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Digital Electronic Control System
Full Authority Digital Engine Control (FADEC)
means just that. There is no direct pilot control over
the engine or manual control mode. If the FADEC
fails, the engine fails. However, system redundancy
makes it much less likely for a FADEC system to fail
than a tradional magneto system. In fact, a double
magneto failure is stascally more likely than a
FADEC failure.
FADEC systems are:
autonomous,
self-monitoring,
self-operang, and
redundant.
FADEC Advantages
FADEC shares advantages with electronic
ignion and EEC systems, but it takes power
management several steps further. FADEC
combines throle, prop, and mixture controls into a
single control. Every throle seng at any altude
results in the opmum power/prop RPM/mixture
combinaon. This enables pilots to realize fuel
economy that would only have been dreamed of
previously.
Automac engine performance monitoring
constantly provides over-speed and over-boost
protecon throughout the operaonal range. Pilots
can command maximum power and the system will
deliver just that and no more. There is no possibility
of exceeding limitaons. FADEC also features
diagnosc processes that constantly monitor the
health and well-being of the aircra powerplant.
The diagnoscs are very good at dening small
problems before they become big problems. It’s not
surprising that FADEC delivers big returns in
increased fuel eciency and reduced maintenance
expense.
FADEC Disadvantages
Pilots, accustomed to managing their
engines directly, may inially view FADEC exclusive
engine control with suspicion, but with experience,
will learn to trust the system. The hardest fact for
most to get accustomed to is that the system
provides no reversion to manual control.
Occasionally, pilots have run engines beyond
operaonal limits in order to get out of ght
situaons. That can’t happen with FADEC.
Maximum allowable power for any ight level is
always available, but no more than that. Also,
sucient electrical power to start and run the
engine is needed. Hand propping denitely won’t
work with FADEC.
Although just a few GA manufacturers are
using FADEC now, we can expect to see many more
in the future.
Resources
FAA Advisory Circular 33.28-1, Compliance
Criteria for 14 CFR secon 33.28, Aircra
Engines, Electrical and Electronic Engine Control
Systems: hps://go.usa.gov/xn89k