Editorial April, 2014 - Navigation Methods Revisited
What do I do in my otherwise idle moments? Aviation of course. Practicing getting from one place to another with precision and certainty, and in style.
Navigation; the business of not getting lost... Imagine you're driving a long distance to a destination that's hard to find, no map to guide you, no watch to know how long since you left, or how long to arrive, no roads at all (let alone no signs on roads or highways to direct you), and of course no GPS.
How would you go? How would you know if you're going the right way? How would you know if you past it already?
Well it's no different in the air, and gets much worse at altitude and at night with varying terrain altitudes, winds, and weather conditions. So there are several methods of navigating (air, land or sea), and it's best to know and use ALL OF THEM.
So how do I get where I'm going? Here's the list:
- Celestial Navigation
By the sun, or moon, etc. To calculate the exact position of a heavenly body (star, planet, moon, sun) in the sky at any given time. Then from knowing the position of the star in the sky, the measure of the angle between the horizon of the observer and the star is enough to determine the observer position in latitude and longitude. Oversimplified, you might be surprised how handy it is to simply follow the sun or moon (if visually available).
Follow yourself along by what you see on the ground, and also compare that to the map. The use of topographic fixed visual reference on the ground by means of sight to guide oneself to a destination, often with the help of the aeronautical charts. What do I see? Is what I see on my path? What does the map show? Am I where I should be? Topography helps greatly here as one tracks the position and passing of roads, cities, structures, railroad tracks, rivers, lakes, hills, mountains, etc. all being the detailed layout of the surface features of land, in reference to the intended course to the destination.
- Compass & Dead Reckoning
Use both direction and time, also compensating for wind. The process of calculating one's current position by using a previously determined position, or fix, and advancing that position based upon known or estimated speeds over elapsed time and course. So many minutes in that direction takes me to my destination.
Non-Directional Beacon / Automatic Direction Finder. The NDB on the ground transmits on a certain frequency, and the ADF in the plane (once tuned in to that frequency), the pointer always points to the NDB. Thus, the from the angle degree reading on the ADF compass rose display, the relationship of the aircraft to the station can be calculated. The “Magnetic Bearing to the station” (MB), is determined by the Relative Bearing (RB) which is the reading of the ADF DIAL, and the Magnetic Heading (MH) of the aircraft. This relationship is given by the equation; MB (to the station) = RB + MH. So if I'm heading north, and the NDB is to my right (east), then the MB is 90 degrees (90RB + 0MH = 90MB). Being decommissioned in most areas.
Similar to NDB, but directional and most often distance measurable. VOR (very-high-frequency omnidirectional radio) on the ground transmits on a certain frequency, and on each radial of the 360 compass. So the receiver in the plane (once tuned in), can tell exactly what is the angle to the station by the station frequency and the radial. By my intended course, I'm not necessarily heading TO the VOR, but I know where I am in relation to it. If I'm on the 270 degree radial FROM the VOR, I know I'm just west of it. Further, if equipped with DME (distance measuring equipment) I can read just how far I am from that VOR. If tuned and read correctly, this really takes the guess work right out of knowing my location at any given time. Even better, by tuning 2 separate VOR stations simultaneously, I can navigate to an intersection anywhere with precision.
GPS (Global Positioning System) is a satellite navigation system that provides location and time information in all weather conditions, anywhere on or near the Earth where there is an unobstructed line of sight to four or more GPS satellites. Among many available functions, the GPS is by far the most handy way to get where I want to go. Most have a built-in database of all airports (and most essential airport info), VOR stations, and either a moving map, and/or a course indicator to let you know if you drift off course. I select a certain airport destination, and the GPS unit tells me where I need to go, how long it will take to get there, and updates itself as you progress. Seems the best of all navigation methods, of course.
- GPS Coordinates
Under the GPS system is the "grid" the Earth is divided into, and GPS is based on. The coordinates are the location X and Y points on the map of Earth; meaning the description of a precise geographic location on Earth, expressed in latitude (north or south of the equator being 0 degrees), and longitude (east and west of Greenwich England being 0 degrees). Example; Empire State Building, New York is expressed as N40° 44, W-73° 59, where the first number indicating latitude (40 degrees north of the equator), and the second number representing longitude (70 degrees west of England---the minus sign indicates "west"). Thus using any GPS receiver you can measure your exact position anywhere on Earth. I use this method for hard-to-find places not identifiable as an airport, beacon, or readily visible as a topographic landmark (middle of the desert or mountains, etc). So it's very handy to simply track your progress, so much north by so much west, etc. to arrive at a destination.
However, putting it all together; using ALL navigation methods at same time is prudent, and serves as backup system should any one system fail for any reason. Cloudy day, can't readily see the angle of the sun. Above the clouds, can't see the land. Miss the timing of that leg, can't estimate the arrival of the waypoint. Electrical failure leaves one without ADF, VOR or GPS, can't rely on any of those to guide. Now what?
And it's all the more difficult and important at night, where entire vast areas are simply black with no hint as to altitude above ground, hills, or surface conditions should a forced landing be necessary.
L35 Big Bear - Airport Wishlist Item
There are quite a few airports I would like to put on my Logbook, and here's one of them, L35 Big Bear, CA.
I find in aviation, mostly the journey is more important than the destination and very often getting there is way more fun than being there.
But not with Bi Bear; Elevation 6750ft, edge of a beautiful lake, surrounded by forest covered mountains, fresh cool air, plenty snow in the winter... oh yeah, this is the life.
Although I've been there many many times, I'm thinking of flying in for once. Fly in one Xmas and rent a nice cabin with a fireplace and good view. Have a big breakfast, and off to the slopes for some skiing. Back to enjoy a warm fire and cozy cabin relaxation. In summer I'd go off to the mountain trails for a day of hiking in the forest, and some kayaking on the lake. Squirrels there all year round to keep me company, I love to embrace the sights and sounds of the pine-tree forest anytime of year.