Service difficulty report · Converter · Cndair CL604

Difficulty date
June 11, 2015
Submitted
August 5, 2015
Operation
General aviation
Make and model
Cndair CL604
Part
Converter
Condition
Failed
Location
Stall Warning
Stage of operation
NR
How discovered
O
Nature of condition
O
Precautionary procedure
O

As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.

What was found

(CAN) AOA SIGNAL CONVERTER INFLIGHT POWER INTERRUPTIONS ABNORMAL SIGNAL BEHAVIOR WAS OBSERVED WHEN ANALYZING FLIGHT TEST DATA FROM INSTRUMENTATION. ABNORMAL AOA SIGNALS ARE SEEN AS SPIKES IN THE AOA VALUE, UP TO 60 DEG & OR DOWN TO -15DEG. THIS BEHAVIOR IS CAUSED BY A MONITOR IN THE AOA SIGNAL CONVERTER DETECTING AN INVALID VANE SIGNAL UNDER CERTAIN CONDITIONS. FOR A BRIEF DURATION AT THE BEGINNING OF THE 150MS WHEN THE AFFECTED SPC CHANNEL IS POWERED OFF. THE OUTPUTS VOLTAGE VALUE THAT IS READ BY THE SPC AS A VANE ANGLE ABOVE THE PUSHER THRESHOLD. THE AFFECTED SPC CHANNEL REACTS IAW DESIGN TO THIS VANE SIGNAL & ACTIVATES THE HORN & PUSHER OUTPUTS MAX OBSERVED COMMAND DURATION OF HORN OUTPUT FROM ONE SPC CHANNEL IS 10 MS, GND TO DCU, BASED ON THE ABOVE. THE DURATION OF PUSH COMMAND FROM ONE CHANNEL IS MAX 20 MS FOR A SINGLE TRANSIENT EVENT.