Fuel Cross Feed

[Jim Meade]

"§ 91.151 Fuel requirements for flight in VFR conditions.

 

(a) No person may begin a flight in an airplane under VFR conditions unless (considering wind and forecast weather conditions) there is enough fuel to fly to the first point of intended landing and, assuming normal cruising speed—

 

(1) During the day, to fly after that for at least 30 minutes; or

 

(2) At night, to fly after that for at least 45 minutes."

 

Normal cruising speed in my CTSW uses about 5.3 gph. (5500 RPM uses at least 6.3 gph in my plane. ) That means that when I start a flight, I must have enough to fly to the first landing spot at cruising speed and to continue for 30 minutes at cruising speed.

 

You may find it odd that we flew the jets down to minimums regularly. One reason is that fuel endurance was often on the order of 2 1/2 hours. Every minute/mile counts on little jets. Airlines fly down to minimums quite often - more often than many pilots like, since they are long flights that may end up at a busy airport where delays are possible.. We had good equipment, watched it and tended to plan pretty carefully.

 

Once a person has met the requirements, it becomes a matter of what other circumstances prevail and what one's personal comfort level is. If it is turbulent, one might feel better adding a little more fuel so as to avoid any danger of unporting.

 

How many of us actually plan fuel in our CT? Many people solve this by not planning fuel needs but rather fill the tank. Bigger planes routinely come in and say "50 gallons a side" or "20 gallons in the mains and 15 in the aux tanks". CT's come in and say "fill it up". All I'm saying is we get lazy and don't plan our fuel usage, so we are uncomfortable when the tank gets low. When we do plan fuel it's likely to be because we're flying with the examiner.

 

30 minutes of fuel in my CTSW is 2.65 gallons, which I will round up to 3 gallons. One needs to be on the ground to be legal at that quantity, I might fly down close to that amount, but I would be watching the inductor gauges and the sight gauges very closely, even nervously. I'd have to have an awfully persuasive reason to fly that low on fuel.

 

Roger's 3 gal/side minimum should give one an hour to fly and seems pretty conservative. I also have no problem with the idea of flying the plane as coordinated as possible and then insisting on fuel in both sight gauges plus at least 3 gallons or one's personal minimum. Obviously, if we are relying on the inductor gauges we should verify them periodically and be very sure they are accurate. The advice to routinely check sight gauges in flight is excellent.

[Duane Jefts]

Jim,

 

In your next to last paragraph, you write "One needs to be on the ground to be legal at that quantity". I think the 30 and 45 minutes are "planning" requirements. If you land with less than your 2.65 gal you may have excercised poor planning or execution or judgement but I don't think you are "illegal".

 

Also, if one lands with that little fuel, it might be time to update the living will.

[Jim Meade]

Duane,

 

Probably right on both counts.