Track crawling

[bjornhall]

Keep seeing "track crawling" pop up in various threads here... That it's unjustly frowned upon, that it is a bad idea, that it's a good idea, etc etc...

Makes me wonder, what's wrong with that approach? :confused:

FWIW, I'm being taught to keep track of my position on the chart at all times, in between waypoints, and certainly not tuck it away between waypoint passages... I reckon that constitutes "track crawling"?

[Check my bad SLF]

I would suggest that flying an accurate heading, and trusting that heading, allows spare capacity to be spent looking out. Sure, have check features along your route, but being head down in the cockpit trying to plot your route as your flight progresses is dangerous.

I've always found having check features approximately every five minutes or so works well. Also, picking the right type of checkpoint works wonders. Intersections of motorways and rivers, railways etc are ideal. Picking a village amongst villages is not so great - they all tend to look the same from the air!

MDR and VFR nav is surprisingly accurate. If you pick check features too close to each other, it is very easy to think you may be off track, and put in unnecessary drift corrections. If after a couple more check features it is still looking as though you are drifting off track, then make a correction.

The stopwatch is your friend!

All the best...

[Chuck Ellsworth]

The stopwatch is your friend!

But not as good a friend as a moving map GPS.

[Tony Hirst]

I wonder if we could GPS out of this one, I think it would be nice to discuss visual navigation without degenerating to the usual arguments :)

[Check my bad SLF]

I'm a great fan of GPS, don't get me wrong. The modern options have some amazing features.

However, why not take a bit of pride in your flying? Flying an accurate heading that corresponds to desired track, and when visually recognising you're off track, making an appropriate heading change to get back on track to your waypoint, IMHO, is much more rewarding.

With proper planning and airmanship, a GPS shouldn't be necessary. A back-up, by all means. Being comfortable with VFR navigation techniques allows you to actually chill out and enjoy your flying; after all, you're paying a great deal for it. You can guarantee that so long as you're flying head-down in the cockpit, somebody else is. The old "Big Sky" theory doesn't work for everybody...

[SNS3Guppy]

We just finished international ops in class, and believe it or not, with three fully capable INS units, supported by two FMS units and four GPS units including an extra stand-alone approach approved GPS, with RNP .1 capability, we STILL plot the course using a pencil, plotting chart, a manual E6B computer, and a plotter. And yes, accurate time measurements. Imagine a room full of professional pilots flying some fairly sophisticated, well-equipped aircraft, hunched over tables with manual plotters and computers in hand, and that was us. Those same things get used on long oceanic routes, too. Especially on long routes where precise navigation is necessary, to support, verify, and check our position constantly.

We do NOT depend soley on multiple long range nav guidance; we do it just like you...dead reckoning, pilotage, and stopwatch and compass is just as important in a B747 as in a Piper Cherokee...and when I'm flying a light airplane, I do it with map, plotter, and E6B in hand.

As for the "tracks crawling," what does that mean?

[Check my bad SLF]

Track Crawling/Feature Crawling is picking features on the ground and relating them to positions on your chart, and flying via them, rather than flying a heading for a certain length of time.

[Chuck Ellsworth]

Those same things get used on long oceanic routes, too. Especially on long routes where precise navigation is necessary, to support, verify, and check our position constantly.

O.K...not including typing into the FMS which uses INS../..RNS.../..GPS .../ VOR's etc. what do you use to determine your exact position over the ocean?

[homeguard]

How on earth do you think Amy Johnson and others crossed the Atlantic!
Do you remember one B747 being shot down by the Russians for not cross-checking the INS

[Chuck Ellsworth]

How on earth do you think Amy Johnson and others crossed the Atlantic!

Map reading?

Track crawling?

[Chuck Ellsworth]

I love these forums...never a dull moment.

What I find fascinating is learning all this new stuff...

....especially this stuff about flying over oceans I wish someone had trained me in how to do it right when I started doing international ferry flights thirty three years ago.

Oh well I'm out of that business now....had to quit because that horseshoe up my ass kept setting off all those alarms at the airports after 911.

[SNS3Guppy]

Track Crawling/Feature Crawling is picking features on the ground and relating them to positions on your chart, and flying via them, rather than flying a heading for a certain length of time.


Ah...pilotage. The most basic navigational skill, and a very important one.

Do you remember one B747 being shot down by the Russians for not cross-checking the INS


KAL 007...and that's one version, depending on which you believe, of course.

O.K...not including typing into the FMS which uses INS../..RNS.../..GPS .../ VOR's etc. what do you use to determine your exact position over the ocean?


Exactly what I said I used in my previous post. Three individual INS units, each with their own separate GPS updating systems. A individual GPS unit, stand alone with approach capability. Two FMS units which take input from two INS units, as well as other sensor inputs when available, including two additional GPS units, for starters. However, plotting is still done on a Jeppesen plotting chart using a pencil, plotter and handheld E6B computer to verify what's being seen on navigation computers. The required navigational performance on the oceanic tracks is RNP 10, meaning ten miles either side of the track centerline. However, the actual navigational performance turned out by this equipment in conjunction with an autopilot is .1...a tenth of a mile either side of centerline, at least 95% of the time.

While ample instrumentation exists in the cockpit to provide ETA's, fuel burns, and other information relevant to the flight (such as equal time points, times to alternates or diversionary locations, etc), we still calculate it by hand to make sure what we're seeing on the instrumentation is correct. We're required to do so. Being constantly in the loop this way means there's not a lot of extra work to do in the event of a failure of a long range navigation system...and it has happened. It also provides an accurate navigation log on paper when we're done, which goes into the trip kit and gets retained at the company along with all the other paperwork associated with the flight.

It's one thing to go from A to B for hours and make an occasional glance at a FMS readout and a multi function display with a moving map. It's another to be completely in the loop and aware of your position at all times because you're constantly following along on the map, recaculating your distances and speeds, and ensuring that you're really where the airplane thinks you are.

[QDMQDMQDM]

Heading and time!
How on earth do you think Amy Johnson and others crossed the Atlantic!
Do you remember one B747 being shot down by the Russians for not cross-checking the INS

How do you think Amy Johnson ended up off course over the Thames estuary and got shot down?

How do you think Amelia Earhart was lost over the Pacific?

[S-Works]

And it does make a break from the monotony of Sudoku or the crossword.......

[Chuck Ellsworth]

While ample instrumentation exists in the cockpit to provide ETA's, fuel burns, and other information relevant to the flight (such as equal time points, times to alternates or diversionary locations, etc), we still calculate it by hand to make sure what we're seeing on the instrumentation is correct. We're required to do so. Being constantly in the loop this way means there's not a lot of extra work to do in the event of a failure of a long range navigation system...and it has happened. It also provides an accurate navigation log on paper when we're done, which goes into the trip kit and gets retained at the company along with all the other paperwork associated with the flight.

It's one thing to go from A to B for hours and make an occasional glance at a FMS readout and a multi function display with a moving map. It's another to be completely in the loop and aware of your position at all times because you're constantly following along on the map, recaculating your distances and speeds, and ensuring that you're really where the airplane thinks you are.

I fully agree, and when delivering piston pounding airplanes trans oceanic we also use Sat phones as a backup for the HF and relays through airliners flying above us......and of course I always have my closest alternate ready for an immediate turn if needed.

I find the Sahara desert is more demanding than the oceans though especially during the Harmattan season.

[homeguard]

I've never heard so much nonsense other than from those, whose claim to fame, is someone elses hard work.

[bjornhall]

I'm guessing it is a fairly subjective term used whenever someone wants to criticise your nav techniques. ;)

I should be safe then, I don't have any nav techniques! ;) Maybe if this crap weather ever lets up I'll be able to obtain some... :hmm:

Not getting so engrossed in map/terrain feature correlation that you neglect all other aspects of flying seems to be a good point tho'... Will keep that in mind...

Pretty hillarious how a question about track crawling results in a discussion about ocean crossing navigation methods... Love this place! :}

[stickandrudderman]

Homeguard,
stop pussyfooting around and speak your mind will you?:)

[Mikehotel152]

We do NOT depend soley on multiple long range nav guidance; we do it just like you...dead reckoning, pilotage, and stopwatch and compass is just as important in a B747 as in a Piper Cherokee...and when I'm flying a light airplane, I do it with map, plotter, and E6B in hand.


Blimey, just doing a rough diversion on your lap in a C152 while flying is tricky. I imagine using a whizzwheel and plotting accurate courses while flying a Cherokee is, um, 'interesting' :hmm::E

[Tony Hirst]

So endeth another proon nav thread. Well at least precluding GPS discussions got us to this point within a handful of posts as opposed to pages :}

[Chuck Ellsworth]

Quote::

Pretty hillarious how a question about track crawling results in a discussion about ocean crossing navigation methods... Love this place!

***************************************

Yes this is a real interesting group full of experts and wankers.

What we should do now is decide which wankers to take advice from......the wankers who go around in circles in the same place every day or the wankers who wank all over the place.

[vee-tail-1]

Glad I did'nt fly flight eng with some of the psuds on here. Mark you I did wake up on a long atlantic crossing to find both pilots asleep and the sun on the wrong side of the 707. :uhoh:

[DFC]

Track Crawling is commonly onserved as the pilot placing finger on map and looking at the ground outside and based on the observed progress of the aircraft, the finger is moved across the chart. Corrections are plentiful and ad-hoc and the system is not desireable because;

1. All the pilot looks at is the ground and the map for most of the time so lookout for traffic is poor.

2. The heading wanders frequently and consequently even if the pilot wanted to completean adjustment, they can't really tell what heading they have flown for the last x minutes.

3. Not being able to spot what the map says should be there leads to panic or the pilot sees what he wants to see and the panic is delayed by some minutes.

That is track crawling.

What is not track crawling is...........

at the planning stage saying that there is a big mountain range there. The minimum safe level based on visual navigation / DR is 5000ft. I plan to fly a heading that will follow the coast from here to there and thus I can ignore the mountains and my minimum level is 1500ft.

or

At the planning stage deciding that having to keep 5nm away from that zone is causing an unnecessary delay because I can fly to that motorway junction and then fly a heading that follows the motorway to that junction where is simply head off on a steady heading again and that will ensure that I do not infringe the zone despite being only some 2nm from the boundary at one point.

or,

the vis is not as good as planned and I am neing forced to operate at minimum level. Rather than fly a heading direct to my airfield, I will fly north along this road for 20nm and then at that junction fly east for 30nm to the airfield.

None of the above are track crawling they are legitimate navigation techniques (usually called handrailing because that is what you are doing) used to resolved a particular issue.

What most schools fail to tell students is that it is perfectly OK to use the above at PPL and CPL level. However, there is a requirement during training and during the test to demonstrate DR and that can not be done while handrailing.

Regards,

DFC

[SNS3Guppy]

Pretty hillarious how a question about track crawling results in a discussion about ocean crossing navigation methods... Love this place!


Seeing as I was the one that introduced the oceanic, I'll respond to that.
The topic is "track crawling," which apparently means pilotage. The art of flying by correlating what's on map with what you see out the window. It's the most basic form of navigation, and accordingly, one of the most important skills to have. All the golly-gee-whiz-bang gizmos in the cockpt don't make up for the basics.

I'm having a hard time understanding why anyone would condemn a pilot for using pilotage. I made a comparison with flying a B747 on oceanic routes to show that while we do have all the gear on board, we still use basic navigation skills, and still use the same tools that most students and private pilots right here use. In other words, these basic skills that some might put down in favor of their garmin handeld, are still very important even when one has far more sophisticated equipment. Basic navigation skills still form the basis of getting from A to B.

If "track crawling" is about basic pilotage (and by default dead reckoning, which falls right in line with pilotage as an elementary skill every student pilot should have mastered long before certification...why on earth is anyone condemning it as inappropriate or even questioning it's place? The need to be conversant in those skills never goes away.

Blimey, just doing a rough diversion on your lap in a C152 while flying is tricky. I imagine using a whizzwheel and plotting accurate courses while flying a Cherokee is, um, 'interesting'


It shouldn't be; it's the basis of how you get from A to B. Even with a VOR or GPS to guide the way, you still need to understand those basics. Even while flying a single pilot airplane alone in the mountains, I have a small metal E6B tucked in a flight suit pocket, and I use it. You could use an electronic calculator to do the same, of course, but the batteries have never failed on that little E6B; basics.

[SNS3Guppy]

I see absolutely nothing wrong if I see I'm off track in flying to a feature that will put me back on my planned track. Far better than flying into something I had not planned for.


There's absolutely nothing wrong with that at all. That's the basic skill of pilotage; being able to correlate what one sees out the window with what one sees on the chart, and thus navigate from one point to another.
Flying along one's course and meandering a bit is called "bracketing," and it's been taught as a part of navigation for many decades now. Fly by pilotage, you're probably going to bracket your course. Fly by VOR, and if the needle drifts left and you correct left, you're bracketing; you're constantly returning to your course, making corrections here and there, but you're doing it by keeping within an acceptable distance from the course line; you're bracketing the course.

A few years ago we had a first officer who was flying a leg. The Captain with him pointed to an airport ahead and asked him what it was. The First Officer didn't know. The captain pointed to a nav display that showed an airport in that position, and asked the copilot if that might be it. The copilot looked at the nav display, then at the airport, then back at the display, and said there was no way that could be the same airport. Why, asked the captain. Well, said the First Officer...that airport down there doesn't look anything like the little symbol on the moving map. (All the airport symbols were identical). He was one of those who routinely went from A to B and let the gizmos do the work for him.

An E6B is a circular slide rule; they come in plastic, cardboard, paper, metal, fiberglass...and some are even electronic. I use a good old fashioned aluminum one that's lasted many years. Some of the numbers long wore off, and every once in a while the face gets some clear ladies fingernail polish to keep the rest of the numbers from wearing away. But it still works, and of course, hasn't required a single battery yet.

I didn't get into flying airplanes to keep my head in the cockpit. I fly so i can enjoy flying, looking down, looking around. Pilotage is the heart of getting from A to B, and certainly one of the most enjoyable parts. It's navigating alright but it's navigating by looking around. And yes, it can very easily be done by seeing what's ahead, flying to that point, seeing what's beyond that, looking ahead, and flying to the next place of reference. Just like magic. Or driving a car. Or walking...but more expensive and considerably more enjoyable. Isn't that what private flying is all about??

I should add that when I was crop dusting in the flatlands of kansas many years ago, we often navigated by flying close enough to read water towers and road signs. Towns with water towers put the name of the town in big letters around the water tower, so flying to a town and reading the name was quick and easy way to find your way along. In days of no electrics and no radios, it worked just fine...and it still works fine today.

[DFC]

G-EMMA,

If you see where you are and where you should be and then position the aircraft where you should be there is absolutely no problem.....provided that you can come up with a reason for needing the correction and make an appropriate adjustment to heading so that the error should not happen again. There is also the time correction that may be involved.

I remember flying with a CPL candidate and it wne like this;

Where are we

We are here (points to correct place on map)

Where should we be

Over there (points out window to town 3nm 9 O'Clock)

OK.

Why are we here?

The heading is in error by 5 degrees.......I should have steered 335

What are you going to do?

Fly over to the town and when overhead fly a heading of 335.

---------

Far too many schools claim that is track crawling but it most certainly is not it is a valid method for regaining track and just as valid as double the error and standard closing angle and 1 in 60.

---------

It would be a very poor examiner who failed a PPL or even a CPL candidate for;

if I see I'm off track in flying to a feature that will put me back on my planned track

Especially if it is used to;

better than flying into something I had not planned for

Provided that having regained track they do not fly the same heading again and get into the same situation 5 minutes later.

Regards,

DFC

[BackPacker]

My instructor introduced me to the term. If I fly by moving from one feature to another, I'm track crawling. Do it in the skills test, I could well be looking at a failure. I just hope the CAA examiner I get isn't reading this

I hope you don't fail because of "track crawling" if you planned on doing a bit of track crawling. As somebody said: if you follow a very easy to distinguish feature to stay clear of controlled airspace and/or other hazards, why not?

Two example: In the Netherlands it is perfectly normal to follow the coastline from Hook of Holland to Den Helder. Very scenic, and it keeps you perfectly clear of both the Rotterdam and Schiphol CTRs. The coastline curves slightly, so you start out heading about 030, ending up due North. DR would take you several miles offshore and with the Schiphol TMA starting above you at 1500', not much chance of gliding to the coast and setting up a decent forced landing approach somewhere in the dunes.

Another example is flying between DET and OCK in the SE UK. If you do DR, or use radio nav, you fly straight through the Biggin Hill ATZ. Whereas if you track along the M25, you stay clear of everything, including the Gatwick and Heathrow CTRs.

So if you plan to use track crawling as your primary navigation method, with possibly another technique as backup, it can be the most sensible method of navigation, depending on circumstances. I can't see your examiner faulting you for it. Me personally, I combine satnav, radio nav, DR and track crawling depending on the route, and may change techniques several times within one single flight, depending on the requirements for each leg.

[bookworm]

I'm guessing it is a fairly subjective term used whenever someone wants to criticise your nav techniques.

conjugating as follows:

I navigate
You use pilotage
He track crawls

;)

[gasax]

Interesting thread - thanks for the graphic gemma. I would comment though that the blue sstuff doesn't look much like 'track crawling'. With the sort of landmarks available on this route student X should have been able to get on and stay virtually on the line exactly if they genuinely were track crawling.

Instead it looks like there was no line and no clear idea of what the desired direction was. That could still have worked whereas the blue line looks like there was little spare capacity for thinking about what the track line looked like and what features would confirm student X was heading in the right direction.

From my experience the only useful thing about having a line is that it makes that point very clearly.

The other item you might think about adding is trackmarks with timing. They can work almost as well as a line and if used as well as a line they give a very clear indication of the last 'known' position and its time - which makes ETA and other estimates child's play to make.

At the end of the day student X should have aan overall 'picture' of where they are and were they are going. DR tends not to do that until turning points, pilotage or track crawling can do it nearly continuously - as can GPS or VOR cuts or other mutiple radio aids. Combinations of these methods can eliminate all the potential errors and ensure you always know where you are. Single methods all have potential pitfalls.

[jb5000]

I've back seated a few of my course mates doing some CPL profiles, I'm sitting there trying to track crawl all the way round and it is so so much more hard work than heading / time!

You spend all your time trying to work out which little town it is off to your right, and this is where it can all go wrong.

It really is so much easier and less stressful thinking: right I'm going to pass a large town just off to the left in 8 minutes (and have a few features that can identify it). You can then spend that time with your head out of the cockpit, talking on the radio, cruise checks, pax comfort etc. rather than chasing your finger across a map.

Once you have positively identified what your fix is in your event cycle then you do what you can to get back on track as fast as you can. You can use standard closing angle or if its easier just 'fly to' where you want to be. You can then adjust your heading with your track error at the last fix.

There also comes a time where track crawling is necessary however. On my CPL test I had to nav from Bournemouth to Frome, with a diversion to the Northeast for circuits at Blackbushe. Once I had turned at Frome I track crawled briefly along the railway line to keep me away from Keevil, yet still outside the Salisbury danger areas. I then flew direct to the southern tip of devises to pick up my planned heading from there. Examiner only mentioned that my nav was 'well managed'.

One final point - How wrong could it go between fixes? If you choose say, every 6 to 8 minutes to have a ground or radio aid feature then every 8 mins you know that you are on track (or adjusting to get to it). Assuming a generous 120kts for most PPL aircraft then thats only sixteen miles covered, that is a thumb and a half! Hardly much time for it to go wildly wrong, especially as you have spent those 8 minutes accurately flying and making sure that you don't run into anyone else!

[gasax]

If your going to 'fix' every 6 to 8 minutes in theory you're virtually track crawling!

If however at your defined time there are no obvious landmarks to confirm your DR then what happens - this is typically where DR goes wrong. A pencil mark in the assumed position means that the next 'fix' could be quite a long way out as it may be based on erroneous previous 'fix'.

I can only claim to holding a course within 5 degrees - which means that 'fixes' have to be reasonably frequent - otherwise read above. I cannot see how 'track crawling' requires such a level of concentration, the technique is to ease 'easy' landmarks, no something obscure that happens to comes into sight at your 'fix' time. Those landmarks vary depending on where you are and what the topography is.

[SkyHawk-N]

SNS3Guppy said...
Towns with water towers put the name of the town in big letters around the water tower, so flying to a town and reading the name was quick and easy way to find your way along

A nice quote from Fletcher Anderson's mountain flying book

"If you drop down low enough to read the signs on the water towers, you learn that one-half of the towns in Kansas are named 'Seniors 99' and the other half are named 'Jesus saves'".

In the same book he goes on to explain the shortcomings of Pilotage, Dead Reckoning, GPS and VOR navigation when it comes to flying in mountainous areas. Each method has it's own weaknesses, they should be used together to obtain the best results. Ok, not much mountain flying available in the UK but it's an interesting read if you get the chance.

[jb5000]

Gasax,

I meant roughly every 6 to 8 minutes find a feature on your route that you can use (I'll be passing 2 miles to the left of this town / 1 mile to the east of this reservoir etc.). If you choose 4 mins for a good fix, or leave it for 10 or 12 then thats fine. I didn't mean make marks every 8 minutes along the leg then force yourself to find something there.

You are flying the heading you have calculated and occasionally referencing that against your track made good.

I guess the most important time for using DR is when you are navving in 3km visibility, which is of course legal. Town hopping may be impractical because you may not be able to see the next waypoint. At times like these DR is the only way to nav (bar radio aid/GPS nav of course) and so surely it must be better to teach people the method that will work for all conditions that their licence allows?

One quick point - I guess there are two types of track crawling, for instance following the railway out of Redhill to Ashford. Dead easy, low workload etc. etc. The other type is the run your finger along the line and update your position every 15 seconds with the multitude of small towns you can see. This is easy enough if you are familiar with the area but constantly referencing the map can lead you very quickly into persuading yourself you are somewhere you're not, and makes your lookout now virtually non existent.

[bjornhall]

Now I know it is long winded, but I hope with the graphic Bjorn can now see what track crawling really is, what the results is, and why it is undesirable.

Yep, now I sure see what you mean! When that is what one means by track crawling, I can see why there might be a problem... But think of all the new, unexpected places you get to visit... :}

Pilotage is certainly a skill I want to have in my toolbox! Can't understand why anyone would have anything against that, either... So certainly see SNS3Guppy's points there!

[DFC]

G-EMMA,

Track crawling is not something that your student X has to worry about.

Overall when one looks at the chart one can see that the aircraft was within a few nm of the planned track at all times. Thus navigation even on the unplanned diversion was quite accurate.

However, what I see as a whole is that the planning of the flight is poor in relation to airspace and in some cases, it is luck that has prevented an infringement.

I say that because;

a) Look at theose nice blue lines within the Andrewsfield ATZ. I do not know what manoeuvering was done but it does not look like a standard circuit pattern but more importantly, the ATZ boundary, the CTR boundary and the flight track all meet at the same place. A puff more wind and a bit more drift in a turn and wham...an infringement.

b) The nice yellow line is on the good side of the planned track and had the flight drifted to the other side by the same amount it would have entered the zone.

Overall, I can't see why the flight did not proceed via the nicely positioned and easy to recognise Braintree VRP outbound and inbound. Especially on the way in since the planned track is very close to the zone boundary prior to entering the ATZ.

I realise that Wallingford was unplanned but having got there, and thus being faced with an unplanned leg back to base, a route via Chelmsford VRP and Braintree VRP would be easier, safer and very unlikely to result in an infringement.

Your instructor needs to teach you defensive navigation i.e. using a slightly longer route at times to keep you safe even if it adds 2 or 3nm onto the miles.

Regards,

DFC

[SNS3Guppy]

I guess the most important time for using DR is when you are navving in 3km visibility, which is of course legal.


If you can't see to navigate, you can't see other traffic well enough to have a high probability of spotting and avoiding it. Time to sit on the ground or file IFR and go get dirty.

Forget trying to squeeze through when vis is at the low end of the VFR spectrum.

Simply because it's legal doesn't really make it smart.