Schweizer 300 fuel boost pump question

[windowseatplease]

Schools seem to differ on the policy of when to have the fuel boost pump on. Some say all the time, some say for takeoff and landing only.

Can anyone shed some light into this?

[BHenderson]

I was told during my training that it doesn't increase fuel usage, so that is the reason I leave it on despite the POH saying: 'on below 450ft'.

[RVDT]

If the engine driven pump stops, so will the engine without the boost pump - your call. Fuel injected models of course.

[Whirlygig]

Flight manual states that the fuel boost pump MUST be on for take-off, landing and any flight below 450ft agl. Any other time is at the pilot's discretion. Can't think why you'd want to switch it off - just extra faffing around at points in a flight when you can do without faffing!!

Cheers

Whirls

[TheVelvetGlove]

Flight School's concern: Boost pumps generally wear out quicker when they are used more, and they are expensive to replace.

Pilot's concern: Aircraft will stop running if boost pumps are off when engine driven pump fails.

Consider this: On turbine aircraft (such as every modern Bell product) even though the aircraft will run without the boost pumps on, we always keep the boost pumps on. Standard Operating Procedure.

"Pilot's discretion"

When making a PIC determination in regards to whether or not to accept a flight or whether or not to have an aircraft repaired prior to that flight, cost should never be considered. Any company that even blinks, when something needs replacing, has no business operating a helicopter.

[RVDT]

There is a modification to have the addition of an AUTO position as well as ON/OFF. Fuel pressure drops - boost pump runs.

NZ Modification Auto-Select Fuel Boost Installation Modification RJAD125

Have no idea who's mod it is though.

[Hughes500]

boost pump does what it says it boosts the fuel. Reason it is there is the engine driven pump at extremes may not be able to keep up with demand, Where does this happen ? On take off and landing and possibly below 450 ft - the avoid curve, can think of no reason to pull max in normal flight. Boost pump seems to last between 500 and 2000 hours.

[Aesir]

There is also the concern that in the event of crash it´s better not to have a electric fuel boost pump on spraying fuel everywhere. Hence the fuel boost/primer pumps on B222 & AS350B3 are always turned off after start.

I think that´s the way modern helicopters are going. No electric fuel pump on during flight. Only suction engine driven pump´s. I think the S-92 does that?

However in the H-300C series as stated earlier the pump should be on to 450´agl in accordance with the manual and can then be turned off. These boost pumps are expensive. I remember replacing one some years ago at a cost of $2500 USD.

Personally I prefer to have them turned off after start.

[Trans Lift]

Our checklist says to turn it on before take-off and we don't turn it off again until after we land!!!!!:ok:

[Pilot DAR]

When I trained on 300's, we left it on all of the time. That's what the operator asked, so it'd be hard to explain not having done it, if the engine driven pump quit. Do they quit? Yup, just had one quit on an IO-360 powered fixed wing aircraft last week - aborted takeoff (well, it aborted itself!). Electric pump had not been on, because the check pilot had told me not to run it during takeoff. The runway was long enough... Now the pump is on all the time, its cheaper that the off runway forced approach I could have had to do!

[KrisRamJ]

I learned to fly in the 300 at Bristows Academy and CFI'd in it at Rotors of the Rockies. The standard procedure at both of these schools was fuel boost ON before engine start and ON for the entire duration of the flight. The fuel boost was switched OFF after landing to check the engine-driven pump hadn't gone TU during the flight.

The reason - as outlined by everyone else - if you leave the fuel boost on then the engine will keep running if the engine-driven pump fails.

[FLY 7]

The boost pump is also switched on prior to start up to check it is providing fuel pressure, left on during priming, then switched off. It's then switched on again during the pre-take off checks.

[windowseatplease]

Thanks all. Opinions seem to differ, but I think the general consensus is.. leave it on during all flight.