SDR ASAA2014040807482

Service difficulty report · Rotor · Boeing 737990ER

Difficulty date: April 8, 2014
Submitted: April 10, 2014
Operation: Air carrier
Aircraft: N408AS
Make and model: Boeing 737990ER
Aircraft serial: 41732
Aircraft time: 5,216 hours, 1,668 cycles
Engine: Cfmint CFM567B27
System (JASC): 7220 · Turbine Engine Air Inlet Section
Part: Rotor
Condition: Out Of Balance
Location: Nr 2 Engine Fan
Stage of operation: IN
How discovered: 9
Nature of condition: O
Precautionary procedure: K

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

What was found

NR 2 ENGINE TREND DATA SHOWS LOW PRESSURE ROTOR VIBRATION LEVELS TO BE TRENDING HIGHER THAN EXPECTED. CURRENT LEVELS NEAR 1.5 UNITS. ACFT GROUNDED. ACCOMPLISHED ON BOARD FAN TRIM IAW AMM TASK 71-00-00-750-830- F00, TEST 14B. BALANCE WEIGHT SCREWS NR 3, P12 CHANGED TO P14. NR 4, P14 CHANGED TO P13. NR 5, P14 CHANGED TO P13. NR 12, P14 CHANGED TO P13. NR 31, P12 CHANGED TO P14. NR 33, P14 CHANGED TO P13. NR 35, P12 CHANGED TO P14.