j2 Aircraft Dynamics has released a new and upgraded version of j2 Flight, the unique plug-in module of the j2 Universal Tool-Kit software, focused entirely on the data processing and analysis activities associated with Flight Test data generation, analysis and flight matching for certification purposes.

Since its original release in 2017 j2 Flight has been used by numerous aircraft and simulator OEM’s around the world in a variety of applications, from troubleshooting flight test anomalies to reducing the actual time taken to move from flight test to certification of high fidelity simulator models by more than 50% in a single step.

Historically, the industry developed an over reliance on spreadsheets, producing columns of data that could be charted to study the flight characteristics, identify anomalies and points of interest that may require further flight test or in some cases, may even result in the grounding of the aircraft due to flight safety concerns. 

The new version of j2 Flight has been able to increase the data processing speeds possible, surpassing what was achieved previously whilst still delivering the functionally that it already delivers i.e. addressing any real-world effects, generating charts of single or multiple flights without recourse to spreadsheets or even going on to identify aircraft parameters for additional more detailed mathematical modelling.

Data Mapping

The j2 Flight plug-in continues to use an intelligent mapping facility to identify and monitor each and every data signal providing both a consistent data signal naming convention and converting all the generated Flight Data into SI units. 

Flight Path Reconstruction

The j2 Flight plug-in continues to produce a “kinematically consistent” set of aircraft states for flight path reconstruction tasks including the removal of signal noise, bias or drift allowing for even greater insight into the aircraft behaviour including the important additional analysis of Re-Prediction, Charting, and 3-D Playback. 

Re-Prediction

The j2 Flight plug-in continues to allow an ‘a priori’ model to be driven directly from the flight test data, placing the ‘a priori’ model at the same point in space and time as the real aircraft.  This unique capability enables the ‘a priori’ to have additional analytical elements added that can use the flight test data directly for additional investigations.

The Data Mapping and Flight Path Reconstruction can be run as a batch process, automatically taking multiple flight test data recordings and processing them before saving everything in the relational j2 Database.  This significantly reduces the effort required to process and store the data and eliminates any possibility of human interference errors.

A Case Study

A customer was in the process of test flying a modified business jet platform for certification and to speed that process up, was attempting to read across a lot of data from the original aircraft certification.  However, when performing some low speed tests, the Pilots were experiencing an un-commanded roll off (wing stall) of the aircraft.  This was occurring at different points, both before and after the stick shaker alert to the pilot.  The problem was further confused by the fact the anomaly appeared to improve as the flights progressed.  The customer was unsure how to progress? They had hours of flight data and were busy processing it using the multiple spreadsheets and Matlab methods but acknowledged it could take weeks just to generate a new chart and to work through the data to see if there was anything of any benefit.  If they were unable to identify the issue quickly, they would have to completely re-certify the aircraft at significant cost.

J2 was brought in as consultant using the j2 Universal Tool-Kit. A simple ‘a priori’ model was constructed to create the relevant parameters.  Several hundred hours of flight data were imported, mapped, and re-constructed in less than an hour.   From the re-constructed data, it was possible to run through all the tests and identify that the roll-off was un-commanded rather than the result of pilot input.  These markers were automatically added to the data. 

The results across all the test points were then cross plotted using templated charts, identifying any unique characteristics that connected to the un-commanded rol- off.  From these charts and templates, it was possible to identify the cause of the roll-off which could then be corrected.

The whole activity duration from initial engagement and provision of data to identifying the cause was less than 2 weeks.  The power to process the data, automatically generate the markers, and then perform multiple cross plots and time histories, all delivered through using the j2 Universal Tool-Kit, far exceeded what could be achieved with spreadsheets and Matlab. 

The end result meant that the fault was clearly diagnosed and the aircraft did not need to be fully re-certified, saving the company many millions of US Dollars.  

To contact j2 Aircraft Dynamics or for more information on j2 Flight or any of the other j2 functional plug ins please contact:

Email: info @j2aircraft.com

Ph: +44 845 0529489

Mob: +44 7908818724  (Paul Jenkins)