying at 14000' without oxygen. His left tank gave him a calulated 6ghp (great) but it had been nicking 3 from the other side. Thus when he swapped to what he thought was a full tank it was less than full. Fortunately when he descended to below 10,000 he realised something was not right and stopped. He then put fuel capacity minus 2 gallons into the tanks to fill them

Thus If I am on a 2 hour journey (1 hour there one back) I will burn the first leg from the right tank. Once I arrive I can check content. Left should be full and right should be just below tabs. I know I have full tank to return on and another one to taxi on. If the left is no longer full I know I have a leaky valve.

ALso if you go local for 1 hour and don't change tanks (other than for the power checks) you only have one side to fill.

If you are going to follow the swapping strategy the left side right side Tony Rs method sounds great.

[A and C]

I should never have picked up that book "eats , shoots and leaves" it was bound to get me into trouble on this forum !.

[Thumpango]

tmmorris

just slightly concerned about your instructors comment about changing tanks on a PA38, is there a known problem here? I passed my skills in a PA38 and have switched tanks many times on my solo trips without incident and am about to fly one again soon!

What with this and the 'interestingl' stall characteristics I am wondering if I should stick to a PA28!!

Please explain! as I am getting a bit twitchy now over a plane I have loved flying.:ugh:

[Genghis the Engineer]

Don't worry about the stall, if you've learned on it, you've seen the worst the PA38 has to offer. If you get a ride along in a PA28 or C152/172 sometime ask somebody to show you the stall, it'll seem incredibly docile - thing is people used to those types get a bit worried about the Tomahawk which requires you to actually recognise the stall warning (rather than rubbing your nose in it) and drops a wing a bit.

As for picking a field before changing tanks, I think that's just sensible practice, and nothing to do with any particular type.

G

[Thumpango]

Thank you Genghis for the reassurance!

I am current on the PA28 as well and I know what you mean about trying to get to the stall, very docile!

The Tommahawk can bite if not driven well I know. Just wondered if there had been an issue with the fuel change-over that I wasn't aware of. I have always changed tanks routinely whilst doing the normal FREDA checks and haven't really given much thought to it leading to a problem, until now.

[Sultan Ismail]

Hope it's not too late in the day to add a couple more points of view.

As part of weight and particularly balance one should share the fuel draw between the tanks.

In published checklists for the PA28-161 it is suggested that the emptier tank is selected for startup and taxi to the holding point.

The fuller tank is selected for the cockpit checks and engine runup, and subsequent takeoff.

This exercise would prove that fuel is being "drawn" from both tanks.

Thereafter, if on a navex or crosscountry, change tanks every 20 minutes, switching the pump on for the crossover and for a few seconds after, until pressure is stable.

Has nobody heard of dipsticks? OK some wiseacre can make a quip on that one, but all my club aircraft have calibrated dipsticks, for the mixed Piper and Cessna fleet. Incidentally the dipsticks are individually engraved with aircraft callsign.

Never any doubt during the preflight as to quantity of fuel available and in which tank.

It is easy to get into a tank selection regime with the Piper PA 28, they do not go far with the switch in the OFF position.

Happy flying

[FNG]

On Bulldogs and Beagley Pups you fly about with the selector on both. If, as happens, you get a bit out of balance, you switch to one tank or the other for a few minutes. For those aircraft with tanks fore and aft, the procedure may vary. For example, on the rare occasions when a Cap 10 has fuel in the rear tank (for touring, aeros prohibited in this configuration), balance isn't really a problem, and you can run the rear tank to the 15 minute light before switching to the front, although I sometimes switch between them a bit as I go.

[Charlie Zulu]

In our group we always fly the Beagle Pup with either left or right selected, we never use both for some reason.

[FNG]

I recall being briefed that if you park a Pup with "Both" selected the fuel runs into one tank and may drain out of the overflow, so we always park with the fuel on "left", and not "off" (for some reason which I have, shamefully, forgotten, although it might be, again, to avoid the fuel draining away). I saw something recently in GASIL or elsewhere about fuel feeding problems in a Pup in flight, but the drills for the Pups and Dogs which I rent specify the use of both tanks for routine operation.

I have a copy of the POH at home but can''t presently recall what it says on this.

[Tinstaafl]

For L / R only a/c I select from the fullest tank for runups/take off & stay on that tank until the nearest 12 o'clock or 6 o'clock. If there was a significant difference I'll delay until a more appropriate 6 or 12.

Thereafter I change every hour. Sometimes every half hour. Depends on the a/c & how much fuel I'd like in a particular tank.

I've also used the quarter hours marks ie 15 & 45 but generally 6 & 12.

[Charlie Zulu]

You're quite right FNG.

We never use the "off" position on the Beagle Pup's fuel tank selector when parked up no matter how long we're going to be leaving the aeroplane.

The pups manual (which I have a copy at home with me) states:

Management of the FUEL SYSTEM

For normal flight the fuel cock control may be kept in the BOTH position. In this condition uneven emptying of individual tanks may occur and periodic selection for left and right tank contents indication should be made to check the associated fuel contents to avoid running inadvertantly dry on one side. This check must also be made during final stage of the descent before commencing the approach and landing.

Note 1. During flight with the fuel selector cock either L or R position, the appropriate tank contents should be selected.

Note 2. When the aircraft is standing on the ground with the tanks full and the wings not level, select fuel cock to L or R to avoid loss of fuel through the tank vents.

Note 3. Modiciation BE13 introduces extra fuel tanks, one in each wing outboard of the standard tanks, to increase useable fuel to 36 imperial gallons.

Now I remember why we don't fly on both... because of the possibility of an uneven fuel balance even then. We also fly on the left / right so we don't "forget" to change to either left or right (normally the fullest tank) for approach and landing.

Also in this configuration we won't "forget" (that word again!) to change from BOTH to LEFT or RIGHT upon shutdown of the aeroplane, thus preventing the loss of fuel if left, wings uneven, on BOTH or OFF selector.

Oh yes, the Beagle Pup only has one fuel guage with a selector to display either tanks contents... so when we change the fuel selector to a different tank we also change the fuel guage display selector to the same tank just so that we know without checking underneath P1's seat and A4 kneeboard etc etc...

Best wishes,

Charlie Zulu.

[QSK?]

I follow similar procedures as Sultan Ismail and Tinstaafl, which is what is contained in my copy of the POH for the PA28-161 in terms of tanks selection for taxying and runup/takeoff. After takeoff I normally run the first selected tank for 30 mins and then change tanks every hour after that.

However, I also like TonyR's little "system" as a useful reminder for making sure you have, in fact, changed tanks and will probably implement that on my next trip.

Now, I understood we pilots all followed POH guidelines, don't we? DON'T WE?

[englishal]

When the engine starts to splutter, its time to change tanks. Then you know that you have half you fuel left ;) Thats the nice thing about PA28's, they have a big reserve tank:}

(every 20-30 mins should be fine, fuel pump on, switch tanks, fuel pump off, keep finger on fuel pump switch, watch the fuel pressure, if it drops to zero, pump on and switch back....)

EA

[FNG]

Cheers, Charlie Zulu. I almost invariably find that the left tank gets out of balance first. This may be because of flying widdershins, but may also be something to do with me being such a fat knacker. The same does not tend to occur in the Bulldog, but that is a bit more stable in the cruise than the Pup, so even cackhanded me can keep the thing level.

[Charlie Zulu]

Hi FNG,

I'll have to do some tests when we get the Beagle Pup back from its extensive maintenance in the next few weeks.

I can't confirm if we have a balancing problem with the fuel tanks myself as the fixed trim tab hasn't been set properly for while on ours. Thus I'm constantly feeding in slight aileron to the left to balance out the right turn tendancy (in straight and level flight).

Interesting that you say the Bulldog is a little more stable in flight, probably due to the longer wings and higher wing loading than the pup. I'm probably going to have to have a go in a Bulldog to see for myself! (My excuse) :D

This should be fixed when we get it back so I'll take a look then.

Back to the subject of the thread...

As I said earlier I use LEFT or RIGHT and never BOTH or OFF(!). As someone else has been using I was taught (and seemed logical!) to use the tank that the minute hand points too on a watch...

For startup its the lowest contents, for take off the highest contents, when at a safe cruising altitude I'll switch to the tank that correspondes with the minute pointer on the watch, if it isn't there already.

Edit: I'll use OFF if I have an engine failure and / or fire... obviously!

Best wishes,

Charlie Zulu.

[FNG]

CZ, if ever you find yourself near North Weald, pop in and have a go on the Dog. Also, I might be visiting Shobdon in it later in the summer, and that's not so very far from Wales. It will be at the Sandown fly-in on 4th July.

[Charlie Zulu]

I could find myeslf flying the Pup to North Weald in the summer...

Would love to make the Sandown flyin myself but I'll be in the land that celebrates Independance Day on the 4th of July undergoing training for my multi rating.

Shobdon is less than an hour away from Cardiff and is quite a nice field.