Twin Otter Extended wing tanks question

[htuna 2]

When using the Wing Tanks on the Twin Otter extended, can the Fuel Pumps be shut off or do they need to stay on?

Last few nights I did a short trip from Nantucket to Boston, and both times at the end of the flight even though I had like 10% fuel left and my generators were on, I got Low Pump pressure lights. then the Engines died.. At first I thought, the generators weren't working and maybe I ran the batteries out so couldn't operate the Pumps..

 

But now I'm thinking maybe IDeal Flight stored some of the fuel in the Tanks, and that was my problem. Last night I did the trip with Full fuel and had no issues.. So I'm really thinking my Wing Tanks had the fuel and I didn't realize and turn them on. But I'm wondering if I turn them on, do I turn the Fuel Pumps off?

 

Will try again tonight with Ideal Flight and see if that is indeed what it was.

[mslim 12]

Hi Htuna,

 

Not totally sure I understand your question but I'll give it a shot.

 

Vol. 2, pg. 8 of the Aerosoft manual states: The Twin Otter has a simple and reliable fuel system but with the tanks low in the airframe and the engines mounted high it is fully depended on booster pumps.

 

It further goes on to explain that the even though the TO is a high wing a/c, the main fuel cells are located below the engines and require fuel pumps at all times.  That is apparently the reason the a/c was certified with a redundant set of back-up pumps. 

 

Regarding the auxiliary wing tanks, Finn at Aerosoft says,

In order to use fuel from the wingtanks, simply turn on the pumps for them found near the wingtank gauges found almost at the bottom of the center pedestal.

 

Hope this helps.

Slim

[htuna 2]

Yeah, this is an older post from before the 'crash'.. What happened was I kept losing power at the end of my flights.. I thought my pumps were dying or something, I just didn't realize that I needed to turn those switches on to use what was in the tanks.. I guess my other solution could've been not to store any fuel in the tanks.. But at least I understand what was happening now..

[theflyingdutchmen 3]

Only turn wingtanks on during cruise and steady climb. The wingtank fuel pump has greater pressure than the main tanks and will overpower the mains even when turned on. Boostpump must always be turned on during flight to keep the collector tank full. In the real world not a whole lot of Twin Otter companies operate the wing tank option ( to my knowledge).