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 […]

Red Eggs
Dave Jesse on February 8, 2018

Welcome back, dear reader. I hope you had a happy holiday and wish you a fruitful New Year. In a few months’ time it will be Easter and some of our Greek friends will be celebrating with eggs coloured deep red like this one.     He’s getting old and slightly crazy, you may think, […]

Who Flies the Aeroplane?
Dave Jesse on January 4, 2018

Looking Back The origins of the Flight Data Monitoring (FDM) process date back over twenty years and are enshrined in ICAO regulations. One of these states that “A flight data analysis programme shall be non-punitive and contain adequate safeguards to protect the source(s) of the data.” This need for data security has been implemented in […]

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 […]