Clock to Map to Ground, or why flying does not need to be boring…

What makes flying dull and boring? How is it possible that an activity that has been making people dream for many centuries, after only a few years becomes a routine that we merely do because it has become a habit, or to make a living, or both? Flying left us breathless when we had our first chance to actually fly away, high above the ground… people like ants, cars like toys. Long distances shrink to a time span that feels like only a few minutes…Wow!

Today the constant noise of the engine and the surface slowly drifting beneath seems to only trigger our yawning reflex. We use the GPS to keep a constant ground track and circumnavigate some airspaces precisely with only half a mile distance, while we watch the time on the clock approach the ETA… I start yawning by just writing this. Because of this lack of excitement, we pilots often start new games. We buy expensive toys like glasscockpits, Autopilots and whatever else is being brought to our attention by the advertisers in the GA magazines. These gadgets fascinate us for some time, until we have learned how to use them and got used to them. Then, the yawning reflex sets in again, this time even stronger. Do we need more gadgets again? 

I have spent quite some time in the cockpit of a small vintage single engine airplane, a Jodel 1050 Ambassadeur. Jola, my former wife, and I have flown it on long distances and to remote places quite often, which was most of the time very challenging and interesting. Especially the planning of the logistics and the performance are interesting when conducting long range flights in a plane that has very limited payload and engine power. But enroute, even during those flights that we still consider the greatest adventures of our aviation careers, we felt the onset of… boredom! Yes, our plane is equipped with a GPS. A coincidence?

Last week on a return flight back home from work, I had an idea. Instead of simply droning along for a few hours, I decided to revert to the old style navigation again. The basics of this art are still very present from the time of my military jet pilot training in the USA. I went through a very intense training course, commonly referred to as ENJJPT. There we learned to fly „Clock to Map to Ground“, and this method, together with exact preflight planning and a few simple formulas, enabled us to locate single houses, tiny bridges over the smallest creeks, and water towers in the desert-like landscape of northern Texas. We navigated so precisely with only a stop watch and a gyro compass, that we could overfly our target point within a few seconds, even after half an hour of low level navigation at 360 knots in 500 feet. This has really impressed me much and until this day I keep these skills like a treasure in my bag of tricks. 

Since I can not recall any signs of boredom on these low level navigation missions, I felt that putting myself to work on a simple routine VFR flight could be a good way to re- connect with the fascination of aviation. After all, I would have to actively work with the outside world, looking for landmarks, comparing them with my map, and actively making decisions based on my findings. 

So I marked my present position, together with the time and my present heading, on the map, and then I switched off the GPS. Of course, there are always reasons to leave it on, for example in case one needs to quickly and precisely divert to the nearest airfield, but considering that it only takes 30 seconds to re-acquire position, it was an acceptable risk for me. 

I always have a ruler and other plotting tools with me, so the first challenge was to find them and put them to work while precisely maintaining heading, altitude and lookout for traffic. 

From my present position I quickly drew a course line on my map. (should it not already be on there anyway?? Then, with my estimated ground speed, I plotted an estimated position for the time 10 minutes after the last known fix. I used 96 knots which is 1,6 NM per minute and 16 NM in 10 minutes. 

Then, at the time for the estimated position I compared my actual position by using landmarks and plotted it into the map together with the exact time. It was approximately two miles off course and also short of the expected distance. 

Using the 1:60 rule I computed the new heading that would be required to find myself back on course at the next 10 minute checkpoint: 

2NM off x 60 / 15 NM flown = 8 degrees (!) error in track. So I corrected 8 degrees to fly parallel and another 8 degrees to return to the desired course within 10 minutes. It is really important to keep the directional gyro aligned, and fly the determined heading as precisely as possible, since the resulting position will be base for the next heading correction. Surely, some of the drift was due to my inattention to the heading, and the drift of the gyro. But most of it was due to the increasing wind further north, which I would not have noted much, had I just followed the magenta line of the GPS.

The next check point was hidden beneath a solid cloud layer, so I started working out the fixes with the VOR, using crossing radials. I have a little round navigation plotter that really helps to plot radials precisely onto the aviation map. With these fixes I could then estimate drift and my current ground speed. I improvised a small log on my scratch paper with the time, the heading, the resulting track and ground speed. Then I had a base for my decisions, which heading to fly in order to stay on track, and which ground speed to estimate. Since I have no DME on board, when fixes with crossing radials were not possible due to the geometry, I used another nice formula that helps determine the distance from the station when passing abeam a Nav Aid: Estimated Groundspeed / degrees bearing change x the minutes duration of the measurement. Example: I fly estimated 100 kts GS and cross 10 radials in 30 seconds. 100 / 10 x 0,5 minutes = 5 NM Distance to the VOR. No rocket science, but it brings me into the ballpark again.

Real professional navigators might shake their heads at such an improvised way of working, but… hey, I have no Autopilot, no plotting table, have other duties to do as well (like maintaining! the! Heading!!!, scanning the airspace for other traffic, and selecting the correct fuel tank) and as long as I stay within a few miles of my estimated position, so what. 

When I arrived near my home airfield, I felt really refreshed from the busy work on board, and I felt much more connected with the world around me. I already had a good impression of the wind that was blowing strong from the west, and the drift angle over the ground that I would expect when flying beneath the clouds again. I identified small towns that I would have normally simply passed over, and used them as distance marker for my calculated top of descend. I had the feeling that I earned this flight, instead of simply consuming it. 

And it was not at all boring from the minute I turned off the GPS.

When flying with students on the PC12 NG with the highly sophisticated FMS, I always emphasize the fact that this Navigation device is only as good as the GPS position that it receives. Most of the time it is extremely precise, but I hope that you agree that it makes little sense to trust your life on a single piece of equipment for any considerable amount of time. On the one hand, we pay so much money for more safety… we invest in a second engine or upgrade to a turbine engine, install synthetic vision systems, traffic warning devices and much more, but then we simply trust the satellite navigation on a regular basis as if it has never failed before… No way! So on many training flights I make it a point to enforce the use conventional navigation systems by deselect the GPS receivers, simulating a failure. Spoofing can also be simulated by creating a false position update, which, when looking at the moving map, is really an eye opener. Most of us who have ever seen a VOR needle pointing left and the moving map showing the VOR on the right side, always keep their VORs and NDB tuned to some sensible station during normal operation, just to have a mode to crosscheck. For a sudden loss of GPS capability in IMC in the mountains, while synthetic vision will be unusable and the moving map can quickly shift with increasing positional uncertainty, the weather radar can help finding the way through the valleys until arriving at a safe altitude or finding a confirmed position again. This, of course, I will not simulate in real life training.

So, thinking about basic navigation can be more than just keeping us awake during flights. It can create redundancy and enhance our situational awareness, and even save our lives one day.

Be careful up there!

Christian