Such an interesting set of events here.

Airplane has lots of fuel, but has a fuel starvation problem and crashes..

There have been numerous statements here about the Lancair 4PT fuels system.

 

For one,, having a belly tank as a header tank is dangerous and stupid.'

 

Anyone that flies a retractable plane knows that a gear problem could mean landing on a bellyful of fuel.

I have looked at this Lancair fuel system and it shows a COMPLETELY UNNECESSARY RISK.

You cannot interrupt fuel flow to a turbine like you can with a piston engine.

So, if you cannot get the air out, you are going to have a flame out. SIMPLE.

Using the belly as a header tank, although at first glance seems convenient, is clearly not the best solution, (even if you can get the air out on a continuous basis).

ANYONE BUILDING A LANCAIR 4PT REALLY NEEDS TO THINK ABOUT THE FUEL SYSTEM.

 

Since my last posting, I have spoken to a guy named John Cook and he designed a beautiful and simple little pressure header tank to be installed in the engine compartment.

It has a simple bleed to purge air,  (as that is one of the prime reasons to even have a header tank).

His fuel system uses the belly tank, but he always consumes the belly FIRST. Then he consumes the wing fuel.

On larger planes, we always try to use fuselage fuel first because from a fatigue standpoint, there is less wing flexing in turbulence, if we can get the fuselage weight lower.

I am not a DER for these little planes, but I can't imagine the fatigue rules being any different.

John also told me that he has spoken, written, and posted warnings to Lancair and Joe Bartel about the dangers of the existing Lancair PT fuel system.

It was also a surprise to me to hear that Lancair had an engine out failure at Lakeland one year and John Cook diagnosed the problem, and it was the

Lancair fuel system that caused it.

Lancair is using solenoids that close the belly/header tank breather lines when master power is on.;

Basically you are locking air out, but if air gets into the system (like running a wing tank dry), it also locks the air in.

 

I am not a Lancair customer or builder, I was hired to determine the best fuel/engine system for a current Lancair customer.

I don't have an axe to grind, but it is really disturbing to see this fuel system and it absolutely amazes me that Lancair doesn't do the right thing.

 

From what I understand now, the failure in Georgia has nothing to do with the engine. Therefore, you have lots of fuel, and a good engine, I would be willing to bet

that the failure was caused by the Lancair fuel system. It was bound to happen. It is a pity someone had to have a loss of life.

 

Bill McDonald

Systems DER

Large aircraft.