Dead Reckoning Tips/Tricks?

[bqmassey]

At this point, I can write up a pretty elaborate nav log. Flying it is another story. Things never go as planned. Now that I've taken my checkride, and can hone my skills where I see fit, I'd like to start working on something that I feel is more important, being able to make those calculations and decisions in the air... dead reckoning without prior planning.

Besides the obvious "what if all of your instruments fail" reason, there's a few reasons why I'd like to be good at this.

• Dead reckoning motivates me to fly more precisely.
• If I'm flying a simple airplane and I'm using a portable GPS, I don't want my range to be limited to how far I can get before the battery dies.
• If I decide to change my plans in the air, I don't want to feel obligated to stick to my navlog because I'm uncomfortable being off of it.

I read a post a while back (not here on PoA I don't think) someone wrote about flying a long cross-country (across several states) in an airplane that had little for instruments. I think he had a portable GPS packed away in case he got lost, but made the trip primarily with a sectional and flight computer. It sounded like he set off in the right direction, and just adapted to varying conditions as he went. I'd like to be comfortable enough in the air to do something like that. I think that I could probably make this happen right now, but I would have a very heavy dependence on pilotage and it wouldn't be very efficient.

Right now, it seems like a lot to manage in the cockpit. Having two hands on the whiz wheel (drawing wind dots and all that) just isn't practical.

So, I'd like to hear any tips, tactics, or strategies you folks may have for doing something like this. For instance, I've been reading about course corrections.

Here are a couple of mine:

• If I'm dead reckoning, whenever I have an exact fix on my location I make an x on my sectional and write the time next to it. If you're straight and level at a constant airspeed it's very easy to figure out where you should be based on your trail.
• I keep the whiz wheel part of the E6B on my lap and every checkpoint I "calibrate" the wheel based on the distance/time of the last leg so it gives you groundspeed, and can easily see the time required for any distance. Once you do it the first time, you only have to make minor adjustments to recalibrate the wheel each checkpoint you pass.

 

[bbchien]

Constantly adjust your next waypoint based on the expected time vs the real time it took to get to the one you just got to. After three waypoints you'll be VERY VERY precise.

We once had to do this off of C-nav (celestial Nav) fixes because there on no waypoints in the middle of the pacific. You get very good, very fast. Do it approximately, that's all it takes.

 

[murphey]

Stop worrying. Your method is great for tracking time & location is great. Until you're flying IFR, specific time at a specific location is not that important.

One of the advantages of VFR is that sectional. It really does look like what's out there on the ground. That, the compass and your watch, you can pretty well figure out where you are, how long it took to get there and how long to get to the next point.

I enjoy flight planning an XC trip. The fact that I rarely end up taking that route is irrelevant. Part of the planning is "what if?" so I'm always looking at options, just in case. And I rarely worry about arriving at a specific point at a specific time.

Carry extra batteries, you'll feel better.

 

[GCA319]

If you're in an area that is mostly flat and lacks prominent landmarks on the horizon to use as a reference, pick waypoints that are close together. Also, never be afraid to grab VOR cross radials to pinpoint your chart position if you're ever unsure.

 

[alfadog]

Pilotage with a bit of DR is my favorite way to fly. Here is how I do it:

• Plot the course on Skyvector.com and set up checkpoints every 30 minutes or so on the flightplan. Could be a road intersection or an airport off the left wing or whatever. Over the 'Glades, the landmarks are somewhat monotonous but they are there.
  
• Skyvector will give you course and time for each mini-leg. I print a one-page screencap from Skyvector.
  
• Go over to Google or VFRmap.com and see what the checkpoints look like from the air.
  
• When you fly just apply Kentucky windage (Google it) for the wind correction angle. That is all you need. If you like numbers, correct 3° for each 5% of groundspeed that you have crosswind component (e.g. 5 kt xwind and 100 kt gs, correct 3°, 12 kt xwind and 80 kt gs, correct 9° - yes, it is actually correct); don't forget to adjust groundspeed for head/tailwind component. But that is not necessary, just guesstimate and make corrections as needed at each checkpoint.

That is how I fly the Luscombe xc with nothing in it but a mag compass. Works like a charm. Of course I have the sectional open but I make all my notes on the printed sheet(s).

 

[GCA319]

Imo, you'd be crazy not to back up DR with pilotage. Not only is there the potential to get lost, but you have to think about airspace violations and other factors. I think Alfadog has the right idea. The only thing I would do differently is to pick checkpoints closer together until you get the hang of it.

 

[rottydaddy]

Imo, you'd be crazy not to back up DR with pilotage. Not only is there the potential to get lost, but you have to think about airspace violations and other factors. I think Alfadog has the right idea. The only thing I would do differently is to pick checkpoints closer together until you get the hang of it.

Amen. DR alone is only an option when you can't see stuff on the ground. Pilotage is OK without DR, but obviously your track and fuel management will suffer. Together, they are all you need, assuming you have a compass,clock, chart, and a flight computer (or killer math skills).
I agree also about shorter segments between waypoints...that helps. You can also use your tools to plot your position or check your average groundspeed with any old waypoints you see, without writing it in the nav log. That habit will help you make the most of using longer segments later, because the essence of navigation is being able to determine your position at any time. Period. It's Step 1, before making any decisions based on fuel, weather, wind, or whatever. It's possible to fly for hours with adequate precision without any nav log at all- just compass, clock, chart (with no lines drawn on it), whiz wheel and maybe a notepad. But the log is a great planning tool, and trying to adhere to it is good foundation-building stuff.

I like the other tip about VORs: I have always used them first and foremost for plotting position, not homing or following airways. Need to cross a wiggly river with no bridge near your course line? Figure out (before you fly, if possible) what radial, if any, crosses the river at your intended crossing point. Need to change course over some little lake that is one of dozens in the area? Pick one that lies on a radial. If you have two VORs with intersecting radials, you've got it made, assuming you are receiving them well. DME can also be a huge help.

Regarding changes or errors: I still have some old nav logs that show where I realized I had pre-planned the wrong distance or whatever, had to divert, or simply failed to spot some intended waypoint. Messed up my beautiful logs, but it all worked out in the end. As Dr. Bruce points out, you just keep checking. You can "reset" that nav log at any point; all you need is to note time of passage over two things you can find on the chart, measure the distance between, etc. It's nothing to worry about. The only serious concern is time since takeoff, as relates to fuel endurance.

 

[bobmrg]

Forget about the GPS. Draw your desired flight path on the sectional beginning at an easily-recognized landmark close to the departure airport. Take off and fly to that landmark, then keep your finger on the line on the chart. When your finger reaches your destination, land.

Bob Gardner

 

[JHW]

in the midwest it's gotten to where you can pretty much fly visually day or night from one windmill farm to the next with no other references.

 

[MCHawk]

Even though I have gps as a backup, pilotage (plus/minus dr) while marking off checkpoints and times on my vfr nav log remains my favorite way to fly cross-country.

You might like www.fltplan.com (don't need to register) Enter a vfr plan, choose "sectional" and then "imagery." your flight path will be plotted on satellite imagery so you can download photos of your checkpoints if you want! (bridges, tank farms, whatever). Also good to see what the destination airport (and it's markings) actually look like.

On the nav log I made, the last column is a +/- (over/under) in minutes compared to each checkpoint's estimated time enroute. This gives me a running total of the flight's progress so I can get a better overall feel of when I'll reach the final destination.

 

[livitup]

Forget about the GPS. Draw your desired flight path on the sectional beginning at an easily-recognized landmark close to the departure airport. Take off and fly to that landmark, then keep your finger on the line on the chart. When your finger reaches your destination, land.

Get some purple nail polish and apply to your pointer finger before flight. Then you can follow the "Magenta Finger of Death".

 

[somorris]

I always like to draw my course line on the sectional, then mark off the course in 10 nm segments with a "Z" bar, with the distance flown on the Z pointing back the way I came and the distance to go on the other leg. I keep my finger on the chart while flying.

 

[bqmassey]

I haven't gotten a chance to fly an airplane lately, but those are some great tips that I'll try out when I get up again. Thanks!

I've done further reading on course corrections, and I really think I'll try to use that in the air. Basically, you find your opening angle, the amount that you are off-track, measured in degrees from your departure point. Then find your closing angle, how far you are off-track in degrees measured from your destination. Add them together and that's the heading change you have to make to arrive at your destination. If you wait to look until you're exactly halfway between checkpoints, the angles will be the same—you calculate one angle and just double it.

There are a few ways to determine your opening and closing angles.

• One is to draw guide lines on your map ahead of time (5 and/or 10 degrees left and right of your desired track, measured from both departure and destination checkpoints). After a bit of flying, you can look at your position on the chart and approximate the angles.
• Another is the 1:60 rule. (explained here). It's relatively easy mental math. The math can also be done on non-wind side of an E6B or CR flight computer.
• A third way is to use the wind side of a CR-2. Set the TAS index marker to the miles flown, find the miles off track on the outside scale, and read the corresponding angle on the inside scale. That's your opening angle. (Repeat with miles remaining, to find closing angle).

All three are quick and easy. The first requires pre-planning. The second is an approximation. The third, I believe, is the most accurate.

As has been mentioned above, GS/ETE can be adjusted for on-the-fly.

Essentially, this is a slightly refined version of Kentucky windage. If you want to take it a step further, you can back-calculate to finds winds aloft (TAS and heading vs GS and track) and use that to calculate WCA and GS for upcoming legs. That's probably only worth it if there is an upcoming turn in your planned path.

If anyone wants to see the three methods worked out, I could probably put a video on YouTube.

I'd like to try out pressure pattern navigation (Bellamy Drift) sometime too, but I don't think I fly far or fast enough for it to be helpful.

 

[Captain]

Here's a saying that applies here:

Measure with a micrometer,
Mark it with a brush,
Chop it with an ax.

Being single pilot in flight is WAY past micrometer stage.

 

[Capt. Geoffrey Thorpe]

I read a post a while back (not here on PoA I don't think) someone wrote about flying a long cross-country (across several states) in an airplane that had little for instruments. I think he had a portable GPS packed away in case he got lost, but made the trip primarily with a sectional and flight computer.

Wasn't me.

When we flew from Detroit to Alaska GPS hadn't been invented.

We did use the original form of digitial moving map technology. A finger on the chart.

Writing the time you cross roads, lakes, whatever on the chart as you go by helps a lot.

Pointing the airplane so that it goes in the direction of whatever it is coming up next is easier than dinking around with an E6-B.

 

[nosehair]

Pilotage. Practice more pilotage. That's how you're going to end up getting there anyway. After all the computations, you still hafta look at the ground to see if your proposed track is working, and adjusting.

Forget computations for a bit, to practice exclusively on flying the sectional terrain. Rivers, valleys, ridgelines, forest lines, railroads, etc, Fly low. Not above 3000. Probably somewhere around 2500. To focus on ground references. When you are comfortable knowing you can just fly the chart with rough compass headings, like north by north west, and such, the anxiety of those compass computed headings will dissipate.

 

[ClimbnSink]

Bacon Savors. Pick stuff you can't miss seeing or will see if you miss seeing that you expected. Oceans work great, large highways, rivers, etc. Then don't sweat the little stuff you'll get somewhere. Depending on where you live you can just fly from bacon saver to bacon saver, no planning, no compass, no time checks(except for fuel management.)

 

[Jaybird180]

Pointing the airplane so that it goes in the direction of whatever it is coming up next is easier than dinking around with an E6-B.

well said sir.

 

[dell30rb]

I did 360nm in the cub this weekend (TTA-W75 round trip)

What I realized is that with 12 gallons of fuel in a 70kt plane that burns 5gph, you don't have enough fuel to get lost.

 

[jesse]

I did 360nm in the cub this weekend (TTA-W75 round trip)

What I realized is that with 12 gallons of fuel in a 70kt plane that burns 5gph, you don't have enough fuel to get lost.

It can be like that in the Flybaby and I've got 16 gallons. What *sounds* like a lot of fuel remaining turns out isn't that far on the sectional. One has to be careful as to avoid being stranded on a long cross-country. I always try and plan for the first airport I'm landing at being out of fuel (have seen that happen too many times now).

 

[e.pie]

Pilotage. Practice more pilotage. That's how you're going to end up getting there anyway. After all the computations, you still hafta look at the ground to see if your proposed track is working, and adjusting.

Forget computations for a bit, to practice exclusively on flying the sectional terrain. Rivers, valleys, ridgelines, forest lines, railroads, etc, Fly low. Not above 3000. Probably somewhere around 2500. To focus on ground references. When you are comfortable knowing you can just fly the chart with rough compass headings, like north by north west, and such, the anxiety of those compass computed headings will dissipate.

I'm going to have to remember this.

I've reached the solo XC portion of my PPL training and feel a bit overwhelmed at times when things aren't matching up as well as they should be to my calculations, especially the compass headings.

I still made it to all of my destinations no problem though, and within about a gallon or so of my computed fuel, so I guess I shouldn't worry too much.

 

[tonycondon]

i once flew what is now Jesse's Flybaby from Ames, IA to the Beaumont Hotel in Kansas for lunch. I almost made it back in the same day. It was in November so the day was short. The trip involved a lot of relatively low altitude cruising, 1000-1500 AGL, mostly dead reckoning and pilotage whenever i happened across an identifiable waypoint. It was a lot of fun, i had no navigation instruments of any kind except a compass and a map. I managed to avoid the Kansas City Class B and make it across the featureless Kansas Flint Hills.

i kept a detailed log of waypoints, distance between, distance remaining and calculated groundspeed. As Jesse mentions, the fuel tank isn't too big and I had to stop short on one leg to fill up as I was going to slow to make it to the planned destination. It was a lot of fun

 

[bqmassey]

Pointing the airplane so that it goes in the direction of whatever it is coming up next is easier than dinking around with an E6-B.

If the uppers are moving and you don't have a unique landmark for 30 miles, it might not be as clear where your nose should go.

Being single pilot in flight is WAY past micrometer stage.

Personally, I don't think aerial navigation is "micrometer" stuff. The course-correction technique I'm talking about is very simple. It's far less work than some of the mental gymnastics involved in single-pilot IFR.

Forget computations for a bit, to practice exclusively on flying the sectional terrain. Rivers, valleys, ridgelines, forest lines, railroads, etc, Fly low.

Yea, that's a great way to get around. Straying off the path, following roads and rivers or zig-zagging between landmarks so you always have something recognizable in sight are fun ways to burn some avgas, but my goal is a little bit different. I'd like to be proficient at flying direct to, or nearly so, without relying on electronics.

I'm not trying to replace pilotage, or replace radio navigation, just trying to add to my bag of tricks.

 

[jesse]

FWIW Brandon -- I've found that I do very well with nothing but a sectional and my head, no DG or compass needed. Trying to run actual calculations on paper isn't something I mess with outside of the training environment. I just don't get much value out of the numbers produced compared to spending that time focusing outside the airplane and coming up with such values in my head.

I've flown hundreds of miles without even looking at a map or sectional. Just going off of what I *remember* being on the sectional when I looked earlier that day.

Looking out the window is key. Learning how to do that effectively is what is going to give you the most gain and the biggest confidence booster.

 

[Jaybird180]

FWIW Brandon -- I've found that I do very well with nothing but a sectional and my head, no DG or compass needed. Trying to run actual calculations on paper isn't something I mess with outside of the training environment. I just don't get much value out of the numbers produced compared to spending that time focusing outside the airplane and coming up with such values in my head.

I've flown hundreds of miles without even looking at a map or sectional. Just going off of what I *remember* being on the sectional when I looked earlier that day.

Looking out the window is key. Learning how to do that effectively is what is going to give you the most gain and the biggest confidence booster.

I found that inspirational. Thank you Jesse.

 

[jnmeade]

A couple of things about sectional - they can be region and topography related.
In the midwest, west of the Mississippi, where the English survey method was used, most roads are on 1 mile section lines. Towns are, too. You get 3-4 towns in every direction you look and you don't know where you are.
Rivers don't look the same from the air as on the sectional unless they are very large. For one thing, some are lined with trees that tend to camouflage the river shape. Lakes change shape dependent on how full they are. That high tension line on the sectional doesn't even show up on the ground unless it goes through a forest.
What you want on sectionals are feature that are unique in shape and location so you are sure to identify them correctly and not confuse them with another feature that looks similar. There are plenty out there.
Just remember, don't try to make the feature on the ground look like you want or think it should look. You try to make sure you are looking in your mind's eye for what is actually there.

 

[MAKG1]

Looking out the window is key. Learning how to do that effectively is what is going to give you the most gain and the biggest confidence booster.

There is quite a bit to that.

At least in VFR conditions and with lots of fuel.

I have quite high confidence that I can get myself home under such conditions with a dead panel and a sectional out the window. This gives me enough confidence to range afar -- with lots of fuel.

Having said that, the precision ded reckoning described here also has some benefits. I've never done it to that level of precision -- mainly, I've done it for fuel management. It will make an interesting exercise to try a cross-country by ded reckoning alone, until nearly at the terminal environment. Of course, in simple airspace (not hard to find).

 

[bqmassey]

That sounds likes a fun way to fly, Jesse. Kind of like getting on the bike in no hurry to get to where you're going, figuring out the route as you go. That's something I used to do often when I was riding regularly.

Jim: That reminds me of a solo flights I made as a student. I wanted to go check out a nearby coastal town. I hadn't flown that way with my instructor often enough to know it well, but it was about the farthest I could get without leaving the 25nm radius I was restricted to. I got lost really quickly. The tide was in and had turned the whole area into one big marsh. All of the river boundaries marked on the sectional were gone. Nothing looked like the sectional. I made a turn towards the Atlantic, figuring I couldn't miss it, and flew up the coastline once I got there. I took the long way back, following roads.

I think I gave off the wrong impression with this thread. It may seem like I'm trying to achieve ultimate dead reckoning accuracy, without regard to how complicated or time-consuming it may be. That's not my goal at all. My goal is rather to learn any techniques or strategies to make it simpler and less time consuming, while still maintaining accuracy sufficient enough to not get lost if there are no good checkpoints for a while.

So, the method I've mentioned above, the course correction method, is about the best I can find. It doesn't require accurate planning from the get go, it's a way to adjust for your inaccuracy. This is how easy it is:

1. "Oh look! There's my checkpoint, it was a 20 mile leg and I'm 3 miles left."
2. "In 60 miles, that would be 9 miles left, so it's a 9 degree error."
3. Turn right 9 degrees, "Now I'm flying the correct true course."
4. Turn right 9 degrees again, "I'll be back on the planned course in another 20 miles".

It's that simple, no flight computer or written math required (but can be used if you're not good at mental math). It's just educated Kentucky windage.

I think that technique, coupled with marking position/time fixes on the map (a breadcrumb trail), would provide a pretty reasonable compromise between accuracy and simplicity.

Alternately, if you have enough landmarks to get frequent fixes for your breadcrumb trail, you could probably hone your heading simply by looking at where the points are leading.