AOPA Turbine Pilot Magazine - April 2020 - 20

WAYPOINTS

Cleared direct

BY THOMAS B. HAINES
Editor in Chief

Not always welcome news

Editor in Chief
TOM HAINES still
tunes in VORs
along the route as a
matter of practice.

20 | AOPA PILOT April 2020

THE HANDOFF from St. Louis Approach to Kansas City
Center was routine. And then, the controller sent a shock
through my headset: "Cleared direct to destination."
Eyes open wide, I stared at the Bendix/King KNS 80
in the center of the stack. Now what do I do? I asked myself
as the 1984 Beechcraft Bonanza A36 continued trucking
eastbound toward Frederick, Maryland, some 600 nautical miles away. I had filed the IFR flight plan with the
description code of "slant R." Today that code has a complex meaning, but in the early 1990s it told ATC that you
had area navigation (RNAV) equipment that allowed you
to fly to any point in space. Few light general aviation airplanes had that capability then and it was a bragging point
to have such gear. But the truth of it was that flying direct
in the days of VOR/DME was complicated.
I acknowledged the clearance, gulped, and then
grabbed the instrument chart on the seat next to me.
I was already navigating to a VOR along my route, but
the filed route had me zig-zagging from station to station toward Frederick. The controller now expected
me to fly a direct route for nearly 600 miles-well
beyond the range of any VOR. Not wanting to disappoint, I went to work, mindful of the head-down task
ahead and thankful for a quality autopilot.
The trick was to draw a line on the paper chart (you
remember those, right?) from your current position to
your destination. On a long leg like this one, you might
have charts spread across the cockpit-trying to draw a
line that crossed from one to the other. Next you would
choose VOR/DME stations along the route and, using a
plotter, choose a radial that intersected with your handdrawn route. And then measure the distance from the
station to the line. Pencil the radial/distance next to the
newly created waypoint and move on to the next one.
With that accomplished you'd then turn to the box-
in this case the KNS 80, but there were others. Narco, for
example, also had an RNAV system. The KNS 80 could
store up to four waypoints. You would carefully select the
frequency of the VOR/DME you were using, then enter
the radial and the distance. Double-check them all to
make sure you don't go heading off into the hinterlands.
With that, the RNAV computer would create a waypoint on that radial at the selected distance. As we used
to say, you were essentially moving a VOR/DME to a new
location along the route and then navigating to it. Once
reaching that first station, you could then choose the second waypoint already stored and then begin calculating

and storing the fifth waypoint along the course in the
now-behind-you number one memory slot.
You can imagine the head-down time-and this
at a time when almost no light airplanes had traffic
awareness systems and no one had terrain warning systems-and most light airplanes either had no autopilots
or, if they did, they were rather rudimentary.
And while ATC was expecting you to fly a great circle route, you were not, since that's difficult to draw on
a paper chart. Still, no one seemed to notice or care.
Technology eventually removed some of the tediousness from the process. A couple of companies came out
with handheld RNAV flight computers that contained
the coordinates for every VOR/DME station. You could
enter your starting and ending points and the computer
would give you list of stations and radial/distances to
create a true great circle route between the points. It all
worked great, as long as the batteries didn't die.
The FAA even created RNAV approaches, which
electronically placed a phantom VOR/DME station at
the runway end. The FAA would provide the radial/
distance points on the approach chart along with vertical navigation guidance.
The FAA's flight test program assured that signal
strength was good for the approach waypoints, but out
in the wild, you were on your own to make sure you
were high enough and the station near enough to provide a quality position.
I've always remembered that flight from St. Louis as
the longest RNAV route I had flown at the time. Some airplanes by then had loran receivers; with their waypoint
databases, they made flying long distances easier-if not
technically legal for IFR purposes. We, of course, backed
up our loran route with legal VOR/DME tracking (wink,
wink). IFR loran was briefly a thing, but GPS came crashing onto the scene and by 1994 we were flying IFR GPS
approaches, also referred to as RNAV approaches. The
Wide Area Augmentation System (WAAS) soon came
online and we were quickly flying LPV approaches to
ILS-like minimums to thousands of additional runways.
Now, "direct to" makes us children of the magenta
line, taking all the tedium out of long legs and, to a certain extent, infusing an element of boredom into the flight.
Still, though, on legs I'm flying from Point A to Point B, I'm
not looking for adventure. Bring on the boredom. AOPA
EMAIL thomas.haines@aopa.org

AOPA Turbine Pilot Magazine - April 2020

Table of Contents for the Digital Edition of AOPA Turbine Pilot Magazine - April 2020