WannFly
Final Approach
I have about 13 hours behind the GFC 500 now and thought will share my experience. Still learning, so I might update this thread as and when i learn more and / or find a quirk that i dont like.
Short Version
Its freaking awesome. If its approved for your aircraft - go get it.
Long version
My previous AP was Century 2000, so thats my frame of reference. I also have few hours behind a GFC 700 in a 172. Apart from CWS button on the GFC 700 I could recall if there are any performance differences between the two. Not sure if the 700 had envelop protection or not, most likely no in a 2000 Cessna model.
Altitude Hold
On the dot, not 70-100 feet off, may be 20 feet off on a mediocre day, at most i have seen 30 feet off on a bumpy day - surface winds 14G23, i was at 550 AGL - still within 30 feet. Yes I am aware of the FARs, i was over a corn field, with black dirt under me and not a soul in sight.
Flying Approaches
On rails. I am pretty sure the controllers in Fargo are surprised by how awesome I fly the approaches all of a sudden .. lol. Coupled approaches with GTN, anticipates the turn, very smooth standard rate turns.
Flying straight and level
On rails. The coolest part is, when you change the altimeter, it will go and capture the new altitude
.
IAS Mode and Altitude capture
I usually climb at 90 kts IAS mode, based on conditions, I have seen it fluctuate somewhere in the tune of 2-3 kts. Altitude - 1000 feet you hear a ding telling you its 1000 feet below altitude. One more ding when its 200 feet to go. approaching about 60 feet it slowly brings the nose down, thats your cue to adjust / put whatever cruise power you want to set. Once captured GFC will cancel the IAS mode, capture the altitude and hold it. There is no separate altitude hold mode. If you are flying by hand, press the Altitude sync button, ALT button and turn the AP on, it will engage in PIT and TOL Mode and fly the ALT you were flying. All banks are standard rate turns, unlike my Century which would at times go to 25-30 degrees and then try to stabilize and make some S turns in the process when it overshoots the magenta line.
TOGA
While taking off, press the TOGA button, AP indicated TO on G5, moves the FD to 8 degrees, just fly that. During missed approach, full power, hit the TOGA, GFC will fly coupled missed approach and take you to Hold and keep holding there until you command otherwise.
Heading mode and Track mode
Nothing special other than it will hold heading or track within 1-2 degrees of whatever you have set.
Under speed Protection (USP) on AP
While on AP, holding altitude, i reduce power to 1700 RPM. GFC kept pulling the nose up to hold Alt. right at 62 (Mine is set to trigger at 60), it gives you a small nudge, right at 60 you will hear "Airspeed, Airspeed" and MINSPEED flashing on the G5, GFC will start sacrificing altitude for airspeed - It wont let the plane stall, period. In a situation where the PIC is unconscious and the only soul in the plane, I can imagine at some point the plane will run out of altitude (say you are out of fuel), and hit the ground at 60 kts. survivable depending on what you are hitting. I did not try the Over Speed Protection. Bank limit is standard rate turn, so over bank protection does not apply.
The Blue button (Level mode)
Not sure why the button is blue, I think Garmin should change it to brown. I have put the plane in all sorts of wired attitudes - hit the Level button, it recovered smoothly, first bank then pitch, just like your CFI taught you. No sudden jolts. Nothing violent. I have heard in Mooneys some people say the return to level is rather violent. Next time my CFI / DPE put me in unusual attitude and ask me to recover I am going to hit that button .. lol
Electronic Stability Protection (ESP) / Envelop protection
Its always on at the background when you are hand flying. There are 3 modes:
Over Bank Protection - At 45 degrees on your PFD you will see 2 green marks on both sides of the AI. Once you cross that mark (right at 45 degrees), the mark changes to yellow and moves over to 30 degrees. thats AP telling you to get back where you belong. If you cross the 45 degree mark, the servos will engage. the pressure depends on how far over 45 degrees you are. I have taken it to 60 degrees and you have to really fight hard, so unless you are trying to get to 60 degrees by force, it just wont let you get there. Yes, you can overcome the servos, I havent tried it and thats not the point of this testing anyway. After 10 seconds in that zone within a 20 second period (not consecutive), you will hear Engaging Autopilot, GFC takes over from you until you get your head back in the game.
Under-speed Protection - Same theory as when it runs on AP. the only difference is, you DO NOT hear OR see "Airspeed" callout or MISPEED visual on G5. it will just engage the AP if you are hanging outside its preset limits. I couldnt even do a slow flight with stall horn chirping without disabling ESP let alone stall. Just not going to happen. I even tried a turning stall and couldnt get to it. The servos will fight real hard. I am sure there are situations where it would stall without warning especially in a sharp bank, but i didnt get to test that out yet. Will do next time i have a chance. so at this point, i am not sure if GFC will save your bacon in a base to final turn. The ESP kicks in based on airspeed, not the greatest measurement of when the stall would happen especially in a bank.
Just doing very rough numbers, at max gross weight, 40 degree flaps, 45 degree bank angle the archer would stall at 57 kts. So in theory, it shouldn't let you stall on a base to final turn, but until I can prove that at altitude, I aint buying it.
At zero or 10 degree flaps, Archer will stall at 65-63 kts - so definitely not going to save your bacon.
At 25 degrees of flaps (thats where i am at base), my stall speed max gross is right at 60. So too close to comfort.
But running those numbers at 250 lbs less than max gross, and you are in the protective zone.
Have to go up at altitude and try those.
Edit: As per the manual "Level mode as activated by ESP is limited by altitude. ESP will not be able to activate Level mode until the aircraft climbs above 2000 feet AGL. ESP will be locked out of automatically activating Level mode after the aircraft descends below 1500 feet AGL as well." - there you go, not sure if it will engage AP or not, but from what the manual says, it is not going to save you from a base to final stall-spin. Something I need to clarify with Garmin. You can however manually engage the Level mode and that is not affected by altitude, so if you are in a hopeless situation in pattern and have the chance to hit the Level button, there is a chance your bacon will be saved.
Over-speed protection - Haven't tried it. Kinda hard to hit 80% of VNE in an Archer and more importantly, I just couldnt find smooth air.. its been windy and bumpy last 2 weeks.
Overall impression
Its expensive, no doubt, but totally worth it. just the Envelop protection alone makes it totally worth the expense in my book. Doesnt mean it will save your bacon 100% of the time, but unless you are doing something crazy or trying out a 60% bank under 200 AGL... it will cover most of anything dumb I might do. Its like having a CFII/ATP sitting on the right seat who doesn't get tired, doesn't pull breakers on you, does not get the leans and don't make mistakes. (Yes, I am aware, one day when need it the most, it will quit on me)
Improvement Suggestion
Add CWS (Control Wheel Steering) - Its not too difficult to sync heading + switch to heading mode and go in a different direction, its still 3 button presses with your right hand VS one button press on the yoke. I hear its there in experimental world, so I have hope.
Add audible alarm and G5 visual warning when Envelop protection kicks in during those few hand flying moments
Short Version
Its freaking awesome. If its approved for your aircraft - go get it.
Long version
My previous AP was Century 2000, so thats my frame of reference. I also have few hours behind a GFC 700 in a 172. Apart from CWS button on the GFC 700 I could recall if there are any performance differences between the two. Not sure if the 700 had envelop protection or not, most likely no in a 2000 Cessna model.
Altitude Hold
On the dot, not 70-100 feet off, may be 20 feet off on a mediocre day, at most i have seen 30 feet off on a bumpy day - surface winds 14G23, i was at 550 AGL - still within 30 feet. Yes I am aware of the FARs, i was over a corn field, with black dirt under me and not a soul in sight.
Flying Approaches
On rails. I am pretty sure the controllers in Fargo are surprised by how awesome I fly the approaches all of a sudden .. lol. Coupled approaches with GTN, anticipates the turn, very smooth standard rate turns.
Flying straight and level
On rails. The coolest part is, when you change the altimeter, it will go and capture the new altitude
.IAS Mode and Altitude capture
I usually climb at 90 kts IAS mode, based on conditions, I have seen it fluctuate somewhere in the tune of 2-3 kts. Altitude - 1000 feet you hear a ding telling you its 1000 feet below altitude. One more ding when its 200 feet to go. approaching about 60 feet it slowly brings the nose down, thats your cue to adjust / put whatever cruise power you want to set. Once captured GFC will cancel the IAS mode, capture the altitude and hold it. There is no separate altitude hold mode. If you are flying by hand, press the Altitude sync button, ALT button and turn the AP on, it will engage in PIT and TOL Mode and fly the ALT you were flying. All banks are standard rate turns, unlike my Century which would at times go to 25-30 degrees and then try to stabilize and make some S turns in the process when it overshoots the magenta line.
TOGA
While taking off, press the TOGA button, AP indicated TO on G5, moves the FD to 8 degrees, just fly that. During missed approach, full power, hit the TOGA, GFC will fly coupled missed approach and take you to Hold and keep holding there until you command otherwise.
Heading mode and Track mode
Nothing special other than it will hold heading or track within 1-2 degrees of whatever you have set.
Under speed Protection (USP) on AP
While on AP, holding altitude, i reduce power to 1700 RPM. GFC kept pulling the nose up to hold Alt. right at 62 (Mine is set to trigger at 60), it gives you a small nudge, right at 60 you will hear "Airspeed, Airspeed" and MINSPEED flashing on the G5, GFC will start sacrificing altitude for airspeed - It wont let the plane stall, period. In a situation where the PIC is unconscious and the only soul in the plane, I can imagine at some point the plane will run out of altitude (say you are out of fuel), and hit the ground at 60 kts. survivable depending on what you are hitting. I did not try the Over Speed Protection. Bank limit is standard rate turn, so over bank protection does not apply.
The Blue button (Level mode)
Not sure why the button is blue, I think Garmin should change it to brown
. I have put the plane in all sorts of wired attitudes - hit the Level button, it recovered smoothly, first bank then pitch, just like your CFI taught you. No sudden jolts. Nothing violent. I have heard in Mooneys some people say the return to level is rather violent. Next time my CFI / DPE put me in unusual attitude and ask me to recover I am going to hit that button .. lolElectronic Stability Protection (ESP) / Envelop protection
Its always on at the background when you are hand flying. There are 3 modes:
Over Bank Protection - At 45 degrees on your PFD you will see 2 green marks on both sides of the AI. Once you cross that mark (right at 45 degrees), the mark changes to yellow and moves over to 30 degrees. thats AP telling you to get back where you belong. If you cross the 45 degree mark, the servos will engage. the pressure depends on how far over 45 degrees you are. I have taken it to 60 degrees and you have to really fight hard, so unless you are trying to get to 60 degrees by force, it just wont let you get there. Yes, you can overcome the servos, I havent tried it and thats not the point of this testing anyway. After 10 seconds in that zone within a 20 second period (not consecutive), you will hear Engaging Autopilot, GFC takes over from you until you get your head back in the game.
Under-speed Protection - Same theory as when it runs on AP. the only difference is, you DO NOT hear OR see "Airspeed" callout or MISPEED visual on G5. it will just engage the AP if you are hanging outside its preset limits. I couldnt even do a slow flight with stall horn chirping without disabling ESP let alone stall. Just not going to happen. I even tried a turning stall and couldnt get to it. The servos will fight real hard. I am sure there are situations where it would stall without warning especially in a sharp bank, but i didnt get to test that out yet. Will do next time i have a chance. so at this point, i am not sure if GFC will save your bacon in a base to final turn. The ESP kicks in based on airspeed, not the greatest measurement of when the stall would happen especially in a bank.
Just doing very rough numbers, at max gross weight, 40 degree flaps, 45 degree bank angle the archer would stall at 57 kts. So in theory, it shouldn't let you stall on a base to final turn, but until I can prove that at altitude, I aint buying it.
At zero or 10 degree flaps, Archer will stall at 65-63 kts - so definitely not going to save your bacon.
At 25 degrees of flaps (thats where i am at base), my stall speed max gross is right at 60. So too close to comfort.
But running those numbers at 250 lbs less than max gross, and you are in the protective zone.
Have to go up at altitude and try those.
Edit: As per the manual "Level mode as activated by ESP is limited by altitude. ESP will not be able to activate Level mode until the aircraft climbs above 2000 feet AGL. ESP will be locked out of automatically activating Level mode after the aircraft descends below 1500 feet AGL as well." - there you go, not sure if it will engage AP or not, but from what the manual says, it is not going to save you from a base to final stall-spin. Something I need to clarify with Garmin. You can however manually engage the Level mode and that is not affected by altitude, so if you are in a hopeless situation in pattern and have the chance to hit the Level button, there is a chance your bacon will be saved.
Over-speed protection - Haven't tried it. Kinda hard to hit 80% of VNE in an Archer and more importantly, I just couldnt find smooth air.. its been windy and bumpy last 2 weeks.
Overall impression
Its expensive, no doubt, but totally worth it. just the Envelop protection alone makes it totally worth the expense in my book. Doesnt mean it will save your bacon 100% of the time, but unless you are doing something crazy or trying out a 60% bank under 200 AGL... it will cover most of anything dumb I might do. Its like having a CFII/ATP sitting on the right seat who doesn't get tired, doesn't pull breakers on you, does not get the leans and don't make mistakes. (Yes, I am aware, one day when need it the most, it will quit on me)
Improvement Suggestion
Add CWS (Control Wheel Steering) - Its not too difficult to sync heading + switch to heading mode and go in a different direction, its still 3 button presses with your right hand VS one button press on the yoke. I hear its there in experimental world, so I have hope.
Add audible alarm and G5 visual warning when Envelop protection kicks in during those few hand flying moments
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