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Do you shut your electric fuel pump off on a lycoming?

Electric Pump During Flight?

  • I keep it ON the entire flight.

    Votes: 6 2.0%

  • I turn it OFF after reaching a safe altitude.

    Votes: 297 98.0%
  • Total voters
    303
Manchu16

Manchu16

Active Member
Just watched a presentation by Rian Johnson about RVP and vapor lock from this spring. He mentioned he leaves his facet pump running all the time outside of run up to test the engine driven pump. I was always taught, pump on for take off and landing then off otherwise.

What do others do?
 
I flew my airplane with a IO-540 for over 14 hours (with 10 take offs) in 2 days bringing it home earlier this month and only turned on the pump for take off and then turned it off, and never had an issue.

I was also taught ON for take off and landing. Like everything, we carry a lot of baggage from our initial CFIs and their thoughts during those times, like don't fly oversquare or you'll blow up your engine :eek:
 
Not a good idea IMHO

We had a pilot on the field who experienced a very unlikely casualty. His habit was to keep his electric pump on all the time. Unbeknownst to him, his mechanical pump failed, masked by the electric pump on all the time. When he experienced a total electrical failure (master switch fried), his engine stopped from lack of fuel. Due to luck and pilot skill, he was able to make it back to the field. While this combo of events is rare, it does highlight the value of not running the electric pump all of the time.
 
On takeoff, I shut mine off once reaching a safe altitude, as I was taught (typically 1000 ft AGL), and anytime flying at an altitude of less than 1000 ft. Also, boost pump ON for landing. My boost pump is a Weldon vane pump on a fuel injected engine, mounted on the firewall, not a facet pump.


..
 
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On the RV 10, with AFP fuel injection I used the electric boost pump for take off and landing. Engine driven mechanical pump only for balance of flight.

The new plane has SDS EFI&I so I always have one of the pumps going, second pump for take off and landing--------no mechanical pump on engine.
 
As others have said

He is masking a problem with excess heat, system lay-out/losses, etc. This is especially true if he's burning AvGas

In my opinion, it is important to know the margins in your system (designs). You don't want to be one of those people where everything was fine, until it suddenly wasn't. Share your configuration, mission requirements, photos, whatever. You could be a shield, some insulation, a re-route, etc. away from some "free" design margin.
 
Sam Staton said:
We had a pilot on the field who experienced a very unlikely casualty. His habit was to keep his electric pump on all the time. Unbeknownst to him, his mechanical pump failed, masked by the electric pump on all the time. When he experienced a total electrical failure (master switch fried), his engine stopped from lack of fuel. Due to luck and pilot skill, he was able to make it back to the field. While this combo of events is rare, it does highlight the value of not running the electric pump all of the time.
Click to expand...

This is why Rian recommends taxiing and doing a run up with the electric pump off, then turn it on for take off. You are ensuring the mechanical pump is working prior to take off. It’s unlikely you’ll loose both pumps on the same flight.
 
IF one searches through OLD Lycoming info, they recommend boot pump on for takeoff, climb, landing, switching fuel tanks, and on the ground when hot engine on a hot day.

I use to have boost pump on for fuel tank changes but after many hours and lots of testing, I determined that it was not necessary in my airplane.

I also start my engine with boost pump on. Have a tendency to taxi with the boost pump on from many years living and flying in the hot southwest of the USA. Still tend to do the same. I shut boost pump off for runup and then turn it back on before taxi onto the runway for takeoff. I also look at fuel flow and fuel pressure numbers during the runup boost pump condition change.

Any time that I am flying below 1,000 foot AGL, I have the boost pump on.
 
Me Too, Pretty Much

Carbureted O-320 on an RV-6. I turn the Facet electric pump on before starting, turn it off before cranking. Taxi and runup with it off, turn on for takeoff and climb to at least 1000’ AGL. Turn it on for tank changes, descents from cruising altitude, pattern work and landing. I think that’s what’s taught for carbureted engines these days. I also turn it on for aerobatics.
 
Use as gump”S” check

Based on my misfortune of unporting at 1,000 feet, I will religiously use the boost pump in my o320 at 2,000 feet or less approaching an airport in descent. The “S” in gumps for switches is turn on my wig/wag lights and boost pump. Like using your seatbelt extra tight.
Cal
 
JDeanda said:
Carbureted O-320 on an RV-6. I turn the Facet electric pump on before starting, turn it off before cranking. Taxi and runup with it off, turn on for takeoff and climb to at least 1000’ AGL. Turn it on for tank changes, descents from cruising altitude, pattern work and landing. I think that’s what’s taught for carbureted engines these days. I also turn it on for aerobatics.
Click to expand...

I do exactly the same thing, and have on every low wing airplane I’ve flown/owned for the last 50+ years. I’m not saying it’s right, but providing absolute fuel pressure on a low wing airplane any time you are close to the ground seems like cheap insurance against loss of fuel pressure because of an engine driven pump failure. After engine start on the ground with my boost pump off, or in flight above 1000’ or so is an area that loss of fuel pressure should not cause a dangerous situation. Running it continuously in cruise flight seems like an unnecessary precaution that could result in fuel boost pump failure because of it wearing out from use. And when that happens, would you know? Well, you would when your other pump (engine) gave up the ghost. All certified low wing airplanes I’ve flown operated this way, and I can’t find any fault with that.
 
Fuel injected engine electric pumps have a return line back to the inlet of the pump. Running it for too long (especially at low fuel burns) heats up the recirculating fuel. Will become counterproductive.

Maybe works great on the Facet pumps in an RV12 running auto gas. Not recommended in an airplane with mechanical fuel injection, where excess fuel from the electric pump recirculates back to the pump inlet.
 
Like most others

Boost pump on for take off and landing.

I see that a few of you do a run up without boost pump, then turn it on just before take off. If you taxi out to the runway you pretty much know the mechanical pump works. Your fuel pressure is a pretty healthy indicator of what the pump is capable of.
I would definitely not change anything in the fuel delivery system configuration after run up and just before take off.
The purpose of the run up is to verify your engine performance in the take off configuration and that includes a working boost pump.
 
electric boost pump

as many others do, i do use it for start up, take off and landing. in addition i have installed an automatic boost pump switch on system that put the boost pump on when mechanical pump pressure fall below 2 PSI. it also bring a warning light that show the electrical pump was trigger due to low pressure.

system is simple with pressure switch and relay :)
 
N427EF said:
Boost pump on for take off and landing.

The purpose of the run up is to verify your engine performance in the take off configuration and that includes a working boost pump.
Click to expand...

Unless you are running up at full power, your run up is not take off configuration. You have no guarantee your fuel pump will provide adequate fuel at take off based on a run up at 1800 rpm.
 
David Z said:
Fuel injected engine electric pumps have a return line back to the inlet of the pump. Running it for too long (especially at low fuel burns) heats up the recirculating fuel. .
Click to expand...

My IO-540 doesn't have a recirculating line (angle valve)

My IO-540 does not know what operating at low fuel burn$ means :(:( but I wanted a helicopter so this thing sucks fuel just like a helicopter. :p
 
Not exactly

Pilot135pd said:
My IO-540 doesn't have a recirculating line (angle valve)

My IO-540 does not know what operating at low fuel burn$ means :(:( but I wanted a helicopter so this thing sucks fuel just like a helicopter. :p
Click to expand...

I think the responder was not talking about a return line from the engine, but rather the pressure relief valve for the pump itself.

He makes a good point. The way the electric pump keeps the correct pressure is by recirculating fuel from the outlet to the inlet.

I never thought os this but he is correct. From now on, I will turn off electric pump in cruise to keep fuel temp down.
 
So, just to bring this back to the OP. We’re all talking about boost pumps and the OP is talking about facet pumps…. Big difference in pumps and how we operate them.
 
Manchu16 said:
Just watched a presentation by Rian Johnson about RVP and vapor lock from this spring. He mentioned he leaves his facet pump running all the time outside of run up to test the engine driven pump. I was always taught, pump on for take off and landing then off otherwise.

What do others do?
Click to expand...

Those that use a Facet (electric) fuel pump as a back-up to the mechanical fuel pump mounted
to the back of the Lycoming, agree that it should not be left on during flight.....

FP on.JPG

So, who is going to change their procedure based on this Thread? Maybe one person out of 122......:)

And those with EFI, DON'T SHUT YOUR FUEL PUMP OFF based on this survey....:eek:
 
I will give you an exception. We bought an RV-4 with a Simmonds fuel injection system on an IO-360. Thebrare Simmonds system has a fuel return line similar to the Continental fuel injection design. The boost pump was only used for priming before start or in flight emergency. If the boost pump was turned on in flight under normal conditions the engine would quit. The return line would feed to the right tank so it would overflow the tank if R wasn't initially selected. My buddy who was ferrying the aircraft home found out about all that through underware changing experience.
 
What Lycoming Key Reprints has to say about boost pump

Here is a snap shot of where I got the info and the permission to reprint.
Screenshot 2023-08-30 at 7.59.01 AM.pngScreenshot 2023-08-30 at 7.59.19 AM.png

The following is a Copy / Paste from the above 12.1 MB PDF document.

Use Of Fuel Boost Pumps With Textron Lycoming Engines

As an engine manufacturer, we are frequently asked
about the proper use of the fuel boost pump with our
powerplants. Although we can't pretend to be an expert on
the fuel boost pump itself, we have some positive
recommendations concerning its use with our engines.
Where a boost pump is provided by the airframe
manufacturer, and the airframe Pilot's Operating Handbook
has a limited treatment of the use of the fuel boost pump,
perhaps this discussion can provide the necessary fuel boost
pump information for the pilot in order to operate his or her
engine as safely as possible.

It is necessary to supply the engine with a steady,
uninterrupted flow of fuel for all operating conditions.
Entrapped air, temperature changes, pressure drops,
agitation in the fuel lines and other factors affect the release
of air and vapor from the fuel system. Under some
circumstances where an engine mounted fuel pump is
provided it may not be able to pump a continuous fuel
supply free of excessive vapor.

An effective continuous fuel supply is provided by use
of the fuel boost pump. As a general recommendation, the
fuel boost pump should be used with Lycoming engines in
all conditions where there is any possibility of excessive
vapor formation, or when a temporary cessation of fuel flow
would introduce undesirable hazards. The conditions under
which Textron Lycoming recommends operation of the fuel
boost pump are as follows:
1. Every takeoff.
2. Climb after takeoff unless Pilot's Operating Handbook
says it is not necessary.
3. When switching fuel selectors from one separate fuel tank to another, the fuel boost pump should be "On" in the new tank until the operator is assured there will be no interruption of the fuel flow.
4. Every landing approach.
5. Any time the fuel pressure is fluctuating and the engine is affected by the fluctuation.
6. Hot weather, hot engine ground operation where fuel vapor problems cause erratic engine operation
7. Some General Aviation aircraft require the use of the fuel boost pump during high-altitude flight. This will be spelled out in the Pilot's Operating Handbook.
8. If the engine mounted fuel pump fails.

If the fuel boost pump is used during ground operation,
don't fail to check the condition of the engine mounted fuel
pump before takeoff by turning the boost pump off briefly,
and then back "on" for takeoff. If the engine mounted pump
has failed, it would be safer to know that on the ground
rather than in the air when the fuel boost pump is turned
"off."

When in doubt, do the safest thing and use the fuel boost
pump with Lycoming engines. Don't be "stingy" with the
boost pump. In most cases they last the overhaul life of the
engine, and are then exchanged or overhauled themselves.
AS A REMINDER, the airframe Pilot's Operating
Handbook is the authority if boost pump information is
spelled out in it.

Following is a photo image of the page as well as a PDF of the page.

Screenshot 2023-08-30 at 8.00.57 AM.pngView attachment KEY REPRINTS (dragged).pdf
 
I don’t understand why anyone would leave it on all the time. Not only would it mask a dead engine-driven pump as noted, it’s also a lot of needless wear and tear on the electric pump.

For that matter, what’s the purpose for having it on for takeoff and climb? I think it might one of those Old CFI’s Tales, like climbing at “25-squared.”

Add: just now seeing the note Gary posted above, I can see why one might follow Lycoming’s recommendations. I still think there’s a high likelihood of Old Lycoming Tales, though.
 
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StuBob said:
what’s the purpose for having it on for takeoff and climb?
Click to expand...

From the people who designed the engine (Textron Lycoming) :
"It is necessary to supply the engine with a steady,
uninterrupted flow of fuel for all operating conditions.
Entrapped air, temperature changes, pressure drops,
agitation in the fuel lines and other factors affect the release
of air and vapor from the fuel system. Under some
circumstances where an engine mounted fuel pump is
provided it may not be able to pump a continuous fuel
supply free of excessive vapor."

So even if the engine mounted pump is working, I think this should be reason enough to use it during those critical phases where the engine is working the hardest to get you safely away from crashing into the ground.
 
RV6_flyer said:
Here is a snap shot of where I got the info and the permission to reprint.
View attachment 47233View attachment 47234

The following is a Copy / Paste from the above 12.1 MB PDF document.

Use Of Fuel Boost Pumps With Textron Lycoming Engines

..................

When in doubt, do the safest thing and use the fuel boost
pump with Lycoming engines. Don't be "stingy" with the
boost pump. In most cases they last the overhaul life of the
engine, and are then exchanged or overhauled themselves.
AS A REMINDER, the airframe Pilot's Operating
Handbook is the authority if boost pump information is
spelled out in it.
Click to expand...


Seems like a pretty definitive answer from the engine manufacturer to the OP's poll...not to mention the impressively lopsided polling results.


..
 
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rzbill said:
Off..........unless I forget.
Click to expand...

Then you would be part of evolution?

"Evolution takes place if members of that species lack the traits they need to survive in the new environment, the likely result will be extinction of those members."
 
Sam Staton said:
We had a pilot on the field who experienced a very unlikely casualty. His habit was to keep his electric pump on all the time. Unbeknownst to him, his mechanical pump failed, masked by the electric pump on all the time. When he experienced a total electrical failure (master switch fried), his engine stopped from lack of fuel. Due to luck and pilot skill, he was able to make it back to the field. While this combo of events is rare, it does highlight the value of not running the electric pump all of the time.
Click to expand...

To add to this, the mech pump often shows signs of struggling bfore total failure, seen by low or erratic FP. Running the elec pump constantly would hide these signs from you, making the above more likely.
 
Pilot135pd said:
From the people who designed the engine (Textron Lycoming) :
"It is necessary to supply the engine with a steady,
uninterrupted flow of fuel for all operating conditions.
Entrapped air, temperature changes, pressure drops,
agitation in the fuel lines and other factors affect the release
of air and vapor from the fuel system. Under some
circumstances where an engine mounted fuel pump is
provided it may not be able to pump a continuous fuel
supply free of excessive vapor."

So even if the engine mounted pump is working, I think this should be reason enough to use it during those critical phases where the engine is working the hardest to get you safely away from crashing into the ground.
Click to expand...

Also, TO and landing are phases of flight where there may not be enough time to get the boost pump on and clear all of the air in time, if the mech pump failed.
 
lr172 said:
Also, TO and landing are phases of flight where there may not be enough time to get the boost pump on and clear all of the air in time, if the mech pump failed.
Click to expand...

The original post by RV6_flyer has all of the times to use it, I was just replying to StuBob's comment asking about take off and climbs.
 
Lycoming IO-360 and -390 here. For what it's worth, here's my electric fuel pump procedure (comments welcome):

• On for 3 - 5 seconds when priming for cold starts
• On again while turning onto runway for takeoff roll
• Off at 1000' AGL
• On at 1000' AGL with destination runway in sight
• Off at landing rollout
​
I understand there are some hot-start techniques that also use the boost pump, but I haven't gotten into those yet.
 
When switching tanks

I was taught also to use the electric pump when switching tanks, but never understood why. Then I read about an accident in the UK to a Cirrus (I think) where a tank ran dry, and the pilot switched to the other tank (which had fuel) but without putting on the electric pump. The engine did not restart quickly so he switched back to the dry tank and consequently lost the aircraft. The accident report commented that when there is air in the fuel line the engine will restart more quickly if the electric pump is on as well as the mechanical pump. I believe this is the reason for the Lycoming advice, but in any case it makes sense to me. So I always use the electric pump when switching tanks to develop the muscle memory in case a tank runs dry.
 
The Lycoming list of scenarios where the electric fuel pump should be on didn’t include “when the nervous spouse is onboard especially when flying over large bodies of water or high Rocky Mountain ranges”. lol

Bevan
 
What’s your landing fuel pressure without the boost pump on?

Mechanical fuel pumps generally do not fail all at once. They weaken over time which becomes much more noticeable at low power. Using the boost pump during low power time can mask signs of a failing mechanical pump. Next time you are coming in to land, instead of reaching for the boost pump switch, put your finger on the fuel pressure gauge so you can make a mental note. If your fuel pressure is low, you may have the symptoms of a pending failure. Safety issue here is always on during low power can mask early warning signs.

For those that use the boost pump, when you use it, why do you use it?
 
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I don't understand arguing against using the auxiliary fuel pump more often rather than less often...

It seems reasonable, even prudent, to run the boost pump in any phase of flight where engine stoppage might leave you short of time to troubleshoot and resolve the problem, like takeoff and landing/go-around. As to tank switching...the micro-moment necessary to hit the switch in exchange for eliminating even the small drama associated with engine stoppage at altitude seems like a good exchange. What's the reason for the boost-pump-reluctance that some of you are expressing?
 
Webb said:
--- snip ---

For those that use the boost pump, when you use it, why do you use it?
Click to expand...

I use it because it is "best practice" to use it and it is recommended by the engine manufacturer.

Most of the time, if boost pump were NOT used and the engine stopped making power or made reduced power, there is not a lot of time to remember to turn it on.
 
For me an [extreme] analogy would be seat belts. I put the them on every flight but have never (knock on wood) needed them. Saves me from fumbling to put them on when I actually would need them.
I use the boost pump as recommended by Lycoming, prime quick shot before start, take off & landing, and tank changes.
The trade off is using up electric boost pump life for a bit more assurance of continuous fuel flow in critical fuel/engine phases of flight.
 
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Pump ON for fuel pressure then OFF
Taxi
Pump ON for run-up, take-off, climb, cruise, tank change, descent, and landing.

Pump OFF upon shutdown.

My logic is that the pump (I think) is good for several thousand hours. Longer than the engine.
If I have an in-flight failure of the mechanical Pump, the electric one is already ON.

I will discover the mechanical failure at next attempt to start.

This worked will during the entire life of my first engine on the RV6.
 
jclark said:
My logic is that the pump (I think) is good for several thousand hours. Longer than the engine.
If I have an in-flight failure of the mechanical Pump, the electric one is already ON.
Click to expand...

In 430 tach hours my airplane is on its second Weldon boost pump and third engine-driven fuel pump, so "once-bitten twice-shy". Fearing that under-cowl heat plays a role in my boost pump failure, I'm judicious about how long I run it. I taxi with it off, turn it on-off during run up to make sure it's working, back on at centerline check for take off, then off at 1000 ft AGL. Back on at GUMP check on downwind for landing, off after I exit the runway. My annunciator does have a visual and aural warning that announces "fuel pump on" after the pump has been running for 5 minutes or so...I don't know how long, never timed it. I don't use it for switching tanks, but it makes sense and may start doing so.
 
jclark said:
Pump ON for fuel pressure then OFF
Taxi
Pump ON for run-up, take-off, climb, cruise, tank change, descent, and landing.

Pump OFF upon shutdown.
Click to expand...

I turn on the pump before engine start to verify it can provide good pressure, then turn it off for engine start. It remains off during run-up to verify the engine pump can provide good pressure. It is then turned on for takeoff and climb, then off for cruise. Back on for traffic pattern and landing, then off for taxi to once again verify the mechanical pump is good.
 
I have only used mine to prime at start up for 1200 hrs. After reading this thread I will mimic Sam Buchanan from now on.
 
There seems to be one condition missing in this discussion:
Pump ON if the engine quits in flight.

I recall this from my ab-initio training PFL drills. It may be covered by the 'when switching tanks’ scenario, but some types of aircraft don’t have tank selection capabilities.

V
 
MacCool said:
In 430 tach hours my airplane is on its second Weldon boost pump and third engine-driven fuel pump, so "once-bitten twice-shy". Fearing that under-cowl heat plays a role in my boost pump failure, I'm judicious about how long I run it. I taxi with it off, turn it on-off during run up to make sure it's working, back on at centerline check for take off, then off at 1000 ft AGL. Back on at GUMP check on downwind for landing, off after I exit the runway. My annunciator does have a visual and aural warning that announces "fuel pump on" after the pump has been running for 5 minutes or so...I don't know how long, never timed it. I don't use it for switching tanks, but it makes sense and may start doing so.
Click to expand...

That is not normal.... Not even close. You need to find the reason.
 
As has been mentioned a couple of times, a mechanical diaphragm pump will often get tired and show reduced performance before ultimate failure, and running the electric boost pump continuously can mask the signs of a weak mechanical pump. One aspect that hasn't been mentioned is an old mechanical pump that suffers from breach of the primary diaphragm, where the boost pump is still able to deliver enough fuel to keep the engine running, but in pushing fuel through the mechanical pump, is actually pushing fuel overboard.
Turning the boost pump off in cruise allows the pilot to identify a failed mechanical pump and equally important, alerts the pilot to a possibility of reduced range from the failed pump diaphragm.
I turn my boost pump off for start, taxi, runup and in cruise.
 
Manchu16 said:
Just watched a presentation by Rian Johnson about RVP and vapor lock from this spring. He mentioned he leaves his facet pump running all the time outside of run up to test the engine driven pump. I was always taught, pump on for take off and landing then off otherwise.

What do others do?
Click to expand...

If you leave it on, how do you know if it becomes inoperative? Only two ways:
1. no prime for the next start
2. engine driven fuel pump fails, and the engine gets very quiet!
It is a prime and back up applicance. If you had a carburated high wing aircraft, no issue. But low wing aircraft need to defy gravity!
DAR Gary
 
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