Monday, April 21, 2008

So many electrons, so little time

A local turboprop operator called me because they were short a pilot.  Their trip to the coast fit my schedule, so I took it.  Get paid to fly a nice airplane to a nice destination with a nice guy?  Sure.

Their airplane has a mixed avionics suite that includes steam gauges all around, an older IFR GPS, but a modern KMD-850 Multi Function Display (MFD) that includes terrain, traffic, weather, and moving map functions.  I have flown this kind of MFD before, and I have to admit that it took me a few flights with it before I became comfortable with it. 

[The photo here is from _Night_Flyer's_ flickr collection, and I believe that it is legal.]

I was a little surprised at how little their pilot knew about the system.  Remember, I just got handed my lunch by the Garmin G1000 system a few weeks ago, so I am pretty sympathetic.  All of these avionics systems have little goodies and quirks, and we have all read over and over again how important it is get to know the avionics before you fly.  The thing is, something like a G1000 hits you upside the head to warn you that it is different, while little incremental changes (add a function here, a few months later add a function there) that leave so much unchanged make it easier not to see that something more is needed.  I think that this pilot had been lulled by the familiarity of everything else in the cockpit.

Here's a picture of another airplane of the same type, but with EFIS.  The EFIS is obviously different, so it's obvious you need to learn how to use it.  This particular airplane doesn't have an MFD, though.

So what can the MFD do?  My favorite function is the terrain function, although it must be used with caution.  Its position depends on GPS position (not some internal position, as my friend thought), and any error in GPS position leads to an error in the display.  It is also subject to abuse.  I wrote an article for comp.risks about this in 1998 which you can probably find by searching for EGPWS; I also wrote a letter to the editor of Aviation Week that appeared around the same time.

Despite the problems, I appreciate having a terrain display during departure and arrival, and it has been my routine to put the MFD into terrain mode before takeoff and during the descent.  

The radar in this airplane is nice, too.  In radar mode, one of the soft buttons on the right says "VIEW", and pressing it gives you a vertical profile in one direction.  If there is a thunderstorm, you can see just how far above you or below you it goes.  We used this during one of those "Are we going to be above that?" cockpit discussions.  He had never seen it before.

You can also use the radar to show traffic.  This takes a little knob twisting and button pushing, but most weather radars can do it.  You need to put the gain up as high as it will go (in this unit, the weather mode has automatic gain, so you have to go into map mode), and set the range to 20 miles or less.  You need to play with the tilt a little, too.  But try it when Center calls traffic 12 o'clock, 1000' above, opposite direction.  You'll see a smudge that gets closer with each sweep of the antenna.

Traffic mode will show you a little icon of a nearby airplane with its relative altitude and derived track.  Switching back and forth between this and the radar will convince you that the radar really saw the traffic.  Since the traffic functions depends on the secondary reply to ATC's radar, you really have two radars showing the same thing, which is quite comforting.

To me, the moving map mode is the least useful.  Some units allow you to superimpose the moving map onto the radar picture, like below, but the MFD we were flying that day with won't do it because the airplane's GPS isn't sophisticated enough.  (The picture was taken a few months ago in the bumps, as you can see.   There are multiple course lines because I was using the FMS offset function to go between the cells.) 

The map is nice to show the passengers just how far away New York is, or to give a more intelligent answer than "White Pigeon" to the "What town is that?" question, but the useful moving map is on the GPS.  The MFD just duplicates the GPS map, anyway, so it provides no new information.  Plus, it's easy to make the map so cluttered that it is useless, by displaying every VOR, NDB, intersection, airport, MOA, restricted area, alert area, class D, class C, class B, and airway.  

I like Jackson Pollack's paintings, but not in the cockpit.

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At April 23, 2008 at 2:40 PM , Blogger Jill said...


Beautiful photos.

I'm from a new company,

I'd love to speak with you about a partnership and can be reached at

J Fraser


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