This Section is for my comments on the joyous art of flying. I am not a professional pilot, nor do I have thousands of hours. But that does not make my opinions and reflections worthless. I have been around a long time and you don't get old by being stupid or not learning from your own mistakes andusing the accumulated wisdom of those around you. So take these "gems" as being worth what you paid for them.
I never really fought against the acquisition of a GPS, it is just my Scot’s heritage that keeps me from spending money for things that I can live without. For seven years, we flew without one. We went from home to Wyoming, to New Mexico, to South Padre, to Savannah and many points in between without having one. We were never “lost” at any point in those flights. Between pilotage and dead reckoning, we could always locate our position on the sectional within at least a couple of miles. So why do we need one?
Cost is obviously a deterrent. We have always believed in buying for need, not status. We could have one for a few hundred just to say we had one, but one with enough capability to be truly useful would cost $1500. Anything not truly USEFUL is just a status symbol. Research
We had talked about going to the west coast since we started, and the chief navigator felt that a GPS would be a nearly necessary backup for flying across NM and AZ. When we started planning the BAC Fest 08 trip, the issue of GPS came up again. So what features did we want (in no particular order)?
- Color.
- Large screen.
- Computer interface with upload/download capability.
- Terrain avoidance.
- Airport DB with taxi diagrams.
- Cost.
The learning curve.
We got it home and opened up the huge package. Sandra went to run some errands while I put it on the charger, read the manual and installed the application on the computer. Downloading the database over the net was a little confusing, but I got it done.
Then came setting up all the defaults. Sandra’s biggest contribution was to demand that it be set for “North up” rather than “Track up”. I eventually came to realize that this was the better way. I did not at this time, play with the defaults for displays and messages, preferring to wait until we had tried it in flight to determine what is useful and what is not.
Next was learning how to enter a flight plan (called Route on the menu). After playing with this and all of the submenus, it was obviously a very flexible and capable function. We then discovered the simulation function. You can enter a route, start the simulation and “fly” the selected route. You can enter a start location, airspeed and altitude, then follow the route to see if the terrain will allow the selected altitude etc.. This function became better when I discovered that you can set the airspeed at 600knots which made the routes go by much faster. This was very useful to learn which button sequences were needed to go from the current screen to the desired screen and to manipulate the data displayed on each screen.
Now, we have to try it for real. I laid out a route from T31 to the Durant VOR to the Paris, TX airport and back to T31. We went out and flew (mostly) that route. Checking carefully to see what happened on-screen when we “cut off” a corner at a waypoint and how the display looked at various zoom levels.
Back home, we downloaded the route and the track record to see what that could tell us after the fact. From that, we learned some more “tricks”. So during the week before departure, I entered all 12 routes for the California trip. Then simulated several of them which had big rocks close to the flight path. I also made some minor changes to the defaults and displays. Satisfied with the preparation, we departed for the left coast.
The deviation for weather on the first leg was easily handled and the Nrst button told us exactly what we already knew when the decision to deviate became inevitable. And changing the departure point for the first leg on day 2 was easy. Adding Tucson as a totally new route was simple and inverting the day 1 route (T31-BPG) to make it BPG-T31 for the last day was also simple.
The navigator’s job now is to plug it in, turn it on, call up this route and activate it while I am handling after startup, taxi, run-up, etc.. Then deactivate, turn off and pack away after touchdown.
Summary…
The route functions are powerful and extremely flexible. We added the HND-BXK-TUS and TUS-LRU-BPG legs while we were in Santa Maria. We altered 2 of the routes the night before the flight and one of them in flight.
We like “North up” for the display as we are hardwired to “see” it that way. It makes comparing the display to the sectional easier.
We put “bearing” on the main screen in place of heading. It is a “real time” item where heading is static. It is easiest, to just make the little airplane fly parallel to the course line and don’t even look at the compass or DG. Watching the bearing start changing rapidly as we approached a waypoint allowed us to actually see each of the VOR stations we used as waypoints. Previously, we could only lay eyeballs on about half of them. This would be very useful for finding a nearly invisible airport. Buckeye was nearly invisible with a light colored runway on a flat desert and few surrounding buildings.
We found that the 5 or 8 mile scales were the most useful. The most useful level of detail depended on where we were. Near restricted areas, MOAs, Class B, etc. higher levels were better. In the middle of nowhere, we could still locate our position easier by looking out the window and comparing that to the sectional than we could on the display. Over NM and AZ, ridges, peaks and valleys out the window are more easy to find on the sectional than on the display. We did not like that it changed to larger scale as we approached a waypoint and then went to a wide scale as we passed it.
The last column on the route screen displays a number of different parameters by pressing the right or left button. The ETE numbers were especially nice on the FCH to HND leg when fuel reserve numbers needed to be monitored. It is like having a Nav Log with several additional columns which gets updated completely to current status.
The altitude calculated by the GPS is nearly useless. During the trip, we noticed that it was always accurate on the ground, but seldom agreed with the altimeter in flight. This discrepancy sometimes exceeded 200’. After considering this for a while, I came to this conclusion. The GPS altitude is correct, but….. The altimeter altitude is what ATC uses and is based on the barometric pressure on the ground at their reporting station. This pressure may be different on the ground where you are and due to weather patterns, the decrease with altitude where you are may not be linear. We noticed that the discrepancy was greatest when we were higher AGL and the altimeter setting was changing with each new controller handoff. For these reasons, the only real use for the GPS altitude was to assure that you will clear the cumulo-granite ahead.
The Track memory held the entire trip (35 hours and 3100nm) and was only 84% full when we got home. The computer app allows lots of different looks at this data. Looking at ours, it is a better record of the trip than our old practice of keeping and annotating old nav logs. We got a chuckle out of our 360s to lose altitude at Wink and Buckeye and the figure 8 due to pattern confusion at Half Moon Bay. We also learned that it starts recording track points as soon as you activate the route. With taxi out and run-up, etc. this had a negative effect on our average speed. In the future, we won’t activate until cleared for takeoff. It appears to deactivate the route as soon as or shortly after displaying the “Arriving at destination” message.
The taxi and run-up track points were easy to delete on the computer, and doing that raised our average speed 2-5 knots per leg.
Conclusions…
If I am sitting in a room with people and a TV, my eyes will always keep going back to the TV. My only previous experience with a GPS found my eyes nearly locked on the display to the point that I lost all sense of where I really was. This was my greatest fear of a GPS. For this reason, we did not use the yoke mount. Instead, Sandra kept in her lap along with the sectionals.
Does it make you a better pilot? No. This tool has no bearing on piloting skill. If it promotes more head in the cockpit time, it can make you a worse pilot. Does it make you a safer pilot? A qualified no. As above, it has no bearing on piloting skill. It will not affect attitudes which have a bearing on safety other than to encourage an unsafe pilot to take even more chances beyond his/her skill level. It will add only confidence to your navigational skills. It will also warn you of terrain conflicts, airspace conflicts, etc..
Is it useful? Definitely yes, but with some conditions.
First, read the manual. Play with all the functions. Become at least aware of all the information that it will provide and how to access that information. We know some local pilots that won’t take off on their favorite hamburger run without it. But the only function they know how to use is Direct to. I have had at least one of these pilots lecture both of us many times at great length about how no one should fly without one. That attitude and usage level became one part of my resistance to getting a GPS. We could accomplish everything they did with a GPS by using a straightedge and marker on a sectional.
Second, do not let it replace preflight planning. I look forward to never filling out a nav log again. But I will still plan the legs completely, be aware of facilities and amenities at every stop and have the kneeboard and taxiway printouts for every airport I intend to stop at along the way (including probable alternates). The biggest advantage of GPS (if you are familiar with all of its functions), is that it allows you to alter and update your plans easily. Even in flight, where it will provide real time information that you previously had to calculate on the nav log.
Third, do not make it your sole method of navigation. We used it only as a backup for navigation and the real time provider of the information normally taken from the nav log. I found it simple to glance at the display periodically to see the ground speed, ETE to the next waypoint and if the little airplane was near and parallel to the course line. Position was easier to determine by comparing the view out the window with the sectional. All the GPS did for our navigation was give us a higher level of confidence and a lot more information.
Are we glad to have it? Yes.
These notes and comments are based on our currently limited experience. One test flight and one long trip; 35 hours, 3100nm, 13 legs to 13 new airports. Some of these opinions may change as we use it more.
