Service difficulty report · Pressure Switch · Saab 340B

Difficulty date
July 18, 2018
Submitted
July 23, 2018
Operation
Air carrier
Aircraft
N343AG
Make and model
Saab 340B
Aircraft serial
340B443
Aircraft time
37,398 hours, 42,019 cycles
Engine
Ge CT79B
Part
Pressure Switch
Part number
1103P0620
Part serial
0965
Condition
Failed
Location
Autocoursen Sys
Stage of operation
LD
How discovered
O
Nature of condition
R
Precautionary procedure
K

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

What was found

FLT 0135 RSW/EYW REPORT. DURING APPROACH BASE TO FINAL, LT ENGINE TORQUE WAS AROUND 20-25% AND SUDDENLY INCREASED TO 60-70% AND PROP DROP TO ZERO. WE GOT LEFT ENGINE OIL PRESSURE LIGHT. PERFORMED BENCH CHECK OF AUTO COURSE TEST PANEL FOR TEST SWITCH OPERATION, NO FAULTS NOTED. CHECK WIRING FROM TEST PANEL TO RELAY 113KF, NO FAULTS NOTED. CHECKED RELAY 113KF FOR PROPER OPERATION, NO FAULTS NOTED. BENCH CHECKED BOTH SIDE AUTOCOURSEN PRESS SWITCHES FOR PROPER OPEN AND CLOSE WITH PRESSURE ATTACHED TO IT AND FOUND LT SIDE SWITCH DELAYING TO CLOSE ON THE HIGH SIDE. R&R LT SIDE P3 PRESS SWITCH IAW AMM 61-22-10-02, OPS CHECK GOOD. PN ON/OFF 1103P0620, SN ON 1819, SN OFF 0965.

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