I don't understand this one. GUMPS check has me switching to the most full tank a few minutes before landing. I've been flying perfectly fine, and there's plenty of fuel in the tank I'm on. Why risk a change like this at the most critical phase of flight?
Gas (on most full tank)
- Thread starter mfisher
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I only switch tanks at top of descent, and only if I will have less than an hr left in that tank upon arrival. Others will have different opinions, but I don't recommend messing with something that is working unless there could be a threat to safety.
Stewartb
Final Approach
Some planes use one tank for landing and takeoff because of fuel outlet configuration. Others have a Both position and don't require switching. Know your airplane.
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Aztec Flyer
I've always considered it a reminder to check there is adequate fuel, not a requirement to switch tanks close to the ground. I prefer not to switch that late in a flight and plan my fuel and tank changes accordingly.
Shawn
En-Route
Yeah...GUMPS for me in my 182 is not necessarily to switch tanks or even to both but rather more of a mental check to make sure I do not NEED to change tanks. Would hate to have a fuel starvation on final or during a go around or missed approcah!
Hank S
En-Route
My Owners Manual says not to takeoff or land on a tank with less than 6 gallons. I treat it as a reminder to confirm fuel level in the tank, and switch if needed. Being based at a field without fuel for the last year, it's a good reminder . . .
gismo
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My airplane (B55) requires use of the main tanks for takeoffs and landings. I often want to run from the aux tanks as long as possible to retain as much fuel in the mains as possible in case I can't get fuel after landing. As a result I often switch tanks a few minutes before landing and I've never had reason to be concerned about this causing an engine stoppage as long as I keep track of the fuel remaining in the mains. IMO there's no more likelihood for a problem with fuel flow from the tank you're switching to than from the one you were using before the switch. OTOH, it does make sense to change tanks at a time when the workload is low so you can give the switch your full attention.
It's a checklist. The items on them are not necessarily instructions to "do this now".
The answers show variety of how that item is handled. Confirm both. Switch if a selected tank is outside limitations. Etc.
But most have a big thing in common. Instead of "read and do" it's "read and think."
The answers show variety of how that item is handled. Confirm both. Switch if a selected tank is outside limitations. Etc.
But most have a big thing in common. Instead of "read and do" it's "read and think."
MAKG1
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My before landing checklist says to turn the autopilot off. Not doing that on a coupled approach in the clouds, nor am I reading checklists at 300 AGL. I like it done prior to final approach fix.
You fly the plane, not a checklist. Deciding not to do something or to delay it is very different from forgetting it.
You fly the plane, not a checklist. Deciding not to do something or to delay it is very different from forgetting it.
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I always take off only on the tanks that I started-up and taxied with. From start-up I do not switch tanks outbound until I am at cruising altitude. Don't see any reason I should ever have to.
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Bro do you even lift
technically if you followed the checklist to a T, if you were doing pattern work you'd be switching tanks every lap around the pattern (or maybe every other lap). I agree with MSUDavid, if I'm going to switch I prefer doing so higher.
My aux tanks are not to be used for takeoff, so it's advisable not to use them for landings when you might have a go around. As others have mentioned, I usually make the switch well in advance of the approach. GUMPS is just a reminder to make sure you've taken care of it.
G isn't always just the fuel tank selector. Some airplanes also require a boost pump (one of my friends who flies such calls it BUMPS because their fuel system is just the standard Navion on-off which you'd realize you'd messed up long before approach).
G isn't always just the fuel tank selector. Some airplanes also require a boost pump (one of my friends who flies such calls it BUMPS because their fuel system is just the standard Navion on-off which you'd realize you'd messed up long before approach).
James331
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Depends on your fuel burn, where the outlets are for the tanks etc.
For me I go both before the IAF, or 10 or so miles out from my landing area for VFR.
timwinters
Ejection Handle Pulled
Depends on what you fly I guess. The Diamond I fly has a "tank switch" in the taxi checklist. This to ensure that the engine runs normally regardless of which tank is selected.
I assume the logic is that it's best to find a line blockage (or other issue that prohibits fuel flow from one of the tanks) on the ground than it would be in the air.
With my 182, it's always on one tank when on the ground to avoid cross feeding. Then goes to both during the pre-takeoff checklist. It's one of the first things, before run-up.
MauleSkinner
Touchdown! Greaser!
How long will the engine run if the fuel is shut off? Taxiing is usually short enough that switching tanks wouldn't tell me anything useful.
timwinters
Ejection Handle Pulled
Not long enough to finish taxiing and then do a proper run-up. Actually, not even long enough to finish taxiing. I've checked. The closest runway is about 300 yards from the Diamond's hangar. IIRC the engine shut down in about 30 seconds but it's been a while. I'll check again the next time I fly it.
Stewartb
Final Approach
Some years ago I taxied away from the maintenance hanger after starting and a brief warm up, went about a half mile doing a rolling run-up along the way, waited at the hold line for tower, was cleared for takeoff so entered the runway, lined it up, pushed full throttle, and it quit. The mechanic had turned the fuel off. Had the taxi been shorter I'd have lost power on takeoff over unhospitable territory. That was the last time I didn't check my fuel valve prior to taxiing.
We've lost a few Navions that tried to take off using the (tip) aux tanks. Always check the fuel selector.
MauleSkinner
Touchdown! Greaser!
Years ago when I was loading spray planes in the summertime, my boss was desperate enough to have me fly his Ag Husky back from maintenance...I spent probably 20 minutes before takeoff trying to FIND the fuel valve. I finally figured if it hadn't quit by then, the fuel must be on.
I think I was halfway home when I finally spotted it.
I think I was halfway home when I finally spotted it.
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I agree with James 331. As is often the case in aviation, there is no single right way to do anything. Changing tanks in the terminal area doesn't make sense to me...change at cruise with an airport withing gliding range.
Bob
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Canis Non Grata
I do not switch tanks right before takeoff. I takeoff on whatever tank I did my runup on. Enroute, I always try to switch when within gliding distance of an airport and I will do my final switch over the closest airport to my final destination whenever possible. To me this adds an extra margin of safety in case something were to go wrong with the fuel selector. While these techniques do not fit all flight profiles, they fit most if not all of mine thus far. We all have different techniques that are molded to both the aircraft we are flying and our comfort level. There is no one size fit all procedure.
Ravioli
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Tank switching threads? Where art thou?
Start up on lessor tank - begin taxi - while taxiing switch to other tank - arriving at run-up pad either select BOTH or don't touch it. Do your run-up and go without touching it again.
Landing? You're probably on the correct tank if already if you've been managing your fuel...
Prior posts have already called it out. The GUMPS check is to think about those things again. And you do GUMPS 1 when established and GUMPS 2 when cleared you're probably not touching anything on GUMPS 2
Start up on lessor tank - begin taxi - while taxiing switch to other tank - arriving at run-up pad either select BOTH or don't touch it. Do your run-up and go without touching it again.
Landing? You're probably on the correct tank if already if you've been managing your fuel...
Prior posts have already called it out. The GUMPS check is to think about those things again. And you do GUMPS 1 when established and GUMPS 2 when cleared you're probably not touching anything on GUMPS 2
Wow! So *that's* why "switch tanks" is in the taxi checklist. Thank you.
BigBadLou
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Matt, you just like coming in here and screwing with us, right?
I agree with the majority: you don't want to be switching tanks on approach, you should have done that earlier while within gliding distance of another airport.
The checklist is a tool. How we use it is up to us.
I don't blindly follow "selector on fullest tank" because I know my airplane and I know which tank will work. Also, I verbalize "Fuel - on a good tank" during my GUMPS checklist, if that helps.
I agree with the majority: you don't want to be switching tanks on approach, you should have done that earlier while within gliding distance of another airport.
The checklist is a tool. How we use it is up to us.
I don't blindly follow "selector on fullest tank" because I know my airplane and I know which tank will work. Also, I verbalize "Fuel - on a good tank" during my GUMPS checklist, if that helps.
Ravioli
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@MauleSkinner - How long do you have to taxi to know if the fuel is flowing? Depends on the plane, but 1 Cherokee 180 I know it's about 3000 ft. I 'switched tanks' as I began a full length taxi but I ACTUALLY turned the selector to OFF. Getting near the run-up pad things got really quiet.
My CFI was quite reassuring. He said, "nobody has ever done that before.... today" Same thing he says when people (I) hit the starter button with the mags off.
My CFI was quite reassuring. He said, "nobody has ever done that before.... today" Same thing he says when people (I) hit the starter button with the mags off.
Nah. This is a real question.Matt, you just like coming in here and screwing with us, right?
I don't always troll. But when I do, I prefer letsrun.com.
Brad Z
Final Approach
MauleSkinner
Touchdown! Greaser!
True enough. One airplane I flew taxied a mile, did a run up, and lost my nerve so I switched back to a good tank.@MauleSkinner - How long do you have to taxi to know if the fuel is flowing? Depends on the plane, but 1 Cherokee 180 I know it's about 3000 ft. I 'switched tanks' as I began a full length taxi but I ACTUALLY turned the selector to OFF. Getting near the run-up pad things got really quiet.
Ravioli
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Almost forgot... he also thanked me for verifying that OFF works. It seems there's something in the emergency procedures for Engine Fire that explains the existence of the OFF position.
My written checklists conform with this philosophy.
They say "best tank" rather than "fullest." And the reminder appears on the checklist for descent from cruise rather than before landing.
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Snorting his way across the USA
What airplane?
That seems limiting. Is it a zero fuel weight limit issue? Does that mean you have to calculate your fuel reserves with six gallons already subtracted? (If you end up with five gallons in each tank, does that mean you can't land?)
kgruber
Final Approach
Some engine ARE started with the starter button and mags off!
Most likely the aircraft can't reliably flow the full power rate at nose high attitudes with that little in the tank. This is why the Navion aux (tip) tanks are prohibited about being used for takeoff. A few who have tried have had a bad experience.
I think you are right. I can't recall which make/model but I have seen in in manuals and for that reason. It's kind of like the no extended slips with flaps in some make/models for fuel flow reasons.
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And possibly the risk of unporting the fuel pickup in the tank during maneuvers in the pattern
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That likely would read "level flight only".
Takeoff limitations almost certainly are a rate of flow issue.
Takeoff limitations almost certainly are a rate of flow issue.
Hank S
En-Route
Oops, apparently my memory isn't what it used to be. Just reread the Manual, it only says to set the fuel selector for the fullest tank . . . There is a note to "avoid extreme sustained side slips toward the tank in use when that tank contains less than 36 lb of fuel." That's where the 6 gal came from.
It wouldn't be very restrictive as I personally land with at least an hour in the tanks, which is 9 gal. Having as much of that in one tank as possible is a good idea.
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whereisrandall
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@MauleSkinner - How long do you have to taxi to know if the fuel is flowing? Depends on the plane, but 1 Cherokee 180 I know it's about 3000 ft. I 'switched tanks' as I began a full length taxi but I ACTUALLY turned the selector to OFF. Getting near the run-up pad things got really quiet.
My CFI was quite reassuring. He said, "nobody has ever done that before.... today" Same thing he says when people (I) hit the starter button with the mags off.
I did that once at 500 AGL. Never again.