how do YOU work out heading correction

[Pilot16]

Hi, still doing my PPL....Ive been taught by my instructor to use the 10 degrees fan lines drawn either side of my track to estimate the heading correction required to arrive over the destination. Ive been using this method ever since.

Just been fiddling with the whizwheel, i think it might be easier and more accurate if I used that in-flight (if i become very profficient with it, and take only little time with heads 'inside the cockpit'). Accuracy would be far more improved.

I wanna see how many people use the whiz wheel or fan lines, or indeed both to cross check...and your views on each method :)

Thanks

[Evo]

For basic VFR dead-reckoning I use double and half. BEagle's standard closing angle approach (here (http://www.pprune.org/forums/showthread.php?s=&threadid=13985)) seems sensible too, but i've never really used it. Using the Whizzwheel in flight seems like a really bad idea.

Of course, now i've got a PPL I use fancy things like RBIs, VORs and GPS to help, but.... :O :)

[bluskis]

Maybe this is a too quick reply, but how would you know what to put on the 'whizzwheel'?

If the answer is the forcast wind, then why not do it on the ground, and make any necessary corrections using the fan line technique.

[QNH 1013]

"if you are using the forecast wind, why not do it on the ground?"

A very good question, but I was taught to use the whizwheel in the cockpit during the NFT which used to involve a surprise diversion. Since you didn't know the diversion track in advance, you couldn't work it out on the ground, but you did set up the whizwheel with the forecast wind.

I now would not dream of trying to fiddle with a whizwheel in the cockpit although I am quite happy to use one on the ground. When in the air, I do all the drift calculations in my head or using the DI if the aircraft is fitted with one. (Some of the aircraft I fly don't have DI's fitted). This is quite accurate enough for VFR navigation, and for IFR you have enough instruments to fine-tune the drift calculation.

I wonder if anyone is still taught to use the whizwheel during the flight? Even at that time I thought it was too distracting and affected the time spent looking out. For a real diversion (possibly at low-level and in bad vis) I would think it could be deadly to divert your attention to using a whizwheel.

[Delta Wun-Wun]

I use the 10 deg fan line method and it works fine. Remember that it is only giving ball park figures on a whizz wheel as you are working with forcast winds and the actual wind may be incorrect. I would use as simpler method as you can, that way maximising the time you spend looking out the window. I don`t like the idea of a whizz wheel used during flight. Even if you are very good you are taking your eyes into the cockpit and away from that lookout.:eek:

[Whirlybird]

Why do you need to be that accurate? Think about it; your compass or DI only has intervals marked at...is it 5 degrees. So can YOU fly to an accuracy of one or two degrees? I certainly can't. Much more important to keep your eyes out of the cockpit. If as well as your planned heading you compare with ground features and dead reckoning, you'll know soon enough if your heading is working or not, and if not you can adjust it, whether that's been caused by inaccurate track correction or the forecast wind being wrong.

Learning to use a whizwheel accurately is a good idea, but I sometimes wonder if the fact it's so accurate means that people lose sight of what's possible, or even necessary, in the air.

[FormationFlyer]

I teach Standard Closing Angle (with Fan Lines).

And a word of warning about whizzwheels in the cockpit - if you meet me in the air then the AIRPROX report coming your way will remind you to get your head out of the window - again today i have had another incident where I have the right of way and yet again remain unseen by another aircraft - this time a PA28 Arrow IV about 5nm N of Westcott - and he didnt take action until long after I had - if you arent heads out the cockpit you aint flying the plane....so how to do diversions without whizzwheels...

1. Know Max drift....
2. Know how to adjust Max drift using the clock method to get a WCA (wind correction angle)
3. Buy a small combined AFE plotter which gives heading & distance in one shot.....
4. fly standard closing andle as a technique on the diversion (less work - less marks)
5. know how to adjust windspeed using the clock method to obtain groundspeed

whirlybird
um why cant you fly accurately? Doesnt the aircraft travel in between the lines on the DI!? ;)

[Speedbird252]

The SCA method ive been shown seems to differ again fom what others have quoted, this one seems real easy to me if you are in flight. If you use the fan lines you should have an at a glance indication of the track error, then use this:

TAS- MILES/MINUTE- Standard Closing Angle

90- 1.5- 20 Degrees

100- 1.7- 18 Degrees

110- 1.8- 17 Degrees

120- 2.0- 30 Degrees

So....

Adjust heading accordingly by the appropriate amount in relation to your TAS as above and fly the revised heading for 2 minutes for every nautical mile off track.

eg: TAS 90kts - alter heading by 20 degrees and fly revised heading for 2 minutes for every nautical mile off track, to regain planned track.

You will need to assesss why the track error occurred (w/v not as forecast or DI and Compass not aligned frequently) but thats another story...

Hey Evo, Ive attempted to answer a NAV question, hey things must be looking up....:hmm:

Speedy:ok:

[FormationFlyer]

Hey? So at 120 kts you are going to fly 30 degs for 2 mins for every mile off track???

That wont work..

At 90 kts its 40 deg for 1 min per mile off,
at 100 kts its 34 deg for 1 min per mile off
120 kts ....30 deg...

to requote the other thread....

Originally posted by BEagle on the In Flight Navigation techniques thread:

quote:
--------------------------------------------------------------------------------
'Standard Closing Angle' is the simplest method we've found for correcting tracking errors and 'proportional correction' for timing errors. No need for lines on the chart such as those ancient 5 deg and 10 deg driftlines!! And no hard sums either. To summarise:

STANDARD CLOSING ANGLE

1. Establish your distance off track.

2. Turn towards track by a Standard Closing Angle of 60/(TAS in miles per minute) i.e. 40 deg for a 90KIAS Cherokee, 30 deg for a 120KIAS Bulldog.

3. Hold that heading for the same NUMBER of minutes as you were miles off track , i.e. 3 minutes if you were 3 miles off track.

4. Turn back onto original heading , recheck DI is synch'd and the rudder trim is correctly stopping flight with a constant yaw.

5. Adjust timing by adding 1/3 of the time spent on the Standard Closing Angle at 90KIAS or 10 sec per minute at 120KIAS.

It's easy and it works!!

[Speedbird252]

i gotta agree FF, the figures for 120kts look a bit odd! I did try it while off track at 100kts and it worked a treat, I didnt examine the figures past that as for me to be doing 120 kts id have to be in steep dive.....:(

Speedy

:ok:

[FlyingForFun]

Have to agree with everyone else who's said not to use the whiz-wheel in flight. You get almost no extra accuracy compared to the 10-degree fan-lines, but you will have to bring your eyes inside the cockpit for far longer - definitely not a good trade-off.

FFF
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[Tinstaafl]

For track correction I use the 1:60 rule (of thumb, for the purists). It lets me use just about any reasonable distance run/to go & off track spacing I want, making it easy to choose just where I want to join track.

I use 1:60 pretty much anytime I need to translate a lateral spacing into an angular deviation (off track correction is an example but there are other uses too).

What's wrong with using the whiz wheel in flight? It's no worse than writing clearances, a nav log, the occasional plotting task, studying an approach plate, using a checklist etc etc etc. As with ALL the tasks we learn to do the key is to cycle between them so that no one thing is left unattended for long AND the most important tasks get a higher priority/more attention. It can be used 'held up' and not down near one's lap too.

My whiz wheel gets used a lot in flight. Takes a couple/few seconds for simple jobs. Things I use it for: TAS calculations/groundspeed & ETIs/1:60, although often done in my head too/using an off track DME to derive along track groundspeed/calculating fuel eg what will I need to upload & where + conversion units etc etc

[FlyingForFun]

What's wrong with using the whiz wheel in flight? It's no worse than writing clearances, a nav log, the occasional plotting task, studying an approach plate, using a checklist etcI don't think that's a fair comparison. Writing clearances or looking at a nav-log or checklist requires very little attention, compared to lining numbers up accurately on a whiz-wheel. I'm not sure what you mean by "the occasional plotting task" - if I need to divert I may draw an approximately straight line roughly where I'm planning on diverting to - again, a task which doesn't demand much attention - but I wouldn't want to do much more than that in flight. I would always study approach plates for my destination and alternates before flight, and use them almost as a reminder, and a crib-sheet for the vital headings and altitudes (a bit like a plog) in flight - I'm a very new IMC pilot, so I don't know if more experienced pilots do the same. None of these tasks takes my attention away from looking out and flying for nearly as long as using a whiz-wheel.

The one task which many people do in-flight, which does take your attention away from more important matters, which you don't mention, is studying a chart (or a GPS). I suspect very few of us would be able to honestly claim that we have never had our head stuck in a chart for too long, only to look up and see something we'd have liked to have seen earlier. And I would think that using a whiz-wheel is more demanding than studying a chart.

FFF
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[englishal]

You have to look down at your charts / approach plates some time, there's no two ways about it until GA comes with a Heads-up display....

An easy trick for working out heading to steer is to [shock....horror:D] put the GPS on CoG, and compare it to my current heading. If the GPS displays a CoG of 300° and I'm steering 290° then I know there is a 10ish° drift to the right. If I actually want to go 290° over the ground then I have to adjust a bit to the left, until CoG=290°. Not forgetting of course that GPS is TRUE heading, and the DI is MAG heading,unless you can enter the Variation in the GPS.

For pre-flight stuff, I enter the wind velocity into my Casio flight computer and it tells me the course to steer :D

Cheers
EA

[expedite_climb]

If a student tries to use a plotter or ruler when I am instructing, I let them get in a state, and then confiscate it.

Whizwheel ? No way !

Heads in VFR is dangerous ! I've had enough airmisses, eyes outside, in NE england where it's quiet, let alone the SE.....

[dublinpilot]

I use 10degree fan lines, and it works fine for me! No mental calculations to do, no significant heads down time. Just a quick estimate of the off track angle, and the closing angle using the fan lines.

[FormationFlyer]

tinstaafl said...

What's wrong with using the whiz wheel in flight? It's no worse than writing clearances, a nav log, the occasional plotting task, studying an approach plate, using a checklist etc etc etc. As with ALL the tasks we learn to do the key is to cycle between them so that no one thing is left unattended for long AND the most important tasks get a higher priority/more attention. It can be used 'held up' and not down near one's lap too.

I sincerely hope it wasnt you in the PA34 that missed the C152 I was in by 30' to my left at the same level directly from behind..........personally the only time I am heads in is

1. in cloud (IMC does not necessarily mean you are in cloud nor on instruments even..)
2. Jotting down airprox information prior to a radio report :E

[TANGOWHISKEYINDIA]

As I don't know how to properly use the "10 degree fan lines" correction method, might some one enlighten me to a small crash course to the methodology, please?

[Pilot16]

Thanks for the replies.

but what wind? I dont think you need wind details to work out Track Error and Closing Angle with a whiz wheel:

1) Set distance flown on inner-scale against distance off on the outer. Read off heading error against the index mark to avoid further error.

2) Repeat Procedure with distance remaining with distance off track. Add both headings to give total correction to arrive at destinaton.

All this is pretty simple, streight forward and takes very little time. Especially when you do it at the half way point where the distance remaining is the same as distance flown. In this circumstance all you would do is double the heading you found in step 1. Simple right?

Now i have been practising a lot on the ground. Havent tried it in air yet. I wonder what would be so distracting about that?

[Tinstaafl]

Not a thing, Pilot16. Especially compared to the myriad other 'head down' tasks and considering a whiz wheel can be held up in front of you.

1. Hold up whiz wheel.
2. Look past the WW to see outside/scan instruments
3. Align numbers
4. Look outside/scan instruments
5. Check alignment, rotate scale if nec.
6. Look outside etc etc
7. Read TE/CA above the
60'
8. Look outside....

Need I continue? It's NOT that much of a drama! It takes a few seconds for most tasks. Often less time than copying a clearance. With practice a 1:60 doesn't have to take as many steps as I've belaboured the point above. Using a whiz wheel for typical inflight jobs is less absorbing than playing silly ******s with a GPS. Christ, even setting up a KNS80/81 RNAV can take more attention than using a whiz wheel.

FFF, you don't always have the opportunity to peruse approach plates or mark up a chart beforehand. I've lost track of how many times I've diverted to somewhere unplanned: Customer requirements, weather, company requirements, aircraft problems etc etc. Similarly, just how many of all of the available approaches do you memorise at your destination & alternate? What do you do if your chosen one isn't available? What if you're doing a multi-sector flight? How many do you try to remember? You have no choice but to be able to brief in the air. The skill is no different.

What about emergency checklists eg an electrical problem? Typically after doing the various memory items then checklist should be used to ensure all items were completed or done correctly. Some of them can get quite involved once the troubleshooting starts.

Plotting tasks: A major diversion, across featurless terrain requires a reasonable accurate track, especially once track corrections are required (they WILL be required...). That straight line is the base line from which your subsequent measurements are compared. Using a scale rule to draw it in makes things a sh!itload easier. And after the initial track assesment (if an immediate diversion is necessary) using protractor all makes things a sh!tload easier. Similarly, using cross bearings is an important part of navigating. How do you plot them? Like nearly all things aviation the tools have to be used 'correctly' ie without becoming so absorbed in the task that other tasks are ignored. Using the EGT to lean is a good example. People tend to want to stare at the EGT while leaning - unless they're taught to do the job differently. Using a whiz wheel, ruler, protractor or any other tool is no different.

FF, no it wasn't. I remember to look outside while doing other things. Perhaps they were looking at their map/GPS/Playboy Magazine? :ooh:

[FlyingForFun]

Tinstaafl, I'll bow to your greater experience on all the examples you list. Except to point out than none of them is a normal day-to-day task, they are all essential to the flight, and there isn't a simpler way of doing any of them.

TWI: the 10-degree fan line method is very simple. During planning, draw your track on the chart. Then (in a different colour) draw a line starting from the same point, but going off 10 degrees to the left (or right, your choice - or both if you want, but I find that clutters the chart too much).

During flight, scenario 1: you take off, and after 20 miles you fix your position as being half way between your intended track and your 10-degree line. You're 5 degrees off track. Correct by 5 degrees to parallel your track. For the first 20 miles, correct by 10 degrees (instead of 5) to put you back onto your intended track.

Scenario 2: after 20 miles, you fix your position exactly on track. After another 20 miles, you are now off to the left of track. Visualise a line, parallel to fan-line but starting where you fixed your position, then continue as per scenario 1.

The beauty of this is that it is surprisingly accurate, and - once you've fixed your position - requires no attention to be diverted away from other tasks except for a very brief glance at the chart.

[expedite_climb]

Tinstaafl, you are indeed correct about gps / kns80 etc..., but i still think anything that requires more than one hand (whizwheel, using a ruler to draw a line), is less safe, and not advantageous.

[BEagle]

Just use Standard Closing Angle and verily I say unto thee that the scales shall fall from thine eyes!

NEVER fart about with a whizz-wheel under VFR! Learn some mental techniques, assess error, do mental correction and LOOK OUT OF THE DAMN WINDOW!!