Maintaining Test Cell Correlation Validity with proDAS

Posted on December 5, 2012

MDS has developed a tool that will help aviation gas turbine engine maintenance, repair, and overhaul organizations (MROs) save time and money on re-correlating test cells for various engine types.

As MROs are required to maintain high standards to keep their engine testing certification, the aerodynamic performance and measurement integrity of the test cell is commissioned, or “correlated”, using an engine previously tested at a traceable “gold standard” test cell.  After successful and repeatable engine running, the test cell is approved by the manufacturer and repeated for each engine model being tested.  Test cells must be re-correlated for each engine type if significant aerodynamic changes are made or if the test cell overall performance is in question, especially after years of operation.

Test cell re-correlation is a common method used to demonstrate that a test cell is operating correctly after initial commissioning. Unfortunately correlation activities are extremely expensive and time consuming. MROs with multiple engine types and test cells are faced with significant schedule disruptions and correlation costs.

Today’s highly competitive business climate requires MROs to reduce costs while of course still guaranteeing a quality product and safe operation. One area where test cell owners can substantially lower operating costs is to consider the alternative to full test cell re-correlation via back to back engine testing.

Figure 1: proDAS Real Time Trending Architecture

One accepted approach is to demonstrate test cell accuracy and performance using trending data for each specific engine type.  The Federal Aviation Administration Advisory Circular AC No: 43-207 defines in detail the parameters to be used for trending purposes. Most test cell data acquisition systems do not provide the long term tracking tools that fulfill these requirements. However, the MDS proDAS Real Time Trending Tool is an optional capability that allows users to view and keep test cell trending data for analysis and reporting.  The system interfaces seamlessly with our flagship data acquisitioning system proDAS.  The architecture enables the user to compare in real time the relevant data acquired over a number of tests of the same engine type.

In regular operation, the measured and calculated engine trending data is automatically transferred to a dedicated database. Calibrations of the relevant parameters are kept current and traceable using the proDAS calibration database.

The proDAS Real Time Trending Tool also allows the user to mark outliers (tests where a known cause has resulted in a data shift) and to baseline tests. Analysis of the trending data can reveal test cell parameter shifts to allow early investigation and corrective action if needed.

proDAS Real Time Trending - Maximizing Test Cell Availability and Efficiency

This tracking and traceable reporting thus conveniently and efficiently fulfills the long term monitoring requirements and removes the need for periodic and costly test cell re-correlation.

The proDAS Real Time Trending Tool is a must-have for the test cell owner!