Friday 2 October 2015

Loving my new HiFi

It's not what you think: I'm talking about WiFi in my Hangar-- hence HiFi

I needed to get broadband into my hangar at EGNS (Ronaldsway Airport, Isle of Man) and there was no possibility of installing a landline (for ADSL etc). Here's my solution which you may find helpful if faced with a similar challenge:

1) Purchased 4G mobile broadband data-only subscription package from local provider

2) The provider in 1) issued me with a MiFi box: specifically a D-Link DWR-921 router (like this)

3) The router in 2) was easy to set up, but the signal was poor inside the hanger.

4) So I replaced the little paddle antennas provided with the router (see the "paddles" in the pictures at previous link)  with an external antenna, specifically this one.

5) I mounted the antenna on the hangar roof (see photo below). The cables attach directly to the terminals of the router, no extra adapters required.

6) I now routinely get 28 MBPS downlink and 10 MBPS uplink, with no dropouts. Without the external the antenna, performance was a few MBPS downlink at best, and frequent dropouts.

Job done.

External antenna mounted on hangar roof provides adequate boost for 4G broadband reception inside the hangar


Thursday 24 September 2015

New magneto failure after just 15 flying hours

Updated 4 October 2015 with result from inspection of left magneto

My recent experience, described here, is quite shocking (pun intended)!

After a pleasant flight around the Isle of Man in my Bulldog last weekend, I discovered (to my horror) when performing the pre-shutdown checks that my right magneto was completely dead (instead of RPM dropping a bit, the engine simply stopped when selecting "R" on the ignition knob). Somewhat strangely, I noticed no loss of performance during the flight. Before take-off, the engine run-ups were nominal (both magnetos working as expected, within the allowable limits of "max drop 175, max difference of 50" when switching between "L", "R" and "Both").

This shouldn't happen to a new magneto!

The magneto in question was replaced less than six months ago, during the aircraft's annual inspection.  Rather than have both (left and right) overhauled (which happened to be due), I opted to have them replaced with new. By "new", this actually meant "factory rebuilt", the only option available for these types. Being based on an island, with a water-crossing (of some degree) on almost every flight, in the interests of safety, I prefer to renew key components rather than have them overhauled. I had flown the aircraft just under 15 hours before the magneto failure last weekend.

So what happened ?

Back in the hangar, having made the aircraft safe (by removing all spark-plug leads, and removing a spark-plug from each cylinder -- to make it easy to hand-turn the engine), I hooked-up the E50 timing synchroniser to the magneto, hand-turned the prop through a few cycles, and watched the lights on the E50 remain steady (instead of sequencing on-and-off as the points opened). This gave a strong clue that the magneto had failed. Just to be sure, I disconnected the "p-lead" and performed the test again: same result, lights stayed on (this latter test verifying that it was indeed a magneto fault and not some fault with the "p-lead" safety cable).

Next step was to remove the magneto and send it back to the engine shop. They quickly diagnosed the issue, described as follows:

"Due to an assembly error, the internal cable leading from the coil was too long, and was routed too close to the rotor. They came into contact, and the spinning rotor wore through the cable insulation and shorted the coil (see attached photos). The resulting heat dried out the bearings. Best to get a replacement magneto under warranty from the factory, rathe​r than repairing this one...and check the left magneto, since it was built around the same time as this one!"

Note the frayed insulator in contact with the rotor

Lessons learned 

Here's what I've learned from this experience:

  • New components can fail
  • Always perform every check in the checklist (I'm fortunate: the RAF drilled that discipline into my head). Each and every check is included on the list for a reason.
  • It is extremely useful to have two magnetos rather than one, especially when flying over the sea!
  • This type of thing doesn't just happen to someone else...

What's next ?

  • When the replacement unit arrives from the factory, I'll ask the engine shop to visually inspect that cable before sending the magneto out for fitting to the aircraft
  • The engine shop will submit a report to the manufacturer based on their findings. Given the seriousness of this incident, I would expect that there will be some sort of action mandated by the manufacturer regarding these magnetos. Maybe the issue pertains to just a specific batch, or maybe to all of that type, or even to all from that manufacturer...
  • So, if you have TCM/Bendix 1200 SERIES magnetos on your aircraft, don't be surprised if a Mandatory Service Bulletin appears pertaining to this issue...and even if no such bulletin appears, I recommend you have your magnetos checked just to be sure. 

What about the left magneto ?

Update 4 October 2015

Just to be sure, since it was replaced at the same time as the faulty right magneto, I had the left magneto removed and inspected. It got the "all clear". As can be seen in the photograph below, the cable lies well clear of the rotor, as it should.

Left magneto inspection (just to be sure, since replaced at same time as the faulty right magneto): observe that the cable is lying in the correct manner, well clear of the rotor.

Friday 4 September 2015

Automated daily MET and NOTAM briefings via Twitter

For greater convenience for iNavCalc Twitter App users, I've recently added an automatic briefing function for METAR/TAFS and NOTAMS. Basically, the feed now publishes a METAR/TAF briefing every four hours, and a NOTAM briefing once per day. The list of stations used in these briefings can be added to by any registered FlyLogical.

Instructions here


Thursday 21 May 2015


Just returned from a fun trip to Abbeville, France (LFOI), where I attended #BULLCHIPMEET2015, a annual gathering of fellow Bulldog and Chipmunk enthusiasts. The focus of the event is formation flying. Here are some videos from the cockpit of my Bulldog taken during the event:


...and here's the route I took to get there...

Saturday 11 April 2015

Announcing #TweetiNavCalc Web App

UPDATED 4 September 2015 to include automated daily briefings

I've just made it easier for anyone interested in viewing and sharing METAR/TAFs, NOTAMs, and Route (Google) Maps on Twitter. Basically, I've built a simple web-app wrapper around the existing iNavCalc Twitter App. The wrapper does most of the work for you. You can find the app here, and it looks like the screenshot below (usage self-explanatory, especially if you've read this):

Saturday 7 March 2015

Global Aviation Database in GoogleDocs

As an exercise in GoogleDocs API programming, I've published a "data dump" from the FlyLogical database in GoogleDocs Spreadsheet format.

The spreadsheet contains all global airports and navaids currently stored in the FlyLogical database (and as used by the iNavCalc and Really-Simple-Moving-Map suite of apps).

The spreadsheet will be updated automatically (every week or so) via the openAIP crowd-sourced data sets. See my previous post for more on this aspect.

Hope you find the database/spreadsheet interesting and possibly even useful !

Thursday 19 February 2015

FlyLogical embraces openAIP

I'm pleased to announce that I have recently hooked-up with to provide weekly automated updates to the iNavCalc airport COMMS FREQUENCIES database. is a free, crowd-sourced resource for global aviation data. I encourage you to register and start contributing.

I was first put on to a couple of months ago by a FlyLogical user who suggested it might be a useful resource to incorporate into iNavCalc.  I wholeheartedly agree, not least since the "official" bodies don't seem to be able to provide such (see my previous rant on the subject), and because the team make it straightforward to consume their global data, from a "machine-to-machine" perspective.

For now, I have only implemented global airport COMMS FREQUENCY automated updates. In future, I will extend to NAVAIDS. Also, the "machine-to-machine" updates lag the website by a number of days, so do not expect to find website updates propagated immediately to iNavCalc. Instead, you will have to wait a week or so for the catchup to occur.

Many thanks to for providing this resource.

Thursday 22 January 2015

Solar Impulse Route Calculations

Given that the Solar Impulse team published their round-the-world route overview yesterday, I thought it would be interesting to perform some basic navigation calculations based on that.

To start with, taking the proposed route overview, choosing relevant airports, filling in the blanks ("Kansas City airport" for "mid USA", and "Marbella airport" for "South Europe, North Africa"), gives the following approximate route in Google Maps, Really-Simple-Moving-Map, and SkyVector.

Distance and Time calculations

The total flight distance is 18,814 nautical miles, with a nominal (zero wind) total flight time of 27.5 days to be flown in sections over a few months from late-February/early-March 2015, to late-July/early-August, 2015. The following table summarises the distance along each leg in the route (assuming great circles), and the time taken to fly each leg assuming an airspeed of 35 mph (30.4 knots, 55.6 kph), derived from Solar Impulse 2's performance (which I simply found on the internet, as the published average ground-speed: is there perhaps a more accurate indicated airspeed I could use ?).  Times are given for zero-wind, 10 knot tailwind, and 10 knot headwind, respectively. This gives an idea of the (significant) effect of (moderate) wind on the performance, given the relatively low airspeed compared with conventional powered aircraft. A wind-speed of 10 knots at the cruising altitude of 5,500 feet would be considered as not atypical.   

Of particular note (highlighted in the table) is the longest leg of 4408 nm, across the Pacific from Nanjing (China) to Hawaii. Nominally (in zero wind), this would take 6 days, or 9 days in a 10 knot headwind, or 4 days 13 hours in a 10 knot tailwind. Many of the other legs also exceed one day, so the solar cells will need to be able to charge the batteries as well as keep the aircraft flying during the day, and the batteries will need to provide sufficient power to keep flying through the night, multiple times in the mission.

Leg Distance (nautical miles) Time (zero wind) Time (10kt tailwind) Time (10kt headwind)
1. Abu Dhabi (UAE) to Muscat (Oman) 206 6h:47m 5h:6m 10h:6m
2. Muscat to Ahmenebad (India) 791 1d:2hr:1m 19h:35m 1d:14h:47m
3. Ahmenebad to Varanasi (India) 578 19h:1m 14h:18m 1d:4h:20m
4. Varanasi to Mandalay (Burma) 757 1d:0h:54m 18h:44m 1d:13h:7m
5. Mandalay to Chongqing (China) 717 23h:35m 17h:45m 1d:11h:9m
6. Chongqing to Nanjing (China) 659 21h:41m 16h:19m 1d:8h:18m
7. Nanjing to Hawaii (US) 4408 6d:1h:0m 4d:13h:7m 9d:0h:5m
8. Hawaii to Phoenix (US) 2532 3d:11h:17m 2d:14h:40m 5d:4hr:7m
9. Phoenix to Kansas City (US) 905 1d:5hr:46m 22h:21m 1d:20h:22m
10. Kansas City to New York City (US) 964 1d:7h:43m 23h:52m 1d:23h:15m
11. New York City to Marbella (Spain) 3155 4d:7h:47m 3d:6h:6m 6d:10h:39m
12. Marbella to Abu Dhabi 3121 4d:6h:40m 3d:5h:15m 6d:9h:0m

Follow the Sun

Sunlight is, of course,  the key to Solar Impulses's success. You can use the SunDial function within Really-Simple-Moving-Map to see just how much sunlight Solar Impulse can expect at each point along the route.

For example, here's the Sun track for the starting point in Abu Dhabi, computed for the day I'm writing this post (22 Jan 2015). 


This challenge represents an extremely impressive combination of engineering, technical, and human achievement. Very best of luck to the Solar Impulse team. I look forward to following their progress in the coming weeks, and hope they manage to break that next set of world-records in their sights.


...and talking of record-breaking, whilst warming-up in Abu Dhabi, I recommend they try the Formula Rossa roller-coaster, the fastest in the world...had a go at New Year. Breath-taking.