Service difficulty report · Valve · Boeing 737890

Difficulty date
June 29, 2016
Submitted
July 1, 2016
Operation
Air carrier
Aircraft
N560AS
Make and model
Boeing 737890
Aircraft serial
35179
Aircraft time
37,951 hours, 11,469 cycles
Engine
Cfmint CFM567B27
Part
Valve
Part number
32145526
Part serial
2971
Condition
Failed
Location
Nr 1 Engine
Part time
79,141 hours, 39,509 cycles
Stage of operation
IN
How discovered
V
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

WHILE ACCOMPLISHING ENGINE BLEED AIR CROSSOVER TEST FOUND HIGH DUCT PRESSURE ON THE NR 1 ENGINE. 20% =20 PSI, 30% = 30 PSI, 40% = 30 PSI, 50% = 32 PSI, 60% = 45 PSI, 70% = 65 PSI, 80% = 52 PSI REF. TSR 817767 NGS DEGRADED BLUE LIGHT ON/. ACFT GROUNDED. ACCOMPLISHED ENGINE BLEED AIR HEALTH CHECK NG-36WC-00001 THRU STEP 5. FOUND CONTROL PRESSURE SENSE LINE (CONVOLUTED BRAIDED) CRACKED. LEAKING LINE SHOULD NOT CAUSE HIGH PRESSURE. REPLACED, LEAK CHECKED HOSE ASSY. LEAK CHECKED HIGH STAGE/PRSOV DOWN STREAM SENSE LINE, NO LEAKS NOTED. CHECKED PRSOV VALVE PISTON SEAL FOR LEAKAGE, NO ABNORMAL AMOUNT OF LEAKAGE NOTED. REPLACED BLEED AIR REGULATOR AND PRSOV AS THEY ARE THE MOST LIKELY CAUSE OF HIGH DUCT PRESSURE WITHOUT A BLEED TRIP. OPS/LEAK CHECK OK. IAW AMM 36-11-03, MM 36-11-04. COMPLETED T/C NG-36WC-00001, OPS CHECKED GOOD.