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Fuel Pressure 912iS Sport


Adam
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My new CTLSi has a 912iS Sport engine with an auxiliary fuel pump that you turn on for takeoff and landing.

 

When the aux pump switch is off, the gauge for fuel pressure reads in the green and does not deviate in any phase of flight.  Green is a range between 42.1 to 45 PSI according to my Skyview setup menu.   When I turn the aux pump on, the pressure increases (seems logical) however it goes into the yellow arc and an audible "Fuel Pressure" warning is enunciated by Skyview.  The Yellow range is 45.0 to 46.4 PSI according to my setup menu.  

 

On a takeoff roll as you increase throttle, hearing "Fuel Pressure" in your ear can be unnerving at first (and then later, annoying).  The pressure never goes into the red and after takeoff when I turn the aux pump off, back to the green it goes.

 

Questions for those of you with 912iS engines:

 

1.) Do you experience this phenomenon?

2.) If you go to "Setup" on the Skyview, and enter the "EMS" page, then "Fuel Pressure", I'm wondering what your "Range 5" yellow settings are?  (mine are 45 to 46.4).  I'm wondering if my yellow arc range is set up correctly?

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My new CTLSi has a 912iS Sport engine with an auxiliary fuel pump that you turn on for takeoff and landing.

 

When the aux pump switch is off, the gauge for fuel pressure reads in the green and does not deviate in any phase of flight.  Green is a range between 42.1 to 45 PSI according to my Skyview setup menu.   When I turn the aux pump on, the pressure increases (seems logical) however it goes into the yellow arc and an audible "Fuel Pressure" warning is enunciated by Skyview.  The Yellow range is 45.0 to 46.4 PSI according to my setup menu.  

 

On a takeoff roll as you increase throttle, hearing "Fuel Pressure" in your ear can be unnerving at first (and then later, annoying).  The pressure never goes into the red and after takeoff when I turn the aux pump off, back to the green it goes.

 

Questions for those of you with 912iS engines:

 

1.) Do you experience this phenomenon?

2.) If you go to "Setup" on the Skyview, and enter the "EMS" page, then "Fuel Pressure", I'm wondering what your "Range 5" yellow settings are?  (mine are 45 to 46.4).  I'm wondering if my yellow arc range is set up correctly?

I have a CTLSi with the 912iS engine, and have had a fuel flow callout a couple of times on takeoff .  One time we aborted and re-looked; it didn't repeat the next time.  Now, we look at the gauge on the roll if the audio callout happens.

 

Andy

Andy

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You could try moving the yellow arc up to begin at a higher value.  If you are getting the alarm at 45psi and the top of the yellow range is 46.4psi, I might try moving the yellow to start at 46psi.  It will make your yellow range very short (46 to 46.4psi), but it will keep the warning at bay if your FP stays below 46psi.  

 

I'm surely no expert on the 912iS, but I don't think there is any harm in the FP being in the yellow for short periods while the aux pump is running.  It's just the alarm that's annoying.

 

What is the highest FP you are seeing?

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Adam,

 

I would call Flight Design USA and see if you can move the yellow arc just above your  highest fuel pressure reading on takeoff. 

 

I have not experienced that particular problem but anything that distracts your attention during takeoff should be corrected. Tell FD that it is a safety issue.

 

Without the AUX on, I will occasionally get a low pressure alert during flight about .1 into the yellow arc.

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My new CTLSi has a 912iS Sport engine with an auxiliary fuel pump that you turn on for takeoff and landing.

 

When the aux pump switch is off, the gauge for fuel pressure reads in the green and does not deviate in any phase of flight.  Green is a range between 42.1 to 45 PSI according to my Skyview setup menu.   When I turn the aux pump on, the pressure increases (seems logical) however it goes into the yellow arc and an audible "Fuel Pressure" warning is enunciated by Skyview.  The Yellow range is 45.0 to 46.4 PSI according to my setup menu.  

 

On a takeoff roll as you increase throttle, hearing "Fuel Pressure" in your ear can be unnerving at first (and then later, annoying).  The pressure never goes into the red and after takeoff when I turn the aux pump off, back to the green it goes.

 

Questions for those of you with 912iS engines:

 

1.) Do you experience this phenomenon?

2.) If you go to "Setup" on the Skyview, and enter the "EMS" page, then "Fuel Pressure", I'm wondering what your "Range 5" yellow settings are?  (mine are 45 to 46.4).  I'm wondering if my yellow arc range is set up correctly?

 

This is normal.  You do not need the Aux Pump on (though the POH says to have it on) on takeoff as it will produce too much fuel pressure.  Especially if you are flying lower, like near sea level.  After hundreds of hours in the plane we determined the Aux pump is really there if you get vapor lock at high altitude on a hot day and are using something like Mogas. 

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This is normal.  You do not need the Aux Pump on (though the POH says to have it on) on takeoff as it will produce too much fuel pressure.  Especially if you are flying lower, like near sea level.  After hundreds of hours in the plane we determined the Aux pump is really there if you get vapor lock at high altitude on a hot day and are using something like Mogas. 

Having an alert on takeoff is NOT normal and should be corrected.

 

I don't know who "we" are in the " we" determined, but I believe the "we" to be setting themselves up for a crash landing. 

 

The reason the POH says to have it on for takeoff and landings is - if the main pump fails - the engine quits immediately.  Without the AUX pump on you will land somewhere you don't want too because there will be no time for an air start during low altitude operations.

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I was seeing 45.7 (+/-) on the takeoff roll.  45 was the setting for the bottom of the yellow segment.  >45.1 would trigger the verbal warning "Fuel Pressure"

 

I exchanged emails with Arian Foldan at FDUSA. 

I'm told this is not an uncommon occurrence, the specs and thinking for what the settings should be for fuel pressure have evolved (continue to evolve) over time.

 

FD Recommended setting the yellow range to 46 - 46.5 

This would make for a small yellow segment but in my case, would end the errors.

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I was seeing 45.7 (+/-) on the takeoff roll.  45 was the setting for the bottom of the yellow segment.  >45.1 would trigger the verbal warning "Fuel Pressure"

 

I exchanged emails with Arian Foldan at FDUSA. 

I'm told this is not an uncommon occurrence, the specs and thinking for what the settings should be for fuel pressure have evolved (continue to evolve) over time.

 

FD Recommended setting the yellow range to 46 - 46.5 

This would make for a small yellow segment but in my case, would end the errors.

Hopefully that will correct your aural warning on takeoff issues.  As long as Flight Design says to go ahead, I would feel justified in doing so.

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Having an alert on takeoff is NOT normal and should be corrected.

 

I don't know who "we" are in the " we" determined, but I believe the "we" to be setting themselves up for a crash landing. 

 

The reason the POH says to have it on for takeoff and landings is - if the main pump fails - the engine quits immediately.  Without the AUX pump on you will land somewhere you don't want too because there will be no time for an air start during low altitude operations.

 

Talk to Lone Mountain  and FD USA....  we did after experiencing this two years ago... the Aux Pump will produce a yellow range fuel pressure warning on takeoff...you do not need the Aux Pump on takeoff.

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Talk to Lone Mountain  and FD USA....  we did after experiencing this two years ago... the Aux Pump will produce a yellow range fuel pressure warning on takeoff...you do not need the Aux Pump on takeoff.

The aux pump is kind of like the parachute, you don't need it until you do.

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Talk to Lone Mountain  and FD USA....  we did after experiencing this two years ago... the Aux Pump will produce a yellow range fuel pressure warning on takeoff...you do not need the Aux Pump on takeoff.

That's true, you don't need the aux pump for takeoff, you just need it when the engine quits on takeoff --- but then it's too late so you crash. 

 

If your OK with going against the POH and common sense then your right, you don't need it for takeoff and landing.

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Good deal, sounds like an easy fix.  

 

You haven't been posting much Adam, how are you enjoying the CTLSi?

Hi Andy,

 

The plane delivered mid June, and then I promptly started traveling (work / pleasure).  I had a 2 month stint that included Germany (Munich, Nuremberg, Dachau), then Sweden (Stockholm) followed by trips to Cost Rica, Hawaii and Toronto.  I literally just did my first 6 hours in the plane over the last 3 days.  Needed a BFR and my insurance required 5 hours dual prior to solo in the new plane.  Its been fun, just starting to get things dialed in.  Sad to say, but my engine was one of the last couple serial numbers effected by the Stator SB, so I'll be dropping the plane off to get the engine pulled here shortly.  I also moved my home base from KHHR to KFUL.  Fullerton is a small airport in North Orange County a few miles from Disneyland.  Its been an airport since 1927.  I have a new mammoth sized man cave to deck out so busy busy summer. 

 

So far I like the plane, but I'm not liking how much useful load Ive lost between the 2012 CTLS and the 2016 CTLSi.  Down to 466 pounds!   I remember the good old days when my 2006 CTSW had 600 pounds!  Time to shed those extra 20 pounds!

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That's true, you don't need the aux pump for takeoff, you just need it when the engine quits on takeoff --- but then it's too late so you crash. 

 

If your OK with going against the POH and common sense then your right, you don't need it for takeoff and landing.

 

Well, in the two years after we were advised by the factory the Aux pump was not needed on takeoff and the yellow indication was normal we had no incident.  The Aux pump is a backup in case you get vapor lock so if you are using Mogas and taking off at 5000 feet and it's 100f outside I would guess turning it on and ignoring the yellow indicator would be prudent.

 

The same applies when the oil temp goes yellow climbing on a hot day.....  have you had that?  All of us have...yet is anyone refusing to fly on a hot day?  Is anyone changing their Dynons oil temp yellow range higher?  No.

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The same applies when the oil temp goes yellow clibing on a hot day.....  have you had that?  All of us have...yet is anyone refusing to fly on a hot day?  Is anyone changing their Dynons oil temp yellow range higher?  No.

 

I've seriously thought about moving the bottom of my yellow to 240 for the sole reason to allay concerns from passengers when I climb out on a hot Texas day.  In end, I decided to brief my passenger on what to expect and the 'yellow' is simply a warning and is normal for my plane on hot days.  Normal being defined as 9 years of consistent behavior.

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Yellow is simply the instruments way of saying hey look at me and keep an eye on me. It's just a pre-warning to watch in case you get to red. Any pilot that doesn't know this should be briefed. Yellow isn't red and it's just a way to catch someone's eye to make sure they watch.

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Hi Andy,

 

The plane delivered mid June, and then I promptly started traveling (work / pleasure).  I had a 2 month stint that included Germany (Munich, Nuremberg, Dachau), then Sweden (Stockholm) followed by trips to Cost Rica, Hawaii and Toronto.  I literally just did my first 6 hours in the plane over the last 3 days.  Needed a BFR and my insurance required 5 hours dual prior to solo in the new plane.  Its been fun, just starting to get things dialed in.  Sad to say, but my engine was one of the last couple serial numbers effected by the Stator SB, so I'll be dropping the plane off to get the engine pulled here shortly.  I also moved my home base from KHHR to KFUL.  Fullerton is a small airport in North Orange County a few miles from Disneyland.  Its been an airport since 1927.  I have a new mammoth sized man cave to deck out so busy busy summer. 

 

So far I like the plane, but I'm not liking how much useful load Ive lost between the 2012 CTLS and the 2016 CTLSi.  Down to 466 pounds!   I remember the good old days when my 2006 CTSW had 600 pounds!  Time to shed those extra 20 pounds!

 

 

Sounds like things are going well.  Enjoy your new bird, and don't so spend so much time in the man cave that you forget to fly!  :)

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  • 2 years later...

I have the same condition in my 912is... meaning, the fuel pressure is in the green and very near the yellow range.  When the pump is activated the pressure goes into the yellow.  Only a visual "warning", no audio however... I have a note into FD USA... they have tackled every squawk quickly. 

FYI, FDUSA instructed me to switch the fuel pump on during takeoff and landing.  Makes sense to me.

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Ran the left tank only for an hour... will check the L and R levels when I am next in the hangar... two interesting points for CT beginners (like me)... first, the Dynon has a simple "Green light" revealing that the L Tank was working, and, a "Red" light revealing that the Right Tank was... off.  Glad to discover that.

Secondly, the CTLSi fuel injected model has a 1.2 gals header tank in the rear and there is a prominent warning light near the A & B lanes check lights... so, if there is a low gas issue in the header tank, the header warning light will light up.  I think that is a great low fuel safety feature.

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In addition to our CTs, we have an Aeroprakt A22 with the 912 iS Sport engine. The standard Rotax fuel pump for the iS is a single unit that contains two identical fuel pumps. I assume that what FD calls the "aux" pump is just one of the two pumps in the same housing while the other pump is always on. In the A22, I have two separate toggle switches, one for each pump, and I can test each pump separately which is part of the POH run-up checklist. We always see higher fuel pressures with both pumps on. It is common for us to occasionally see pressure up to 49 with only one pump. When this happens, it is typically time to clean the fuel filter for the iS which is very fine in order to avoid clogged injectors.

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  • 2 years later...

It’s going on 5 years and no related accidents are known. Is it because pilots don’t use the aux FP or still do and no problem?? This thread wore-out back in late 2016, however the pilot is still stuck in the middle.  If there are no recent updates about the same issue for new/second generation CTLSi owner/operators, then how about having an informed discussion regarding the cause and effects of yellow and red band Fuel Pressure indications-for pilot decision making? What’s the worst that can happen operating a CTLSI aircraft in yellow and red band FP ranges? And if the latest Dynon SW upgrade doesn’t adjust the range, can FD issue a notice for this seemingly, non-problem, nominal (short duration yellow) indication during takeoff and landing phases? Oh, and as one previous reply suggested maybe address vapor lock flight conditions, if that has merit? 5 years is a long time for a standing issue to not be closed in my opinion.

 

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