Originally Posted by
Pull what
From an instructors teaching point of view, its important that students actually practice operating fuel cocks, especially at schools where the cock is not routinely turned off after flight, otherwise you can be asking a student to turn tbe fuel off in an emegergency situation without ever having shown him how to actually do it and on some a/c turning the fuel cock off can be difficult while flying the aircraft. especially if you have never done it before!
I wouldnt call exercising and/or proving a fuel system stupid or mindless, I would call it good attitude, airmanship and CRM which prevents stupid and mindless mistakes
First off we are not talking about "some aircraft" we are talking abut the C 172. The fuel selector is a pretty simple, very accessible handle. If a student needs to continually practice rotating it from the 12 o'lock position to the 6 o'clock position in either direction, than in order to get it right then he/she is not smart neough to be a pilot.
I show the student how the fuel selector works in the cockpit orientation at the beginning of the PPL syllabus. I make them go through the vital actions required for an EFATO before every take off, one of which is point at the fuel selector and say they will tun it to off.
When doing the dual cross country we will select one tank to even the fuel flow because the tanks will never feed evenly and if there is an imbalance the pilot has to continually hold up the heavy wing. This is how Cessna intended the fuel selector to be used. There is IMO, no requirement to add any extra "checks". The ground check is very unlikely to actually identify a fuel feed problem which is in turn a very unlikely event to occur in the first place.
It does however introduce the potential that if the last action of the check is for some reason missed, the aircraft will take off with only one tank selected, an unsafe condition. This is much less likely to occur if the POH procedure is followed
Originally Posted by
Pull what
However there are plenty of instances of C172s not feeding from the left tanks as these posts below show in a discussion you took part in!
A 1968 Cessna Skyhawk, Continental O-300-D, in flight, doesn't feed from port wing tank, with fuel selector on Both.
Running on the ground, tank selector to port, no problem. Timed static fuel flow from both tanks is identical.
and these
"A 1968 Cessna Skyhawk, Continental O-300-D, in flight, doesn't feed from port wing tank, with fuel selector on Both. "
You make my case. In the example quoted doing a ground check of individual
tank feeding would not have identified the problem, which reinforces my point that there is no practical value in the check.
The problem in the airplane above was almost certainly a blocked vent line. Of note Cessna's are supposed to have vented fuel caps on both sides. I occasionally see airplanes with only one vented cap or in one case a plane with solid caps on both sides
. This can happen when caps break or wear out and are replaced with a "serviceable" spare
