Watch those fuel levels

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old no 7
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Watch those fuel levels

Postby old no 7 » Thu Oct 02, 2008 3:45 pm

Hi All,
Just want to share an experience I had last weekend in the hopes to save somebody from a similar situation.
I was on a reasonably long cross-country haul and had an extra 25l jerry of fuel on the back seat.
I've done this route a few times and usually burn about 40 lt.
I started out with 66lt in the tank. After taking off from Kitty Hawk, I landed at Rhino, left and returned again because my flying buddy was having trouble with his engine.
After a second start I headed out west towards Groot Marico into a fairly hefty headwind.
En route, I said to myself that if I have 20 liters or less in the tank at Morningside Airfield, I will do a precautionary and refule from the spare jerry-can.
At Morninside I had exactly 20liters left which was more than enough for the remaining 15 minutes to my strip in Groot Marico, but I nevertheless decided to land and refuel. Well that hefty head-wind turned out to be a howling cross-wind at Morningside airstrtip, so much so that I had to abort my landing as I did not have sufficient rudder and stick controls left in order to counter the crosswind.
With at least 30 minutes of fuel more than I needed, I thought I would be fine to get to Groot Marico so on I went.
On arriving at my farmstrip, I wanted to do a few low-level runway inspections to make sure the runway was clear.
As I entered a steep descending turn the engine cut out. Being only about 500ft agl, I tried re-starting, but to no avail and with little time/height left to play with managed to put ONS down safely on the newly prepared 2nd runway.

As I stopped the strong smell of fuel was quite frightening with the memories of recent gyro incidents fresh in my mind. I evacuated and after a few minutes, retried the engine and it started fine.
There was still about 15 litres of fuel left in the tank.

The conclusion drawn was that in the steep descent, the fuel ran to the front of the tank and on the MT-03, I was told later, the fuel pick-up is in the back of the tank.
Lessons Learned:
* The situation could have been a lot worse. I was lucky that it happened over the airfield.
* If you deviate from your past route, in this case the extra landing and take-offs at Rhino, take into account the extra fuel burned.
* Trust your instincts and when you want to stop and re-fuel. Do it.
* Leave a little more than the usual fuel buffer in hand
* Don't enter steep descents when low on fuel and also not when you have little height to play with.

I am just glad that I came out of that unharmed but armed with the experience and learnings from the incident. (^^)
ZU-f-ALL
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Learjet
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Re: Watch those fuel levels

Postby Learjet » Thu Oct 02, 2008 6:18 pm

Well done on handling the engine out and safe landing! A couple of us in the Cape have fitted the Optifuel unit in our gyros and it's a really worthwhile investment. I've found huge peace-of-mind from the real-time fuel flow measurement and range and reserve data when linked to GPS. :)
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weedy
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Re: Watch those fuel levels

Postby weedy » Thu Oct 02, 2008 6:38 pm

I can second the recommendation of fitting Optifuel, it was great peace of mind on the Numbi trip, nice and accurate and coupled to my Pilot 3 I always new how much reserve time I had in getting to the next planed stop.
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old no 7
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Re: Watch those fuel levels

Postby old no 7 » Thu Oct 02, 2008 9:24 pm

Yes I have the MGL Avionics equivalent of the Optifuel, which gives me all good stuff like fuel-flow, fuel remaining, range at current burn-rate etc.
Overhead the farm my readings were 15 lt remaining, 35 min duration left. The problem arose when I went into a steep descending turn and that 15 liters shifted to the front of the tank whereas the fuel intake is near the back end of the tank.
I guess my thread is really aimed at warning MT-03 owners that they must not do steep diving turns/descents when their fuel is running on the low side.
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Re: Watch those fuel levels

Postby FO Gyro » Fri Oct 03, 2008 1:15 pm

On a recent trip, the winds were a lot stronger than forecast, and I ended up landing with minimum fuel (around 5 litres!). Knowing I was on minimum fuel, I positioned myself overhead the threshold at around 300 feet, and then knowing I could then make it in the event of a powerloss, I then closed the power and dived down at the runway. As sure as nuts, the engine died on me!

In hindsight, even though the engine can quit when assuming a low nose attitude when landing, I still think it is safer to keep high when low on fuel, get above the threshold, and then dive down. The last thing one wants is to fly a flat approach, and then the engine quits at an inappropriate time, and one ends up landing short of the runway.

Also, if running short of fuel, by slowing down, the gyro flies in a slightly more nose up attitude, so the fuel would run all the way to the back, so it would be safer to fly at 70-80mph than 90mph+.

Can anyone explain why at the point of the engine starving of fuel, a very strong fuel smell is smelt?
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Re: Watch those fuel levels

Postby Grumpy » Fri Oct 03, 2008 1:28 pm

Excuse my ignorance, but surely repositioning the fuel outlet can solve this problem? Or possibly the fuel tank has a design fault.
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old no 7
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Re: Watch those fuel levels

Postby old no 7 » Sat Oct 04, 2008 6:57 am

FO Gyro wrote:In hindsight, even though the engine can quit when assuming a low nose attitude when landing, I still think it is safer to keep high when low on fuel, get above the threshold, and then dive down. The last thing one wants is to fly a flat approach, and then the engine quits at an inappropriate time, and one ends up landing short of the runway.

Also, if running short of fuel, by slowing down, the gyro flies in a slightly more nose up attitude, so the fuel would run all the way to the back, so it would be safer to fly at 70-80mph than 90mph+.
Yip Glenn, Now that I know the issue of fuel pick-up, I will certainly keep it high and nose up when low on fuel.
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Re: Watch those fuel levels

Postby OptiFuel » Sat Oct 04, 2008 10:50 am

It would be interesting to see if you could replicate the problem even with a full tank of fuel, it might have nothing to do with the fuel tank. One would think that if there is a strong fuel smell then there is unburnt fuel getting to the carburetors which is the only outlet?

Thanks Learjet and Weedy for the good words about Optifuel.
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Re: Watch those fuel levels

Postby t-bird » Mon Oct 06, 2008 8:55 am

If your MGL was calibrated correctly you would have zeroed with 5 liter unusable.
If the reading is 15 liters the actual would be 20 liters.

I think that something else is wrong.
15 liters is more than enough
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Re: Watch those fuel levels

Postby FO Gyro » Mon Oct 06, 2008 9:58 am

The problem with the MT-03 is that when the fuel level is 15l or below, if one flies the type of approach where you end up very high with a speed of around 30mph, and then dive down at the runway building up the speed to 60 mph, the fuel flows forward to the front of the tank, and an engine out if possible.

If a normal flatish approach is flown, then there is no problem. It's only if one does one of those diving approaches that present a problem.
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Re: Watch those fuel levels

Postby t-bird » Mon Oct 06, 2008 2:40 pm

Hi Glen

Would this not be the cause of the Mosselbaai crash where the passenger got seriously burnt.
They were on final approached when the engine cut .
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Re: Watch those fuel levels

Postby FO Gyro » Mon Oct 06, 2008 8:26 pm

I wasn't aware that the engine cut on final approach. Interesting!

That might very well have been a cause.
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