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FUEL SYSTEM QUESTION


joegoersch

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I'm reviewing Mooney emergencies procedures.  During "Power Loss During Takeoff Roll" the fuel management involves "Fuel Selector--OFF".  For engine fire-ground--"Mixture--IDLE CUTOFF.  Fuel Selector--OFF" for Landing Emergency Power On--"Fuel Seletor--OFF.  Mixture-IDLE CUTOFF".

I understand (I think I understand, if not, help me out) that the mixture control is downstream from the fuel selector.  Thus if you shut off the Fuel Selector first, there will be a little fuel in the line between the fuel selector and the mixture control in the fuel injector box which would get burned off until mixture put to idle shutoff.

Any idea how much fuel would be in line between the fuel selector and mixture control ?  Does the order in which you turn these off matter at all ?

 

thanks

 

 

 

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Not sure what model you are referring too, but it certainly can be important. But in general, not limiting the discussion to fuel, it often isn’t and we can use a cockpit flow to help us remember everything when we don’t have time to review the checklist.
But back to your specific question using the power loss on the takeoff roll - that procedure should have throttle being reduced first, followed by mixture and then the fuel off. Reason being it may not be a 100% power loss and throttle has an immediate impact to help us slow even more so than mixture. But mixture has a much more immediate impact over the fuel selector to shutdown the engine to help us further brake and reduce chance of a prop strike if we go off the end. Fuel selector off has the least impact at this point and frankly is in the nice to do if able. Fuel selector off time till engine shutdown will really vary. A carburetor will still have quite a bit of fuel in the bowl. A fuel injected engine will die sooner but not nearly as fast as using mixture.

If you have an older model POH, your emergency procedures are limited and more general; so it certainly helps to ponder the various circumstances that can be encountered to develop a flow that will work in the majority of emergency. But if you have a chance to review the more modern POH’s you'll see significant refinements over the years that you can apply to your model with some common sense adjustment. Consider the Acclaim emergency procedures - they provide much more detail for a loss of power on takeoff breaking it up into 3 categories I) on the runway, ii) below 400' and iii) above 400'. The details may vary between models but the concept or considerations apply to all Mooneys.


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I don't know about you, I'm a short legged fella who needs the seat almost full forward to reach the rudder pedals, but if I am in that situation, experiencing  an engine loss or fire that low to the ground, I know I wouldn't be able to reach the fuel valve in a timely manner. Ride through the scenario with me...

1. I'd have to slide the seat back rapidly, which would cause me to balloon up from pulling the yoke back as the seat slams into the aft seat stop and the stall horn sounds in protest. 

2. Bend down and try to or three times before I got the valve turned off.

3. Probably get vertigo when I lifted my head up.

4. Try to slide the seat forward so I could reach the rudder pedals again which would most likely cause me push the yoke fore and aft several times as I oscillate through the air trying to scoot the seat into position if I hadn't already buried the nose in the ground.

5. How much altitude do I have before the failure? I might stand a better chance just dropping her in and sliding her in on the belly then running like hell away if it is a fire. That I could do pretty quickly and smoothly.

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Always keep flying the plane....

Keep in mind that some of the procedure can be related to some odd stuff or odd happenings...

If you are preparing for a 'crash' you will want to shut off the fuel in as many ways as possible...

If the engine has died it might be a mixture control problem.  Cutting the mixture off may not be working...

If the plane bumps into things, a broken fuel line can be a problem. Shutting off the valve will minimize the fuel that can be released to a fire.

If the wing hits a tree and breaks open the tank... it won't matter much that you pulled the mixture first or last...

Shut it all down as many ways as possible.  We have seen mooney tanks spray fuel everywhere.  It is best to not let Even a small amount of the fuel touch any hot surfaces....

PP thoughts that come to mind, once the commitment to not keep trying to restart the engine is made... not a CFI...

Best regards,

-a-

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12 hours ago, outermarker said:

I don't know about you, I'm a short legged fella who needs the seat almost full forward to reach the rudder pedals, but if I am in that situation, experiencing  an engine loss or fire that low to the ground, I know I wouldn't be able to reach the fuel valve in a timely manner. Ride through the scenario with me...

1. I'd have to slide the seat back rapidly, which would cause me to balloon up from pulling the yoke back as the seat slams into the aft seat stop and the stall horn sounds in protest. 

2. Bend down and try to or three times before I got the valve turned off.

3. Probably get vertigo when I lifted my head up.

4. Try to slide the seat forward so I could reach the rudder pedals again which would most likely cause me push the yoke fore and aft several times as I oscillate through the air trying to scoot the seat into position if I hadn't already buried the nose in the ground.

5. How much altitude do I have before the failure? I might stand a better chance just dropping her in and sliding her in on the belly then running like hell away if it is a fire. That I could do pretty quickly and smoothly.

Sounds like you need rudder pedal extensions, available in 1-1/2” & 3” lengths and a fuel selector extension handle like many have fabricated.

Clarence

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15 hours ago, outermarker said:

I don't know about you, I'm a short legged fella who needs the seat almost full forward to reach the rudder pedals, but if I am in that situation, experiencing  an engine loss or fire that low to the ground, I know I wouldn't be able to reach the fuel valve in a timely manner.

What's your inseam?  I'm just one step up from being a dwarf, and I can reach the fuel shutoff.  Yeah, I need to take of the shoulder belt to do it, but I can.  And yeah, if you're in IMC you're probably going to get vertigo down it.  I'd probably have the autopilot oneas I did it.  You realize our airplanes came new with autopilots, right?

That said, if you're actually sorter than me I'd like to thank your existing and making me look tall.  Not many people do that outside of Japan.

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Well, a 29" inseam is all the length I got with stubby lil' arms.......but also being a bit on the thick side limits one trying to bend over and reach downward in a time of excitement. It might be easier in a newer Mooney, don't know, never flew one, I just know if I put an iPad mini on the yoke, it might as well be on my belly.

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21 minutes ago, steingar said:

What's your inseam?  I'm just one step up from being a dwarf, and I can reach the fuel shutoff.  Yeah, I need to take of the shoulder belt to do it, but I can.  And yeah, if you're in IMC you're probably going to get vertigo down it.  I'd probably have the autopilot oneas I did it.  You realize our airplanes came new with autopilots, right?

That said, if you're actually sorter than me I'd like to thank your existing and making me look tall.  Not many people do that outside of Japan.

 

6 minutes ago, outermarker said:

Well, a 29" inseam is all the length I got with stubby lil' arms.......but also being a bit on the thick side limits one trying to bend over and reach downward in a time of excitement. It might be easier in a newer Mooney, don't know, never flew one, I just know if I put an iPad mini on the yoke, it might as well be on my belly.

Why do I get this mental image?

maxresdefault.thumb.jpg.7e6efd52e5faa72e1fcc7f36a77c1c1c.jpg

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On ‎1‎/‎25‎/‎2018 at 4:30 PM, kortopates said:

Not sure what model you are referring too, but it certainly can be important. But in general, not limiting the discussion to fuel, it often isn’t and we can use a cockpit flow to help us remember everything when we don’t have time to review the checklist.
But back to your specific question using the power loss on the takeoff roll - that procedure should have throttle being reduced first, followed by mixture and then the fuel off. Reason being it may not be a 100% power loss and throttle has an immediate impact to help us slow even more so than mixture. But mixture has a much more immediate impact over the fuel selector to shutdown the engine to help us further brake and reduce chance of a prop strike if we go off the end. Fuel selector off has the least impact at this point and frankly is in the nice to do if able. Fuel selector off time till engine shutdown will really vary. A carburetor will still have quite a bit of fuel in the bowl. A fuel injected engine will die sooner but not nearly as fast as using mixture.

If you have an older model POH, your emergency procedures are limited and more general; so it certainly helps to ponder the various circumstances that can be encountered to develop a flow that will work in the majority of emergency. But if you have a chance to review the more modern POH’s you'll see significant refinements over the years that you can apply to your model with some common sense adjustment. Consider the Acclaim emergency procedures - they provide much more detail for a loss of power on takeoff breaking it up into 3 categories I) on the runway, ii) below 400' and iii) above 400'. The details may vary between models but the concept or considerations apply to all Mooneys.


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Great point !  I've always thought of the POH as the bible, but modern interpretation may be just as important !  You are 100% right, older POHs are often "lacking" at best.

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