Funny you should mention that.

viewtopic.php?f=49&t=112926&start=1110

Great system with no issues.
Keep it simple and copy it.



TBM does the same thing every ten minutes, IIRC. I think it's a certification requirement that there be some system to prevent forgetting to switch tanks.

Not particularly that simple:


There's a lot to know about it:

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AUTOMATIC TANK SELECTOR (Figures 7.7.2 and 7.7.3)

Automatic tank selection allows, without pilot’s intervention, feeding the
engine from one tank or the other in predetermined sequences. These
sequences depend on airplane configuration (ground, in--flight, fuel low level
CAS messages appearance).

Automatic tank selection system comprises an electronic sequencer, an
actuator attached on the fuel unit, ”FUEL SEL” two--position selector (AUTO,
MAN) and ”SHIFT” knob located on ”FUEL” panel.
To operate the automatic selector, set ”FUEL SEL” switch to AUTO position
and manual selector to R or L.

Selector operation

When the system is operated, ”AUTO SEL” CAS message disappears ; the
sequencer chooses a tank (R or L) and through the actuator, positions the
fuel unit selector on the selected tank. The sequencer controls the time
during which the selected tank will operate. This time varies, depending on
airplane conditions.

Airplane on ground : tank is changed every minute and 15 seconds.

Pre--MOD70--0402--28

Airplane in flight : tank is changed every ten minutes, as long as a fuel low
level CAS message does not appear. When the first low level CAS message
lights on, the sequencer immediately selects the other tank. The selected
tank will operate until the second low level CAS message lights on. When
both low level CAS messages are visible, the sequencer changes tanks
every minute and 15 seconds.

Post--MOD70--0402--28

Airplane in flight : tank is changed every five minutes, as long as a fuel low
level CAS message does not appear. When the first low level CAS message
lights on, the sequencer immediately selects the other tank. The selected
tank will operate until the second low level CAS message lights on. When
both low level CAS messages are visible, the sequencer changes tanks
every minute and 15 seconds.

NOTE :

The manual selector is driven by the fuel unit and is positioned on R or L mark
corresponding to the tank selected by the sequencer. Therefore, the pilot
continuously knows the tank which is operating.

Test for system proper operation

”SHIFT” push--knob allows the pilot to test system proper operation anytime.
When the system operates, the fuel tank is changed when ”SHIFT”
push--knob is pressed once.
If airplane is on ground or in flight, low level CAS messages not visible, the
new selected tank remains operating and a new sequence is initiated.

NOTE :

This procedure allows the pilot to preferably choose the tank from which he
wants to take fuel.

In all cases, proper system operation is indicated by rotation of the manual
selector.

Setting ”FUEL SEL” switch to MAN position or setting manual selector to OFF
position leads to system de--activating and appearance of ”AUTO SEL” CAS
message. ”AUTO SEL” CAS message also lights on when order given by the
sequencer has not been executed after 12 seconds.

AMBER WARNING CAS MESSAGE

“AUTO SEL” ON

Indicates there is no more automatic control mode running

1 -- ”FUEL SEL” switch ................................. AUTO

If it is on “AUTO”, failure is confirmed

2 -- ”FUEL SEL” switch .................................. MAN

3 -- Select tanks manually as required

CAUTION

MAXIMUM UNBALANCE IS 15 USG

---cut---

Appears the switching time in flight was lowered to 5 minutes by a mod, and I find it odd it switches every 75 seconds on the ground. I surmise they want roll trim to be very near neutral for takeoff?

Mike C.

From what I have read, it really is not that simple. A good system, and maybe simple from an operator perspective. But from engineering, not so much.

Tim

From what I have read, it really is not that simple. A good system, and maybe simple from an operator perspective. But from engineering, not so much.

Tim

Ok Mike,
Redudency not complicated.
It is really simple. The odd time that you get a fuel imbalance CAS message, you just switch to the fuller tank and it fix itself. If you ever loose the automatic electric fuel selector, you just switch it manually every 10 min.
Show me the MU2 fuel system. It takes a course just to fuel it.

https://www.youtube.com/watch?v=w4QuxNbi_8k

Video from Business Insider.

Looks like Cirrus may have, in fact, flight tested the SF50 airframe parachute.

Great video, nice to see it works as predicted...

Yup...... The chute was tested. Another outrageous claim in this thread has been debunked.

Cirrus is gonna sell a million SF50's. Even Gulfstreams don't have parachutes. Great video.

I Love the video.

How could they not have tested the parachute? I mean really. That would be idiocy. I too am glad to finally see it shown.

I'm a bit surprised that the parachute sequence didn't also lower the landing gear. Maybe that's a later feature, but given the energy absorption that the gear provides I would think it would be a must to put it down.

I Love the video.

How could they not have tested the parachute? I mean really. That would be idiocy. I too am glad to finally see it shown.

I'm a bit surprised that the parachute sequence didn't also lower the landing gear. Maybe that's a later feature, but given the energy absorption that the gear provides I would think it would be a must to put it down.

Under canopy putting the gear down helps in most situations, and hurts in none. In water it likely makes no difference. In trees it may help to get you stuck in the trees, but wings and tails are going to be more effective at that, and in the meantime it dissipates energy if the plane falls through the trees rather than perching. Slopes? Are we saying that it's going to roll down hill? I don't imagine that the gear would survive the impact intact, but just in case have the system lock the brakes! Otherwise anything sticking out is going to resist sliding.

It's great that the seat structure et al is strong enough to not need the gear to take up energy on landing, but personally I'd still want the gear out. That's what it's made for.

Oh here we go......

1. The chute will never work on a jet
2. The chute has never been tested
3. Well, it wold work better if the landing gear deployed automatically

This SF50 thread should be a case study for "Armchair QB'ing".

I personally would like the option of gear up or gear down in my parachute descent.

Would gear down be more likely to penetrate and rupture fuel tanks upon impact? I have no idea, just ruminating.

I have heard they have a separate lever for the gear. Unless it's locked out by chute deployment the pilot could do what they want with landing gear.