Model 2 Header tank, re: SB 29

[Slyfox]

I had an anoying problem with my right tank. I originally thought it was the style of tank on the right side. My problem, the right tank would not empty all the way, there was 5 gal left in the right tank. This was with ball valves installed on each tank to stop flow if I wanted. I was able to empty the left tank with just about nothing left in it. The right tank, different situation. I changed the right tank, it was a vintage 95 tank so I was also concerned with alki fuel. so I went through the trouble of replacing the right tank. I get it installed and here we go again, now I have 3 gal of fuel left and it won't flow into the header tank in flgiht. so now I'm checking and replacing fittings to match the left tank. Still I would get down to the last 3 gal of fuel and it would stop flowing through the lines. I do have the low fuel light, very nice. I called John and we talked, he mentioned that the header tank has been moved to right behind the seat because of fuel starvation, mainly on decents. I didn't think this was my problem. He also mentioned that he doesn't have any ball valves and both tanks empty together and do it fine on his SS. Still determined to find out why I can't empty the right tank like the left I continued to think on it and finally come up with the fact that the only vent for the header goes into the right tank. So I went and flew one more time and got down to 3 left in the right tank and started having troubles with flow at which time I reached up and pinched off the vent line, walla, the flow resumed to the header tank from the right tank, gotcha you sucker. I landed and installed a ball valve in the right tank vent. I than went up for another flight and when the fuel quit this time I closed the valve and yes the fuel resumed, I played with it and found if I closed the valve and opened it just a little I emptied the right tank, cool , an answer to my problem. Buy one draw back, you need the vent to empty the right side. So my answer is to not use this unless I need the extra 3 gal in the right tank. So for now the vent is open, but us it only when getting that last 3 gal out of the right tank.

Why is this important, I fly around with minimum fuel for performance on my local flights. I want this 3 gal of fuel for safety reasons. Now I have it.

[cap01]

so steve , whats happening when your down to 3 gal in the right tank and left tank empty with the vent valve closed your getting vent thru the left empty tank ?

[dholly]

@Jacob - What was the fuel tank and fuel line configuration? (1) or (2) wing tanks into a small header tank, directly with no vent lines? Vented caps? Fuel line over the door frame I presume? Sorry for the confusion, but I've never seen a small header tank on the firewall (which side?) as you describe. Or are you referring to the gascolator possibly?

@JP/ALL - I've read the SB and not 'complied'. Why? Because I have a single (right) wing tank and panel tank on my M-III, both with vented caps. The fuel line exits the wing tank to a shut-off in the head rack, across the rear carry through tube, over the pilot side door, down the vertical door post, along horizontal tubing under the dash tank, then into the fuel selector below the dash tank near the dash tank outlet fitting.

Based on wording in SB#29 (emphasis mine):

"NOTE: For those operating wing tanks in conjunction with the large, front main tank, the wing tank fuel lines should route: forward from the wing tank, above the door frame work, down the diagonal bracing in the windshield area, and plumbed directly into the filler neck of the main tank. The wing tank fuel valve can be installed in the headrack above the door. Because of the capacity and fuel visibility in the main tank, the question of fuel flow stoppage from the wing tanks is not as critical. With the fuel routed into the filler neck, you will have a constant visual on all fuel."

This reads somewhat ambiguous to me, ie. when utilizing the panel tank is it applicable to single, or multiple wing tanks only? Regardless, as the SB was originally issued to remedy multiple wing tank usage issues, I question whether it is anything I need worry about. Is head pressure sufficient to keep fuel flowing even if my current routing is not continuously downhill?

In any event, I have NEVER seen fuel line routed down diagonal bracing into the filler neck. Has anyone done this? The SB recommendation for my fuel configuration seems problematic as it just dumps into the main panel tank. With the wing high, I should think the potential for in-flight overfill spillage exists if one were distracted.

I dunno, I'm inclined to leave well enough alone...

[Slyfox]

generally when I fly I have 10total gal fuel on board (I have two 13gal tanks)with what ever is in the header tank. this gives me some good performance in the aircraft. I fly around and empty one tank generally, either the left or right and than run on the other tank to the airport. Now I know I can fly for 20 minutes on the header tank at a lower speed setting, this has been tested also. When I fly at full speed I burn 5 gal of gas an hour. so I know when I really run out. I generally emtpy the right tank first, I know what the left one does, I have a red light that blares at me when the fuel flow stops, I love this thing.

If I read you right, your concerned with a what if. There is really no what if, that's why I have flight tested what the tanks do. I fly my plane a bunch, like over 150hrs this last year and the previous years over 300. I know my plane. I just was uncomfortable about carrying around 3 gal of fuel that I couldn't use.

[jtpitkin06]

Dear Chuck,

RE: Missile.

Please note in my profile I retired from American Airlines (which merged with TWA). I have a particularly close association with the pilots and flight attendants of TWA. Read the following list and maybe you’ll understand why I don’t waste my time with conspiracy theories. I have an equally long list from AAL11 and AAL77, most of whom I knew personally.

To all aviators gone west…

Capt John Pitkin ret.
American Airlines
Check Airman B-757/ B-767
DFW International division


From TWA 800

Campbell, Richard G., 63, TWA Flight 800 flight engineer, of Ridgefield, Connecticut
Carven, Paula, off-duty TWA flight attendant, of Bel Air, Maryland
Charbonnier, Jacques, 66, TWA flight 800 crew, of Huntington Station, New York
Charbonnier, Constance, 49, TWA flight 800 crew, of Huntington Station, New York
Christopher, Janet, 48, TWA flight 800 crew, of Stamford Heights, Pennsylvania
DiLuccio, Debra Collins, 47, TWA flight 800 crew, of Agropoli, Italy
Dodge, Warren, 50, off-duty TWA employee, of Brentwood, New Hampshire
Edwards, Daryl, 41, off-duty TWA service supervisor, Jersey City, New Jersey
Eshleman, Dougas A., 35, off-duty TWA flight engineer, of Aurora, Colorado
Gough, Capt. Donald, off-duty TWA pilot, of Mill Valley, California (married to Ana Leim)
Griffith, Joanne, 39, off-duty TWA employee, of Brooklyn, New York
Harkness, Eric, 23, off-duty TWA employee
Hull, James, 48, off-duty TWA employee, of Southampton, Pennsylvania
Ingenhuett, Lonnie, 43, off-duty TWA employee, of Scottsdale, Arizona
Johnsen, Arlene E., 60, TWA Flight 800 flight attendant, of Grand Junction, Colorado
Kevorkian, Capt. Ralph G., 58, TWA Flight 800 pilot, of Garden Grove, California
Krick, Oliver, 25, TWA Flight 800 flight engineer, of St. Louis
Kwan, Barbara, 40, off-duty TWA employee, of Scottsdale, Arizona, mother of Alec, 7
Lang, Ray, 51, TWA flight 800 crew, of North Massapequa, New York
Leim, Ana, off-duty TWA flight attendant, of Mill Valley, California
Lockhart, Maureen, 49, TWA flight 800 crew, of Merriam, Kansas
Loffredo, Elaine, 50, off-duty TWA employee, of Glastonbury, Connecticut
Luevano, Elias, 42, off-duty TWA employee, of Albuquerque, New Mexico
McPherson, Pamela, 45, off-duty TWA employee, of Atlanta, Georgia
Meade, Sandra, 42, TWA Flight 800 crew, of Camano Island, Washington
Melotin, Grace, 48, TWA Flight 800 crew, of Corona, New York
Miller, Gideon, 57, off-duty TWA pilot, of Sarasota, Florida
Rhoads, Marit E., 48, TWA Flight 800 Crew, Bellevue, Washington
Rhoads, Scott, 48, Bellevue, Washington (married to Marit Rhoads)
Schuldt, Mike, 51, TWA Flight 800 Crew, Safety Harbor, Florida
Simmons, Olivia, 50, off-duty TWA employee, Orange, New Jersey
Snyder, Capt. Steven, 57, TWA Flight 800 pilot, Stratford, Connecticut
Torche, Melinda, 47, TWA Flight 800 crew, Irvine, California
Verhaeghe, Rick L., off-duty TWA flight officer, 48, Goldsboro, North Carolina
Warren, Lani, 48, off-duty TWA flight service manager, Sherman Oaks, California
Ziemkiewicz, Jill, 24, TWA Flight 800 crew, of Rutherford, New Jersey

[Slyfox]

as noted I don't close the vent all the way off, I close the valve and open it slightly and than the tank empty's itself all the way.

[cap01]

capt john , i have also spent a career associating with crews and do understand to losses , although not as closely as you . i certainly didnt mean to bring up a tender subject as i dont pay attention to conspiracy theories .

[dholly]

Still curious, has anyone routed fuel line from a wing tank down diagonal bracing in the windshield area directly into the panel tank filler neck per SB#29?

[Hoenshell]

John,

I now own this plane that Bob referred to over 13 years ago. I've not owned very long and I am noticing a problem with the fuel system and came across this thread. The model 1 still uses a front header tank with the wing tanks feeding over the doors and then curve up so slightly to the valve. This location has caused a problem, and more so with the valve starting to weep and allowing air to enter the fuel system. I'm working on change this over to an aluminum behind the seat header tank as soon as possible. It's amazing that I was able to come across the thread so many years later. The concerning thing is this airplane is located and flies in Alaska where there isn't as much room error with fuel starvation problems. Thanks for the write-up over a decade ago.

Shawn

Bob,

Thanks for the opportunity to respond to your question about whether you should comply with service bulletins and service letters.

Let me preface my reply with a quick note. Often, emails and postings can sound a bit harsh. It’s hard to know the tone of the person doing the posting. I do not want to sound like I am pontificating or flaming you in any way. Just read this as if we are two aviators having a cool drink under the wing of your airplane in a friendly discussion.

You asked why should you comply with service letters and service bulletins when your plane is working fine. The real question is, “Why would you not want to comply?”

When a manufacturer of certified aircraft or kit supplier identifies a problem they notify all users via service letters and service bulletins.

A service letter indicates there may be a problem and operators should investigate and inspect their aircraft. Service letters often include possible remedies. A service bulletin is a red flag saying there is a definite problem and compliance is mandatory for safety. An airworthiness directive [AD] is when the FAA steps in and says you must comply or your aircraft will be grounded. (AD’s do apply to homebuilts. Just ask the owners of the Zenair 601)

When your aircraft is up for annual inspection, either your mechanic, or you as the certified repairman must sign in the logbook that the aircraft is airworthy. This means you have inspected the aircraft and researched any letters, bulletins and directives that may apply to your aircraft. It is your responsibility to ensure compliance with service letters, bulletins and directives. As the operator, you must ensure that the logbook indicates required maintenance and inspections were performed.


A fuel flow problem was identified with early Kitfox aircraft. Not all aircraft experienced a problem every flight. Some never reported a problem. While your aircraft may have operated without fault for the last 100 flights, can you be sure it will operate OK on flight 101? The simple fact is this: fuel starvation can occur, and there is a fix.

If you do have a fuel delivery failure resulting in a damaged aircraft or bodily injury, and investigation reveals you did not comply with the service bulletin; your insurance may be void, You may be personally liable for damages. You also may be subject to a violation under 91,9 for careless and reckless operation. The key issue is you are now aware the bulletin exists.


Aviation is not without risks. We do our best to minimize those risks. To ignore it because you think your aircraft is working fine is not the wisest choice, even if the risk is remote.

About 15 years ago TWA 800 exploded and went into the ocean off Long Island. It appears a fuel pump caused a spark in a near empty center tank. The same type of pump was used in 737, 747, 757, and 767. They had logged millions of flights and multi-millions of hours without a problem. The odds of it happening again are extremely remote. And still, those odds are unacceptable. All of the Boeing aircraft are affected by an AD to prevent that remote possibility.

The same goes for your Kitfox. Any known possibility of fuel starvation is an unacceptable risk. The key word here is “known”. This is not a theory on how it might happen, it is a report of several fuel starvation incidents. The modification to prevent it is neither difficult nor terribly expensive.

As to the actual installation and modification, the fuel pump doesn’t have to suck up fuel from way below your present location. There is positive fuel flow or head pressure to the pump inlet. In fact, my Kitfox doesn’t even have a fuel pump. Gravity works just fine.

The rear header tank location provides sufficient fuel drop to ensure proper venting. That occurs because of higher head pressure at the tank. It also creates a superior place for water condensation removal.

The additional length fuel lines are probably less risk of fuel leaks. Most leaks occur at fittings and valves. The modification reduces the connections by eliminating individual wing valves, if installed.

The revised fuel line routing goes under the door instead of over it. The loop over the door created a "p-trap" in the vent line.much like your kitchen sink.


With fuel going under the door, a fuel line leak will likely drip out the bottom of the aircraft instead of on your shoulder.


While the above is a somewhat lengthy reply, I hope you take it in a friendly tone and consider it merits. It is not meant to be derogatory in any way. I hope you will modify your aircraft and enjoy many hours of trouble free flying.

Regards,

John Pitkin
Greenville, TX

[avidflyer]

Do you have the 1/4" ram air tubes on the fuel caps? That does help fuel flow a some as it will pressurize the tank a little bit.