Why GPS will Never Replace Maps
My dad and I were flying from Fort Worth to Port Arthur (Jefferson County Airport) after visiting his family. He had a ‘high performance’ Grumman Cheetah at the time. He had a faily complete navigation setup, but had not completed IFR work so couldn’t fly through clouds or at night. He also had an early GPS that was about the size of a hardback book that he strapped to his leg and showed the position of the airplane and a map of the local area.
So we’re flying along and I’m trying real hard not to be seasick. There are a lot of heavy storm clouds and dad is busy flying around them. Can’t go through… no IFR ticket. I glance down at the instruments on my side of the plane (to keep from looking at the horizon as dad does about a 20 degree bank) and notice something.
“Dad,” I say. “Is this gauge supposed to be at zero?” My dad leans over, gets a strange look on his face, and starts turning things in the airplane off. The gauge was the alternator and it was at zero.
I said, “At least we have the GPS…” as Dad turns it off. “I didn’t charge the battery,” he says, unplugging it from the plane. “Kev, you know how to navigate?”
“Sure,” I reply. He hands me a paper map, a pencil, a drafting compass, a ruler, and shows me how to work the VOR.
Basically, almost every airport and several spots not around airports have an omnidirectional transmitter that operates on a ver specific frequency. It doesn’t ‘say’ anything, just the signal. However, there is a device in every aircraft that, when tuned to the frequency of a particular VOR will point an arrow in the direction of the signal.
So what I did was
- find two VOR transmitters on the map.
- Tune the gauge in the airplane to the first.
- remember the directional reading
- On, the map, I drew a line from the transmitter along that direction
- Repeat for VOR number two
- where the two lines cross is our current location (or close enough)
- Draw a line from our current location to our destination.
- Copy that line to the nearest compass rose
- read off the heading to dad who would
- steer that direction
Of course, it was an estimate because the plane was constantly moving… and dad was dodging thunderheads and looking for clear sky to fly us through. So I had to repeat this every 20 minutes or so for the rest of the trip… at least until we got to highway 69 and could follow that to the airport.
So kids, learn to use your brains and paper instead of toys. You might need it someday.