How well do you know your fuel tanks

[challenger_nami]

Who cares. You're the one advocating a procedure that goes against a dozen or more flight manuals. One could reasonable expect the onus of proof lies with you.

Sure. Let’s say you are right.
whoever thinks I was advocating a procedure that goes against any flight manual:

• Write me a Brief summary of what you actually understood from the procedure I was advocating,..... don’t just quote what I said, write a one or two sentence summary from what you understood in your head.

• Then tell me the flight manual of which type of airplane it goes against.

I will give it a day or so to see what responses I get, then I will respond to them all in 2 days or so.

[goingnowherefast]

You said "It's good practice not to let the fuel level in the tanks go too low". Pretty sure that means leave a little fuel in each tank. You even went on to talk about avoiding drawing sediment or dirty fuel into the engine(s). Now if you had said to leave sufficient fuel in the primary tank(s) that feed the engine(s), I'd agree. But that's not what you said.

It's been a number of years since I flew a King Air. However, there was always several hundred pounds left in each main tank. The aux tanks were usually bone dry. I emptied the aux fuel before reducing the quantity in the main tanks. I did it that way because that's what the AFM says. The King Airs I flew, the aux tank pumps had 3 options, ON, AUTO or OFF.

Been a while since I flew Navajos too. Take-off and landing is to be conducted on the inboard tanks, and I always had lots of fuel in those tanks. The outboard tanks were usually sucked dry, not to the point of the engine stumbling, but very close. I'm not going to leave 30 minutes of fuel in the outboard tanks because I'd rather have that fuel in the inboard tanks. Get stuck with unforecast weather and a diversion, I'd rather have 45 minutes in the inboards than 15 minutes in the inboards and 30 minutes in the outboards. That's just good fuel management.

[NotDirty!]

I forgot to talk about the MU-2. It has a somewhat unique fuel system... both engines draw out of the centre tank, but there are also small tanks in the outer portions of the wings, and large tip tanks. The tip tanks are actually hold the largest volume of all the tanks, but because of the anhedral design of the wings, the fuel must flow up hill to be transferred to the centre main tank. The tips are pressurized with bleed air, and this transfers the fuel from the tips to the centre, where it is then used by the engines. In order to transfer the fuel out of the outer tanks and into the centre tank, electric pumps in each outer tank are used. In the auto mode, the outer transfer pumps will not be activated until both tips are empty, and have been empty for two minutes. Once the outer tank is empty, the respective outer empty light illuminates to remind you to turn fuel transfer off. Later models have an outer fuel gauge, but earlier models with extra small outer tanks had no gauging system for these outer tanks, you simply transferred until the outer empty lights came on.
In none of these aircraft I have mentioned is it a good practice to leave useable fuel in aux/centre/ACT/tip/outer tanks. At the same time, it is not recommended to allow the main tanks in any of these aeroplanes to run completely dry, as in each case you will have a sudden decrease in engine noise, and corresponding increase in pucker factor as you are suddenly at the controls of a very expensive glider.

I think what you are fundamentally forgetting is that all of these fuel tanks are designed with a certain amount of unusable fuel, which serves a function you are talking about trying to duplicate with usable fuel. The unusable fuel should be where the water and whatever other sediment collects, and by draining the fuel strainers on a semi regular basis, we should be able to remove the worst of this from the fuel system.

Now back to your regularly scheduled discussion.

[challenger_nami]

It's been a number of years since I flew a King Air. However, there was always several hundred pounds left in each main tank. The aux tanks were usually bone dry. I emptied the aux fuel before reducing the quantity in the main tanks. I did it that way because that's what the AFM says. The King Airs I flew, the aux tank pumps had 3 options, ON, AUTO or OFF.

So are you referring to King Air 200?

[goingnowherefast]

Every king air and 1900 has the same basic fuel system. Exception being the original 100 and perhaps the 90 series (never flew any of the King Air 90s).

So to answer your question, I'm referring to the A100, 200, B200, 300, 350, 1900, 1900C, 1900D. Transfer ALL the aux fuel into the mains. If the mains aren't full, there better be no fuel left in the aux tanks (exception being an aux transfer failure, but that's through no fault of the pilot).

[challenger_nami]

I was hoping more of the people who questioned my idea would tell me what & why they were opposing, as I requested. But it’s all good, and thank you #GoingNowhereFast. Here is my friendly rebuttal :

It's been a number of years since I flew a King Air. However, there was always several hundred pounds left in each main tank. The aux tanks were usually bone dry. I emptied the aux fuel before reducing the quantity in the main tanks. I did it that way because that's what the AFM says. The King Airs I flew, the aux tank pumps had 3 options, ON, AUTO or OFF.

Been a while since I flew Navajos too. Take-off and landing is to be conducted on the inboard tanks, and I always had lots of fuel in those tanks. The outboard tanks were usually sucked dry, not to the point of the engine stumbling, but very close. I'm not going to leave 30 minutes of fuel in the outboard tanks because I'd rather have that fuel in the inboard tanks. Get stuck with unforecast weather and a diversion, I'd rather have 45 minutes in the inboards than 15 minutes in the inboards and 30 minutes in the outboards. That's just good fuel management.

Every king air and 1900 has the same basic fuel system. Exception being the original 100 and perhaps the 90 series (never flew any of the King Air 90s).

So to answer your question, I'm referring to the A100, 200, B200, 300, 350, 1900, 1900C, 1900D. Transfer ALL the aux fuel into the mains. If the mains aren't full, there better be no fuel left in the aux tanks (exception being an aux transfer failure, but that's through no fault of the pilot).

the Beechcraft King Airs A100, 200, B200, 300, 350 and 1900, 1900C, 1900D which as you correctly indicated, have the same fuel systems. In these aircrafts the fuel from the Auxiliary tank automatically gets fed to the engine. The pilot does not have any choice in that and can’t stop/change the process even if (s)he really REALLY wanted to. The fuel in the Auxiliary tanks get used before the main tanks, unless there is a malfunction. That’s how the system is designed to function,

so when you say you did it that way because the AFM tells you so, that’s inaccurate: You had no other options.

Now if I am not correct, I appreciate if someone current & credible can refer me to the appropriate AFM.

You were right about About Navajo’s. You have the option to use either Inboard or outboard tanks. As far as remember, the only limitation was that you can only take off and land on the inboard tanks and can only use the outboard tanks in cruise or non critical phases of flight.
There was no limitation as to whether or not the outboard tanks needed to be fully empty for take off and landing. I am rusty on the Navajo, so if I not correct, I appreciate if someone current & credible can refer me to the appropriate AFM.

[challenger_nami]

I have a little time in the A100 and B200... and I will echo his question: how much fuel should I leave in the Aux tanks? It’s easy to turn aux transfer off in the BE10, but IIRC in the BE20 you have to pull CBs if you don’t want it to continue transferring until the Aux’s are empty.

#NotDirty, I think you are confusing it.

• In Normal Operations in a B200, if you don’t want it to continue transferring until the Aux’s are empty , NAME Which CB would you exactly pull?

• AND what do you think the result of that pulled CB would be?

[NotDirty!]

I have a little time in the A100 and B200... and I will echo his question: how much fuel should I leave in the Aux tanks? It’s easy to turn aux transfer off in the BE10, but IIRC in the BE20 you have to pull CBs if you don’t want it to continue transferring until the Aux’s are empty.

#NotDirty, I think you are confusing it.

• In Normal Operations in a B200, if you don’t want it to continue transferring until the Aux’s are empty , NAME Which CB would you exactly pull?

• AND what do you think the result of that pulled CB would be?

I seem to recall that the B200 had Aux transfer switches with two positions: “auto” and “override” (as opposed to the A100 which just had on and off). In the Auto position, the motive flow control valve was opened any time the aux empty float switch did not read empty; the override position allowed you to override the float switch in case the switch failed, so the motive flow control valve is open the entire time the switch is in the override position. In either case, the only way to manually close the motive flow control valve, thus preventing the jet transfer pump from drawing the fuel out of the aux tank, while the float switch thinks there is still fuel in the aux tank, is to pull the CB labeled “Aux Xfer” for that side.

This is my recollection, it is a little rusty, and may have some confusion with similar systems in other types - my King Air experience was 99% on the A100, and I haven’t flown one in a few years.

What is your suggested practice for fuel management in the King Air?

[challenger_nami]

I seem to recall that the B200 had Aux transfer switches with two positions: “auto” and “override” (as opposed to the A100 which just had on and off). In the Auto position, the motive flow control valve was opened any time the aux empty float switch did not read empty; the override position allowed you to override the float switch in case the switch failed, so the motive flow control valve is open the entire time the switch is in the override position. In either case, the only way to manually close the motive flow control valve, thus preventing the jet transfer pump from drawing the fuel out of the aux tank, while the float switch thinks there is still fuel in the aux tank, is to pull the CB labeled “Aux Xfer” for that side.

This is my recollection, it is a little rusty, and may have some confusion with similar systems in other types - my King Air experience was 99% on the A100, and I haven’t flown one in a few years.

What is your suggested practice for fuel management in the King Air?

Without wanting to be argumentative, I disagree with what you described above. I don’t believe the AUX TRANSFER does anything to the Float Switch in the Aux Tank. The float switch is only a sensor and only indicates whether or not there is fuel in the Auxiliary tank. However, I am not familiar with 100’s.

In 1900’s and King Air 200 and above:
If the AUX TRANSFER is set to AUTO, the motive flow valve is open as long as the Float switch indicates presence of fuel in the Aux tanks.

the motive flow valve fails in the closed position , placing the AUX TRANSFER Switch to OVERRIDE, directly energizes the Motive Flow valve with DC Electric current and puts it to OPEN position .

I would never manipulate CBs unless there is a justified reason for it. And also I don’t think popping the Aux Transfer CB will have the outcome you mentioned above.


So What’s my Suggested practice for fuel management in King Air?
KISS: By that I mean: keep It Stupid Simple:
I make sure I have more than enough fuel ... PLUS SOME ... I keep monitoring my gauges and keep verifying.

I ll do everything I can not to run out of fuel, and have to fly a King Air as a glider ... just to fall short of that runway by less than a mile

[NotDirty!]

I think your description is pretty much identical to mine... different wording for not empty vs presence of fuel in the tank, same meaning.

I am not suggesting that one should normally stop aux transfer, I believe my original statement was that there was not a simple way to do it on the 200, other than pulling CBs. I was trying to make the point that the idea of NOT transferring all of the useable fuel in order to be kind to your engine was foolish and difficult to accomplish.

I’m not sure why you don’t believe that the method I described would function in that manner. The motive flow shutoff valve is a normally closed solenoid valve, which opens when energized as you described, either by the float switch detecting the presence of fuel in the aux tank, or the switch in the override position. This circuit is powered off the Aux Transfer CB on the fuel panel. Thus tripping that CB will remove power from the valve, causing it to relax to its “normal” position.... aka it is spring loaded closed.

The A100 has a very similarly laid out system, however the controls are different. The switch on the fuel panel is Aux Transfer ON/OFF. In the ON position, it opens the motive flow valve, in the OFF position, it closes the motive flow valve. There is an Aux Empty Light below the switch (where the No Transfer light is on the 200) that illuminates when the float switch reads that the aux tank is empty. The motive flow valve will not close until you manually select Aux Transfer OFF. So it was not a big jump to switch to the auto system in the 200/1900/etc., all of the required parts were already there, it just needed to be taught a little logic.

[pelmet]

Or fuel rate of consumption. Might not want to try a max range flight on your first flight......

"C-GVBU, a privately registered Piper PA28-180, was enroute from Winnipeg/St. Andrews (CYAV),
MB. to Thunder Bay (CYQT), ON. with the pilot and 1 passenger on board. While on approach to
CYQT, the pilot noticed a low fuel indication and switched fuel tanks. During the base leg, the
engine (Lycoming IO-360) then lost complete power. The pilot declared an emergency and then
successfully completed a forced landing on Runway 25. The aircraft was able to roll off the runway
onto the taxiway under its own momentum and was then towed to the ramp. It was reported that
both fuel tanks were empty. The aircraft was refueled and then departed a short time later.
The pilot had just purchased the aircraft."

[RedAndWhiteBaron]

https://en.wikipedia.org/wiki/Gimli_Glider

That I think will be the sum total of my contribution to this discussion.

[ahramin]

What kind of contaminant would be floating on top of the fuel?

Bread.
Apples.
Very small rocks.
Cider.
Grape gravy.
Cherries.
Mum
Churches, churches.
Lead, lead.
A duck.

Fantastic. You just made this thread worth reading . Thank you.

[RedAndWhiteBaron]

What kind of contaminant would be floating on top of the fuel?

Bread.
Apples.
Very small rocks.
Cider.
Grape gravy.
Cherries.
Mum
Churches, churches.
Lead, lead.
A duck.

Fantastic. You just made this thread worth reading . Thank you.

* RedAndWhiteBaron high-fives everyone who gets this joke.

[rigpiggy]

the 1900 Aux system
off....self explanatory
auto 10 psi motive flow, 5 psi transfer line, float switch, thermal shutoff
On bypass all but thermal shutoff

at least as far as I can remember the flightsafety course

now King Air(s) forget which one uses motive flow through a jet pump to get aux fuel into the main. ie run out of fuel in the main, no aux transfer

[pelmet]

Following through on the knowing your fuel tanks idea, One can do several shorter flights and see if the fuel burn matches expectations.

Leaks from a fuel cap can be an issue. I ferried an aircraft once and ended up having to land short of destination due to a leak at one of the fuel caps. It turned out to be fairly significant. The cap and its o-ring looked fine as far as I could tell. What I did notice after landing was a stain/discoloration behind the fuel cap on the wing, but only with the sunlight at a proper angle. Not a bad idea to look at the top of the wing from behind and vary the angle to possibly discover fuel staining.

These days I am renting a couple of aircraft at different flight schools where I don't trust the fuel endurance. One has a fuelhawk measuring device for the aircraft. However, while the Fuelhawk is for that aircraft type, it is not for that fuel capacity. It is off by a couple of gallons. But is that something that I should consider as insignificant? Maybe, but I don't know if the other fuel tank type is the same shape. Maybe one type of tank is longer and flatter or shorter and deeper. There is a universal FuelHawk that can be purchased where one makes their own measurements but the mechanic told me that he doesn't he want to take the time to drain the tanks and make measurements, so I just take extra fuel. Maybe overly cautious but a little paranoia is a good thing in my opinion. Tougher situation for those with more payload.

The other aircraft has obvious fuel stains behind the tank and an inspection panel on each wing. Perhaps slow seeps but until I can figure things out for sure, extra fuel. Of course, the school is operating the aircraft regularly but on a flight with minimal reserves, one could get a surprise if those guages are not fully accurate.

[digits_]

I'd suggest doing multiple long flights. Your results will vary too much if you do short flights. The fuel burn during climbs and descends is not as well/accurately documented as flying in a long cruise. For accurate results, you'll want a consistent power setting for a long time.

[pelmet]

I'd suggest doing multiple long flights. Your results will vary too much if you do short flights. The fuel burn during climbs and descends is not as well/accurately documented as flying in a long cruise. For accurate results, you'll want a consistent power setting for a long time.

Sounds like a good idea. Just have a more comfortable amount of reserve fuel for those first couple of flights. Perhaps measure from properly topped off tanks, the expected burn versus fuel added, to properly topped off the tanks again.