When Do You Stop?
Dave Jesse on July 22, 2019

It sounds like a simple question, but sometimes the task seems to grow while the target moves further from your grasp. Here is a tale of one such case which illustrates how hard it can be to decide when to stop working on a problem. An Undefined Error One of our customers raised a support […]

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 […]

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 […]

Self-Healing Aircraft
Dave Jesse on March 29, 2018

Sounds impossible? Well by now, dear reader, you should be ready for the unexpected. In today’s blog I shall reverse the natural order of things, turn the arrow of entropy back to front and disprove the second law of thermodynamics. I am going to show you two graphs from the same flight and demonstrate a […]

Dropping Drinks on your Toe
Dave Jesse on February 12, 2018

..or the link between TCAS and apples…     Recently my Safety Manager, Capt Herb Feller, asked if an aircraft carried out a Traffic Collision Avoidance System (TCAS) avoidance manoeuvre, and a loose drinks trolley ran down the aisle, what would be the force when it hit something or someone? As an engineer, it seemed […]

1 2 3 5