Saturday 22 September 2012

Greetings, SkyVector !

Update 18 April 2017: completely re-written iNavCalc mobile apps with streamlined command-line interface for iOS, Android, and Windows 10

Update 23 September 2015: now supports the recently-modified SkyVector URL (exported link) format

Update 15 March 2014: iNavCalc: a complete nav planning solution for SkyVector

Update: iNavCalc V3.0 mobile app now released

Update: iNavCalc now includes NAVCOM frequencies

Update: iNavCalc now includes NOTAMs

Update: related, see recently-added Route Viewer which further extends the route-sharing capabilities of iNavCalc...

Always on the lookout for fun flying apps, I recently came across SkyVector . This is a very cool, free, web-based application which provides vectorised aviation charts with global coverage. You can define your own route via a simple waypoint entry dialog. At present, there is no flight-planning capability beyond the basic route-entry. However, you can simply copy-and-paste the list of waypoints from the SkyVector dialog into the subject-line of an email and send it to . A few seconds later you will receive a full VFR nav plan by email (click here for an introduction to this free service, and here for a detailed example).

Here's a worked example...

First open the SkyVector web-page (I used Chrome on a Windows 7 PC, in this example). Then specify your desired route as a sequence of space-separated waypoint identifiers in the Flight Plan dialog. In this example, I've specified the route from Newcastle airport (EGNT) to Isle of Man airport (EGNS) via Carlisle airport (EGNC) and the Dean's Cross VOR (DCS):

Press "Add". This will produce the following route in SkyVector:

To generate your Pilot's nav LOG (PLOG) -- including automated wind & weather, magnetic deviation, sunlight etc, copy-and-paste the list of waypoints into the subject-line of an email and send it to

In a few seconds you will receive an email with your PLOG as an attached PDF file. Here's the first two pages of the PLOG you will receive:

That's all there is to it !

Click here for another detailed example of using our free email nav planning service.

Enjoy !

A trip to Garmin's Toy Shop...

I was in Chicago on business a couple of weeks ago and happened upon the Garmin store. It's on the corner of Michigan and Erie...

What a fine place. The upstairs is best: full of aviation kit on display....

Knowledgeable and friendly staff. Took the time to describe and demonstrate all the devices I cared to look at.  As a result, I am now the happy owner of a 795...

A rock-solid unit, tons of features. Helped me through some nasty weather on the way back from Leuchars airshow last weekend. Perfect size. Fits tidily in my Bulldog cockpit via the versatile hefty clamp supplied in the box. Goodbye iPad (at least as a moving-map)...

Tuesday 18 September 2012

Bulldogs and Red Arrows in Newcastle

When we arrived at Newcastle (EGNT) on 16 September due to weather diversion from Leuchars, we taxied-in and parked adjacent to the Red Arrows, who also happened to be there overnight (following their display at The Great Northern Run)...

Video of Bulldog return flight from Leuchars

Video clip of Bulldog (G-BZFN) return flight from RAF Leuchars on 17 September 2012. I actually departed Leuchars on 16th, but had to make a weather diversion with overnight stop at Newcastle (EGNT). The next morning, I completed the return home (EGNS) from EGNT. This clip shows the cruise over the Irish Sea  at 10,200 feet with the Isle of Man just visible on the horizon...

Bulldogs at Leuchars

Our Bulldogs (G-BZFN aka XX667 and G-WINI aka XX546) on static display at RAF Leuchars Airshow, 15 September 2012.

Sunday 2 September 2012

Programming routes into SkyDemon and AirNavPro on the iPad via email

In my previous post, I described the main steps I follow when planning a VFR flight. As an example, I planned my upcoming route from Prestwick to RAF Leuchars where I'll be exhibiting my Bulldog on the static display in the 2012 Airshow.

In my VFR flight planning, I use a mix of "the old" (map, ruler, etc) and "the new" (automated PLOG computation via iNavCalc, plus other internet resources for NOTAMs, etc., all accessed via my Samsung Galaxy S2 smartphone).

A notable omission from that post was the use of my iPad in the cockpit. I'll cover that topic now.

Like most private pilots these days, I use my GPS device as my primary nav reference on-board. Specifically, I use my (IFR-approved) Garmin GNS 430. Owing to the inconvenience of programming non-standard waypoints on this device, I tend to use the "Direct-To" function between successive major (standard) waypoints to monitor the progress of the flight, and mostly to ensure I avoid controlled airspace. Even when monitoring progress on the Garmin 430,  I fly the nominal headings as prescribed by my pre-planned PLOG (see STEP 2 in previous post), making ad hoc corrections for wind (that differs from the forecast in the PLOG), and making routine visual reference to my physical chart (line on map, STEP 1 in previous post). I also routinely look out the window for the corresponding relevant ground features (it is VFR, after all).

That said, there are some powerful, feature-rich VFR flying apps available on the iPad. Notably, SkyDemon and AirNavPro, which are two of the most popular apps (at least here in the UK and Europe).

...but first, a couple of caveats

 I do not use the iPad as a primary nav reference in-flight, owing to the fundamental lack of robustness of the iPad (very much a consumer media device, not a true avionics device). I do, however, use the iPad flying apps for specific functionality that is very handy but not absolutely essential i.e., I can continue flying my route even if my iPad falls over (as it tends to do, every so often).

Also, a non-insignificant consideration is that there is simply no room in my Bulldog cockpit to accommodate my iPad in permanent view throughout the flight. Instead, I have to store it between the seats and take it out to view on occasion. 

What I use SkyDemon for

I use SkyDemon on my iPad for the following:
  • Getting a list of frequencies for my route when I'm confident I will not require any IFR materials (in which case, I use full JeppView trip-kits). Although I find the SkyDemon export to be slightly clunky (since it does not render directly in PDF format), it is more convenient than JeppView for quickly retrieving a list of comms frequencies for purely VFR purposesI do not use SkyDemon for airfield plates since it provides only the relatively crude AIP files.
  • Vertical nav sanity-checking. The "virtual radar" function is visually slick, and helps me to verify that my planned altitudes do, in fact, avoid CAS and terrain, as intended. 
  • A backup GPS-enabled moving-map when in-flight. I basically "play" with this in-flight, but do not rely on it due to the fundamental non-robustness of the iPad. That said, SkyDemon helped me considerably on my recent flight from EGNS to EGPK (see opening paragraph to previous blog post) when Prestwick approach asked me to "report Dalrymple". I couldn't find "Dalrymple" on my physical chart, it wasn't on my Garmin 430, but it was on the SkyDemon map, so I quickly adjusted my heading and flew direct to Dalrymple using the SkyDemon moving-map.

What I use AirNavPro for

I use AirNavPro on my iPad for the following:
  • A backup GPS-enabled  moving-map when in-flight. Again, I just "play" with this in-flight, but do not rely on it due to the fundamental non-robustness of the iPad. However, because AirNavPro incorporates the UK CAA 1:500k charts, I find it helpful for increasing situational awareness since I can quickly compare "one-to-one" with my identical physical chart. I somehow find this more natural than the SkyDemon vectorised charts (visually very attractive and appealling, as they are). That said,  AirNavPro wouldn't have helped me in locating Dalrymple !

Loading routes on to the iPad

Assuming I've already generated my route via iNavCalc's email interface, I will have received an email with the following attachments (as described in detail in the previous post, repeated here for convenience):

In the previous post, I described in detail the "PLOG_....pdf" and the "MET_...pdf" attachments. I'll now describe the "ROUTE_....gpx" attachment. 

As the filename suggest, this is just an XML file (in the open-standard GPX format) which encodes the route.  It is almost trivial to load this file into the iPad using either SkyDemon or AirNavPro. Here's how:

Within the iPad email app, click on the "ROUTE_....gpx" attachment. The GPX content will be displayed in the main window (human-readable XML script), and, moreover, can be "opened in" any supporting installed app (as per the usual iPad functionality for embedded email attachments), as shown below:

Selecting SkyDemon, will load the route as follows:

Likewise, selecting AirNavPro, will load the route as follows:

That's really all there is to it !

In summary

So, to recap from the start of the previous post to the present:

Starting with a simple iNavCalc email:

I can construct an entire route based on a list of waypoints (specified in a natural manner i.e., reading-off from the line I've drawn on my paper chart), then import the route in to my chosen (GPX-compliant) iPad flying apps in a couple of clicks. Viewed in this way, iNavCalc can be considered as a natural, efficient, shorthand way of creating routes for your favourite iPad flying apps. 

Leuchars airshow, here we come !

Flight route-planning the old-fashioned way -- almost...

Update 18 April 2017: completely re-written iNavCalc mobile apps with streamlined command-line interface for iOS, Android, and Windows 10

Update: iNavCalc V3.0 mobile app now released

Update: iNavCalc now includes NAVCOM frequencies

Update: iNavCalc now includes NOTAMs

Update: all described functionality now available via mobile app...

First, a big thank you to Prestwick Flight Centre for looking after our Bulldogs in the lead-up to the RAF Leuchars airshow where we will proudly exhibit them in the static display. We positioned the aircraft at Prestwick in August so we can maximize our chances of actually getting to Leuchars on 14 September 2012, given the vagaries of the British autumn weather (EGPK being considerably closer to EGQL than either of our home bases EGNS and EGSF).

I now need to plan the (VFR) route from Prestwick to Leuchars. I'm going to use a mix of old and new technologies, demonstrating the power of iNavCalc (and it's interoperability with other apps) along the way. Here goes...

STEP 1: Draw a line on the map 

Call me old-fashioned, but I find the very best way of panning a route is to have the physical chart spread out on the table in front of me. In this case, the UK CAA 1:500k chart for Scotland. Also, I will need this the ultimate nav reference in the cockpit, in case the GPS fails or gets messed-up by jamming trials (an albeit rare but nevertheless possible occurrence). In case the weather is sub-optimal, I want a reasonably direct route which avoids Glasgow and Edinburgh Controlled airspace, avoids the most significant terrain, and which gives me some practical diversion opportunities along the way -- just in-case the weather closes-in. Inspecting the map, here's the set of waypoints I've come up with.

Navaid Altitude
1 EGPK (departure)
2 Road junction, south of Kilmarnock GOW188/16 2000
3 Strathaven microlight strip GOW139/16 2500
4 EGPG (overfly) 2500
5 Road junction west of Dunblane PTH237/26 2500
6 EGPT (overfly) 2500
7 EGQL (destination)

Importantly, I've included the radial(magnetic)/range(nm) of each waypoint from an appropriate radio navaid: again, in-case the GPS fails. I simply eyeball these from the chart using a protractor and a ruler (the CAA chart conveniently has magnetic compass-roses centred on each VOR, making the task of eyeballing the radials very simple). I've also shown nominal altitudes (in feet) which avoid CAS and terrain, again, derived from inspecting the chart.

STEP 2: Generate a PLOG ("Pilot's navigation LOG")

Let's recap. So far, I've used very old technology (map, ruler, protractor). With these, I've got a sensible route drawn on the chart which I will use in the cockpit as an essential nav reference if my GPS and radio navaids fail. I now want a PLOG which I can print out and use in the cockpit to monitor my progress with regards time, fuel (primarily) and diversion-planning. I will also use this PLOG (in combination with a stopwatch and chart) as my primary nav reference in the event that my GPS and navaids fail.

Rather than doing the calculations by hand (the old-fashioned way with whizzy-wheel etc), it is appropriate to now switch to using new technology. Nothing very fancy, however -- just my Samsung S2 Galaxy Android smartphone equipped with email. No other apps required.

Specifically, I now send the following email (via my smartphone):

You can see that I've simply specified the waypoint ICAO names and/or navaid radials from the above list, separated by spaces, on the email subject-line (i.e., Subject: EGPK GOW188/16 GOW139/16 EGPG PTH237/26 EGPT EGQL). That's it. A few seconds later, I receive the following response with the following attachments:

The first of these file attachments (named "ROUTE_..."), I'll discuss later. Let's focus on the second (named "PLOG_...") which contains the desired PLOG (our goal in this step of the planning). I'll extract and describe the pertinent sections from the PLOG PDF document below.

The first section is the FLIGHT SUMMARY, shown below:

This contains the key information summarising the flight at-a-glance. Importantly, it shows that as long as I depart on full tanks (32 UK gallons in my Bulldog), I will have plenty of margin (approximately 3 hours / 250 nm) in case I need to divert. It also shows that the expected flight time is 48 mins. Given that RAF Leuchars has specified a precise arrival slot time (12:20 local), this suggests I should aim to depart Prestwick at 11:20 local, giving 10 minutes margin (can always hold for 10 minutes if I arrive early).

The next section in the PLOG PDF doc is the NAVIGATION page, as shown below:

This contains the essential navigation information required for conducting the flight (headings, timings, fuel consumption for each leg). This would be essential for continuing to fly the route in the event of failure of GPS or navaids. Winds aloft are automatically retrieved from internet-based forecasts (valid at the point in time when the PLOG email was sent) and accounted for in the heading computations. Also, importantly, the "ETA/ATA" column has space for writing in (by hand) the actual times observed in flight so that the ETA's can be updated accordingly. Finally, the "Diversion available" column gives the (still air) range and endurance available from each waypoint along the route, should it be necessary to consider a diversion at any point along the way.

The next section in the PLOG PDF doc is the WAYPOINT DETAILS section, as shown below.

This contains the coordinates (latitude and longitude) of each waypoint, expressed in all common formats. This is useful for transcribing the non-standard waypoints into a built-in GPS device such as my Garmin GNS 430 (which, being IFR-rated, does not permit automated electronic upload of user data). Also displayed is the magnetic variation at each location.

The next section in the PLOG PDF doc is the ALTIMETRY section, as shown below.

This shows the QNH (and QFE) computed for each waypoint location, computed via MET reports automatically retrieved from the internet (valid at the point in time when the PLOG email is sent). Importantly, the "Freezing altitude" column shows the (approximate) altitude when the outside-air-temperature  drops to zero degrees centigrade. The lower half of the page contains the TRANSITION LEVEL computations (note: requires the user to specify the appropriate transition altitudes along the route, defaults to 3000ft if not explicitly specified).

The next section in the PLOG PDF doc is the PERFORMANCE section, as shown below.

This shows density altitudes (at ground level and at flight altitude) computed for each waypoint location,  using data from MET reports automatically retrieved from the internet (valid at the point in time when the PLOG email is sent). This is useful for assessing the expected engine performance (especially important for takeoff and climbs). The lower half of the page shows the TAS (and Mach Number) along the route (for the user-specified IAS) computed for each waypoint location, using data from MET reports automatically retrieved from the internet (valid at the point in time when the PLOG email is sent).

The next and final section in the PLOG PDF doc is the SUNLIGHT section, as shown below.

This shows the sun position along the route, useful for determining if the given part of the route is in daylight or darkness. If daylight, the sun direction (as viewed from the cockpit) is shown, enabling the assessment of the potential for glare (and thus preparing for the associated hazards). The computations are based on the user-specified departure date/time (defaults to the point in time when the PLOG email is sent, if unspecified). The lower half of the page shows the sunrise, sunset, and hours-of-daylight for the date of the flight, computed for each point along the route.

STEP 3: Check the weather

Now let's turn to the third of the email file attachments (named "MET_..."). This is a PDF document containing the TAFs and METARS along the route, automatically retrieved from the internet, as shown below.

You can see that the MET stations in the report are automatically chosen based on their proximity to the route. There is no need to manually specify them.

STEP 4: Save the route 

Since I am pre-planning this route a couple of weeks before the date of the actual flight (on 14 September 2012), I want to save it so I can recall it on the day, and, more importantly re-compute based on the then-current weather.

It is simple to save the route in the FlyLogical database by sending an email as follows:

Note that the route specified in the previous email will be remembered (since I haven't updated it with a subsequent PLOG email request with different waypoints in the meantime). Now I am simply requesting that this previously-defined route gets saved in the database under the name "PRESTWICK TO LEUCHARS VIA PERTH". A few seconds later I received the following response:

The URL contained in the email ( ) is a link to the saved route in the FlyLogical database. 

STEP 5: Re-compute PLOG on the day of flight

Let's recap. So far, the only actions I've taken were to (i) draw my desired route on my map; (ii) send a simple email to create a PLOG based on my desired waypoints; (iii) send a follow-up email requesting to save the route to the FlyLogical database for later use. Everything else has been done for me by the iNavCalc servers.

Now let's imagine we fast-forward to the 14 September 2012, the day of my flight to Leuchars. I want to re-compute my PLOG given current weather. To do so, I could simply carry out STEP 2 again (i.e., re-specify the waypoints on the email subject-line).
Alternatively, I can retrieve the previous email response and click on the link ( ) to open the iNavCalc web-app (in the web browser on my smartphone, iPad, or PC etc), and load the previously-saved route into the GoogleMap interface, as shown below:

Opening the "Route" tab (left-hand-side) and clicking the "Get detailed PLOG..." button, opens a window from which the re-computation of the PLOG can be triggered, as follows:

Clicking the "Get PLOG by email" button will generate a PLOG delivered by email, as in STEP 2. 

The "PLOG_....pdf" (and "MET_....pdf", though less-compelling) file(s) from the email attachment can be printed-out for carrying on-board. I can also archive them on my smartphone (and/or iPad). Note: I find the Kindle app (from Amazon) to be particularly good for this, on both my Android phone and my iPad. I can simply email the PDF files to my Amazon Kindle account, then sync them to my portable devices, free-of-charge since the files are already in PDF format and do not need to be converted (for which Amazon would charge a small fee). I also use this approach for other PDF documents such as checklists, approach plates, airfield plates,  and whatever other useful references I wish to carry along without having to carry piles of paper.

STEP 6: Comms frequencies, airfield plates, approach plates

Now that I have my route and PLOG computations ready for flight, I need the list of relevant comms frequencies (radios and navaids), airfield plates, and approach plates (in case I find myself  in IMC and have to carry out an IFR approach). In my opinion, the best and most comprehensive source for these is Jeppesen JepView since they provide complete VFR and IFR coverage. I therefore prepare a Jeppesen trip-pack for the route, print it out "as PDF"  (using the excellent and free  Bullzip PDF printer app), and archive it (via the Kindle app) on my smartphone and iPad. I also take a physical printout of these just in case. However, I also have all the relevant frequencies within easy reach via my Garmin 430. They are also printed on the UK CAA chart. So, plenty of redundancy in this regard.


My favourite source of NOTAMs for the UK is via the website, a sample screenshot as shown below.

The reason I find this so useful is that it provides an at-a-glance view of the whole country, and I can zoom-in on the areas of interest, not just my nominal route. The SkyDemon iPad app (more on this in a later post) also has a powerful (and visually slick) NOTAM facility, but it is limited to the route in question, and it is therefore not very convenient for gaining a general overview e.g., when considering diversion pre-planning, etc.

STEP 8: Load route on to iPad

See my next post which covers this topic.

Saturday 1 September 2012

VFR flight plans: are they worth filing ?

I recently posted this very question on the PPRuNe pliots' forum. Here's the thread. Bottom line seems to be that VFR Flight Plans are not considered very useful in the UK, but may be better elsewhere. Then again, given the ease with which they can be filed nowadays (e.g., ), probably worth doing. You never know, might be a useful 'get out of jail'...