Jump to content

Fuel exhaustion with 4.5 gallons in one wing


tennesseect

Recommended Posts

 

We CT owners have something far better, our sight tubes.  It takes a few seconds in flight when fuel is below 10 gallons total to confirm.  This can be done on virtually every flight and done en-route to keep fuel even so there is no issue on approach.

 

  • With the sight tubes the question of 'level' is taken out of the equation
  • The tubes confirm coordination in an error free manor, the left confirms the right.
  • The tubes show the net of all yaw forces that effect fuel flow not just level / gravity.

 

 

That is only true if everything is working properly. I know of 2 cases on CTLS's where there was a problem with the vent line that caused uneven fuel drainage. one was a disconnected line the other was a plugged line. The same thing could happen to a CTSW from a plugged vent tube with worse results. The CTLS has interconnecting vents that the SW does not have.

 

A pinched off fuel line can cause similar issues.

Link to comment
Share on other sites

  • Replies 63
  • Created
  • Last Reply

A couple of observations about my CTSW.  This story is somewhat scary because I landed once with 3 1/2 gallons in one tank (I don't remember which) and the dipstick didn't measure any in the other.  Still legal for VFR daytime.  It was a bumpy summer day and I remember looking at the sight tube levels going up and down, but centering around 3 gal on each side.  Not a good way to estimate fuel.  On final (I crab in until I cross the numbers) I looked at the tubes again and one said 3 gal and the other one didn't show any fuel at all.  No issues with the engine.

 

I posted this a while back and talked to Tom P about this episode:  I was at a Fly-In (Washington Is, WI) and parked my plane for a couple of hours.  When I took off from the grass trip I could hardly control the plane, it wanted to go left so badly.  Once I got a few hundred feet up (I'm sure I scared the crowd there) I noticed no fuel in the right sight tube, and I had probably 15 gallons left.  Turns out I had parked with the left wing low and in a few hours all the fuel had moved to the left wing.  The same thing had happened to me at OSH while camping.

 

So it seems fuel on my CT can move from one side to the other quite easily.  I now keep a level with me when I land or park on grass.

Link to comment
Share on other sites

That is only true if everything is working properly. I know of 2 cases on CTLS's where there was a problem with the vent line that caused uneven fuel drainage. one was a disconnected line the other was a plugged line. The same thing could happen to a CTSW from a plugged vent tube with worse results. The CTLS has interconnecting vents that the SW does not have.

 

A pinched off fuel line can cause similar issues.

 

Those bullets remain true always.

Link to comment
Share on other sites

 

So it seems fuel on my CT can move from one side to the other quite easily.  I now keep a level with me when I land or park on grass.

Page Az is where we learned to park sideways on the ramp to avoid transferring and losing fuel.

 

I often fill only one wing, usually the right.  It always equalizes overnight in my plane and I sometimes do it in the mornings when flying solo and allow the additional weight to offset the empty seat.

Link to comment
Share on other sites

Again no difference.  When you fly in a slip you add a 2nd vector for fuel flow to the low wing tip.  

 

  1. Inadvertently empty 1 tank by flying in a slip due to slip / skid ball calibration error.  This is easily tested, see my post above.
  2. Continue in the same configuration until there is no fuel at the port/fuel pickup located inboard.(because you don't bother to watch your fuel drain over time) Now all the fuel is at the outboard end of one tank and will remain there until slip is terminated. Gravity feed to your header tank cannot happen at this point and your engine will starve

The fact that you landed with empty wing tanks early on suggests that your ball calibration is good and you have not been prone to this scenario.

 

Not talking about uneven fuel in the wing tanks...talking about the fuel injected system is different than just gravity fed wing tanks into a carb'd setup.  The header tank is a common feeding point for the gravity tanks as you know.  If either or both wings stop filling the header tank then an ennunciator light flashes bright red forewarning that about 1.7 gallons of useful fuel remains in the header and time to get down.   That would at least keep the engine running till you can get down.   The gravity only planes have no such warning...once the fuel stops reaching the carbs the engine dies.

 

And as we have had threads on the subject, the sight tubes are lousy IMHO for any kind of fuel determination.  There is still fuel left when the fuel drops out of sight you just don't know how much.  And worse?  The sight tubes are complete inaccurate and cannot be trusted before takeoff either, again IMHO.

Link to comment
Share on other sites

Happy to paste a picture, but not sure how I do it!

 

Andy

Place the link between jpg tags (first in square brackets, last in square brackets preceded by a "/".

 

(Img)yourlinkendinginjpg(/img). But with square brackets.

 

Or email it to me and I'll post it.

Link to comment
Share on other sites

According to the diagram, CT is correct with his analysis.

Mis-leading and marginally safe information continues to be posted on this forum. Why is this tolerated?

 

Nice try...the diagram illustrates what I have described.  And CT has acknowledged the difference.  Do you need help understanding the diagram?

Link to comment
Share on other sites

The light does make the CTLSi different in that, if operational, it provides an adequate warning prior to loosing your engine.  That is a very poor substitute for monitoring and managing your fuel in flight.

 

Below is a 15 minute alert from my EFB.

 

post-6-0-00940200-1464663673_thumb.jpg

Link to comment
Share on other sites

That and... how do you know if the light isn't having an in flight failure? :-D.

As an aside, my Sky Arrow has a cluster of "idiot lights". One is for "Fuel Low" and it begins to flicker with between 3 and 4 gals left, eventually just staying on.

 

15421910260_8b4b5597be_z.jpg

 

Checking them all via the "Push To Test" button on the right is part of the "Starting Engine" checklist.

 

Not to say the bulb could not fail in flight after that, but the light is best thought of as a last line of defense, not standard SOP.

Link to comment
Share on other sites

That light should NEVER be used as a fuel quantity indication. For one reason or another, imagine it being inoperative!

As far as I am concerned, if no fuel is observed in either fuel sight tube, that annunciator light is an indication of an emergency situation which has already developed.

 

No one said that...I point out that in the emergency described in this thread the SW went engine out on a fuel starve.  That can't happen in the CTLSi as long as at least one of the dual fuel pumps are still working.  When the light comes on there is 1.7 of useable...at 3/4 throttle that's a half hour of fuel.

Link to comment
Share on other sites

Eddie, are those "push to ack" lights that can be turned off by pushing them, or just simple indicator lights?

 

Either way, I like that setup.  I just have an "alternator" light that alerts me if the stator fails, I would like to have a few more alert/idiot lights. 

Link to comment
Share on other sites

No one said that...I point out that in the emergency described in this thread the SW went engine out on a fuel starve.  That can't happen in the CTLSi as long as at least one of the dual fuel pumps are still working.  When the light comes on there is 1.7 of useable...at 3/4 throttle that's a half hour of fuel.

 

But as others have pointed out, it actually *can* happen if a simple light bulb fails.  

Link to comment
Share on other sites

But as others have pointed out, it actually *can* happen if a simple light bulb fails.  

 

Judging by the 'lack of awareness' leading to a lack of fuel usage monitoring and fuel management I wouldn't be confident that once the light comes on the CT driver would know to check for fuel sloshed outboard in the remaining wing and then recover that fuel and then fly in a slip with that wing high to keep remaining fuel visible and available?

Link to comment
Share on other sites

Exactly.

Did you have anybody in mind? :D

 

Yeah, most of us.

 

I notice the silence when the incident was reported by one owner about the other owner no-one even mentions if fuel was checked prior to landing.  This is your primary defense after you have failed to monitor where your fuel is.

 

Then experts start chiming in and we learn that this happens, not that it should never happen.  It feels to me like this is one of a couple of areas where most CT pilots remain clueless.

 

This isn't the first time, think about how much discussion Bernath's crash started yet we as a group still lack awareness.

Link to comment
Share on other sites

 

 

This isn't the first time, think about how much discussion Bernath's crash started yet we as a group still lack awareness.

 

I hear what you are saying, but Bernath's case is different in that he landed and checked fuel, determined he had insufficient fuel, and took off anyway.  There was essentially no fuel in either tank, I think NTSB said one was empty and the other contained less than a gallon.  No pre-landing check will save you if you ignore what you see in the check!

Link to comment
Share on other sites

I hear what you are saying, but Bernath's case is different in that he landed and checked fuel, determined he had insufficient fuel, and took off anyway.  There was essentially no fuel in either tank, I think NTSB said one was empty and the other contained less than a gallon.  No pre-landing check will save you if you ignore what you see in the check!

 

The basis for his suit was that the CT ran out of fuel with fuel on board due to design deficiency. He claimed fuel on board that drained from the inverted plane.  

 

With the claim by the pilot that he ran out with fuel on board followed by much discussion awareness of how to prevent fuel starvation in is this type of design should have been the result. 

Link to comment
Share on other sites

The basis for his suit was that the CT ran out of fuel with fuel on board due to design deficiency. He claimed fuel on board that drained from the inverted plane.  

 

With the claim by the pilot that he ran out with fuel on board followed by much discussion awareness of how to prevent fuel starvation in is this type of design should have been the result. 

 

Yeah, I know what he claimed, but the airplane came to rest upright and never went inverted, which the accident photos show clearly.  He had no appreciable fuel on board.

 

But you are right that pilots should make sure that they have enough fuel in *both* wings to not unport one with a slip.  Like many on this board, on longer trips I fly uncoordinated for periods as needed to keep the fuel tanks as equal in level as I can.  When I am down to about 7 gallons per side it's time to be landing, and 5 per side I want to be on the ground. 

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.


×
×
  • Create New...