Re: REFLECTOR: Fuel tank venting

["James F. Agnew" <Jim_Agnew@ibm.net>]

A simple check of the vent system by hooking an altimeter to the vent line
manifold should show if you have a positive (lower altimeter reading) or
negative (higher reading) pressure in the vent system.  I agree with Duane that
the fuel cap should be the #1 check, however, checking the pressure at the vent
manifold is #2.

Jim

Duane Swing wrote:

> Fuel Venting Problem
>   I totally agree with Jim Agnew on this one.  Since it was not a
> persistent problem, I would suggest a fuel cap not seating properly and
> allowing a slight vacuum on one side stopping any fuel flow from that side.
>  The single common vent system on the Elite almost always points to a fuel
> cap if uneven fuel flow is observed.  I have personally seen a 1/2 full
> tank actually increase to 3/4 while the other one depleted far faster than
> the engine could use it.  The best thing to do is always monitor your fuel
> system and land before fuel starvation ruins your day.  If the problem does
> not go away, start checking fuel cap seals first.
>    Sincerely,  Duane Swing
>
> -----Original Message-----
> From:   James F. Agnew [SMTP:Jim_Agnew@ibm.net]
> Sent:   Tuesday, March 02, 1999 6:09 PM
> To:     reflector@awpi.com; Carl Hoffman
> Subject:        Re: REFLECTOR: Fuel tank venting
>
> This all sounds a little strange assuming that both tanks are connected to
> a
> common vent.  You will always get some fuel in your vent lines when you
> bank and
> the fuel is higher than the vent line.  When you level out the fuel
> draining from
> the tank will create a partial vacuum that will suck the fuel/air into the
> tank.
> Since the tank with more fuel (deeper) will have more output fuel pressure
> it
> will always try to seek an even level with the other tank assuming a slight
> positive or neutral vent pressure evenly applied to both tanks.  A water
> level
> would not work if this was not true.  Therefore, I would be suspicious of
> the
> vent system possibly having some restriction on one leg or a leaking fuel
> cap
> allowing a slight vacuum in one tank.
>
> Jim
>
> Carl Hoffman wrote:
>
> > Peter Beaty wrote:
> > >
> > > O-kay...
> > >
> > > What's the fix?
> > >
> > > At 05:37 PM 3/1/99 -0800, Scott Baker wrote:
> > >   We believe that fuel must have entered the vent line
> > > >during the (initial) fueling of the aircraft and that the common
> > > >vent/pressurization was not strong enough to overcome the initial b
> lockage
> > > >to this one tank.  Just wanted to share.
> > > >
> >
> > If there is a fix, how do you know it is a fix. Last week a "fixed" 737
> > had a uncommanded rudder excursion. The pilots are now trained to cope
> > with them. i.e. periodically check the level in both tanks.
> >
> > Carl Hoffman
>
> --
> //------10--------20--------30--------40--------50--------60--------70--
> ------80
> // James F. Agnew
> // Tampa, FL
> // Velocity 173 FG Elite ( http://www.VelocityAircraft.com/ ) under
> construction

--
//------10--------20--------30--------40--------50--------60--------70--------80

// James F. Agnew
// Tampa, FL
// Velocity 173 FG Elite ( http://www.VelocityAircraft.com/ ) under
construction