Diversions

[Mamakim]

Just interested to hear people's thoughts about the way they carry out diversions in flight (for small aircraft).

I was taught to do the CLEAR method which is:

Compass - align to DG
Course - draw or freehand draw the course on map
L - Log time when turning onto new heading. Work out distance and an ETI for the leg.
E - Engine Checks
A - Altitude (correct cruising level)
R - Radio (inform ATC of diversion)

When my instructor asked me to divert, he asked me to do it straight away, not from a point say 5NM ahead where I would have time to plan the diversion. This got me into a fluster as I would draw the track quickly using my protractor and then measure the angle (this only takes about 10-15 seconds), but he insisted that I did it freehand and estimate the heading and work out the correct heading when back on track.

Is this a bad way to do a diversion??

Do people do it this rough freehand way or do they spend 30-60 seconds and make sure things are accurate??

I'm interested to hear people's methods of diversions so please let me know the process in which you do it.

Many thanks in advance.........



MK

[Piltdown Man]

Note the time. Guess the heading (sod the protractor, it will be close enough, honest!). Turn onto your guessed track. Now monitor the track. Do your sums, but remember to "back-date" them when you actually turned. Adjust track as appropriate. Adjust estimate. Enjoy view.

[Mamakim]

Do you carry a protractor with you anyway??

[Dream Land]

My instructor had me do the same by using the compass circles from a nearby VOR, he may be grooming you for the examiner that he expects you will get. Cooperate and graduate.:ok:

[FlyingForFun]

When my instructor asked me to divert, he asked me to do it straight away, not from a point say 5NM ahead I always teach my students to divert from a known point. If your positoin right now is the middle of nowhere, then fly to a definite point and start your diversion from there. You might choose to use the time it takes you to get to that point to do your planning. On the other hand, if you are currently overhead a definite fix, then start your diversion immediately - or, if you're not comfortable doing that, orbit around your point while you plan. (Actually, a square is easier than an orbit, because you can do your planning on the straight parts of the square.)Do people do it this rough freehand way or do they spend 30-60 seconds and make sure things are accurate??I teach to do it freehand, for two reasons. Firstly, you might not have rulers and protractors with you - I certainly don't carry them on most flights. Secondly, accurately drawing and measuring tracks involves, IMHO, too much heads-in time - a subject which is particularly relevant given recent events in Goucesteshire, and even more so in poor vis (which is probably one of the most likely reasons you'll need to divert in real life). The lack of accuracy really shouldn't be a problem if you can confidently read from chart to ground and fix your position along the way, even just once or twice, and if you have line features to follow then even better.

But, as with so many aspects of flying, there is more than one way of doing it. For my CPL, I had to use a ruler and protractor for planning unplanned diversions. I found the workload very high, trying to meet the required level of accuracy of planning whilst still flying the aircraft, but it can be done with practice.

FFF
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[High Wing Drifter]

Mamakin,

I would second FFF's comments. I wouldn't want to contradict your instructor as that just adds confusion. However, something to keep in mind if you haven't been taught it. Unlike FFF the technique that reduced the workload immensly for my CPL was to maintain my PLOG on the chart, not the PLOG. By that I mean I wrote my ETA and ATA as well as fixes and times at fix on the chart as I went along.

As described above, again for the CPL diversion I was told to freehand the line. You then align your pencil with the wobbly freehand one and transpose to the nearest VOR rose to get your magnetic track, then just use the common rules of thumb to calculate your heading. You then turn on heading and mark an X with the time (two digits) as and when you identify your position. Estimate your course correction and proceed. It works beautifully.

My advice is don't fall into the trap of getting into inflight calculus. Your thumb is about 10nm, just count thumbs to get the distance. Just think of 100kts as being 1.5nm/min. Use the straight edge of the pencil to guess a 10 deg drift line to estimate your heading correction. Simple.

It is very satisfying and liberating being able to go aloft and navigate very accurately with just a watch, a line on the chart and pencil.

[DFC]

I always teach my students to divert from a known point. If your positoin right now is the middle of nowhere, then fly to a definite point and start your diversion from there

You are asked to divert. Ask why!

Sick passenger, deteoriating weather and the like - divert immediately.

Operational reasons - divert as soon as practical which could mean continuing to a suitable fix.

Again with the sick passenger, you can not spend time doing a nice hold while you draw and calculate but if the diversion is operational then you could spend the time but your boss would prefer someone who can waste as little fuel as possible.

Thus to demonstrate the ability to operate to commercial standards, I would expect an immediate diversion done roughly and then fine tuned......hense when asked why I always say seriously ill passenger! :)

Regards,

DFC

[tmmorris]

Worth getting one of those combined plotter/ruler things (compass rose on one end of a ruler, basically) as these make life much easier. I got one free with a book, I seem to remember, or they're about £5. I always keep it in the kneeboard. Absolutely fabulous for VOR cross-cuts - works in seconds.

Tim

[RatherBeFlying]

I'm finding a straight edge yields a better line -- there's usually a checklist on board that will do the job;) -- however I have been informed the flight test criteria disallow rulers and straightedges.

As for distance without a ruler handy, after you hold the pencil against a VOR rose for heading, line it up against a longitude line and read off the nautical miles from the scale -- there's 60 nm / degree of latitude.

Does not work with latitude lines as minutes of latitude = nm only at the equator; so, make sure you know which is which;)

I have a mini-binder with plastic pockets inside; so, after marking and measuring the line, I stuff the map inside and note times with a grease pencil. Saves wear and tear on the map.

Yesterday as we were doing a bunch, I circled the to and from spots on the plastic and freehanded a line between the two.

Reviewed diversions yesterday between 600 and 800 AGL over nondescript snow covered countryside and cloud that did not allow for much more altitude. It was a good day for that kind of practice although we did get into some heated discussions over the minutiae of map reading. The ceiling was low but vis was 15 sm if you could get high enough to see that far.

[Mamakim]

Thanks everyone for the great replies. Thats been very helpful


MK

:}