Time markers not recommended?

[Guest burbles1]

Been looking through the Dyson-Holland x/c training manual, and they state quite emphatically that time markers along flight planned track are "not recommended". Their argument is that when the wind varies, and your groundspeed is affected, the markers become "virtually useless". I can't see the logic of this - if the headwind increases, your groundspeed decreases, and you will know this when you check your next marker - you will be ahead of or behind it, and can revise your estimate quickly - one minute late on that last leg, three legs to go, so add four minutes to arrival time.

 

I was first taught to use six-minute markers, which will vary in distance apart depending on the wind velocity for each leg. This has worked for me so far, and having six-minute markers makes it easy to revise the arrival time, which is a main aim of navigation - to get to a destination on time (it also affects when you cancel SARTIME).

 

The D-H book needs revision to explain why some things should not be used - or better still to say that time markers are just another option, rather than slamming the method.

 

 

[rgmwa]

I was taught to use 10 min markers, and make arrival time adjustments as you describe. However there was a thread on here not long ago about time vs distance markers, that showed that about 80% of people (from memory) use 10 mile markers. I don't know if its a GA/RAA training difference, or whether it's an individual flight school preference. Guess it doesn't matter which method you use, as long as it gets you there.

 

rgmwa

 

 

[Tomo]

I always work 10nm rather than 10 minutes, or 6 minutes for that matter... which is roughly 10nm anyway, but;

 

I think It's more the point of working with a distance = time, rather than time = distance.

 

I guess it's a matter of working from map to ground, rather than ground to map.

 

That's my thoughts on it anyway.

 

 

[motzartmerv]

6 minute markers work perfectly well. What ever method your taught, as long as it works for you then don't let other peoples opinions corrupt your confidence in the method. I have used 10 miles, 10 minutres, and 6 minutes and the latter in my view is the best. I have never been a fan of the DH text's. Poorly written IMHO.

 

 

[kaz3g]

My TAS is 100 knots and I mark my track in 10 NM segments, too. Very handy when doing a 1:60 calculation.

 

If GS is also 100 knots then these equate to 6 minute intervals.

 

I have used the Airnav program for the last few years and it automatically puts them in on the chart. I find this very useful as they then also show on the moving map display which I run on a 5"TFT screen in the cockpit. I found this facility immensely helpful when I did a trip around the Centre a couple of years ago. Much of the country I passed over was almost featureless and distances covered between refuelling stops were often around 300 NM. AirNav allowed me to continually update my position on paper (it uses digitised Air Services charts) and correct for drift when my dead reckoning got a bit skew whiff (it was the old DG's fault, promise).

 

kaz

 

 

[Tomo]

My TAS is 100 knots and I mark my track in 10 NM segments, too. Very handy when doing a 1:60 calculation.

Yeah same.

 

I just mark 10nm on the map along the track, makes it easier to calculate the leg distance as well, not sure how the 6 minute marking works? do you mark off set 6 minute marks? Or is it a thing you do in the air, not pre planning?

 

 

[motzartmerv]

Yes, its done during the planning stage. Useing 10 % of your predicted groundspeed, so, 100 kts is 10 miles.

 

Winds are often different then forcast, so the markers stay but become 5 minutes or 7 or woteva, which gives u an instant revised eta.. Works a treat.What you end up doing is things like :i will cross that road at 16 (eg) and then that river at 19 etc...not just waiting for the feature to arrive, you know WHEN it should pass under you.. Makes very accurate navving possible.

 

 

[Guest Maj Millard]

Tomo, You still here ???....I was just watching a show on the birds of paradise in PNG thinking of you up there swating mossies !!...........................maj...

 

 

[Tomo]

Yes, its done during the planning stage. Useing 10 % of your predicted groundspeed, so, 100 kts is 10 miles.Winds are often different then forcast, so the markers stay but become 5 minutes or 7 or woteva, which gives u an instant revised eta.. Works a treat.What you end up doing is things like :i will cross that road at 16 (eg) and then that river at 19 etc...not just waiting for the feature to arrive, you know WHEN it should pass under you.. Makes very accurate navving possible.

Makes sense, I guess I already half do that in a way. Just put differently.

 

Maj - Yeah, head off end of this week.

 

 

[Guest burbles1]

I draw the 6-minute markers in preplanning after calculating the groundspeed. Depending on the headwind component, the markers could be around 8-10 nm apart and will be slightly different for each leg. This works well when you need to re-estimate the arrival time, but when you need to do a 1-in-60, you need to measure the distance since the last fixed point on the map.

 

My gripe though was that anyone relying on the D-H manual could get confused because it doesn't explain time markers too well. I'm also disappointed that the CLEAROF check has been reduced to CLEAR or CLEARO.

 

 

[motzartmerv]

How have you found the texts otherwise burbs?..interested to hear what you think..

 

 

[jcamp]

Time markers are only useful if you have the wind ie after you have worked out the wind using what? People who rely on the forecast wind will have nav problems. There is also the issue of redoing them for every flight; I do the lines and 10nm marks in biro, on routes I use a bit I have the 10 nm marked in both directions (different marks obviously).

 

 

[motzartmerv]

Jcamp, do you update the maps when they become out of date?

 

Minute markers are useful regardless of wind. And finding wind in flight is no problem either. Its not rocket science....

 

 

[Guest burbles1]

How have you found the texts otherwise burbs?..interested to hear what you think..

I can't help but look at texts with an editor's eye for detail:

Why wasn't that explained properly?

 

This detailed info about time zones isn't relevant.

 

etc.

 

I've read the Bob Tait PPL and thought I'd also try the D-H manual for x/c, because their BAK manual was comprehensive and relevant to the BAK exam. I had high hopes for the x/c manual, but I'm a third of the way through it and it has too much detail about time (UTC, local, etc) and not enough of the practical stuff like drawing flight planned track on maps and working out TTI correction. Some parts have too much text and not enough graphics to be descriptive.

 

 

[motzartmerv]

Yes burbs. I was wondering how an editor like yourself would view these texts. I shouldn't put them down too much in public, but suffice to say, not a big fan.

 

 

[jcamp]

Jcamp, do you update the maps when they become out of date?

Yes 6 months for VTC, VNC whatever for WAC. IF I had so many lines on the chart it was confusing I wouldn't need the chart anyway

 

Minute markers are useful regardless of wind.

You don't know the wind until you are at cruise altitude, do you then carefully work out that your 156 minute mark is in fact 173 min and change it. An hour later the wind has changed do you then change them all again. Lot of work and more chance of error.

 

 

[motzartmerv]

So if using mile markers, you just dont worry about groundspeed?..eta's??... is that what we are saying?

 

 

[motzartmerv]

CFI, you better call all the ga schools in sydney, and the raaf, with your expert knowledge, we are all doing it wrong.

 

What exactly is the difference between raa and ga cfi?..care to enlighten us all on this recreational forum??

 

 

[octave]

I agree with Ingnition, also our CFI with over 19500 hours also taught aviation at the university of NSW and prefers 6 minute markers, good enough for me

 

 

[motzartmerv]

Lol, clearly you don't understand how the system works, so perhaps before you offer an opinion, go out and get some practice, then get back to us all us lowly Raa guys with your expert findings.

 

 

[djpacro]

My copy of CASA's Flight Instructor's Manual only has this to say on this particular subject:

 

"Show the student how to select unmistakable check features every 20 miles or so along the track."

 

The USA FAA's Handbook of Aeronautical Knowledge has somewhat similar guidance, in many more words but doesn't get as specific as suggesting a specific interval of distance. See Fig 15-25 at http://www.faa.gov/library/manuals/aviation/pilot_handbook/media/PHAK%20-%20Chapter%2015.pdf

 

Incidentally, I do not represent either CASA or the FAA so I won't be debating the content of their documents.

 

 

[foxy]

hi guys,

 

just my little opinion on it all.

 

when i first started my nav's, i was taught ten mile markers. yes they worked fine, but then i learnt the 6 minute markers. as an initial learning stage, by comparison, the 6 minute markers were far easier to learn, and were also easier to figure everything out when you're actually en route. figuring out the 1:60 with the 6 minute markers, i dont see being a problem, because you need to know not only how far along course and off course you are, but when you try to get yourself back on course with the details, you also need to know how long you have been travelling off course, so that you can alter your headings per time travelled, etc.

 

ten mile markers are great for working out distance, fine, but, for any work done en route, ease is the key, so that you're able to continuing navigating....which is what you're there to do in the first place. the time aspect, i believe, is far easier to work it all out not only quickly, but also efficiently. distances are easy to read from a ruler...time...you have to get out the calc wheel and still work out the distances.... i figure you may as well take the fastest way to work it out, so you can keep aviating.

 

i know now, after having learning the navigation.....exactly which way i will teach it. obviously my students will know both ways, but i will focus the majority of time in training these students, using the way, which will work quickly and easily for them.

 

sorry its so long

 

liz

 

 

[motzartmerv]

Interesting that you quoted the casa flight instructor manual, but neglected to add lines from the paragraph below the one you quoted. Seeing as your copy must be missing this page i will add it for you.

 

ENROUTE NAVIGATION

 

It must be stressed to the student that after the compass

 

the aeroplane’s clock (or a watch) is navigationally the

 

most important instrument, as the time factor is vital in

 

fixing a position. With a knowledge of the flight planned

 

time intervals between check points, regular reference to

 

a time piece will provide an approximate but continuous

 

indication of the aeroplane’s position, the value of which is

 

sometimes overlooked by the student when too intent on

 

map reading. In essence the normal emphasis is on time,

 

then map followed by ground.

 

Perhaps you could print this section from the CASA instructor flight manual (which you mentioned) and add it to yours.

 

PS, did captain cook have maps of the globe to find australia with did he??..i was under the impression he was working blind, hence the whole "he discovered it" business.

 

 

[dazza 38]

Hi Guys, im not going to get into a argument, whether minutes or miles marker.I use 10 mile markers.The reason im commenting is that a relative on is a Sunstate Training Captain on Dash Eights out of Brissy. She told me, just use what your comfortable with.

 

Ps- No they dont read maps for their positon, or where they are going.Thats what modern avionics and Navigation systems are for before any body asks.

 

 

[motzartmerv]

...why are we (RAA) teaching 1 -in- 60's ???...they are rubbish....what students need to be able to do is pinpoint there position on the map...then we can make a heading correction.

Thats exactly what a 1 in 60 is cfi.

Thats it dazza ;)