ACES Systems designed and builds the Jet Engine Data Acquisition (JEDA) unit for conducting the five point performance run on the older EEC and N2 DEEC controlled engines. These engines use the N2 as a reference speed for controlling changes in fuel flow. This reference speed was changed to N1 with the introduction of the newer –20, --40, and –60 engines. The N1 DEEC was then introduced as a retrofit to some of the older engines equipped with N2 DEEC computers. Although the data collection harness may still physically connect to the retrofitted N1 computers in the same manner as it did to the N2 DEEC computers, and the runs conducted as always, the data is not dependable. The data collected in this manner is easily corrupted by sudden and uncontrollable changes of the fan speed (and therefore N1) by external influences such as any, even, light wind or the jet or prop blast from a passing airplane.

ACES Systems is currently in the process of writing new software and designing new hardware which will allow you to collect data from these newer N1 DEEC computers. The data collected with the new software, called EMS, will be just as valid as the data collected from N2 DEEC with JEDA. In the meantime, it is important to understand that, even though you can physically connect the equipment and collect data from the newer N1 DEEC computers, the data is not valid or highly questionable at best. Before you attempt to conduct a five point performance run on any engine, verify the computer type, EEC, N2 DEEC, or N1 DEEC, before starting.