Archive for February, 2013

Flight Planning : Nav. #1

Thursday, February 28th, 2013 | Permalink

Briefing in preparation for a day when the weather turns good.  I was feeling about 90% myself, having just recovered from a cold, mentally all with it, but looking back it’s probably a good thing the cloud base was low.

One of those, write it down and maybe some of it will sink in (might even be right) posts and it may even be useful or interesting to someone else, you never know 🙂

Trip to East Bergholt

East Bergholt (Location)

East Bergholt (Location)

This is the standard “Dual Nav #1” destination and at this stage I’m happy to fly almost anywhere, so no I’ve never heard of the place either, but that doesn’t matter – it’s just somewhere to go (no doubt picked for a variety of good reasons – possibly because the locals haven’t got sick of Cessna’s doing 180’s over their village yet).

To plan the trip we’ll be needing the following toys (and a pen):

  • Flight Computer
  • Square Protractor
  • Ruler (scale markings in Nautical Miles, 1:500,000)
  • A current aeronautical map
  • Some paper (preferably with relevant columns and such like for flight planning).

If you need sticky back plastic, something has probably gone wrong…..

Magnetic Variation

Is the angle / difference, from magnetic north to true north, aviation maps are based on Truth North but once in the plane everything (Direction Indicator) is setup with reference to a compass which will measure magnetic north (ignoring some other errors which are calibrated out and we won’t go into).

If your variation is West, add it……if it’s East, subtract it.   Giving to the slightly politically incorrect phrase

West is Best……East is Least

It could be a big number, but for around these parts it’s variation comes out at roughly +1 to the true heading

So when we’ve compensated for wind etc. our final heading needs to be adjusted by +1.

A useful website if you want to know your magnetic variation.

Safety Altitude

Map Marked for East Bergholt

Map Marked for East Bergholt

This potentially will impact the wind velocities we need to input – we know where we’re going so we can figure out the safety altitude, then we can think about a flight altitude for the trip and finally that will let us think about the wind velocities.

There are generally two ways to determine a minimum safety altitude.

Option 1:  Plot the route as per something like the picture on the right, then taking 5 miles either side of the route, find the highest obstacle – but be weary some items do not need to appear on the map (e.g. a mast that is 299ft), which means a mast on top of a hill could catch you out.

Option 2: You’ll see on the map (chart), some elevation markings “09”, “08” etc. in purple, take the biggest number your route crosses and add 500ft.  This is the absolute minimum safety height.

Our route crosses 900ft, so our absolute minimum is 1,400ft.

Flight Altitude

Above 1,400ft but we can’t fly in cloud and we might also get restricted by airspace.

On this particular route, anything above 5500ft and we’ll be heading into Class A airspace, we can’t do that.   So something below 5,500 and above 1,400ft.

What about the clouds, well I’m rarely lucky enough to get a cloud base above 4,000ft, so something below that.   How about we aim for a nice round 2,000ft.

The Wind

Whatever it happens to be on the day – but we actually care about what the wind is doing at our intended flight altitude for the trip, not the surface wind.   You can find this quite easily thanks to the Met Office and Form 214 (UK Spot wind chart).  For the purpose of walking this through let’s say 330 degrees, 15 knots (330/15).


If there was no wind and no magnetic errors, this is the direction we’d want to fly – we’re never that lucky, but to work out the rest you need a reference.   So using our map and a square protractor we can figure out which way we’d point the plane in an ideal world – just to highlight the route, I’ve emphasized it in yellow.

Protractor Overlay

Protractor Overlay

The picture doesn’t do it justice, but trust me it’s about 115 degrees (True).


East Bergholt - Distance Measurement

East Bergholt – Distance Measurement

Hopefully you’ve noticed that we’ve marked up the route on the map (we know where we are, we know where we want to go and give or take, there’s nothing stopping us from going in a straight line to get there – the beauty of flight!)

What you might not have noticed is that the starting point is from a known reference point, a point by which we will hopefully have set our speed, be straight and level and not have much else to do but press “start” on the clock.  In this case, it’s 6 mile bottom and as luck would have it, is about 6 miles from the airport.

Using the most expensive piece of plastic you may have ever bought, measuring the distance in nautical miles is a 10 second affair, place ruler on line, read off the distance (just be sure you’re using the correct scale!)

Give or take a little, we can call that 29 nautical miles (flying in knots remember).

Now all we need to do is figure out which way we should actually point the plane in order to reach our destination (i.e. do our best to avoid going randomly off course due to wind and magnetic variation).


Keep it simple a nice round cruise speed of 100 knots today.

Flight Computer

Flight Computer (CRP-1)

The Flight Computer

You can do this next bit with graph paper and a calculator, but it’ll take you longer and would be using the universal language of mathematics……to hell with that, we’re paying £3/min to be in this party, time to crack out the toy that make this flying business look complicated to the outside world 🙂

Firstly we know that if there was no wind and we could fly a true heading, we’d want to fly 115 degrees (see track).   There is wind, 330/15, so we need to correct for this.

Using the “Wind Down” method on the flight computer:

  1. Flip it over to the “wind” side and set the little circular dot to the top of the ‘low speed wind’ chart.
  2. Turn the dial until “Index” is set against the wind direction (330)
  3. Now mark the wind speed, perpendicular to the circular dot (see picture), 15 knots today.
Wind Speed Marked

Wind Speed Marked

Heading & Groundsped on a Flight Computer

Heading Correction & Ground Speed

Now to find out what the heading correction needs to be:

  1. Slide the centre plastic part up until the circular dot is against our intended airspeed (100).
  2. Now turn the dial until it’s set to the Track (115)

As you can see and might expect, the mark we made for the wind speed, has now moved out to the right, give or take 1 degree (largely hinges on how good your marker pen skills are), if you look down from the mark to the line reading “10, 20, 30…”), you’ll see the difference between the centre and where the mark crosses this line is about 5 degrees.

So we’re going to be pushed at an angle of 5 degrees to the right, therefore we fly a heading (True) of 110 degrees.

However, the flight computer has one other trick up its sleeve – when walking through the briefing, when asked how could I work out the groundspeed, my first thought was “I know the wind, I can therefore work out the headwind/tailwind component”.   You could, but this involves a new set of tasks with the flight computer……..look again at the flight computer, you’ll notice that the marked cross is horizontally aligned with 112, that will be our ground speed if the wind stays constant.

So we now also know our ground speed will be 112 knots.

We know our ground speed (112 knots), we know our distance (29 nautical miles), thus we can work out how long the trip will take.   Just flip the flight computer over.

Setting Ground Speed on a CRP-1

Setting Ground Speed

The first thing to remember is that a flight computer is a circular slide rule.  Therefore it’s up to you to remember where you put the decimal place (e.g. 10 can be, 1, 10, 100, 1000….) and as long as you keep track of where the decimal point is today you’ll be good……..the task of doing so however introduces risk of human error.

The steps are as follows:

  1. Find the Index marker (Red Triangle marker in this case, marked “60”).
  2. Rotate the dial such that the point of this index is aligned against your previously calculated Ground Speed (112) on the outer maker.

Note what I said about a slide rule, in the photo on the right you might easily think I’ve just aligned it to “11.2”, but what is actually happening is I’m essentially shifting the decimal place out to the right by one place and thus it’s now “112”

All that’s left to do now is to find the distance we’re traveling and read off the time it’ll take to get there:

Time to Travel on a CRP-1

Time to Travel

  1. Find the distance to travel on the outer scale (29 nautical miles in our case) – note that the outer scale changes its precision at some points (e.g. some points like 11->12 have 10 increments and others, 21->22 have only 5 increments), thus the precision of the answer you get will vary.
  2. Now read off the number from the inner scale, you’ll see in our example it reads around 15 minutes 30 seconds – you can round up.   We’re going to break the flight up into shorter legs anyway, this just tells us within 30 seconds when we should be at our destination.

The process for measuring the distance on the map and then computing ETA’s can be repeated to break the trip up into shorter legs, thus ensuring that you don’t drift to far off track (at least that’s the general theory).

One final correction to Heading

It flowed better to go through the flight computer stuff in one hit, but waaaaay back at the top of this post I mentioned magnetic variance and about 6 paragraphs or so back I mentioned the flight computer had told us we wanted to fly 110 degrees True.

All good, but we need to compensate for that variance or we’ll have an error creeping in that will send us off track the further we fly.

The variance was 1 degree west, so we add this to the True heading (110) to get our final heading (magnetic) of 111 degrees.

And that is the theory……Verifying your Answer

Humans make random mistakes, the Flight Computer is very accurate, but lacks precision and prone to errors.   Digital Machines however are very repeatable things, so a well tested digital tool is a good way to verify your own multi-step, manage your own decimal place, try not to get distracted human process 🙂

Enter SkyDemon Lite set where you are, where you want to go.   Add your speed and the wind and you’re done!!!

SkyDemon PLOG

SkyDemon PLOG

Our mechanical numbers agree to within 1 degree, that’s about as good as it’s going to get (and good luck flying +/-1 degree anyway), so I’ll take that. The time looks about right to, remember I rounded up to 16 minutes.  Oh yeah and the level is wrong, just ran with their default, we were flying at 2,000 in my example but doesn’t matter for our example as we’ve set the wind the same.

Meteorology Exam : Passed

Monday, February 18th, 2013 | Permalink

Meteorology - PPL3

Meteorology – PPL3

After months of putting it off and finally just putting a date in the aero clubs books a few weeks back – which makes it a heck of a lot easier to revise for once you have a deadline you can’t ignore.   I finally sat my Meteorology exam.

With a final revision blitz over the weekend and not stopping until my head was about to explode with information about weather fronts and Form 215 interpretation.   It was time to see how I did for real.

Passed :  100%

I was quite amazed by the score, there was a question on icing I was 50/50 on and the last question I spent a good 5 minutes hmmm’ing and ahhh’ing about if the flight was safe or should be delayed.  Still, after a weekend of revising this much and all the previous months of opening the book and reading it over and over again.  I’m not sure I could have faced having to re-sit it, so I’m very glad it’s a done deal 🙂

…… on to the next one.

Lesson 42: Instrument Flying

Tuesday, February 12th, 2013 | Permalink

All week the weather forecast had been for blue skies, but ridiculous crosswind, so I hadn’t counted any chickens on this lesson – in fact at 8:50am I was still waiting for the phone to ring.  It didn’t.

Upon arrival, it seemed like we were very much on – even with the briefing room windows being thrashed by the winds outside.   Might be out of my limits, but not my instructors.

“Stop looking at the instruments”

Finally a lesson where I won’t get told this 🙂  It’s safe to say I rarely ‘believe’ the big instrument outside the window and am much happier with the gyroscopes and pressure sensors…..yes it’s wrong, yes they lag, no I can’t keep my eyes off them.   I’m sure everyone has their ‘thing’ when learning, this is mine.


A bunch of stuff to get through & tick off today if possible:

  • Suction System Failure (Flying on a Compass)
  • Diverting to another airfield
  • Straight and Level on Instruments
  • Climb/Descend on Instruments
  • Rate 1 turns on Instruments
  • Unusual Attitudes on Instruments
6 Basic Flight Instruments

Basic Flight Instruments

I’ve seen my closest alternate airfield, during the briefing the concept of having to find it on my own was making me think “Not a chance……”  

After a year and a half you’d think I’d know the ‘Basic T’ of instruments off by heart, and yet it was amusing to find that when put on the spot I couldn’t put them in their positions…….weird – but then I can touch type, but I couldn’t tell you where all the keys are.

Plane Checkout

G-HERC (Golf Hotel Echo Romeo Charlie)

G-HERC (Golf Hotel Echo Romeo Charlie)

It’s been a while but back in Romeo Charlie, you can’t go wrong with this plane, I dunno why but it always feels shiny and new.

Except today it had a build up of ice on its wings.   Time to become taxi driver and turn it around so its wings were facing the sun, that soon had it sorted.

Other than that, looking good as always.

Pre-Checks & Taxi

My morning coffee hadn’t been fully absorbed yet, I was doing some strange things in the checks…..   I always, always, always now inform instructors if the temperatures are not in the green, but for some reason today I just assumed it was ok for them not to be today and carried on.  Of course it was picked up – I mean come on, there was ice on the wings 10 minutes ago!

With the crosswind I found it doubtful I’d even do the take-off, but we formulated a plan for me to do it during the take-off brief.

Climbing : Rudder, Rudder, Rudder

God you’d think this should be instinctive by now, but I must have been wearing the record out today “rudder”, “more rudder”, “don’t forget the rudder.”    My other sin of the day was not lowering the nose in the climb, thus essentially meaning you’re not able to lookout and see if you’re about to climb into something else.

Suction System Failure

The artificial horizon and direction indicator (and in some cases, but not this one the turn coordinator) are all driven by gyroscopes – being antique technology, they’re all driven from a suction system whereby the engine drives a pump which creates a vacuum, resulting in an airflow which makes respective gyroscopes spin.   There are better (and safer) ways to do it, but we won’t go there today.

Best case scenario of failure then, if we lose the suction pump, we lose the artificial horizon and the direction indicator.   An easy failure to simulate:  they were covered up by a piece of paper.

Now I’d have to fly on the compass and the big picture outside (which my instructor will tell you I hate flying on 😉 ).

By some miracle, upon request to fly a heading of East, I managed to turn the plane and level out almost spot on East.   Now to try the same game for a heading of North, this time I undershot a little but by and large, it was north(ish).   Put a tick in the box, we’re done here 🙂

Practice Diverting :  Map??

Now I went through this in the take-off brief, if you’re thinking of suffering from a heart attack, you really shouldn’t go flying.   It didn’t do me any good though, I’d still need to find that alternate 🙂

Having done the practice call of telling the current frequency we were going to divert, this just left the amusing moment of

“So get your map out…..”

“Map?   Nobody said anything about needing a map”

“It’s a legal requirement to fly with one in the plane”

“Yeah, I’ve got one in the plane, it’s in my bag on the backseat – we’re legal 🙂 “

Other readers who are learning to fly might find this absurd, how can I be this far in and be leaving a map in my bag?   I’d want to agree with you, but the reality is, in all my flight training I’ve used a map in a plane:  Once and even then it was an instructor passing me his, there’s been no development of getting into a habit of having it in the side pocket because it might be needed on a lesson etc.

Still, my instructor was having a “heart attack” (if she wasn’t before, the map revelation may have triggered one), seems reasonable to borrow the victims map 🙂

Fen Drayton & Lakes

Fen Drayton & Lakes

All that turning for suction system failure, meant that initially I had no idea where I was.   However, now I needed to find Bourn, a few seconds looking out of the window and suddenly my first local area solo was paying dividends.   Just off to the right was the now familiar lakes just north of Fen Draydon, where a few weeks ago I’d been getting in some practice advanced turns.

I knew ball park where Bourn was, but a quick look on the map suggested that it’s dead south of Fen Draydon, so all I needed to do was turn the plane 90 degrees to the left to fly south of Fen Drayton and we should find ourselves an airfield.

What I hadn’t quite appreciated (though I’ve noted this before), is that because we were at 3,000ft, trigonometry tells you that your forward visibility on the ground is immense!    As a result I was stunned by how quick the airfield was in sight.

Phew, found it…….navigation is a weird thing, it should be quite obvious that if you point a plane at the heading for something, given some time, it will appear!!   Yet it’s amazing how, almost relieved, you are when you discover this holds true.

Instrument Flying

Time to see if I could fly straight and level with my eyes closed.   The temptation once you do this is to move the control column, but knowing the theory that my internal balance system will go to hell upon doing this, I found myself consciously fighting the desire to move the control column and change nothing.  Sure enough upon opening my eyes we were still straight and level at ~3000ft, but my god does it take some concentration and commitment to the idea that all the sensations in your head are a lie.

To emphasis the point, I was asked to close my eyes, my instructor would fly the plane and all I had to do was tell her what she was doing.   Sounds simple huh?   I waited a few seconds, all the time feeling like we were rolling right, but initially I resisted that this could be the case – soon however it felt there was a definite right turn going on.   A few seconds later I was starting to be convinced we were climbing……and upon opening my eyes, we hadn’t moved!!  We’d just been flying straight and level.   The human body is rubbish!  🙂

Next it was time to do some instrument flying proper, using a set of Foggles, essentially these glasses block your view of the big instrument outside the windows and let you only look down at the instruments.

The scan of the instruments changes when flying on instruments (not that you should be on a PPL).   Due to the fact that the Artificial Horizon is the only instrument that tells you about pitch AND roll, this becomes the primary instrument and all scans start and end here, then only a reduced set of other instruments are focused on in the scan, depending on the maneuver.

So for straight and level the sequence is:  AH, ALT (Altimeter), AH, DI (Direction Indicator), AH, ALT, AH, DI, AH…..and just keep repeating this.

The trick is to not stop concentrating on the scan and make small corrections.

One thing I have no issue with is in trusting my instruments, so I found myself quite happy to cycle this scan and fly it straight and level with no real issues, I could have happily done that all day (or at least until the fuel got low).

Next up, climb on instruments, this uses a slightly different scan but the fundamentals are the same.  Followed predictably by a descent.

Finally some turns, which rather than the normal 30 degrees of bank for a level turn, on instruments are done at ‘Rate 1’ – which is marked on the turn coordinator as the the white marks under the wings of the aeroplane, this equates to a turn of ~15-18 degrees.

Flying into the Sun : Communication

One side effect of making these turns was being asked to turn onto a heading of 120 degrees, no problem.  Until when I got there, I was hit by now flying directly into the sun – which foggles don’t protect you from, now you just have a diffused blinding light, rather than just blinding light.  Resulting in an interesting mis-communication moment:

I’m no longer flying on instruments….

What I meant was “I can not see the instruments, therefore I’m not able to fly on them.”   However, by the time I’d brought myself to accept that and say something, my attempts to fly straight and level into the sunshine were looking pretty shocking.   So I think the statement got interpreted as “I’m doing a pretty rubbish job of this aren’t I….”, resulting in some tips on bringing it all back together.   Though moments later the question of “Can you actually see the instruments?” came and we changed heading soon after 🙂    When you see stories on the news about flight crews being confused in the cockpit, this is how easy it can happen….

Once I could see the instruments again my flying returned to normal, but it made for another good point.  While flying into the sun I was seeing the instruments through the glare maybe once every 5 seconds, at that response rate, the control loop was broken – I wasn’t able to react sufficiently to keep the plane flying and was essentially just losing control.   Which tells you a lot about how much you need to concentrate on the instruments once outside of visual flight conditions – and why it’s not allowed on a basic license.

Unusual Attitudes

Essentially this task involves you closing your eyes with your head down, while the instructor sets the plane up into some bonkers configuration (e.g. no power, pointing at the ground, rolling right….).

I was quite happy recovering from the no power conditions, but my Achilles heel turned out to be when the power was left full on.  I’d recognise there being too much power and reduce it, but I wouldn’t bring it all the way back to idle, this is the trauma that Charlie Bravo has done to me, so expectant of a engine stall at idle (and yes I know I’m not even in the same plane) I can’t unconsciously just pull the power to idle.   Resulting in the airspeed at times sitting at borderline yellow [caution] speed, but my tendency seemed to be to take off just enough power to keep it bordering green.   There had to be something a little off today, the rest had gone quite nicely.

Head for home: Massive Crosswinds

It had felt a minor miracle we’d gone up at all, even more so I’d got to do the take off in the winds we were getting.   On return to the airfield they hadn’t let up at all, in fact as we flew downwind they were at the limits for an instructor, possibly beyond.   Resulting in another first.

I’ve never flown Runway 28, it’s a grass runway rarely used except I guess for times like this.

The thing to watch in bad winds is the ease in which you can lose airspeed, essentially wind shear, so you want to come in a little faster than normal – and I guess faced with the shorter grass runway and not wanting to overshoot, but also a flock of birds and an ATC request to not land on its numbers.   I let the airspeed get a bit lower then we’d like.

The landing however seemed all good (though I suspect there was a lot of help involved).


Some good points made, it’s been a while since I’ve done the fundamentals, so a reminder on the climb out that I need to lower the nose and have a good look out, I can’t just point the nose for 80 knots and sit back until the altimeter reads 3,000ft 🙂    and if I’m going to descend, I can pick any speed I like, but I should know why we’re descending at that speed (e.g. I’ve decided to do a cruise descent, so we’re descending at 90 knots……fine, but don’t descend at any old rate the plane happens to give on the day etc.).

Other than that, to read up on navigation because the flying bit is now essentially done and we’re into navigation proper from here on in.