When is a Sample Rate not a Sample Rate?
Dave Jesse on July 12, 2019

That is the question. Whether it is nobler… OK, let’s stop quoting Shakespeare and get down to engineering.It is common for us to talk about sample rates as 1Hz, 2Hz etc. and in flight data recording we are usually talking about sample rates that are powers of two. If we have a parameter at 8Hz […]

Runway Marking Quiz Results
Dave Jesse on June 11, 2019

OK, I have to admit to a little subterfuge.  I wanted to ask a question which I thought might be a little embarrassing and so, rather than ask the tricky question straight out, I hid it inside a quiz.  For all those who took part in our recent runway marking quiz, I thank you for […]

Dave’s Runway Marking Quiz
Dave Jesse on May 7, 2019

Flight Data Services are interested to understand where pilots aim to land when flying a visual approach.  Of course, visual cues are not recorded on the Flight Data Recorder – how could they be?!  Please take part in our little quiz and when you send in your answer, we will return a more detailed explanation […]

Monitoring TCAS Resolution Advisory Alerts
Dave Jesse on April 25, 2019

It’s been some time since I last posted on this blog. There are some weak excuses (lots of work to get the TCAS RAs working correctly, busy running a business) and some strong excuses (three weeks holiday on a narrowboat, son’s wedding etc.). Anyhow, I’m back on the blogging trail and I can tell you […]

Automating Flight Data Conversion
Dave Jesse on August 22, 2018

I have been working on TCAS monitoring recently, and I’ll tell you more about that in future blogs, however in the middle of this work a friend asked why we didn’t just automate the processing of flight data. On the same day I sorted out one confusing data format, and, by putting the two together, […]

Monitoring TCAS Traffic Advisory Alerts
Dave Jesse on August 2, 2018

A quick recap for those unfamiliar with TCAS. The Traffic alert and Collision Avoidance System (TCAS II) helps to protect aircraft from hitting each other, so is a Good Thing. Please don’t ask me what happened to TCAS I or the differences between versions 6.04a and 7.1 etc. I’m not a TCAS expert. If you […]

How High is the Deck?
Dave Jesse on July 5, 2018

Customers who land helicopters on oil rigs need to know how high they are on the approach with respect to the deck height, and not with respect to the water. Of course, during the approach they are over the sea and the radio altimeter gives good readings for the sea and, as all good mariners […]

A crisis of confidence (intervals)
Charles Newey on June 14, 2018

Lately I’ve taken to exploring some of the aggregated event statistics that we have on file at Flight Data Services — and as a side project, I was using my knowledge of statistics to develop a fairly straightforward anomaly detection algorithm. My first approach was to compute the daily average of a particular key point […]

Traffic Collision Avoidance System (TCAS)
Dave Jesse on June 6, 2018

The TCAS system is designed to avoid traffic collisions between two aircraft. At first a Traffic Advisory (TA) warning is given to alert the crews of approaching aircraft. Then, if the separation continues to reduce the two aircraft exchange position, direction and speed information and, in a clever piece of negotiation, agree which aircraft needs […]


The Simple Question It’s a simple question, and for today’s ditty I am only going to consider aircraft where the maintenance manual limitation is expressed in normal acceleration units (g). There are a number of aircraft (Embraer types and BAE 146 for example) which express hard landing criteria in vertical speed at touchdown, and this […]

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