Ground Clearance Switch

AggieMike88

AggieMike88

Touchdown! Greaser!
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The original "I don't know it all" of aviation.
Found an aircraft online that had the following listed in the avionics section of the ad:
Dual Garmin GNS 430 GPS/Coms
Garmin GMA 340 Audio Panel
Garmin GTX 327 Transponder
Dual Garmin GI-106A Course/Glide Slope Indicators
STEC 30 2-Axis Auto Pilot
Avionics Master
Ground Clearance Switch
​
What specifically is the last item? If it helps you, the aircraft was a Tiger.
 
It powers one comm and not the whole deal so you can get your clearance before start without running all the avionics, T&B, etc.
 
Each gear leg has a 6" pneumatic extension that can be activated from the cockpit. Especially handy for rough-field ops.
 
But Wayne, knowing you, that's 6 more inches from you pulling my leg.

Here's a photo if it helps you guys... look in the lower right near the master.

88989512.jpg
 
That switch provides power to Comm1 (and maybe the audio panel) so you can get your clearance, and not the rest of the avionics bus.
 
Actually it lets you use a com radio without turning on the aircraft master switch.
 
Mike, these other guys clearly don't know anything about airplanes, and here's how you can prove it. When you go to look at this airplane, stand outside the cockpit and tell the owner to activate the ground clearance switch so you can see if the gear extension legs work properly.
 
Wayne, that is old technology. The new Ground Clearance Switch actually retracts the prop blades to provide the required Ground Clearance.
Try to keep up with the times, man.
 
Well, I certainly defer to your superior technological grasp of the subject, and understand why it's something you would know about. If I had as many landing gear extension problems as you do, I'd want a prop retractor too. ;):D
Let'sgoflying! said:
Wayne, that is old technology. The new Ground Clearance Switch actually retracts the prop blades to provide the required Ground Clearance.
Try to keep up with the times, man.
Click to expand...
 
wabower said:
Each gear leg has a 6" pneumatic extension that can be activated from the cockpit. Especially handy for rough-field ops.
Click to expand...

I'm just thinking how cool it looks if you flip it on and off in time with the music from your ginormous sub-woofer.:D

John
 
wabower said:
Mike, these other guys clearly don't know anything about airplanes, and here's how you can prove it. When you go to look at this airplane, stand outside the cockpit and tell the owner to activate the ground clearance switch so you can see if the gear extension legs work properly.
Click to expand...
You know I am picturing an airplane doing something like this now.

 
The "priceless" aspect of this scenario is the look on the owner's face when Farlow says "If you don't mind, I'd like to stand outside and watch the ground clearance system activate, just to be sure the leg extensions work properly."

ScottM said:
You know I am picturing an airplane doing something like this now.

Click to expand...
 
It's also commonly referred to as an avionics dispatch switch. We have that on one of our CJ3's at work. It powers the #1 RTU so we can pick up a clearance without turning the battery switch on.
 
Interesting. It may be a common term where you work, but it's the first time I've ever heard it after a number of decades hanging around the airport.

HPNPilot1200 said:
It's also commonly referred to as an avionics dispatch switch. We have that on one of our CJ3's at work. It powers the #1 RTU so we can pick up a clearance without turning the battery switch on.
Click to expand...
 
IOW, it's about being able to get ATIS/AWOS/IFR clearance without either starting the engine(s) or eating the battery (much).
 
So if you activate the ground clearance switch in flight does it cause the plane to climb?
 
Only if you have a radar altimeter attached to the gear leg.

COFlyBoy said:
So if you activate the ground clearance switch in flight does it cause the plane to climb?
Click to expand...
 
The one I am familiar with is as seen above.
 

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AggieMike88 said:
Found an aircraft online that had the following listed in the avionics section of the ad:
Ground Clearance Switch
​
What specifically is the last item? If it helps you, the aircraft was a Tiger.
Click to expand...

wabower said:
Each gear leg has a 6" pneumatic extension that can be activated from the cockpit. Especially handy for rough-field ops.
Click to expand...

wabower said:
Mike, these other guys clearly don't know anything about airplanes, and here's how you can prove it. When you go to look at this airplane, stand outside the cockpit and tell the owner to activate the ground clearance switch so you can see if the gear extension legs work properly.
Click to expand...

Mike, these guys are giving you old false information - don't listen to them. The newer Tiger ground clearance switches allow you to taxi and take off without a clearance, penetrate Class B/C/D at will without a call-up and ATC provides automatic FF without having to give any info to them (they also figure out where you are headed and clear the way for you). The switch creates an automatic Class G bubble around your aircraft whenever activated - I just tape my down to keep it active at all times.:D Next year's model you don't even have to be IFR rated for approaches to minimums! And as always, leaning forward, slips with flaps, LOP operations and running over-square won't damage the unit.:goofy:
 
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I'm shocked someone didn't drag this out by saying the photo looked Photoshopped. ;)
 
wabower said:
The "priceless" aspect of this scenario is the look on the owner's face when Farlow says "If you don't mind, I'd like to stand outside and watch the ground clearance system activate, just to be sure the leg extensions work properly."
Click to expand...
Just for that, buddy, I'm cutting off your supply of blinker fluid and cancling your order for the passenger rear door on the Camaro... :D :D :yes:
 
I should have known better than to trust a scrap-yard guy in the first place. ;)
AggieMike88 said:
Just for that, buddy, I'm cutting off your supply of blinker fluid and cancling your order for the passenger rear door on the Camaro... :D :D :yes:
Click to expand...
 
wabower said:
Interesting. It may be a common term where you work, but it's the first time I've ever heard it after a number of decades hanging around the airport.
Click to expand...

To be fair, Wayne, several of those decades predated the invention of the wireless.
 
Watch your mouth. Pterdodyctal Airlines was a visionary company that was ahead of its time. I flew for them for a while, but finally had to quit. The damn birds kept eating the passengers.

SCCutler said:
To be fair, Wayne, several of those decades predated the invention of the wireless.
Click to expand...
 
Now I realize just how quiet this place was during the summer. Glad to have ya back, Mr. Bower.
 
ScottM said:
You know I am picturing an airplane doing something like this now.

Click to expand...
Just joined the forum and saw this. Ironically enough, there is something like this out there. The C-2A Greyhound has a switch in the cockpit labeled "CAT EXT". It's the catapult extend for the mains, and used the create more clearance for the tail to not impact the catapult shuttle at the end of the stroke.
 
Are you guys sure about this? The ground clearance switch is part of the autopilot. When activated it couples the autopilot to the 430 terrain function so altitude changes are made so the aircraft clears the ground. Very useful for napping and mile high adventures in the mountain west.
 
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