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Old 17th Jul 2003, 21:27   #1 (permalink)
 
Join Date: Jul 2003
Location: Sydney
Posts: 5
Map reading techniques.. what do you use and does it work?

Hi ppruners..

Currently training for my PPL, I am reading into my navigation theory (Dyson-Holland) and about different techniques used for when plotting on the WAC/VNC for easier inflight navigation. Things such as the track error guides, distance/feature/proportion or time markers, time boxes etc.

Of course, all of these are used depending on the pilot's personal tastes and I wanted to put it to you guys with experience, what would you normally plot on your route to assist navigation and which do you find helps most..

Currently, we are taught to simply plot our track with time markers of 6 minute length, (yet Dyson-Holland discredits the use of time markers), and also plotting feature/distance markers as necessary.

Apprieciating any input..
tobago boy is offline  
Old 17th Jul 2003, 22:21   #2 (permalink)
 
Join Date: Feb 2001
Location: near the hangar , australia
Age: 46
Posts: 33
navigation

the only thing i can help you with is i was tought to use 10 mile markers on my wac charts as they dont change if your gs picks up or slows down ( after a gs check you use your wis wheel to work out the ete for 10 miles. i learnt to fly in a 172 6mins to ten miles then flew a baron 3mins to 10 miles , no need to change the map marking , at worst go to 20 mile markers , MILE MARKERS DONT CHANGE WITH SPEED
enginair is offline  
Old 17th Jul 2003, 23:29   #3 (permalink)
 
Join Date: Jan 2001
Location: Springfield, USA
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Tobago boy

At 2nm/min, 10 mile markers will work on any visual chart.

The trick that I've found is to keep it simple (for my lazy brain), but to have enough info/guides on my chart to stay ahead of the a/c.

Track M, 10nm markers, 1/2 or 1/3 way marker (proportional nav for updating ETI/ETA), and where a frequency boundary crosses my track. Plot time as part of your workcycle after a +ve fix.

Clock-Map-Ground-Next Event, not Ground-Map-Ground-Map-Scratch head-GPS.

Do 1 in 60s. They do become easy with time.

Almost sent myself to sleep .

Hope this helps
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Old 18th Jul 2003, 09:12   #4 (permalink)

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tobago boy,

It's been a long time since I instructed at ab-initio level but here goes.

The method I was taught as a student pilot and used as an instructor was to mark the track on the WAC with 6 minute markers (a similar concept to 10 nm markers).

Say you pass a feature at your 12minute marker in 10 mins, then you're faster than planned by 1 minute per marker. 10 markers to go to destination, therefore ETA 12 mins early.


For distance measurement, place your thumb reasonably firmly on the Lattitude marks on a WAC chart and determine the width of said thumb in nm. Then when calculating 1:60 your thumb becomes an easy measure of distance. For one thing, it should be easily found on your hand, rather than having to hunt out a rule.

1:60 works, practice it until proficient at completing the calculations in your head.

The more preparation you can do on the ground the more you can enjoy the view on the flight and usually, the lighter the cockpit workload.

When map reading, read from map to ground. To do it the otherway, you'll almost certainly convince yourself that you are somewhere, when you are not. One then becomes geographically embarrased.

Again when map reading, don't try to find every feature on the map to the point wher little attention is spent on flying because most of it's on the map. Look at the map, decide on a feature on or near track that you should be able to see relatively easily. Identify that feature, and fly to / abeam it.

Above all, work hard and enjoy!!
Capt Claret is offline  
Old 18th Jul 2003, 09:19   #5 (permalink)
 
Join Date: Mar 2000
Location: North son, I say go North..........
Posts: 599
Hows it go?

Big Natural features first rivers, mountains, lakes, black soil planes...
Big Man made features second, towns, towers, lakes, bores, roads, railways.

Speaking of WAC's when will the WAC's be changed to indicate the new railway Alice to Darwin... Don't need to follow the road anymore can go pure IFR, I follow Railways...
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Old 18th Jul 2003, 10:32   #6 (permalink)
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Hit direct go to..................................


No only Kidding..

Well first off make sure your WAC is amended, make sure you have all the VEC, VTCs and PCA Charts current.

Draw you track and work out you time intervals dependant on winds etc, after getting an upto date forcast.

Actual map reading in an aircaft is the reverse of what it says. Dont look at the map and then look outside to interpret where you are. You can come to conclusions too quickly. Look outside first then, take in all the features as HA has said, then interpret the map. Use accurate time keeping and adjust your estimates every so often with position fixes. This will keep your estimates up to date and youll have an idea where you should be, if you have trouble interpreting the terrain as depicted on the Map.

This method works at all altitudes. Its obviously better at high altitudes with good vis. But works just aswell at low level navs where time keeping is the essence. Maintain heading, Altitude, and time keeping will put you in the general area everytime. And youll be surprised how accurate it is.

Ithink it all comes down to experience and confidence in Deduced Reckoning. When I first tried it in Central Australia I wasnt confident until I proved it with my Instructor, and he proved it too.

Try going Hodgsen River to Birrimba at 500 agl in a C182. I did it and it proved me that DR is as allways aproven method.


Have fun dont get lost out there guys


Regards
Sheep

P.S. If you use 10 mile markers, 20 mile markers it desnt matter. But dont forget the 1:60 rule for drift.
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Old 19th Jul 2003, 20:41   #7 (permalink)
 
Join Date: Mar 2003
Location: Brisbane
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Talking

Haven't got the time now to give you my own brilliant method Tobago Boy, but I noticed that you're on line so just letting you know that I will post something later.

It is simple and easy, but requires some discipline. That's probably why it's not taught. It is just too bloody easy.

Well, not really. But it is the way I still do it, after more than a few hours ... Okay, it's more than 100! See, I really am experienced...

Copyalater
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Old 19th Jul 2003, 22:25   #8 (permalink)
 
Join Date: Jul 2003
Location: Sydney
Posts: 5
Thanks for all your replies

It seems like Captain Claret and Sheep Guts have given conflicting opinions about reading from map to ground or vice versa.. I always thought in a normal situation you are taught to read map to ground.
tobago boy is offline  
Old 19th Jul 2003, 22:41   #9 (permalink)
 
Join Date: Jan 2001
Location: The Hornets Nest, NSW
Posts: 845
I'd agree with most of the above, and would also like to add what might be "simple, yet unrelated concepts" to some, but they might make your navigating technique somewhat easier.

Firstly. Always ensure that your aircraft is trimmed to fly hands-off and ball centered so that you are not constantly required to divert your attention from one task to another. Once you can do this you may notice that your fatigue rate may diminish quite markedly, allowing you to free-up more brain space for your nav technique. You can actually fly the aircraft (usually successfully for up to a minute or so) by just using your feet to lift a wing slightly if required to. You'll also notice that once trimmed properly you'll need much less control forces to actually manipulate the flightpath of the a/c, thus also "saving yourself" a bit. This will allow you to hold your heading much better. Keep an eagle eye on that compass too, and make sure that it is aligned with the DI at all times (part of your CLEAROFF checks).

Once you've got that one sussed....

Quite often one mountain is in the company of others, so the shape and relationship (to other features), of each feature becomes important. HA pointed-out a good and tried and trued way of feature recognition. It works. Sheep Guts is right on the money also. On one of the legs across a desert that my company flies each week on one of it's runs, there are almost no physical features to navigate with for an entire 90 odd minute sector, save for some salt lakes off to one side just after getting airbourne that look nothing like what is depicted on the WAC chart and a small sqiggly creekline (that is about an inch long on the WAC and runs directly across the direct trackline at around the halfway mark), in company with a small saltlake off to one side of track. Accurately being able to hold heading is something that will enable you to dead reckon with more certainty and a much higher degree of precision, thus keeping the heat away from those fragile and easily overloaded brain cells when you need them most. No, I'm not saying you're thick, but it is certainly easy to become overwhelmed when embarking upon your first difficult navs.

Using 6 min markers or 10 mile markers is completely your choice. Try both and make-up your own mind what works for you best. Do keep an open mind about both ways as they both have advantages and disadvantes for someone learning the trade.

Then there is that old favourite...

ML Ctr *** request?

"*** go ahead"

ML Ctr, *** request transponder check.

"*** squawk ident..... identified 12 miles south of....."

Cheatery I know, but worked much better than calling up and saying you are "uncertain of your position"

Regards,
Ops.

Sheepy, Minyeri or the River? Them trees at HDD get a bit close on a hot day in a well loaded 210.
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Old 20th Jul 2003, 08:50   #10 (permalink)
 
Join Date: Dec 2001
Location: Oz
Posts: 93
Gidday TB,

I will tell you the biggest mistake most of my ab-init class (including me) made, we made too big a deal of it all. Don't mis-read me, you need to know where you are, but you don't need to know the very speck of dirt under you compared to your map.

Remember, you are generally flying to strips and bigger airports, they are larger objects to find rather than trees and hills. As HA pointed out, big features first. Mountains and stuff dont move.

OpsNormal hit on a very important point. Good basic flying skills make navigating easier. If you can master holding a solid heading and having the aircraft well trimmed, accurate nav is easier.

I am going over covered ground here a little, so I will throw in my 2 bob.

My testing officer said to me after my flight test these two things.

Rule A : HEADING - GROUNDSPEED - TIME.

If you have been flying (HEADING) at (GROUNDSPEED) for (TIME).

There is NO where else you can be.

All encompassed in reading WATCH TO MAP TO GROUND. Use your 1-in-60 if you a little either side of track. Holding yor heading right will make your 1-in-60's smaller calc's.

Rule B : LOOK AT THE BIG PICTURE.

you are high up, you can see a long way. look at the big things. get a general idea of where you are on your map, then find something specific for a positive fix. Use your positive fixes for GS checks. Refer Rule A.

keep it efficient, keep it simple.

Oh, and on your map, draw a line from point A to point B, and go to work.
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Old 20th Jul 2003, 18:37   #11 (permalink)
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Be carefull with those winds obtained from the area forecast and used to determine your planned heading. They are not always correct and can put you a long way off course despite your accurate flying.
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Old 20th Jul 2003, 21:19   #12 (permalink)
 
Join Date: Mar 2003
Location: Brisbane
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Thumbs up

Tobago Boy,

as you can see, there is more than one way to find your way from A to B.

I've used most of the techniques, and taught them too, however, I find it difficult to justify most of them based on experience. I reckon they are just a way to get the job done that pleases some CFI's and FOI's, and there is no way they'd do it that way themselves.

I might be wrong on this last point. There is usually going to be one CFI or FOI who staggers belief by managing to progress no further in their technique than their CPL training. However, I'd like to see them actually do it for myself to believe it.

As we get older we get wiser, also lazier. You'll notice that old pilots who know what they're doing don't waste too much excess energy. And this technique is for me, provided I don't have a GPS.

Disclaimer: The advice contained hereafter is not actually used by me at present, I've gotten a bit older and a lot lazier now. This description is the novice's version. To describe the advanced version to you would be useless until you can do it this way. It's identical in principle though.

This is a melding of military and civilian navigation technique, more military than civilian. Theirs is better than the civvie way.

First you need to prepare for your flight this way. Draw a boxed arrow alongside your track. This looks like a triangle on top of a segmented rectangle. Fill in the details required for each leg in the boxed arrow. The triangle is left blank, this is for your departure time. The first segment on the rectangle has your TR in 3 figures. The next has your planned ALT, eg A075, the next is left blank, then the last has your ETI for the leg in minutes, eg +57. The + sign signifies that you are to add the departure time to the ETI after departure to end up with your ETA which goes in the blank segment below the ALT box.

If the stage is relatively long, at least 30 minutes, measure the 1/2 way point. Then work out your ETI to the destination at your planned G/S. Mark the number of minutes next to your 1/2 way marker this way, +28. When you get there you simply add the current time in minutes to get the revised ETA.

This only will work when there is something at the 1/2 way point that you will be able to positively identify that is oriented perpendicular to your TR. This is your G/S check, hence the orientation perpendicular to your TR. If there is no easily identifiable feature there, then find one on TR where it will be of some use, ie. not just 5nm out from the Departure or Destination.

It is also useful to mark points on TR where you need to change frequencies or contact Approach etc. These don't need to be actually marked on the map, you can cut out some Post-It notes in the correct shape and mark the details on them. That way you can move them if they're in the way, and they stand out better than pencil on WAC.

The longer the leg, the more G/S check points you will be able to find, but don't go berserk. This is where the discipline comes in.
To gain maximum benefit from this technique you will need to have faith in DR. If there are no features to orientate for departure, just make sure your compass is correct, by checking it against the actual R/W heading on departure, and fly HDG accurately until some feature presents itself.


After this preparation, you then proceed during the flight as follows:

1. Orientate prior to departure. Just before T/O, after the pre-T/O checks.

Put the TR on your VOR, and the HDG on your ADF. The ALT on the Assigned ALT Indicator, if you've got one.

Check where your track goes and find two features that will help you to visualise the line on the ground that is your track. This is not as easy as you'd think since some things on the map look great until you have to identify them from the air. Hint, it will depend on your altitude. Hint, look for features as far away as possible that you will be able to recognise from your Departure A/D.

You are visualising your track reference the features on the ground, once you've done this there is no need to refer to your DI or compass again-except to make sure it agrees, otherwise you discard the numbers!

Once you've positively established yourself on TR by orientation to the features you have also automatically allowed for wind. Discipline is again required to stop yourself from habitually looking inside at your map. Force yourself to trust your memory.

2. Continue to Orientate after departure once comfortably established on TR and you are approaching the features that you've been using to TR with. Now you are again looking for features as far away as possible that will be recognisable. Hint, it's a good idea to get two features identified in a particular orientation to each other, that together can help you visualise the TR on the ground.

3. Check the features on the map that you've identified pre-flight as your G/S check features. Hopefully, they will give you some TR guidance as well.

After you've done this, look for them. And don't stop looking for them until you either find them or some other readily identifiable features that will positively fix your position. Then you can look again at your map.

4. Finally, look for some features that will help funnel you in to your destination field. Beware! Some of these suckers are bloody hard to spot, eg. grass strip in a field surrounded by sheep grazing fields.


This is pretty much it in a nutshell !! Obviously, it will require some artistic licence to make it work properly, just like any thing that is an art.

It is not a rigid standard technique that demands marks where none are required, but it does require some thought. The big advantage is that once you've done the thinking, the actual navigation is much easier.

Hope you like it. I do.
Manwell is offline  
Old 23rd Jul 2003, 19:44   #13 (permalink)
 
Join Date: Jun 2001
Location: Australia
Posts: 172
A few of my thoughts!!!

KKKeep Nav as simple as possible

THE LESS CRAP ON YOUR CHART THE BETTER

If you are going from a to b then draw a srtaight line joining the points(this is your "flight planned track")

Prepare your flight plan with the forecast winds and calculate headings and time intervals

After TKOF, intercept the flight plan track visuallly and then turn to planned heading

PINPOINT where you are on the chart (Iuse a 2B pencil to mark my position and record the time(UTC) that i an at it eg, "28" mins past the hour


Now I RELAX and concentrate my efforts in keeping the aircraft at the planned altitude and heading- easy if your in trim.

I also spend 90% + of my time looking outside

After say 15 to 20 mins again pinpoint your position on the map and note time at that position

Aline joining these 2 points is your "Track made Good" that is the actual line the aircraft flew over the ground (it rarely has anyrelationship to your planned track!!!)

NOW the 1 in 60

Chances are you need to go from your last pinpoint to B or even an ALTERNATE.

Simple

Draw a`line from the pinpoint to where you want to go

Slap your protractor centre over the last pinpoint with the 'tail' of the protractor(180degrees) along the track made good

Read off from the 360 degree line of the protractor the number of degrees you need to turn left or right to track to the destination
If its to the left then Subtract that many degrees from your flight planned heading , turn aircraft to new heading and your on your way (what you have just done is a 1 in 60 without the bullshit


Hope this is of interest, i havent mentioned updating your estimates 'cos my finger is tired

Regards
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Old 24th Jul 2003, 09:23   #14 (permalink)
 
Join Date: Apr 2002
Location: Australia
Posts: 463
Crikey.. its a lot lot easier to do a 1 in 60 in turbulence than using a protractor and ruler. 1 in 60's are very easy to do.

Once you've had a bit of practice, guessimating tracks off a map is pretty easy to within +-10 degrees, and is invaluable when planning diversions enroute. Once established on new track do a 1 in 60 1/2 way along to revise your track made good to plop you over your destination.

Bevan..
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Old 24th Jul 2003, 15:30   #15 (permalink)
 
Join Date: Jul 2003
Location: Sydney
Posts: 5
Your opinions are great to read,
Thanks for sharing your tips :-)

Im sure that I will find the techniques that work best for me with more experience.
Is anyone game to share a tale of getting hopelessly lost or are we all good navigators? (or know how to operate a GPS!)

TB
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Old 24th Jul 2003, 22:02   #16 (permalink)
 
Join Date: Dec 2001
Location: Great Southern Land
Age: 48
Posts: 409
VFR Nav Technique

G'day Tobago Boy

Two stories, one of a nav cock up and one of nav heroics. Please be assured that I'm a run-of-the-mill GA PPL wannabe.

On an early navex heading north from Sydney I was all set up for a heading of 010 from Patonga, at the north end of the lane of entry. I took up heading 100 and after 30 seconds or a minute of looking fair square at Barrenjory headland I knew I wasn't tracking to Maitland. Despite knowing that something was dreadfully amiss I kept droning on struggling to figure out how to resolve my problem. Thankfully the instructor sitting amused in the right seat of VH-PBS asked me to have a good think about things. I looked once more, sure enough, Barrenjoey. Looked at the WAC, that's NOT Maitland out infront. Problem resolved itself, lesson learnt - don't fixate on the number. I set a number in my mind and almost tried to fly a Cherokee to Tahiti. Apply some common sense! Maitland is North of Patonga, Palm Beach is East.

Second story. Departing Canberra in a Duchess I set myself a target of overflying Bindook at the most precisely correct time possible. I asked my wife (then GF) to put a Post-It note over the GPS and I flew accurate DR outbound from Canberra, correcting for lower GS on climb, then asked Wifey to uncover the Post-It note as we turned for 2RN. I had flown to THE SECOND an accurate DR from Canberra to Bindook using forecast wind, time, heading. It can be done, very easily.

I had no pressing need to arrive overhead BIK at precisely 'xx' past the hour, and I suspect that many of us weekend warriors play fast and loose with DR. But it sure was rewarding to have the principles reinforced.

Good luck with the PPL!

LTDT
Like This - Do That is offline  
Old 24th Jul 2003, 22:47   #17 (permalink)
 
Join Date: Dec 1998
Location: Escapee from Ultima Thule
Posts: 3,942
What works for me:

Don't use a plastic covered chart. You have to use a particular pen to write on it, another to write on other things, a pencil for the whiz wheel etc etc. Use a paper chart & a soft pencil (eg 2B - my preference. It's soft enough to write on the various things and hard enougth to last between sharpenings. 2B is also soft enough to be erased without harming the chart).

Draw the desired track. I don't bother with 10nm/20nm/6min/whatever markers. I use Track as Heading, TAS as Groundspeed on the plan to get ETIs. Sometimes I jot in the wind if it's significant or unusual.

In flight always get a fix at or near top of climb. This starts my groundspeed & 1:60 run. If I'm significantly off track half way up a longish climb then I'll do a 'double the track error' 1:60 then so that I arrive at TOC somewhere close to track.

At TOC & after each fix I look ahead of position on the chart & choose whatever feature I think will be appropriate for my next fix - usually about 20mins ahead but really depends on what's available. Then I work out my estimate there & sit back and do other things.

Approaching the pinpoint time it's the usual very big --> big --> small --> individual creek bends to pinpoint position. Prior to overhead it's possible to get sufficiently accurate info to pre-calculate the 1:60 track correction. Over the fix turn onto the new head & note the time. I choose where I wish to regain track & base my 1:60 closing angle on that

All fixes are marked on the chart with the dot/circle around it/minutes past the hour notation. I also use a square if it's a DR position or not really confirmed. That's so that later if nav. goes awry I won't fixate on it as an "I was definitely there" sort of thing.

After a fix I always check my G/s if the time is different from planned.

I use a range of nav. techiques, singly or in combination: Pinpoints, visual radio & running position lines, boundary features that would tell me if I've gone too far or too far off track, deliberate track error etc etc.

I plan descents at either 500 or 300'/min. 500'/min takes twice your height in thousands and call it minutes, 300'/min takes 3 times. Descent starts at that number of minutes before arrival. I usually add a couple of minutes to allow for deceleration if I'm doing a straight in approach. If visual I also use the sight angle to the destination as a reminder that a descent is due ie when the destination looks similar to a normal final approach profile then it's definitely time to descend.
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Old 28th Jul 2003, 14:02   #18 (permalink)
 
Join Date: Sep 2002
Location: Eastside
Posts: 543
A couple of things I found useful:

Forecast winds are often inaccurate, but do give a rough idea. Its important to get a real appreciation of the wind as soon as possible once you're in the air. Get a significant landmark fairly close to your departure point, and visually fly a constant heading to that point. You now have an accurate drift and wind component (remember slower GS in climb). If you keep using that for your whole leg you won't go far wrong (as long as the legs aren't too long).

I used half way markers on my maps, moving it a couple of miles towards the departure point to allow for the climb, depending on my aircraft, cruise level, etc. Can't remember the exact figures I used.

With a bit of 1 in 60, I reckon thats about all you need.

Oh and the old transponder trick... Handy when available, but I wouldn't make it a habit - it can go embarassingly wrong. A certain new charter pilot I have heard of requested radar vectors to the Bungles from the middle of the Kimberley. oops!

grrowler
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Old 3rd Aug 2003, 21:32   #19 (permalink)
 
Join Date: Feb 2001
Location: Somewhere near here
Posts: 46
Thumbs up

All good gouge....

1. BIG to small.
2. Clock (what time is it?) - map (where should I be?) - ground (where am I??!).

3. Plot fix on map with time.
4. When do I need to look at the map again? (10-15 mins is fine ... at 2 miles/min...say 30nm...even with a 10 deg average error, you'll only be 5 nm off track (-/+ actual vs planned wind)...that's only 5 average runway lengths).
5. PUT THE MAP AWAY!!! Flt HDG and AIRSPEED until 2 mins before next checkpoint, then go thru the hoops again.

A bit disjointed...but hey!
Whizzwheel is offline  
Old 4th Aug 2003, 19:40   #20 (permalink)
 
Join Date: May 2003
Location: Australia
Posts: 294
All good so far, I find that 1 in 250 000 maps like vtc's work well below 5000 agl, above 5000 the picture on the wac looks more like the picture outside. Also find a good spot for your pen/pencil and use it religiously nothing worse than not being able to find your pen on a test as it makes you look unprofessional. Above comments on less being better are spot on - keep the clutter down. I just write all over my maps a new one comes in the mail every few months anyway.
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