Fuel Pump Usage For TO & Landings

[BigTex]

If been asking around to see who follows the POH and turn on the aux fuel pump for take offs and landings. For the folks that do not use it, it seems the reason is that the pumps are a POS and are expensive to replace.

I remember being in Mexico and notice a large number of cars running around without headlights at night. I asked why and the answer was that headlights are very hard to find and very expensive. So are we being a penny wise, pound foolish when it comes to using the aux fuel pumps?

What's the groups options on what should be the SOP for the aux fuel pump?

[M20F-1968]

There is a retrofit number to replace the expensive Dukes pump with a more reliable and less costly Weldon pump. This should not be an issue. You want to use the aux pump in critical flight situations such as take-off and landings. That is why it is there.

John Breda

[jetdriven]

If you turn on the Dukes fuel pump for every takeoff and landing it won't last a year. It also costs over a grand to have it overhauled. Ours was replaced at purchase and it failed the first time it was flown. It lasted ten minutes.

Its a crappy design. The Weldon would be a far better choice, and it is approved for continuous operation.

[KSMooniac]

I only use mine to prime the engine and on takeoff.

[Oscar Avalle]

I use mine for starting, take off, to switch tanks and landings. My Dukes died about three weeks ago and I am waiting for a Weldon to replace it. Meanwhile I borrowed a Dukes from "the only other Mooney in Guatemala".

[Magnum]

Same procedure here. I once had low fuel pressure during takeoff in a Warrior with the electrical fuel pump on. Fortunately my brother was flying with me, he is a IA. He took care of the engine and I concentrated on flying. There were no nice emergency landing fields around and we were able to keep the engine alive until landing. With the electrical fuel pump off the engine would have died. As the primer tube had a leak I don't know if switching the pump on AFTER the engine died would have helped to start it again. I ALWAYS have the pump on during take-off and landing, no matter how much the overhaul costs.

[201er]

Does the fuel pump provide any useful benefit during steep climbs other than acting as a backup? In other words does it improve fuel flow in climb attitude?

[AndyFromCB]

Nice thing about the Bravo, it does it for you on take off. Not much of a choice, it just turns itself on with full throtle, then goes off with cruise climb reduction.

[Bennett]

I normally only use the aux pump for starting (3-5 seconds with a cold engine), and when switching tanks while in the air (about 30 seconds or so). In other aircraft, I have turned on the pump immediately if there is an engine "burble", and/or if I change tanks in response. My prior Mooney, a 231 with the 261 Trophy conversion, had a two position pump, that failed in the flight levels - long story, but with a fortunate outcome.

[Becca]

If you turn on the Dukes fuel pump for every takeoff and landing it won't last a year. It also costs over a grand to have it overhauled. Ours was replaced at purchase and it failed the first time it was flown. It lasted ten minutes.

Its a crappy design. The Weldon would be a far better choice, and it is approved for continuous operation.

As a further "safety" thought, given their frequency of failure, running it for takeoff means you have just cycled in one more time to a failure that could occur when you need it (maybe later in the flight in an emergency). I recognize that you are accepting some small risk not running it for takeoff and landing, so when I review my takeoff and landing check list, I always remind myself of the fuel pump, so if there's even a hiccup, switching it on will be my first action.

[rbridges]

I didn't realize it was so temperamental. I use it for priming, take offs, landings and switching tanks. With my instrument training, I've been running it quite a bit lately. Great, now i"ve got something else to worry about.

[Hank]

Why use the pump when changing tanks? It only takes a couple of seconds to move the switch. Never ran the pump, never thought about it, never had a burble or cough.

[sreid]

The retrofit kit for the Weldon pump is not easy to come by. If the factory actually had one, ha, they get $2800 for it. (Includes pump and all brackets, lines, and fittings)

Steve

[OR75]

Why use the pump when changing tanks? It only takes a couple of seconds to move the switch. Never ran the pump, never thought about it, never had a burble or cough.

I try to switch tank when close to an airport.

If far from any airport or over terrain, i turn the pump and check the the fuel pressure "rebuilt" then turn it off

[Lionudakis]

I'm awaiting an overhauled dukes that made it 13 months and the owner only used it to build pressure on start up for a few seconds, and only has around 100 hrs in the plane since it was installed, it sounded weak and built no pressure, he had it overhauled in florida by CJ Aviation, overnighted it to them yesterday, it shipped today back to him overnight for 850ish With a pretty good warranty.

[jetdriven]

I didn't realize it was so temperamental. I use it for priming, take offs, landings and switching tanks. With my instrument training, I've been running it quite a bit lately. Great, now i"ve got something else to worry about.

using it to switch tanks is not needed. The fuel pressure fluctuates a few PSI but is fine. Give that a try sometime.

[rbridges]

using it to switch tanks is not needed. The fuel pressure fluctuates a few PSI but is fine. Give that a try sometime.

Just doing what the CFIs taught me. Thanks for the info.

[M016576]

Why use the pump when changing tanks? It only takes a couple of seconds to move the switch. Never ran the pump, never thought about it, never had a burble or cough.

I don't run the aux pump while switching tanks either. The motor will run for quite a while on just the fuel from the gascolator to the fuel divider... Ask the guys who start and take off fine only to find that water was in their fuel lines at 400 ft.. Don't see the need to impart extra pressure on the system (even if its only a couple psi). I do use the pump for every take off (I do not use it for landings... Again lower demand on the system). 3 years / ~250 hrs trouble free so far... Haven't seen any blue stains on the hangar floor yet below the vent... But from what I understand, that's the first sign of a bad aux pump (and unfortunately fairly common)

[Lood]

I always turn the pump on during all take off's and landings. Been doing it for the past 4 plus years and over 300 hrs and never had a problem. I've had to replace the on/off switch on the panel though.

[Alan Fox]

I have a 65 E and noticed that the aluminum cover on the bottom has a dimple hammered into it to accept a larger pump , Is that the "weldon conversion??

[sreid]

I have a 65 E and noticed that the aluminum cover on the bottom has a dimple hammered into it to accept a larger pump , Is that the "weldon conversion??

I don't currently have the Weldon on my airplane either, but I have seen the drawing from the Weldon conversion kit. It says to "reform" the panel as required. So it sounds like you probably do have it.

How big is the dimple? Does it still look ok or is it obvious that it has been modified and looks a little "hacked" together?

[Hank]

using it to switch tanks is not needed. The fuel pressure fluctuates a few PSI but is fine. Give that a try sometime.

I'll have to watch the needle the next time. But Cs only have a few PSI fuel pressure to begin with. I typically fly around 3½-4", and the green line stops at 6". Injected models are much higher. No pump tank changes are not a problem.

[fantom]

I always turn the pump on during all take off's and landings. Been doing it for the past 4 plus years and over 300 hrs and never had a problem. I've had to replace the on/off switch on the panel though.

I've been doing it for 18 years on the same pump, without issue.....

[jetdriven]

is it a Dukes pump?

[fantom]

is it a Dukes pump?

On a '94...of course not.