Primarily for general aviation discussion, but other aviation topics are also welcome.
#1663681
Question for anyone flying an SR22.
How do you use the fuel boost pump?

On the ground in most aeroplanes with low wings and two position fuel cocks I teach to swap tanks as part of the preflight actions.
Often start on one side then swap tanks for the runup and take off using that tank.
If it takes a while for the engine to stop running on one tank I run it for a little longer than the expected fuel off endurance, change tanks while taxying if I want it to run longer on the tank I will use for takeoff. ***

In any case on the ground I like to do this with the electric pump off so that the engine pump is proven to be operational.
I prefer to do the runup with the electric pump off as well.

The Cirrus SR22 checklist does not have anything about turning the fuel pump off after engine start.
It is optional on or off in the cruise.

So I am curious since I do not fly this type as to what Cirrus pilots on here do on the ground after engine start.
Do you leave the electric boost pump on for taxy runup climb cruise and approach? Or do you give it a break on the taxy and in the cruise?

In most aeroplanes the electric pump is a support unit rather than an essential full time unit.

***I often ask pilots how long will the engine run on the ground before it stops with the fuel turned off.
This especially when the fuel is swapped from one side to the other as part of the checklist, but too quick for the engine to potentially stop. A Cessna 172 will run for longer with the fuel off than the amount of time I have seen pilots take to change left and right.
One would hope that the engine would stop on the runup if there was a problem with the fuel flow before takeoff if there’s a problem.
#1663684
My experience is like Pauls (and I also don't have SR22 time)
Fuel pump used to prime (which confirms it works)
Off for start / taxi (which confirms engine driven pump works)
On for critical stages of flight (before lining up for takeoff, off in cruise, on for aeros & approach / landing)

I understand though - that the Bulldog (which we both fly) had known issues with its electric fuel pump. It wasn't designed to be left on all the time so it wore out. I believe this was fixed with later fuel pumps so no real issue now in leaving it running - so something less to turn on in the event of an engine failure.
#1663687
For SR20 I was trained to use the Prime position about 10 seconds then go to Boost (Electric pump on) to start the engine and then taxi using tank one, switch tanks for run up and take off all with the electric pump on. Once in the cruise I turn the electric pump off and only use it when switching tanks every 30 mins and for landing. I think the SR22T guys tend to leave the electric pump on all the time to stop fuel vaporisation at altitude but I don't fly a SR22T so take that with a pinch of salt
#1663696
From the AFM

Fuel Pump Operation
Fuel pump operation and engine prime is controlled through the Fuel Pump rocker switch located adjacent to the fuel selector valve.
To prevent over-priming, the system uses a lockout relay that only allows HIGH BOOST/PRIME for engine start and operations at high power settings. When the manifold pressure is less than 24 in-Hg and engine RPM is greater than 500 RPM, pressing the HIGH BOOST/ PRIME limits the fuel pump to low-speed mode BOOST.
Selecting BOOST energizes the fuel pump in low-speed mode regardless of engine speed or manifold pressure to deliver a continuous 4-6 psi boost to the fuel flow for vapor suppression in a hot fuel condition.
The fuel pump operates on 28 VDC supplied through the 5-amp FUEL PUMP circuit breaker on MAIN BUS 2.


I use the BOOST as I would with a PA28 (departure, approach, tank change).
#1663899
I completed the Cirrus Owner Pilot Training (on an SR22G6T) at Knoxville Tn in July 2018, during which we were advised to leave the fuel pump in the "Boost" setting at all times - except during engine start (when "Prime" is used).

I've just read the POH line by line - and found this:
On page 4-21, Under settings for Cruise Flight it says:

Fuel Pump : As Required

Note The fuel pump must be set to Boost during climb and during any manoeuvring flight (i.e., fight training manoeuvres, Chandells, stalls etc)

At the end of the section, (page 4-22) there is another "Expansion Note":

"The fuel pump is used for vapour suppression during climb. It is also recommended that the fuel pump be left in Boost after levelling off for 30 minutes following climb, and at anytime fuel flow or EGT anomalies occur. Under some previously described extreme environmental conditions, the use of "HIGH BOOOST/ PRIME" may be required for vapour suppression during cruise flight. The fuel pump can be returned to the BOOST or OFF position as conditions permit.

This would explain why, during the factory training, we were told to leave it on BOOST - as all of our flights comprised climbing, manoeuvring and we never had longer than 30 minutes straight and level after climbing.

I've emailed my Cirrus factory instructor for confirmation.

Hope this helps
#1663936
Thank you Tom,
The factory training is what I am interested in.
I just completed a ground school course delivery for a pilot here converting onto the SR22T and this fuel pump method of use is different to any other aeroplane I have flown.

In other aircraft types the pump is used for start, for takeoff, off at a safe altitude, sometimes on for air exercises (not always because some fuel injected engines run rough with the pump on) , and on for final approach.

100% reliance on an electric fuel pump is unusual.

The DA40-180’s electric fuel pump is clearly marked Not for Continuous Use, or similar wording, but the pilot does not know this! In China they got fifty hours between electric pump replacements!
A friend read about vapour lock suppression and switched the DA40’s fuel pump on at 12,000 feet. It burnt out and that weekend was a holiday in the USA. They landed there and had to wait a few days before a new pump arrived at AOG expense.

Back to the SR22T here, the current pilot leaves the fuel pump on all of the time.
I wonder if this pump fails in service, and if so how often?

I seem to know the SR22 POH and FCOM very well now, but since I am not a Cirrus instructor I have to leave the flight training to someone else.
The ground training however I needed to do. It was hard work.
I could make some unkind remarks about standards here.

I once trained a private pilot in a Mooney 231, and I have trained people in DA40/42. The Lancair 320 probably being the dodgiest of the many similar performance types I have flown.
#1664024
Michael,
Which version of the POH are you using? There is an A5 fully bound, which is the official POH, AND they also issue an (almost) quarto sized landscape spiral bound glossy - which is all about “procedures”. Neither is written very well, but the bound A5 is much more informative. In particular the fuel burn / climb / time / distance tables are extremely accurate. It is quite a chore to extract the salient info to create a cockpit checklist. (Cirrus expect pilots to use the on-screen checklists! But as an experience pilot you quickly find them too laborious).

Does your guy have access to the Cirrus online training programme? It comes as part of the new aircraft package and is very good.

Re the fuel pump, my friend (who owns the new Cirrus), did 1800 hrs in 10 years on his previous SR22G3 (TN) without it failing (with the pump on boost for all 1800 hrs).
Let me know if I can be of any further help.
#1664053
I downloaded a couple of official POHs, and the official FCOM which I think is very good.
Just a little surprised at having the fuel pump on full time.
Of course most cars have full time electric fuel pumps...
I sent Cirrus an email, but I suppose it was lost in the holiday business.
You answered my question. Thank you.
#1665700
Vo replaces Va it seems, and is 140 KIAS at 3600 lbs

There seems to be no reduction list for lighter weights.

Since 50% flaps may be applied at 150 KIAS how do you answer the student if asked about Vo with flaps applied?

I know how I would answer this, but is there an ‘official’ answer?