The fuel pump, also called the Boost Pump or Emergency Fuel Pump in some aircraft, is one item whose proper usage I've completely ignored over the years. Main reason is that it has no real function with FSX aircraft. It's just a dummy switch.

 

However, with the upcoming A2A C172, I think using it properly is going to become more important.

 

My understanding is that you turn it on when an engine failure would be particularly inconvenient, such as when taking off or landing. Is this correct? When would you normally use it and when would you typically turn it off? If it reduces the chance of the engine quitting, why not leave it on all the time?

It truly depends on the aircraft. With the C172, we only use the fuel pump to prime on start, and that's it. The only other time it would be used is during an engine failure in flight. The flow goes Airspeed 68, flaps up, landing site, fuel selector both, fuel shutoff in, mixture full forward, fuel pump on, ignition both (start if not windmilling).

 

If that doesn't work the next flow's difference is mixture cutoff, throttle full forward, fuel pump off, ignition, etc.

 

Other aircraft like the Piper Arrow you will use the fuel pump on takeoff, approach and landing, when switching tanks, etc. Like I said, depends on the aircraft and manufacturer/maintenance recommended SOP's.

It differs per type.

 

In fuel injected engines, the fuel pump is turned on, and the mixture level slowly increased until a fuel flow is observed, then it's turned off for the actual engine start (it's not needed once the engine is primed with fuel for the start).         AFAIK for the C172 that's the end of the use for the fuel pump in *normal* circumstances.

 

In other types, as you've said, the fuel pump is turned on before take-off, and also turned on as part of an Approach  or Landing Checklist.

 

AFAIK it's not left on all the time because, certainly in GA aircraft, gravity does a better job anyway in normal circumstances and also pumps are expensive and would wear out fast, if they were always on.

 

I'm not a real world pilot, and am just offering my understanding on the subject. :smile:  Hopefully you'll get some proper expertise to the party. 

 

Good question - I didn't know either :-)

 

Found this: http://www.cessna172club.com/forum/ubbthreads.php?ubb=showflat&Number=139641

 

and this: http://us.generation-nt.com/answer/use-fuel-pump-switches-help-126724231.html

When flying a PA-28 the fuel pump is usually checked pre-flight, turned on for takeoff and approach/landing and switched on when changing fuel tanks and switched off again when the tank has been switched over. 

 

Rich

As dmbusmc said the pump is usually used for takeoff, landing and switching tanks. 

 

Rich

We use them (boost pumps) in emergency procedures or when we have switched from one fuel type to another (I.E. JP4 to JP8) or having added prist (anti fuel icing additive) when it isn't already pre-mixed with aviation fuel. UH-60 A/L Blackhawk.

As stated before it really depends. It's use is always dictated in the POH.

 

And in FSX world I would use it for take offs and landings.

And to REALLY throw a wrench into things, on a large jet, they're normally always on.

At C172 we use pump just for prime, and do not increase mixture during that period.

I have a different procedure

 

Cold start :

 

- Throttle set to half

- Mixture full rich

- 5 sec fuel pump

- Throttle back to quarter of an inch

- Prop cleared

- Start

 

Hot Start :

 

- Throttle set to quarter of an inch

- Mixture full rich

- 1 sec fuel pump

- Mixture cut-off

- Prop cleared

- Start

- Once engine fires, mixture full rich

Short version, high wing, no need for pump, low wing, on for takeoff and landing.....

 

I've been flying 172's for 40 + years and never saw a fuel pump yet in one so scratching my head on this one

You need a pump for a fuel injected engine

 

One is engine driven and the other is electrical for priming and backup. The amount of fuel delivered by the distribution valve is calculated via the A/F control unit

Aerosoft's Twin Otter Extended needs two on to keep fuel flowing, and it's an overhead wing plane.

On Pipers, I make sure the electric fuel pump is on at or below 1,000 ft AGL.  If departing or approaching over unfriendly terrain (urban, forest, water, etc.), I sometimes keep it on up to a higher altitude.  The thinking is, if you lose the mechanical fuel pump at even 2,000 ft, you may be doing a rapid re-start at a lower altitude than you would like.

 

Scott.

On Pipers, I make sure the electric fuel pump is on at or below 1,000 ft AGL.  If departing or approaching over unfriendly terrain (urban, forest, water, etc.), I sometimes keep it on up to a higher altitude.  The thinking is, if you lose the mechanical fuel pump at even 2,000 ft, you may be doing a rapid re-start at a lower altitude than you would like.

 

Scott.

Shouldn't u be working on the 172 release?   :Nail Biting: The suspense is killing me.