Service difficulty report · Hmu · Boeing 737890

Difficulty date
February 14, 2016
Submitted
February 17, 2016
Operation
Air carrier
Aircraft
N535AS
Make and model
Boeing 737890
Aircraft serial
35200
Aircraft time
20,166 hours, 5,882 cycles
Engine
Cfmint CFM567B27
Part
Hmu
Part number
1853M56P14
Part serial
BECW8800
Condition
Failed
Location
Nr 2 Engine
Part time
20,166 hours, 5,882 cycles
Stage of operation
TO
How discovered
O
Nature of condition
J
Precautionary procedure
C

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

What was found

ON TAKEOFF, THE LT ENGINE ACHIEVED THE FMC COMMANDED N1 POWER OF 94.5 PERCENT N1, THE RT ENGINE ONLY ACHIEVED 90.4 PERCENT N1 AND WAS NOT RESPONSIVE TO MANUAL THROTTLE ADVANCEMENT. AUTOTHROTTLES WERE USED ON TAKEOFF WHICH RESULTED IN PERFECT THROTTLE ALIGNMENT EXCEPT FOR WHEN RT THROTTLE WAS ADVANCED TO MAX WITH NO CHANGE IN RPM. RT ENGINE N1 CONTINUED TO LAG LT ENGINE N1 UNTIL FL190. ON TAKEOFF RT ENGINE EGT WAS NOTED AT 770 WHILE THE LT ENGINE EGT WAS AT 815 VERIFYING LOWER POWER ON RT SIDE. A SMALL AMOUNT OF LT RUDDER WAS REQUIRED ABOVE 110 KIAS TO MAINTAIN RUNWAY CENTERLINE. ACFT GROUNDED. RAN NR 2 ENGINE AND ACHIEVED 85.7 PERCENT N1, AT FULL THROTTLE POSITION, ACCOMPLISHED FIM 73-05 TASK 808 FOR LOW ENGINE TAKEOFF THRUST, NOTED REGULATOR 9 ON INPUT MONITORING AT 84.9 PERCENT, REG 3 ALL OTHER. TSR ACCOMPLISHED. ACCOMPLISHED FIM 73-05, TASK 808 E. 5 NO DEFECTS NOTED. REMOVED MAIN FUEL FILTER AND FOUND METAL CONTAMINATION, REMOVED FUEL PUMP PACKAGE REF AMM 73-11-01-000-801-F00, STEP 2. INSTALLED FUEL PUMP PACKAGE REF AMM 73-11-01 3.H. 3. REPLACED HMU IAW TC N8473001. COMPLETED INSTALLATION OF FUEL PUMP PACKAGE IAW AMM 73-11-01-400, STEP 3H, 4 THRU J. ACCOMPLISHED TEST 5 POWER ASSURANCE, NR 2 ENGINE ACCELERATED SMOOTHLY TO 95 PERCENT N1.