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Landing Height System for Mooney


Microkit

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It is often the case that the terrain short of the runway is lower than the runway.   EGPWS systems on modern airliners have high resolution digital terrain databases around commercial airports and use this to generate callouts.   The callouts are height above touchdown.  Its not strictly off a radar altimeter. The minimums callout is based on the dialed up baro or RA minimum but baro is typical and also has the flag on the altitude tape.    There is a RA readout on the EFIS...but until you cross the threshold...its maybe only a cross check.   RA is an autopilot input for auto-land and used in the flare mode - there have been accidents from RA failures and there is currently an advisory regarding 5G frequencies.

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3 hours ago, LANCECASPER said:

Has anyone with a G1000 installed this yet? (I had it previously on a Bravo I sold)

 

We have several TBM's (700 & 800 series) that installed our LHS and are using G1000.  Obviously, it is not related to the EFIS as it just connects to the Audio Panel, but most G1000 installations would have Garmin GMA 35 similar to those TBMs, and it was installed to that audio panel with no issues.

No effect from 5G due to the huge difference in the wavelength/frequency used.

 

Regards

Nidal

 

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23 minutes ago, Microkit said:

 

We have several TBM's (700 & 800 series) that installed our LHS and are using G1000.  Obviously, it is not related to the EFIS as it just connects to the Audio Panel, but most G1000 installations would have Garmin GMA 35 similar to those TBMs, and it was installed to that audio panel with no issues.

No effect from 5G due to the huge difference in the wavelength/frequency used.

 

Regards

Nidal

 

I was referring to a Mooney with a G1000 and the Garmin GMA 1347 Audio Panel.

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18 minutes ago, LANCECASPER said:

I was referring to a Mooney with a G1000 and the Garmin GMA 1347 Audio Panel.

Also works with the GMA 1347.  

LHS is not related to EFIS.  The only case the type/brand of EFIS comes into play is if the panel was certified as a whole (as Flight Deck).  Newer TBMs use Flight Decs and if Gamin did not enable an extra audio channel in the "certified" settings file used for the certification, then the installer is unable to change the settings file to enable an extra audio panel through the G1000.  Airplane Panels that have an audio panel with a face interface and not remote mounted can connect extra audio channels with no issues.   Panels that uses remote audio panel unit which is controlled by an EFIS can also be used, as long as it does not affect the certification of the EFIS.

As far as the audio panel is concerned, the LHS is just another audio source such as ADF, COM3, NAV3, Music-IN, AUX and so on, and it should work, even connected directly to speakers as well or connected to 3.5 mm Audio Jack and put into the headset 3.5 mm input.

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In my O2 GX G1000 we simply connected the LHS's audio output to the (unused) DME input channel of the GMA 1347 (LHS is a vertical Distance Measurement Equipment, isn't it?).
Works like a charm, fulfills the requirement of simply muting the LHS's audio and is easy to remember (did not relabel the DME button (rationale see above)).

Best,

Matthias
 

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I installed mine last June at annual.  It is installed on a left sided inspection plate just outboard of the left main gear.  Left side was chosen to keep it away from the exhaust.  The install went well.

I had not flown recently and was out of Biannual currency and Instrument currency.  We went out and did some landings and my instructor (one of the Mooney Proficiency Instructors) commented that all of my landings (except for the first one which was flatter) were all consistently the best landings had had seen me do.

It is all about knowing how high you are at 5 feet down to wheels touching.  Knowing you are 2-3 feet above the runway makes it so much easier to bring the airplane's nose up and get the stall warning working.  Without the landing height info, I wanted to take a flatter attitude since I did not want to drop it in.  The combination of Airspeed, AOA, and Landing Height Info makes it much more reliable.  

I have not yet used it at night, but I am sure it will be a big help there as well.

Great Product!

John Breda

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4 hours ago, Oscar Avalle said:

One issue that surprised me was in IMC the altitude warning also goes off!

Óscar
 

Yes, this is just part of laser element characteristics.  When flying straight & level in an IMC layer that is 'near' freezing, it can hit a target such as cooled water droplets ice crystals and report it back.   The procedure for those who fly IMC regularly, is to either ignore it or disable the audio using the "Switched" input on the audio panel and add a note to their landing checklist to enable it.

 

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If you didn’t get what you wanted for Christmas…this is a great treat to add to your plane.

once you buy it, you will get to use this great tool for every landing.

please keep in mind with every marginal and poor landing you have you shorten the useful life of your landing gear components and sealing of the in wing fuel tanks.  Even consider that it could help you avoid a gear up event with the “check your gear” call out.

you can minimize installation expense if you run the interconnecting cable during your annual when panels are removed.

with LHS i grease over 90% of my landings…Ito me this couldn’t be accomplished without it.  My testimony is without any compensation…I have no connection to the company I just feel it offers such value for fellow M20 owners

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I got my LHS unit early on, but due to a bunch of stuff not relevant here, I did not get it installed for a long time. The first time I flew with it, I could not hear it in my headset until I was actually on the ground, and then only faintly. My avionics shop originally hooked it to the DME circuit, but after much head-scratching and talking to Nidal, they used the ADF. (My audio panel is a KMA-24). Since then, the unit was sent back to Microkit for testing (which confirmed the unit was putting out the proper power), it was sent back to my shop with equipment to check it in the plane. I am too ignorant to understand all that is going on, but I still do not have enough volume to hear it. Nidal has offered to refund the cost, but I am still out the installation cost, and worse, I still do not have a functioning unit. It has been suggested that updating my audio panel may resolve the issue, but that would be a terribly expensive process. I really want it to work. (Anyone who has flown with me understands that if anyone can use help in improving landings, it is me.)

Any and all comments appreciated.

Don

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@DonMuncy @Microkit

If the output of the LHS is solid when bench tested, then it seems driving the KMA-24 is, somehow, weakening the signal.  You have tried two inputs, DME and ADF, with no luck.  I assume that the NAV and COM audio goes through the KMA-24 and work correctly?  If so, then do you know if the shop hooked DIRECTLY to the KMA-24 inputs, or did they use 'existing' wiring that was left over?  Some work, but you could try temporarily removing a COM input and using that input to test (since you know that input works properly)

Let me know what has been tried (Nidal).  Also, not sure what the impedance of a KMA-24 audio input is vs. newer panels (and output impedance/drive capability of the LHS)

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1 hour ago, DonMuncy said:

I got my LHS unit early on, but due to a bunch of stuff not relevant here, I did not get it installed for a long time. The first time I flew with it, I could not hear it in my headset until I was actually on the ground, and then only faintly. My avionics shop originally hooked it to the DME circuit, but after much head-scratching and talking to Nidal, they used the ADF. (My audio panel is a KMA-24). Since then, the unit was sent back to Microkit for testing (which confirmed the unit was putting out the proper power), it was sent back to my shop with equipment to check it in the plane. I am too ignorant to understand all that is going on, but I still do not have enough volume to hear it. Nidal has offered to refund the cost, but I am still out the installation cost, and worse, I still do not have a functioning unit. It has been suggested that updating my audio panel may resolve the issue, but that would be a terribly expensive process. I really want it to work. (Anyone who has flown with me understands that if anyone can use help in improving landings, it is me.)

Any and all comments appreciated.

Don

If the KMA 24 is bad, the PS Engineering PMA7000 audio panel is a plug and play replacement  for the KMA24. There are used ones of both models on Ebay. But I still doubt that's it if everything else works on the audio panel. This can't be the only Landing Height System installed with a KMA24 audio panel. 

They give you two wires to go to the ADF input (ADF Hi and ADF Lo) although they suggest that you first try just ADF Hi and see if that works. ADF Lo is used if it needs to be internally grounded. I would get your Nidal to talk to your installer if that hasn't already happened. It sounds like something simple.

 

 

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The LHS audio volume is adjusted on the wifi page on your phone during the first three minutes of power-on time. I have mine adjusted to less than half volume, at full it will blow your ear drums. I have a PS Engineering audio panel, and I am using the AUX port for the LHS input. I have Lightspeed Zulu 3 headsets which cut exterior noise very well. 

What level is the LHS audio set to?

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@DonMuncy @MikeOH

I am sorry you are having issues with the audio volume.  per our certification, we are unable to push out more than 1W of audio power through the audio line, so we have set our audio output to about 0.95W when loading 8 ohm speaker.  It was tested with older type audio panels (KMA 20) that uses 500 ohm audio input spec and it worked as expected with no difference than the newer audio panels.   We have checked the unit here and it was within spec (0.92W output), we sent back an extra quick-disconnect wiring along with attached external speaker to the Avionics shop for them to do bench testing and show how volume is adequate when using a speaker on the bench.   

We did suggest borrowing another KMA 24 and swap the unit on the airplane to check if was just that specific KMA 24. 

Another suggestion was to hookup the audio directly to the headset using a 3.5mm audio jack if your headset have an audio input on the side of its controller.    

The 3rd suggestion was to see if they can tie it to the big jack of the headset directly, few on the Comanche group actually did just that, got a T for their headset jack and split it to it connects to the airplane from one side and the LHS on the other.

I would not recommend changing the audio panel if you (they) are not 100% sure that this will cure the volume issue.

 

 

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12 minutes ago, philiplane said:

The LHS audio volume is adjusted on the wifi page on your phone during the first three minutes of power-on time. I have mine adjusted to less than half volume, at full it will blow your ear drums. I have a PS Engineering audio panel, and I am using the AUX port for the LHS input. I have Lightspeed Zulu 3 headsets which cut exterior noise very well. 

What level is the LHS audio set to?

The unit default is MAX volume.  The tech did say he tried various range on the volume and I believe he returned to back to MAX at the end of their testing.  They would have noticed lower volume on the external speaker we sent them.

Not sure why the KMA 24 would be different than the KMA 20 which we have on the bench here and use it for 500 ohm impedance testing.  

All audio panel should amplify the signal internally, maybe on that airplane, someone added a series resistor to the audio lines to limit power?  

One way to check if wiring to the panel is ok is by pulling the KMA 24 out, get a low cost tray from eBay for the KMA 24, tray would include the back connector for the KMA 24, hookup external speaker (or headset) to the tray and test audio.  If the Avionics shop already have a bench tester for the KMA 24 then they would have the back connector already, it just needs power & speaker out to test it externally, eliminating all the airplane wiring.

 

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3 hours ago, Microkit said:

@DonMuncy @MikeOH

I would not recommend changing the audio panel if you (they) are not 100% sure that this will cure the volume issue.

Don, no matter whether you install the LHS, upgrading the audio panel is something that I think you should do.  As you know, the KMA 24 is a mono audio panel, and more than 30 years old.  Even before I did my major upgrade I did upgrade my audio panel to the PMA 7000B.  What a difference!  If you have a new stereo headset like the Bose A20, the difference is dramatic, including possibly having 3D audio depending the audio panel you get.  Audio panels are reasonably inexpensive compared to other avionics.

At our age a few thousand dollars either way for the benefits provided are well worth it in my opinion.

I highly recommend getting the LHS working, hopefully with a more modern and useful audio panel.  Two of the best and most reasonable items I have installed in my plane have been the Alpha Systems AOA and the Microkit LHS.  I have recommended the LHS to all my students and the ones who purchased it have reported back excellent results.

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Is there possibly a confused stereo/mono switch in the wrong position somewhere?

Sounds like something I have run into before…

Just use caution… when you get the switch flipped correctly, it may be quite loud.   Depending on how you left the volume set last…

-a-

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I have a KMA24b that came out of my plane …I will send it to you if you’d like to try it…LHS worked perfectly with my old KMA other than fact that my LHS had to be set on full volume.  Just send me $20 for shipping.

carusoam made a great point of making sure your headphones are set for “mono”

I replaced my audio panel late last spring because a friend of mine got a new one on his Musketeer and I learned how nice it was to have crystal clear audio, and direct Bluetooth music to me and my passengers.  The new audio panel did cost close to $5,000 because the avionics group wanted to pull all new wires….including rear jacks…I went with the garmin gma345.  You can install the PMA but you still have to wire out the intercom system.

crystal clear audio system improves ATC communication and cuts the fatigue of flying.

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20 hours ago, carusoam said:

Is there possibly a confused stereo/mono switch in the wrong position somewhere?

Sounds like something I have run into before…

Just use caution… when you get the switch flipped correctly, it may be quite loud.   Depending on how you left the volume set last…

-a-

I am not aware of a mono/stereo option. Where would I begin to look for it?

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