Skydemon Archives - Get Your Wings

27th February 201922nd March 2019

PilotAware and Skydemon the perfect VFR pairing?

I had an exciting and varied day Sunday, first I taught lesson 7 from the new syllabus (climbing and descending ) ending up with a bit of lesson 6 (straight and level) revision in poor conditions, where the horizon was barely visible. The student did very well in difficult conditions and its always nice when they say they really enjoyed it.

Today was for me about PilotAware and Skydemon, regular readers will know I think that currently, this is the best possible combination; during the lesson in the haze it was difficult to see other aircraft but, with PilotAware and Skydemon I could see the other aircraft, which we knew was out there, as it was from our club. The indicated position on Skydemon allowed us to quickly locate it and ensure we remained a safe separation. +1 for the combo.

Next up was my opportunity to occupy the co-pilot seat in a Twin Otter. The Twin Otter has Mode S transponder but, no ADS-B Out and no ADS-B In, thus they wanted to see PilotAware in operation. The Twin Otter in question was Skydive one the parachute aircraft, the test was very successful, in part because most aircraft at our home airfield have ADS-B Out or PilotAware. On the first flight we got a traffic service from Lakenheath as normal and shortly after we were showing a contact on Skydemon, the pilot said it will be interesting if ATC reports the same or not, just as he finished speaking or the radio came traffic information relating to the aircraft. This was interesting and helped show how pilot aware could help. On the next lift an aircraft was showing ahead and, on the left, Skydiveone would have normally turned left but, an alternative routing was taken to maintain separation. Now the worth of PilotAware and skydemon was proving interesting! Then a little later in the flight we asked for clear drop and ATC came back with another aircraft in the zone, we had heard on the other frequency that an aircraft was leaving the circuit and with the traffic information we were able to positively ID the aircraft, thus there was no need to abort the drop. Fantastic news for both the safety and the cost of a go around!

There was few other contacts that helped too but, above was enough to convince them the effectiveness!

Then after a few lifts in the Twin Otter, I got to be the passenger in our C42A while my friend and co-owner did a few circuits.

10th February 201922nd March 2019

What is EC or should I say Electronic Conspicuity or even ADS-B In and Out?

What is EC or should I say Electronic Conspicuity or even ADS-B In and Out?

And why do we care anyway!

In today’s world of aviation, technology is becoming the norm and if that helps to increase safety then I for one am in favour of it and I hope you are too.

It was not long after I got my NPPL that I was using and EC in the form of the then beta product of an upcoming technology called Pilotaware. Fast forward a number of years and Pilotaware, SkyEcho 2, Stratux, Power FLARM and more are all affordable in cockpit EC devices. Add to these the traditional transponders which have various modes A, C and S as well as ADS-B Out and some systems having ADS-B In and then there is weather reception, TCAS and secondary surveillance radar (SSR) too!

So as a member of both the UK Microlight and GA community what is best for me and what do all the TLAs (Three Letter Acronym) mean?

ADS-B stands for Automatic dependent surveillance-broadcast, for your starter (yes I know that is a four-letter acronym).

But first to set the scene, I would not consider myself an expert, but I do have some knowledge having researched the subject to enable me to write my transponder decode application which is available for free download from this site.

The short version of this blog is that I remain happy with my current combination of devices, which consist of ADS-B Out, and Pilotaware for ADS-B In and Pilotaware device reception including OGN (Open Glider Network) when near a ground station that is up-linking and all displayed on SkyDemon.

The Transponder

The transponder is a powerful device and comes with various modes depending on its age and capabilities. Older aircraft have Mode A & C with newer Aircraft/transponders having Mode S also

Mode A: In response to Mode A interrogation the transponder transmits an identity code for the aircraft in the octal range 0000-7777 the Squawk code.

Mode C: Transmits the aircraft’s pressure altitude automatically and augments mode A hence sometimes called mode A/C

Mode S: Mode S has over 17 million unique 24-bit aircraft addresses known as the ICAO number or mode S address allowing the unique identification of every aircraft, altitude reports in 25 feet increments and the call sign (or tail number) is transmitted along with other information also.

Unlike traditional Secondary Surveillance Radar (SSR) stations which elicit multiple replies containing the same information from all aircraft within their range, Mode S makes selective (Mode S is abbreviated from Mode Select) interrogations of each specific aircraft. ‘All call’ interrogations are also made to identify new aircraft to be interrogated. Mode S transponders are backward compatible with Mode A/C radars.

Civilian Mode S supports a number of different messages Each message has a particular purpose. The formats DF0, DF4, DF5, DF11, DF16, DF20, DF21 and DF24 are used in civil aviation at present.

Number	Message
DF0	Short Air to Air ACAS
DF4	Surveillance (roll call) Altitude
DF5	Surveillance (roll call) IDENT Reply
DF11	Mode S Only All-Call Reply (Acq. Squitter if II=0)
DF16	Long Air to Air ACAS
DF20 DF21	Comm. B Altitude, IDENT Reply
DF24	Comm. D Extended Length Message (ELM)

Location Reporting

Now some people think as they have a mode S transponder it transmits their position and that their exact location is displayed to other aircraft, but this is not the case. Location information is transmitted in the ES (Extended Squitter) messages DF17 and DF18.

DF17	1090 Extended Squitter
DF18	1090 Extended Squitter, supplementary

For a mode S transponder to transmit ES DF17 (we will come to DF18 later) the transponder must be connected to a position source i.e. a GPS, and these come in different levels of certification from uncertified up. This configuration is known as ADS-B Out.

It is DF17 (and DF18) that devices like Pilotaware and SkyEcho use to show the exact location of other Aircraft. For non-ADS-B Out aircraft, they use the signal strength only to show proximity but, not location and they show altitude received too.

If only ADS-B Out gives the position how does Flight Radar 24 and 360Radar work their magic and show position of the other aircraft without ADS-B Out? Well, this is done by a system called MLAT which is out of scope for this blog as it requires multiple ground stations.

So DF18, this is essentially the same as DF17, however, it is the message used by a new breed of EC devices which are low power and low cost. They are regulated under CAP 1391. CAP 1391 (First published 2016) specifies Electronic Conspicuity devices that have the ability to signal their presence to other airspace users, thereby turning the “see-and-avoid” concept into “see-BE SEEN-and-avoid”.

It must be noted that CAP1391 states that they must not transmit if carried in an aircraft equipped with a Mode S transponder as this will result in mode S messages and DF 18 being broadcasted.

A system receiving DF18 implicitly knows it cannot interrogate that device, hence no aircraft can transmit DF18 if it has a mode S transponder as it will block or confuse SSRs (CAP1391 6.35). You cannot switch your mode S transponder off due to SERA.13001.

SERA.13001 requires the pilot of an aircraft equipped with a serviceable SSR (Mode S) transponder to operate the transponder at all times during flight.

Additionally, these new devices are intended for UK Annex II aircraft; non-complex EASA aircraft of <5700kg MTOM and for gliders and balloons. (CAP1391 Executive summary 7).

Lastly, they do not allow access to TMZs.

GPS

Mode S sends more information then just the location received from the location source, it sends information about how reliable that data is and if it were to fail, the size of containment that is required and more. The data that most advertisers quote is the SIL value but, this is just one of the parameters.

Much is made of some of some of the new devices having a SIL1 GPS in their ads, however, most have an SDA of 0 which means they are not trusted!

SIL (Source Integrity Level) field is used to define the probability of the reported horizontal position exceeding the radius of containment defined by the NIC value. 0 is unknown integrity or untrusted!

SDA (System Design Assurance) field defines the failure condition that the ADS-B system is designed to support.

NIC (Navigational Integrity Category) is reported in conjunction with the SIL, NIC of 0 is unknown integrity or untrusted!

Can I be seen on TCAS?

Yes, if you have a mode C transponder because most TCAS system utilises an aerial array to determine the position of other aircraft using mode C transmissions.

TCAS II has to be linked to a mode S transponder if fitted so its presentence is encoded in the mode S messages. But TCAS systems below version 7.1 don’t use the ADS-B out messages from other aircraft.

TCAS II Hybrid Surveillance does use Mode S messages but currently has limited adoption.

Hybrid surveillance is a method that decreases the number of Mode S surveillance interrogations made by an aircraft’s TCAS II unit. This feature, new to TCAS II version 7.1, may be included as optional functionality in TCAS II units. TCAS II units equipped with hybrid surveillance use passive surveillance instead of active surveillance to track intruders that meet validation criteria and are not projected to be near-term collision threats. With active surveillance, TCAS II transmits interrogations to the intruder’s transponder and the transponder replies provide range, bearing, and altitude for the intruder. With passive surveillance, position data provided by an on-board navigation source is broadcast from the intruder’s Mode S (ADS-B Out) transponder. The position data is typically based on GNSS and received on own aircraft by the use of Mode S extended squitter, i.e. 1090 MHz ADS-B, also known as 1090ES. Standards for Hybrid Surveillance have been published in RTCA DO-300. The intent of hybrid surveillance is to reduce the TCAS II interrogation rate through the judicious use of validated ADS-B data provided via the Mode S extended squitter without any degradation of the safety and effectiveness of TCAS II.

What to buy?

Should you buy a CAP 1391 device such as a SkyEcho 2? Well that’s up to you but, if you have a Mode S transponder you will need to disable the only feature it has over Pilotaware, which costs less and has mode compatibility with other systems.

If you don’t have a Mode S transponder then Yes, it is an option and will increase your visibility, but not to most TCAS equipped aircraft including military jets and helicopters as they are looking for mode C transmissions.

Conclusion

Finally, for me a proper transponder with ADS-B Out (certified GPS or uncertified) is also essential in the increasingly busy skies for your visibility and Pilotaware as your ADS-B In device gives you the best low-cost solution currently.

Today I was told a story of an instructor doing a PFL and they got a Mode C alert on Pilotaware but, at first could not see the other aircraft. Then at a low level saw a chinook below them. The instructor’s aircraft also had a transponder with Mode A/C and S also with ADS-B out, so the TCAS in the Chinook would have been going off too. “see-BE SEEN-and-avoid” in action.

17th July 201715th September 2017

Little Snoring and the 60th anniversary of the McAully Flying Group

Today we thought we would be brave and visit it a predominantly GA fly-in our C42 Microlight!

The Fly-in was at little Snoring an ex RAF base for the Mosquitos (and other aircraft) opened in 1943, sadly only one of the runways remain operational. The fly-in was hosted by the McAully Flying Group who are celebrating their 60^th anniversary. Two C42 aircraft from Chatteris flew over and that was 66% of all the microlights there, the other was an EV97 Eurostar. I guess due to the weather there was not as many as was hoped for but there was sufficient planes to make it worthwhile and as with my last two flights and blogs there was more changes in PilotAware and SkyDemon to test, I think I’m get obsessed with this combination now!

So there are a number of changes too both pieces of software, but the main items of interest for me today was the PilotAware’s native connection in SkyDemon and a PilotAware patch to fix the issue with not being able to access the internet while connected to PilotAware.

The native PilotAware connection in SkyDemon connects a lot quicker the old method of Flam, which took a few seconds and would show “seek satellites” while it connected, the new method seems to connect instantly!

And the patch also worked fine allowing us to use live date while navigating.

The whole setup for the third consecutive flight remained rock solid.

Below you can see the combination showing an aircraft near us (we both took off from the same airfield) it is showing in the main screen and on the traffic radar.

The actual flight to Little snoring was uneventful, however the return was to be a fun trip the first C42 return back to Little Snoring so we decided to wait before leaving, eventually a break in the weather came and we confirmed on a couple of weather radar sites that we could fly out and down between two fronts. In a couple of places we were down to 650ft but as the radar had shown we were soon through the worst of it and flying back to Chatteris behind the front that moving through.

We were not operating at minima, but the training we had for that was certainly a help as was SkyDemon confirming the presence of obstacles on route well in advance so we could make certain we had good visual contact and this helped lessen the workload in the cockpit. As it turned out if we have wait 3 more hours we would have had a perfectly fine flight back, however in many ways the practice of navigating in low visibility and at low altitude was quite satisfying and Simon who was flying that leg did a great job ably assisted by myself!

29th November 201610th August 2017

A quick blog about a short flight testing PilotAware with SkyDemon

So a great day to fly on Saturday, however our microlight was booked out for the whole day, well actually it wasn’t, it was just that a booking failed to be cancel that a member of our group said they had cancelled, man vs machine! Not to worry Sunday was looking promising, but as it turned out it was not so good, rain and low cloud was the order of the day. I did get a 10 min flight in and my friend Simon and I went up for another 20 mins later too.

Hardly worth blogging about really, but I had built my PilotAware into a single case and wanted to ensure it worked so 10mins and a further 20mins was indeed worth it, well for me any time spent aloft is worth it!

So this is what PilotAware looked like before I rebuilt it:

And now it’s more robust in a single case:

I have also removed the casing from Both the GPS and DVB-T TV tuner dongle RTL2832U that is used for the ADS-B receiver. The ADS-B receiver runs quite hot so I have ordered some SMD heatsinks for it, but they have yet to arrive.

So on the first flight I had it wide open to all traffic and wow with the change of aerial to the “Rubber Duck” meant I could see traffic everywhere, all way out or way high! It could have also been that I had enabled the feature “Mode-CS (Beta)”.

The first thing to note was I was seeing myself as a target on my Skydemon, When back on the ground I added the Hex of our aircraft and rebooted the PilotAware, this resolved the issue of seeing myself. Next I downed the range from long to medium and the height in Skydemon from 50,000ft to 10,000.

So on our next flight and with Simon at the controls I had time to play with it and we were picking up traffic, but with the new settings the screen was a lot less crowded, however we did not see a Mode S equipped aircraft below us and landing and I’m unsure why that was, it was showing in the Traffic screens so I will be asking that question to see if it is my configuration.

Overall I would say this is a great supplement to your own lookout, which remains the primary way to observe in VFR.

Next up I have ordered a plug to connect my headset to the audio out so I get any warnings without needing to watch the screen. I will let you know how I get on with that soon.

13th July 201523rd December 2023

First flight as a qualified pilot!

Almost 3 weeks beforehand I had taken my GST and passed yesterday (Friday 10^th July) my licence dropped through my letter box. In eager anticipation I ripped the envelope open, there was a nice looking blue book, which I assumed would be like a passport, I opened it and it was just a plastic wallet, I don’t know what I was expecting, but the black and white piece of paper that purports to be my licence was not it! oh well, the main thing is I can now fly and as it has been less than 30 days, I can fly without needing a check flight too. The 30 day rule is not a legal requirement is just written into our aeroplane’s syndicate rules.

I arrived at the Chatteris airfield and could not believe on such a fine day there were not more people flying, what a waste of a great day, I thought to myself, I was also quite pleased as it was not busy for my first fight. It’s a very odd almost unnerving feeling, not needing to ask if it was OK to fly and OK to fly to wherever! I checked the aeroplane out and got her out of the hangar. I went back into the clubhouse and said I was off and where I was planning to go and off I went!

I climbed up to 3,000ft and I had my trusty Skydemon and Garmin Glo set with the route and I had loaded it onto my iPhone too as a backup. After about 10mins Skydemon reported a loss of GPS signal, WHAT NO, I thought, lucky I loaded it on my iPhone too! I knew where I was going so it was not a big problem, however, it was a little upsetting, I switched off the Bluetooth on my phone and the iPad reconnected to the Glo and started to work, the problem did not reoccur! The Glo should be able to handle 10 concurrent connections, so I don’t know what went wrong, I will look into this later…

The trip was up to the Wash and then along the coast to Hunstanton around Hunstanton and back over Grimston on to south King’s Lynn and back to Chatteris this took 80 minutes from taxing to parking up on my return. The landing was good it floated longer than normal, possibly due to the crosswind, but alas no one saw it, funny how everyone sees a bad landing but no one sees a good one!

To sum up, it’s an incredible feeling of freedom and responsibility to decide, plan and fly your own route without needing anyone to endorse it!

I’m planning on another couple of solos and then maybe taking some friends up with me!

Some pictures from my flight are below:

3rd May 201514th August 2017

Short field Takeoff and Landings

Short field Takeoff and landings were the order of the day as it was a UK bank holiday weekend thus it was too wet, too windy and too low a cloud base for a cross country!

Mike decided to demonstrate short field approaches and take offs, but first we would take off and fly out to the south and check what the cloud base was and also I wanted to switch headsets and try Mike’s out to see if it was much better than mine or not.

We were using runway 19 so after take-off we just continued out in the same direction we got to 1,100ft with the clouds just above us. Mike offered to swap headsets, he is a great David Clark fan and has a H10-13XL I have an HX20-10XL, but the ENC never seems that great to me, there is a difference, but it’s not massive. My headset being second hand and old also has the older larger battery pack. Mike’s headset did seem a lot quieter than mine without the ENC switched on and the noise reduction was more dramatic when switched on; so I guess either I have a problem or the H10-13XL is a better headset, on the plus side for the H20-10XL it is more comfortable!

I then flew us back to the circuit and landed we turned down the peri-track to clear the runway for Tom and Katie who were inbound behind us and taxied to runway 21 as the wind had moved around a little. Here Mike demonstrated a short field take-off; with the normal single stage of flap he increased to full power while holding the aircraft on the brakes, with the stick full back he released the brakes and as soon as we were airborne he lowered the nose allowing the aeroplane to accelerate in ground effect until we reached 60 knots and then we climbed away as normal. I then flow the circuit and Mike took over for the short field landing; we were to come in lower and with power, the normal 2 stages of flaps deployed, as we take the power off the aircraft decelerates rapidly, as the main wheels touch we apply full braking, while keeping the nose wheel off the ground as long as possible.

The remainder of the lesson was me trying to emulate what Mike had shown with me having various levels of success. The take offs where mainly fine, putting the nose down early enough was an issue the first time! The my first landing was OK and we stopped nice and short my next two were go arounds, where the approaches were ok but the round outs were not great, my penultimate landing was good and final landing was fine too, however the right wheel locked up under the heavy braking, I instinctively released the break and corrected with the rudder, which I was told after was the correct thing to do, however I just allowed it to rollout as normal after, forgetting this was short field practice!

This was fun lesson that I really enjoyed, the take-off and landing performance of the C42 is quite remarkable I don’t know the exact distanced and I was helped by the head wind but I would guess we were up in less than 60m and landing in 50m!

During the week I have been playing with an SDR (Software Defined Radio) a cheap USB TV tuner with the RTL chipset from eBay (about £4.00 + P&P), with the right software you can receive ADS-B messages and I wanted to see if we could see the C42 with it and we could! The strange thing is that while on the ground the code (normally 7,000 for VFR) is not seen, but once airborne it is, after discussing this we think it’s due the difference between Squitter messages and Squawking, squitter being the unsolicited broadcast of information every second or so from a mode S transponder and Squawking being the reply transmitted by the transponder in response to an interrogation message, I will try to confirm this and update the blog.

Lastly I have Skydemon (which I think is great) loaded on my iPad mini WIFI model and it uses an external Bluetooth Garmin Glo GPS. Following the update by Apple to iOS 8.3 this and many other GPS units have stopped working. This is a major issue if you intend to navigate using and external GPS, however I found that upgrading the firmware in the Glo to 2.7 and then “forgetting” the connection on the iPad and reconnecting it (this is an important step) it was working once more!

To upgrade simply follow the instruction found on the Garmin site

A shameless plug as a closing thought! with the looming domain and hosting cost upcoming, I would ask you to consider clicking on one or more of the ads on the site to help me offset the site costs!

11th January 201523rd December 2023

Triple First

Today Sunday the 11 Jan 2015 was triple first for me as it was my first flight in 2015, my first flight in a microlight over my home and my first flight using Skydemon to navigate!

On arriving at the club I met Alan who was just leaving and had not been able to fly, thus I thought this would be the fourth consecutive week the weather would stop me from flying too!

After the normal greetings etc. Mike ask what would I Like to do, normally I reply whatever you think I should be doing to work towards my GST, however today I had some new toys with me, over Christmas I had got a Garmin Glo satellite receiver and a Skydemon subscription, I had a little play with these at home, but not flown with them, so I asked Mike if we could fly using them and plot a route over my house and back, he agreed.

So the first task was to install the partly homemade iPad Mini 2 bracket. I’m using a homemade one as we have a Garmin satnav bracket in the aeroplane and I therefore needed to adapt a Garmin arm to take an iPad mini. This was made from a sheet of 3mm Perspex I had ordered and then cut to size and bent to shape using a heat gun, this was a lot easier then it may sound! An existing Garmin mount arm and ball and socket purchased online for around £5.00 the lot, some nuts, bolts and a circle of aluminium provided and assembled by a friend. The end result can be seen below.

The GPS mount was a universal phone suction mount that my son no longer uses, purchased online for around £3.00.

This post is not meant to be a review of Skydemon or the Garmin Glo, which I plan to do later, once I have got to know them better, however I will give my first impression of them both.

First Mike showed me how to remove the inadvertent waypoints I had added which was simply a case of dragging them to the next point, or the origin, or destination.

He next showed me pulling the compass up and out to reveal the HSI display, but the collapsed view is preferred.

Now with it all installed it was time to go flying, it was windy again so no flaps for take-off! We departed on runway 24 and flew the circuit leaving on the downwind leg to converge on the course shown on Skydemon, the first thing I noticed and liked is you could roll out on the heading as there is no over or undershoot, and the display shows you the direction you are travelling and the direction you need and when you are within a few degrees it turns green. It made it very easy to fly accurately, I just can’t see myself flying without it once I have my license the way it calculates the direction means you don’t need to allow for drift as it does this for you too!

We flew out to just south of King’s Lynn, then turned east over Bawsey Lakes and on to the village where I Live Gayton.

The Garmin Glo had a rock solid fix throughout so there is not much to say re this it just does what it says it does!

Flying back, Mike did his normal of, ok take me back, but this time I could use Skydemon and I flew us back without issue I used the extended centre line shown on the Skydemon map to line up on the runway very early. As I was about to touch down a gust of wind caused us to balloon, but I held it on the stick and made a very soft touch down, Mike complimented me on the land too!

This is what flying should be like, well for me anyway!!!

Back on the ground and with the aeroplane refuelled I was about to go home when Stuart asked if I would like to go for a fly with him, I did not turn him down! We stayed local as he flew a few circuits and then around the drains and back for some more circuits. It was very interesting to see how someone else flies, the main difference being he comes in much higher than I on the landings. I think I may have picked up a few tips from watching him fly.

6th July 201416th August 2017

Navigation to Boston Airfield and Triangle of velocities

I arrived at Chatteris on what seemed a damp and grey day around an hour before my lesson to plan my flight to Boston as I was nearing the airfield I saw a C42 flying in the circuit and I was thinking to myself that the parachutists would not be jumping with such cloud cover, however as I turned into the track leading to the airfield I saw the twin Otter taking off closely followed by the main training C42. It often seems to have its own micro climate which allows for the microlight and the parachutists to go up while all-around the weather would not permit! When I left home it was layer cloud and raining but here it was scattered cloud and improving all the time.

In the clubhouse I made myself a cup of tea and set about planning out my route to Boston, possibly my last dual navigation to Boston, all was going well and I drew out the triangles of velocities on the whiteboard and then checked my results on Skydemon light http://www.skydemonlight.com/ which is a great piece of software and I hope to buy and evaluate it on either on an Android or iPad once I have my license (so Lookout for a future review of flying with this!) most of my calculation worked out ok and with little head or tail wind I didn’t notice my fundamental error! In fairness to me it has been a while since I did the Navigation exam!

Triangle of velocities

So how do you draw the triangle of velocities?

First Draw a vertical line to represent North with a diamond on the top to show it as a true north.

Next plot the course you want to fly, for this draw a straight line from A to B on a map and read off the heading using a protractor. For Chatteris to Boston we want a heading or Trk(T) of 349° so next we draw this line on.

Next go to the Met Office and get the spot wind for your altitude, Sunday this was 260/15 so we now need to draw this on.

The wind is drawn across the north line e.g. above I marked off 260° on the left of the north and drew through N and out far enough to be able to mark off the wind speed on the wind line. Add 3 arrows to show it’s the wind line. Take a ruler and mark the wind speed on the line from the north line, it doesn’t matter what scale you use mm, cm, your map ruler, whatever so long as all the measurement use the same scale. I used mm on this drawing for the blog.

Next draw a line from 15mm along the wind line the length of the speed you will be flying and make the line intersect the Trk(T) line at that point . So below I have drawn from the 15mm mark a line that is 70mm (we fly at 70knts) where it joins the Trk(T) B – C below.

So above we have:

A – B 260° line with point B marked at 15mm (from the Met office 260/15)

A – C our Track True from the map

B – C 15mm along the wind line (wind speed) 70mm long (our speed in knots) drawn to intersect our Track true at the 70mm point

If we now measure in mm A – C we get 67mm and this is by the magic of pythagoras theorem our Ground speed allowing for the wind 67 knots.

If we measure the angle of the line B – C from north we get 336° our heading true.

And if we measure the angle D we get our drift angle 13°

Thank you Pythagoras!

So back to my flight planning well the fundamental error I made was I measured B – C as the ground speed even though I had drawn it 70 long for my airspeed!!!

The flight to Boston went ok, I got a bit off course, but spotting Fenland airfield I re aligned and was ok from there. I soon spotted Boston and just to the left was the airfield.

We landed OK (in fact for me it was quite a good landing!) and I got the teas in, while we were drinking our tea Mike was asked to do a check Flight which he agreed to do as no one was booked in after me. I stayed drinking tea and chatting to people. Sometime later we all watch Mike land and needless to say it was a perfect landing in every way.

Once Mike was done we set off back to Chatteris and the navigation all went to plan we joined on a long final for runway 24 and again the landing was not bad. I refuelled the plane and cleaned the prop and some of the birds muck off the wings, as while we were out Stuart had booked the aeroplane and it was not good to hand it over in the state it was in.

My next lesson in a couple of weeks’ time and weather allowing is going to be a solo to Boston and back!!!