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Dual GI-275’s performance in a Low IFR RNAV Approach


Fly_M20R

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This video shows how the dual Garmin GI-275’s perform superbly in an RNAV approach into KFHB in low IFR conditions getting me down to minimums. The scan is easy and clear. Horizontal and vertical deviation indicators on both the ADI and HSI are clear and easy to fly with. The KFC 150 autopilot is driven perfectly by the top GI-275 (ADAHRS+AP). Just remember to put autopilot in APR mode once the Navigator (in my case a 530W) shows an approach mode such as LPV!! :o

 

 

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Nice work, Chris!

I came across the video there first, then here... :)

For any new pilots...  a nice example of an IFR flight...

With houses next to the runway...

And radio communication that is pretty rapid fire...

I like the runway... it looks similar to a small rural street... with a long displaced runway...

Best regards,

-a-

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11 hours ago, milotron said:

Nice. What is the blinky green LED to the left of the displays?

 

 

Hi Milotron,

It is a remote annunciator for the 530W. It blinks whenever the 530W has a message, such as change tanks, arriving at waypoint, or turn to heading xxx in yyy seconds. Quite useful to have it closer to the scan than catching it on the 530.

Edited by Fly_M20R
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8 hours ago, carusoam said:

Nice work, Chris!

I came across the video there first, then here... :)

For any new pilots...  a nice example of an IFR flight...

With houses next to the runway...

And radio communication that is pretty rapid fire...

I like the runway... it looks similar to a small rural street... with a long displaced runway...

Best regards,

-a-

Thank you carusoam!

As a friend of mine said, "neat to takeoff and land a Mooney on a sidewalk". :D Runway is 24 ft wide.

Rapid fire ATC is up in NY Center where you live!! Been through it several times. The busiest i have ever heard ATC was on a flight to MIA area (KOPF) on Dec 31st, a couple of months ago!!  Kept me kn my toes!!

Edited by Fly_M20R
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1 hour ago, flyboy0681 said:

I've noticed in all of your videos that you twist the throttle to apply power. Can't you simply push it in?

Good question flyboy0681!

Yes, I could push it by pressing the knob to release the throttle. However, it would be easy to advance too fast and cause the engine to "surge". Not so good for it. I have not really found much difference in takeoff performance between pushing it at a speed it won't surge vs twisting. I have more "control" by twisting. If I were to go over a bump while pushing it could advance more than intended. 

I was introduced to "twisting" when I bought a Mooney 252.

In case you were to fly formation then you need to keep the button pushed in with some tape so that you can respond faster to changes in the lead plane.

I occasionally push in the button on some landings when I need greater changes in power in a short period of time than twisting would. I keep it pushed in with the palm and keep my index on the panel as a "reference". 

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"Surge" is a vague term.  Any chance you can elaborate on the exact concern with quickly advancing the throttle?  Inability of the fuel servo to keep up with the sudden change in air volume?  Inability of the prop governor to change the blade pitch quickly enough to maintain RPM?  Something associated with the turbocharger?  Something else?

Enquiring minds want to know.  :D

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4 hours ago, Vance Harral said:

"Surge" is a vague term.  Any chance you can elaborate on the exact concern with quickly advancing the throttle?  Inability of the fuel servo to keep up with the sudden change in air volume?  Inability of the prop governor to change the blade pitch quickly enough to maintain RPM?  Something associated with the turbocharger?  Something else?

Enquiring minds want to know.  :D

Hi Vance,

First, please note that I am not an A&P and just a private pilot who tries to handle the plane as best as possible. However, I have been told by my friendly A&P/IA that quickly advancing (or retarding) the throttle can detune the crankshaft counterweights, as noted by FAA AC-20-103 which I have attached. See section 4(d). If they get "detuned" then the crankshaft will eventually end up overstressed since the counterweights will not be able to perform their function of dampening engine/crankshaft vibration. It seems that the counterweights are quite sensitive.

The other reason to "twist" is because it increases a bit the time between which the engine is at idle power and temperature to max takeoff power and temp. It may be a few seconds (5 at the most) but still helps decrease the time of this thermal event and therefore should help with the longevity of the engine. Think $$$ :D

That is why I twist rather than shove or just push with the possible risk of shoving. Smooth application or reduction of power is the ideal situation. 

Finally, this could be my greatest reason: I also remember an adage that one should handle a plane like a lady - smoothly... :)  ;) :D

AC_20-103.pdf

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Thanks for the explanation about the counterweights, that sounds reasonable.  I'm less convinced about the thermal argument, but no need to start a debate on it.  What's most important is that you have a set of procedures that work well for you, and you obviously do.  Enjoyed the video, thanks for posting.

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14 hours ago, Vance Harral said:

Thanks for the explanation about the counterweights, that sounds reasonable.  I'm less convinced about the thermal argument, but no need to start a debate on it.  What's most important is that you have a set of procedures that work well for you, and you obviously do.  Enjoyed the video, thanks for posting.

 

You are welcome Vance. I would actually like to thank you to prompt me into reading more about the counterweights because I just trusted what my A&P told me. Turns out I learned quite a bit with your asking that I explain further. I video quite a few of my flights because I can learn quite a bit from my mistakes and from questions I get about them. It is like an after action debrief for me. 

Yep, I have developed a set of procedures that work well for me. It is a continuous work in progress and greatly appreciate your putting my feet to the fire.

Regards,

Chris

Edited by Fly_M20R
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On 2/17/2021 at 11:35 AM, flyboy0681 said:

I've noticed in all of your videos that you twist the throttle to apply power. Can't you simply push it in?

My first plane was a 1984 J model, like yours except for a single piece belly and speed mods already installed at the factory. It didn’t have a vernier throttle and I just pushed smoothly not getting “ahead” of the engine. Got a vernier with the first 252 I got and then with a couple of Bravos. Different engines plus have a turbocharger which require a more controlled application of power. 

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