Fuel reserves

Henning said:
I still don't understand why you keep going on about your charging system being "unhealthy". You have not said one thing that indicates in any way that your charging system isn't doing exactly what it should be doing. What it does is exactly correct and the voltages are what they are because it can't do what it's supposed to do on a bad battery.
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Do you have a reference that explains that? How does a bad battery prevent an alternator from putting out its rated current?

You do not need an A&P mechanic to replace the battery in your plane.
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Okay, that's good to know. I thought an A&P had to sign it off.

BTW, if there is a Battery Minder on the hangar floor, why the hell isn't it hooked up to the battery huh?
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Because I have no idea at all if it even works. It doesn't have a model number and I don't have the manual for it. It's just something I found on my hangar floor. I'm only guessing that my mechanic was actually using that, for all I know it's something he tried, found it was broken, and then used something else which he removed after use because he needed it elsewhere. Like I said, I want to talk to him first.

If I can't, because he's really out of the game for whatever reason, then I'll just order one because I'll need it to keep my next battery from dying an early death. But I'm not going to just hook up something from my mechanic's junkpile without knowing what condition it's in.

p.s. let's move this discussion over to the other thread, okay?
 
You're all good to replace a battery...

14 CFR Part 43 Appendix A lists all the "Preventive Maintenance" stuff that a pilot/owner can do to their aircraft with appropriate logbook entries, in case you weren't aware. It's a pretty extensive list, and there's a few things on it I wouldn't attempt without qualified assistance the first time around, but a battery is "do-able" to me, since I've changed tons of them in cars, etc.

Depending on where the thing is located, though -- I might have someone else deal with the headache. Heh heh. Tail mounted batteries can be a pain in the butt.

Anyway... it's number 24 below...

Not enough pilots are taught anything about Part 43, which is a shame. But then again, you need to be a pilot/owner, a rental pilot can't do most of this stuff legally...

Owners get to know Part 43 a little better than renters. ;)

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(c) Preventive maintenance. Preventive maintenance is limited to the following work, provided it does not involve complex assembly operations:

(1) Removal, installation, and repair of landing gear tires.

(2) Replacing elastic shock absorber cords on landing gear.

(3) Servicing landing gear shock struts by adding oil, air, or both.

(4) Servicing landing gear wheel bearings, such as cleaning and greasing.

(5) Replacing defective safety wiring or cotter keys.

(6) Lubrication not requiring disassembly other than removal of nonstructural items such as cover plates, cowlings, and fairings.

(7) Making simple fabric patches not requiring rib stitching or the removal of structural parts or control surfaces. In the case of balloons, the making of small fabric repairs to envelopes (as defined in, and in accordance with, the balloon manufacturers' instructions) not requiring load tape repair or replacement.

(8) Replenishing hydraulic fluid in the hydraulic reservoir.

(9) Refinishing decorative coating of fuselage, balloon baskets, wings tail group surfaces (excluding balanced control surfaces), fairings, cowlings, landing gear, cabin, or cockpit interior when removal or disassembly of any primary structure or operating system is not required.

(10) Applying preservative or protective material to components where no disassembly of any primary structure or operating system is involved and where such coating is not prohibited or is not contrary to good practices.

(11) Repairing upholstery and decorative furnishings of the cabin, cockpit, or balloon basket interior when the repairing does not require disassembly of any primary structure or operating system or interfere with an operating system or affect the primary structure of the aircraft.

(12) Making small simple repairs to fairings, nonstructural cover plates, cowlings, and small patches and reinforcements not changing the contour so as to interfere with proper air flow.

(13) Replacing side windows where that work does not interfere with the structure or any operating system such as controls, electrical equipment, etc.

(14) Replacing safety belts.

(15) Replacing seats or seat parts with replacement parts approved for the aircraft, not involving disassembly of any primary structure or operating system.

(16) Trouble shooting and repairing broken circuits in landing light wiring circuits.

(17) Replacing bulbs, reflectors, and lenses of position and landing lights.

(18) Replacing wheels and skis where no weight and balance computation is involved.

(19) Replacing any cowling not requiring removal of the propeller or disconnection of flight controls.

(20) Replacing or cleaning spark plugs and setting of spark plug gap clearance.

(21) Replacing any hose connection except hydraulic connections.

(22) Replacing prefabricated fuel lines.

(23) Cleaning or replacing fuel and oil strainers or filter elements.

(24) Replacing and servicing batteries.

(25) Cleaning of balloon burner pilot and main nozzles in accordance with the balloon manufacturer's instructions.

(26) Replacement or adjustment of nonstructural standard fasteners incidental to operations.

(27) The interchange of balloon baskets and burners on envelopes when the basket or burner is designated as interchangeable in the balloon type certificate data and the baskets and burners are specifically designed for quick removal and installation.

(28) The installations of anti-misfueling devices to reduce the diameter of fuel tank filler openings provided the specific device has been made a part of the aircraft type certificiate data by the aircraft manufacturer, the aircraft manufacturer has provided FAA-approved instructions for installation of the specific device, and installation does not involve the disassembly of the existing tank filler opening.

(29) Removing, checking, and replacing magnetic chip detectors.

(30) The inspection and maintenance tasks prescribed and specifically identified as preventive maintenance in a primary category aircraft type certificate or supplemental type certificate holder's approved special inspection and preventive maintenance program when accomplished on a primary category aircraft provided:

(i) They are performed by the holder of at least a private pilot certificate issued under part 61 who is the registered owner (including co-owners) of the affected aircraft and who holds a certificate of competency for the affected aircraft (1) issued by a school approved under §147.21(e) of this chapter; (2) issued by the holder of the production certificate for that primary category aircraft that has a special training program approved under §21.24 of this subchapter; or (3) issued by another entity that has a course approved by the Administrator; and

(ii) The inspections and maintenance tasks are performed in accordance with instructions contained by the special inspection and preventive maintenance program approved as part of the aircraft's type design or supplemental type design.

(31) Removing and replacing self-contained, front instrument panel-mounted navigation and communication devices that employ tray-mounted connectors that connect the unit when the unit is installed into the instrument panel, (excluding automatic flight control systems, transponders, and microwave frequency distance measuring equipment (DME)). The approved unit must be designed to be readily and repeatedly removed and replaced, and pertinent instructions must be provided. Prior to the unit's intended use, and operational check must be performed in accordance with the applicable sections of part 91 of this chapter.

(32) Updating self-contained, front instrument panel-mounted Air Traffic Control (ATC) navigational software data bases (excluding those of automatic flight control systems, transponders, and microwave frequency distance measuring equipment (DME)) provided no disassembly of the unit is required and pertinent instructions are provided. Prior to the unit's intended use, an operational check must be performed in accordance with applicable sections of part 91 of this chapter.
 
Thanks Nate! I knew some preventative maintenance was allowed (such as replacing landing light bulbs) but didn't know that batteries were on the list.
 
azure said:
Do you have a reference that explains that? How does a bad battery prevent an alternator from putting out its rated current?
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You are confusing "voltage" being an indicator of "current". Current is amperage, call it the density of electrons, and voltage is the pressure it is being put through with. The alternator can only produce so much pressure differential. When the base value of the differential equation drops, so does the upper value.
 
Henning said:
True, most of the time I go full fuel because I need full fuel and then some. I fill 2-3 times westbound coast to coast and 1-2 times eastbound. Normal cabin load is maybe 375lbs with me, my luggage, toolbox, stuff...
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My typical trip requires me to have more than full fuel as well, hence the extra stops. Given that, it ends up making the most sense to fill up each time. Plus, for accounting purposes, it makes the most sense to fill the plane after returning each time.

As for Navajos, the only ones I think are worth buying are the 325CR and the Chieftain. The 325 is a comfortable 4 passenger cabin + cockpit, 210 cruise you can even make a lav in the back and have a great family Bahamas plane. Now, if you want to load up 2 golf cars of buddies and clubs and do a scramble 2 states over, you can't beat the Chieftain. IMO the Chieftain is the only all around "winner" Piper has had in that class of aircraft. You can even put it to work.
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The one I fly is a 310. As with anything, it depends on what you're doing. In Canada, they love the older Navajos with 2-bladed props because if they bang up a prop, it's easy to put a new one in the back and fly it up. I like the 310 because it's what I fly. A Chieftain would be better for the missions that I do with it, but the 310 does the job just fine.
 
azure said:
No, but Cherokees don't have a "both" position on the fuel selector. The pre-landing checklist in every Cessna I've flown says fuel selector: BOTH. Since the fuel system is gravity-driven, I'm not sure it's a good idea to be maneuvering in the pattern with a dry tank.

Maybe that's a misconception on my part; if so, I hope someone will correct me. :)
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Inorder to have a "Both" position on the selector the FAA requires that it still supply fuel to the engine normaly if one tank is empty but the other isn't.:yes:
 
Henning said:
How do you empty one tank in the "both" position?:D
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Position of the fuel outlet port in the fuel tank is one way so that one tank has a slightly higher usable than the other would be one way. :dunno:

FWIW, twin engine helicopters it's usually set up so one tank feeding one engine has slightly more fuel than the other tank/engine to avoid a dual flame out.
 
Henning said:
How do you empty one tank in the "both" position?:D
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Has happened to me more than once. Although, I don't have a both selector. I have one selector per side, and if both are set to main, the right main always seems to get drawn from quicker than the left.
 
Henning said:
How do you empty one tank in the "both" position?:D
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Most single-engine Cessnas have so many vents and unintended cross-feeds to try to equalize fuel burn, they do the exact opposite. If the tanks are full, you'll suck gas from whichever tank has the higher head pressure, and on the Cessnas with only one vent...

Cessna Pilots Assn has a good presentation on this on their website. You can stick that selector on Left or Right and still be sucking fuel from the other tank in most Cessna singles.
 
Skylane81E said:
Line boy doesn't pump equal fuel into the tanks, preferential draw etc...
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Your FBO always pulls the planes out on the ramp facing the same direction, which is just slightly left-wing-down, but enough that fuel drains from the vent on the left wing and crossfeeds out of the right wing...
 
flyingcheesehead said:
Your FBO always pulls the planes out on the ramp facing the same direction, which is just slightly left-wing-down, but enough that fuel drains from the vent on the left wing and crossfeeds out of the right wing...
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Won't it crossfeed and equalize when leveled in flight? Unless there is a checkvalve in the system it's self regulating. If you have a pressure differential issue, then that will keep the "fuller" tank from feeding fuel anyway and the plane will run out with fuel in a tank. Unless you have staggered tank heights, a check valve of a venting problem, you will run both tanks dry at the same time in a "Both" system.
 
Henning said:
Won't it crossfeed and equalize when leveled in flight? Unless there is a checkvalve in the system it's self regulating. If you have a pressure differential issue, then that will keep the "fuller" tank from feeding fuel anyway and the plane will run out with fuel in a tank. Unless you have staggered tank heights, a check valve of a venting problem, you will run both tanks dry at the same time in a "Both" system.
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Through the crossover? No. I think it's close to the top of the tank as it's meant for air, not fuel, to be flowing through. Because of that, it's also very small - the rate of drain on the ramp is fairly slow. But, once you get going, if you're feeding equally from both sides, the "crossfeed" will only have air in it.

Now, there would probably be somewhat increased pressure on the fuller side so all else being equal it'd probably feed a little faster out of the fuller side. Dunno if there'd be enough of a difference to equal the tanks out before one runs dry, tho.

But, I don't think I've ever flown a "Both" plane for any length of time where both tanks really fed evenly. They all seem to "prefer" one or the other, especially in the top half.
 
flyingcheesehead said:
Your FBO always pulls the planes out on the ramp facing the same direction, which is just slightly left-wing-down, but enough that fuel drains from the vent on the left wing and crossfeeds out of the right wing...
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Put fuel selector in left or right when parked, stops much of the cross feed. Just remember to go back to both for take off.:wink2:
 
Skylane81E said:
Put fuel selector in left or right when parked, stops much of the cross feed. Just remember to go back to both for take off.:wink2:
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Actually, Off would be better - That way, nobody's gonna be taking off with the selector in the wrong position. :yikes:
 
flyingcheesehead said:
Actually, Off would be better - That way, nobody's gonna be taking off with the selector in the wrong position. :yikes:
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Maybe, but they teach you switch to the left with the Cessna Pilot Center course. My instructor, as a training aid and a lark, switches things around during the run-up and touch and goes to see if you really follow the checklists. Nothing too serious or dangerous, but enough to impress upon you the value of double-checking.
 
A little late here, but:

1 - I was a pax in a fuel exhaustion accident 20 years ago. My back and hip has hurt from wakeup to bedtime every day since. Two broken vertebrae, dislocated hip, over 200 stitches in my face, another 200 on my head.

2 - I plan for a 1.5hr reserve. That allows me to be on the ground even with a divert with an hour of fuel in the tanks.
That hour is NOT my flying reserve, it's my margin of error for the mistake that I don't know I've made (filled up on a slant, flying at lower altitude, overly rich mixture, whatever).
So, about .5 is my diversion reserve, about 1.0 is my "I screwed up something" margin of error.

Some will say it's excessive. But the cost of doing it is very low (an occasional fuel stop that might not have been needed), and cost of snapping some accident-chain links together is very, very high.
 
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Henning said:
No, the fuel systems equalize to the head pressure of each tank at the valve if you have it on both.
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At rest they might. In flight they won't necessarily do so. I can open both my fuel valves, and they will equalize when in the hangar. But in flight, it almost exclusively pulls from the right tank.
 
flyingcheesehead said:
Actually, Off would be better - That way, nobody's gonna be taking off with the selector in the wrong position. :yikes:
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Supposedly some of the selector valves have a T arrangement so when in the off position they can still x-feed.

However every one I've ever seen was a Y and wouldn't have that issue.:dunno:
 
PilotAlan said:
Some will say it's excessive. But the cost of doing it is very low (an occasional fuel stop that might not have been needed), and cost of snapping some accident-chain links together is very, very high.
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I think the real trick to avoiding fuel starvation is to disconnect yourself from the social obligations and impatience that you've been programmed to obey without question since you were a kid.

When the clock says it's time to find fuel, you go find fuel right then. Don't fly another 20 minutes because the destination is right there in front of you where you can see it. When it's time for fuel, you land at the next airport, that one the line on the chart goes to for your refuel stop or the one that the timer insists is next. If you have to land 10 miles short and refuel and end up taking 45 minutes to do so, then so be it - even if you have snotty passengers or irritated people waiting to pick you up.

On long range flights, or even short flights, absolutely every leg of the flight is fuel stop to fuel stop. The only exception is when the destination just by chance happens to be closer than the next required fuel stop.
 
fgcason said:
I think the real trick to avoiding fuel starvation is to disconnect yourself from the social obligations and impatience that you've been programmed to obey without question since you were a kid.

When the clock says it's time to find fuel, you go find fuel right then. Don't fly another 20 minutes because the destination is right there in front of you where you can see it. When it's time for fuel, you land at the next airport, that one the line on the chart goes to for your refuel stop or the one that the timer insists is next. If you have to land 10 miles short and refuel and end up taking 45 minutes to do so, then so be it - even if you have snotty passengers or irritated people waiting to pick you up.

On long range flights, or even short flights, absolutely every leg of the flight is fuel stop to fuel stop. The only exception is when the destination just by chance happens to be closer than the next required fuel stop.
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I just carry enough fuel that I am going to have to stop before the plane will. Over 6-1/2 hours of fuel on board, my bladder is about a 3-1/2 to 4 hour limit.
 
EdFred said:
I just carry enough fuel that I am going to have to stop before the plane will. Over 6-1/2 hours of fuel on board, my bladder is about a 3-1/2 to 4 hour limit.
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I did this last summer, took off and loaded final destination into my GPS (1000nm away) and started flying there. At four and a half hours I picked a fuel stop, landed and topped off. We then finished the trip going about 5.5 to the destination. As the plane is 7hrs to empty it wasn't worth stopping an hour short on the second leg as the 4.5 limit was a human one:yes:

I also use both my clock and fuel guages for telling me when to stop. What ever says I have the least fuel wins!
 
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