Aural Warnings

What audio panel do you have?

The IFD sends out alert audio on pins 52 & 53 (HI & LO respectively) of P1001, and this should be wired to an available audio input port on your audio panel.  Since you have two IFD units, I would just wire up #1.  There's no advantage in hooking up both of them.

It seems like most upgrade airplanes (from brand G equipment) never had these wires installed originally.

My IFD installation was "from nothing" and I hooked up the wires described above, and mine works as expected.

David Bunin

Just the IFD in my airplane.  No external TAWS for me.

There are two different alert audio outputs (37/38 and 52/53).  I did a significant amount of research while designing my installation, and decided that the 52/53 output would work better with my audio panel.  The output impedance is different giving improved volume control and clarity.  It was an instance where Avidyne found a way to improve on what Garmin had done, and I wanted to take advantage of that.

I also get terrain warnings from a portable GPS.

David Bunin

I went with the PS Engineering PMA-450, and very happy with it so far.  I have the alert audio connected to a Switched Input port, which I leave switched on all the time (so far).  I will switch it off when I fly into an airport that isn't in the database (grass/dirt/bush) to avoid nuisance terrain alerts while landing.

I have the IFD standby comm audio wired into another switched input, and I turn that one on and off quite a bit to use the feature as necessary.

Aside from the front panel pilot/user interface, the PMA-450 is technically similar to the Avidyne audio panel (APX-240?) so my information in input impedance and other technical factors for the Alert audio interface should transfer nicely between the two products.

David Bunin

DavidBunin wrote: I went with the PS Engineering PMA-450, and very happy with it so far.  I have the alert audio connected to a Switched Input port, which I leave switched on all the time (so far).  I will switch it off when I fly into an airport that isn't in the database (grass/dirt/bush) to avoid nuisance terrain alerts while landing. I have the IFD standby comm audio wired into another switched input, and I turn that one on and off quite a bit to use the feature as necessary. Aside from the front panel pilot/user interface, the PMA-450 is technically similar to the Avidyne audio panel (APX-240?) so my information in input impedance and other technical factors for the Alert audio interface should transfer nicely between the two products. David Bunin

Not sure when you got your PMA-450, but mine had to be RMA'd for some new hardware/firmware. The music inputs would not power cycle nicely (first 3hr leg was fine, refuel and next 3hr flight nothing would come through).  I spoke with PS at KOSH and it was a known issue.  They gladly fixed in a day (new hardware and firmware).  Overnighted it on Monday had it back Wednesday AM.

BTW, my IFD standby audio works perfectly with it (minus the IFD not muting it).  I don't think the APX-240 has common hardware/firmware with the PMA-450.  I recall PS showing me @ KOSH how the APX board had a minor change from the 8000 series.  In fact PS showed me how they modified the board for the second knob for the APX.

Now, on topic.  How do the warnings sound to everyone else? Mine sound extremely "tinny" and 1980's ish.  I have to really listen hard to understand it.  "Airspace Ahead" is particularly hard to understand. I was expecting something like I hear in military jets or maybe a Boeing/Airbus cockpit.


Edited by roltman - 16 Oct 2015 at 2:07pm

I purchased my unit in May this year.  I think I went through Aircraft Spruce and took advantage of their ability to pre-fabricate the harness to my specifications.