You Can’t Have a Binary KPV
Dave Jesse on December 8, 2017

  A long time ago I explained that our analysis of flight data is based upon the concept of a Key Point Value, where an aspect of a flight is reduced to a single number. For example,  the airspeed at takeoff or the maximum angle of bank during a flight. These are analogue measurements, that […]

Women Pilots
Dave Jesse on December 1, 2017

  A “just for fun” blog – nothing mentally challenging this time! Portsmouth Guildhall Every month I help our local scout group to raise funds through a jumble sale. I run the book stall, selling second hand books for a few pence each. At the last sale someone had brought in some old local newspapers, […]

Computing Charts
Dave Jesse on November 16, 2017

Well, it seems an age since I last blogged – somehow work gets in the way. I’ll have to complain to the boss about that one day. Anyway, we recently had a case where we needed to convert a chart into an algorithm, and I thought I’d give you the recipe I have used for […]


This was one of the more interesting discoveries of the last few weeks, and I thought that it would make a fun post for Flight Data Community. As a part of my role as a Data Scientist, it is one of my responsibilities to ensure that the data we record and monitor is of high […]

Does an Aircraft Fly or Travel?
Dave Jesse on November 2, 2017

Today I was asked what the difference is between the Distance Flown and the Distance Travelled. Like so many things in life it seems obvious if you know the answer, but confusing if not.   An Extreme Example I will explain this by referring back to a time when I was working at Bristow Helicopters, […]

From Autocorrelation to Fourier
Dave Jesse on September 12, 2017

Just for fun Here is a little interlude to get back to helicopter accidents – and do some more tricky maths in the process. Autocorrelation Here are two combs from the previous blog, which was about autocorrelation. You will recall that we compared one comb with another to see how good the match was.   […]

Decoding the Falcon – Part 2 Triple Teasing
Dave Jesse on August 17, 2017

Well, I cheated. The autocorrelation plot at the end of the last blog was particularly poor because I included the text header of the file and only processed the first 1000 words. It looked like this: Simply by removing the text header (which is clearly not part of our repeating patterns) the plot improves to […]

Decoding the Falcon
Dave Jesse on August 9, 2017

Decoding the Falcon Occasionally an aircraft operator will send us data that is in a format we have never seen before. The aircraft maintainer has followed the manuals and downloaded a data file and sent this to us and, quite reasonably, he thinks we must be able to read it. He supplies all the information […]

Under Pressure
Dave Jesse on August 1, 2017

  I couldn’t resist the opportunity to quote from Queen and Bowie. Or just show my age as I remember Under Pressure as a new song, not a golden oldie. Actually we’re going to have a quick look at pressure measurements. Like this:     Pressure Units As the gauge above (I cannot bring myself […]