What it covers
The system components and parts including which indicates negative air pressure in the vacuum lines. Includes the indicator and warning systems. Typical parts are the vacuum indicator and associated lines.
Service difficulty reports · 6
Reports filed under 3720, newest first.
| 1995 | 1 |
|---|---|
| 2000 | 1 |
| 2001 | 1 |
| 2003 | 1 |
| 2004 | 1 |
| 2021 | 1 |
SDR IKBR2021042800026Transducer · abnormalTHE VACUUM TRANSDUCER WAS INCORRECTLY INDICATING LOW VACUUM AND DIDN'T ENTER THE DESIRED OPERATING RANGE UNTIL 2000RPM (THE AMM CALLS FOR THE VACUUM TO REACH DESIRED RANGE AT 1200 RPM). REMOVED AND REPLACED THE VACUUM TRANSDUCER WITH NEW P/N P-165-5786 (8130-SDR CA040625008Drive Shaft · sheared(CAN) ON LT ENGINE WARMING UP, FOUND LIGHT WARNING INDICATION (ON) IN RANGE OF RPM. WHILE TROUBLESHOOTING FOUND LT VACUUM PUMP DRIVE SHAFT SHEARED. NO OTHER DAMAGE FOUND AT VISUAL INSPECTION.SDR BAQA086456Actuator · inoperativeACTUATOR INOPERATIVE. HARD CARD ENCLOSED. REPLACED WITH SERVICEABLE UNIT.SDR 20010206CW003Indicator · reads lowWHILE COMPLYING WITH AD, 3.5 MINIMUM VACUUM COULD NOT BE OBTAINED, EVEN AT SEA LEVEL. TROUBLESHOOTING REVEALED VACUUM INDICATOR WAS 2-2 1/2 IN HG LOW AND REGULATOR HAD BEEN MIS-ADJUSTED. INSTALLED NEW GAGE, WHICH WAS CALIBRATED, AND RESET REGULATOR DOWN. STSDR 20010205CW002Valve · failedREPLACED LEFT VACCUUM PUMP. ON OPS CHECK, BOTH RED INDICATORS WERE SUCKED IN(RT ENGINE NOT RUNNING) ADVANCE THROTTLE AND RIGHT SIDE POPPED OUT. TESTED MAN VALVE, VALVED FAILED. CORRECTIVE ACTION: REPLACE VALVE.NOTE: MFG REC 10YR REPLACEMENT BUT DOES NOT HAVESDR 95ZZZX6927Gauge · contaminatedTHE AIRCRAFT IS EQUIPPED WITH A DUAL VACUUM SYSTEM. THE SUCTION GAUGE FILLED WITH CARBON DUST DURING A VACUUM PUMP FAILURE. THIS OBSCURED THE PILOT'S INDICATION OF A LEFT OR RIGHT VACUUM PUMP FAILURE (RED BALL), SINCE THE GAUGE STILL SHOWED VACUUM IN THE GRE