With over 4,800 CF6 engines in service, the CF6 is one of GE's most successful engine families and the cornerstone of their high bypass turbofan engine business.  CF6 engine configurations range in thrust from 40,000 to 72,000 lbs and lift everything from A300s, A310s, and MD-11s to 767s and 747s.

All Engineering and Manufacturing Development (EMD) FADECs (Full Authority Digital Engine Control) were built at GE in Johnson City, NY.    GE Johnson City is also an FAA repair depot for FADECs.  FADECs get their power from Ground Support Equipment (GSE), Auxiliary Power Units (APU), a three phase alternator core built into the turbine shaft or any combination of these three.   The Power Supply Unit (PSU) of the FADEC accepts and monitors these three inputs as well as several other FADEC status indicators.  The PSU automatically and seamlessly adjusts to variations in the source and quality of the input power and supplies input power status to the FADEC CPU.  GSE is typically a DC input and APUs supply 115v 400Hz.  The engine core alternator supplies a three phase variable voltage and variable frequency input which the PSU uses to power the FADEC during normal flight.   The PSU will sense the alternator voltage and frequency and switch from full-wave to half-wave rectification automatically to avoid overpowering.  The PSU will use this input power to provide the FADEC with a half-dozen output voltages and several status indicators.  All this from a PSU the size of a video cassette.

I designed functional test software and developed a functional test platform which applied all possible input conditions to a FADEC PSU including fault conditions.  I developed software that used a Pulse Width Modulated (PWM) AC source to simulate every possible envelope of engine core alternators and alternator fault conditions.  The PSU is designed to 'stay alive' during any engine malfunction to give pilots the maximum opportunity for recovery.  If an engine core should begin to disintegrate and the alternator being to arc and short circuit, the PSU must adapt to the input and survive intact.  If an engine failed in flight and had to be restarted without APU or GSE input, the PSU must be able to supply enough power for the FADEC to re-light the engine using only the small bit of alternator power created by the air windmilling through the turbine blades of a stalled engine.  The functional test system I designed and built tested every PSU for all these conditions and more.    The test system interfaced with an AGREE environmental chamber to test each PSU at every temperature in the operating range of the FADEC and every PSU was tested several times at each of those temperatures.  The test software I designed recorded massive amounts of data on every PSU tested and along with its the flexible structure it allowed design engineers to test,  verify, analyze and mature their design more thoroughly and quicker than ever before.

.