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JEDA-Less 5-Point Performance Run on TFE731 Engines

Simplify TFE731 Performance Runs With the New EMS Direct Connect System

ACES Systems is proud to announce a new EMS (Engine Management Software) Direct Connect feature for the Viper II that does not require the use of the Model 1752B JEDA for 5-point performance runs on Honeywell TFE731 engines.  Using the Viper II, the EMS Direct Connect feature is capable of conducting an automated performance run on most N1 DEEC (Digital Electronic Engine Controls) controlled engines without the need for complicated wiring and cabling.

Old method of using JEDA for 5-Point Performance runs New Method of 5-Point Performance runs using Direct EMS



(using 1725B JEDA) (Using EMS Direct Connect)


Model 1752B Jet Engine Data Acquisition ModuleDevelopment of the first JEDA, the model 1750, began in 1990 and was released in 1993 by ACES Systems.  Consequently, the model 1750 JEDA used an ACES 17xx analyzer via a serial RS-232 connection for control. Data collected by the 17xx analyzer using the EMS procedure transferred to a PC using the JedaCom software. Afterwards, the EMS data transferred from the analyzer, MEDRA 4.3 performed the data reduction. The model 1750 JEDA measured N1, N2, N3, ITT (Interstage Turbine Temperature), OAT (Outside Air Temperature), PBAR (Atmospheric Pressure), TFUEL (Fuel Temperature), T2.35 and P2.35, P3 and T3, and station 7/8 pressure and temperatures. In addition, the model 1750 used engines equipped with EECs (Electronic Engine Control) and N2 DEECs.  In 2001, the Model 1750 was updated to the Model 1752B that added RS-422 for N1 DEEC communication.

Ensure Valid Data Collection For Performance Margins

Honeywell states that a verifiable, thermodynamically stable condition is essential when collecting performance data from the TFE731 engine.  However, some field personnel will manually gather performance data using cockpit readings and tower temperatures rather than the Model 1725B JEDA and Viper II.  Unfortunately, this data can be highly volatile due lack of verifying engine stabilization, inaccuracies of single point readings vs. averages, and minor winds or disturbances (passing aircraft) of the ambient temperature in the immediate area of the engine.  If the engine is equipped with a more modern N1 control there is no guarantee of a thermodynamically stable condition due to changes in fuel flow.  With the EMS Direct Connect feature, the Viper II uses algorithms to overcome these issues while monitoring stabilization and shortening performance run time, thus saving fuel and money.

Field Challenges

As technology improvements were made to the TFE731 engine controls,  N1 became the measured speed from which engine power changes were regulated.  Unfortunately, N1 speed wasn’t always stable due to  wind speed over the fan which made it impossible to establish a stable engine condition for collecting accurate performance data.  It became necessary to electronically revert the engine back  to N2 control in order to establish a stable engine condition.  Fortunately, software changes to the Viper II analyzer made this possible and introduced the possibility to completely control and collect data from most N1 DEEC computers with the Viper II analyzer and without the need of a JEDA or its accessories.


Using the new EMS Direct Connect feature, the user can now make a direct connection to the N1 DEEC using the Viper II.  Also, the Viper II supports a direct connection to the OAT probe to ensure the best possible measurement accuracy.


  • Reduces Setup Time – 2 connections instead of 8, and no need to connect in sequence
  • OAT Measurement Reliability – No need for manual tools if communication issues occur
  • Faster Data Collection – When using a direct connection, data lag times are minimal
  • Maintains MEDRA Software Compatibility – No need to worry about re-licensing your current MEDRA software
  • Less Capital Equipment Expense – If upgrading to a Viper II, decrease your expenses without the need of a new JEDA

Ready to Upgrade?

Please contact our ACES Systems Sales Team for more information on the kit that works best for you.  Also, if you have an existing Model 1752 JEDA, don’t forget to ask about our trade-in program.

  • This field is for validation purposes and should be left unchanged.

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