Service difficulty report · Outflow Valve · Bombdr DHC8402

Difficulty date
October 12, 2016
Submitted
October 13, 2016
Operation
Air carrier
Aircraft
N434MK
Make and model
Bombdr DHC8402
Aircraft serial
4227
Aircraft time
19,343 hours, 20,869 cycles
Part
Outflow Valve
Condition
Malfunctioned
Location
Cabin Pressure
Stage of operation
CL
How discovered
O
Nature of condition
J
Precautionary procedure
A

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

What was found

DURING CLIMB, PASSING 11,000 FT, HEARD AN AUDIBLE POPPING SOUND AND FELT A PRESSURE CHANGE, OBSERVED THE CABIN RATE OF CLIMB MAXED, CABIN ALT CLIMBING AND DIFF PRESS DECREASING. DESCENDED BACK DOWN TO 10,000 FEET AND COMPLETED THE LOSS OF CABIN PRESSURIZATION CHECKLIST. PRESSURIZATION OPERATION RETURNED TO NORMAL OPERATION. FOUND CDS FAULTS, CP CONTROLLER FAIL AND CPC/OF VALVE DATA FAIL. REPLACED CPC IAW AMM 21-31-06-000-801, 21-31-06-400-801 WITH ENGINES. PRESSURIZED AIRCRAFT IAW AMM 21-00-00-863-801 WITH ENGINES. PRESSURIZED GOOD. DEPRESSURIZED IAW AMM 21-00-00-863-802. PER MTX CONTROL, REMOVED AND REPLACED AFT OUTFLOW VALVE IAW AMM 21-31-10-000-801, 21-31-10-400-801. FUNCTIONAL CHECK GOOD AND PRESSURIZATION GOOD. PER MAINTENANCE CONTROL PERFORMED LEAK DOWN CHECK OF RESERVOIR. LEAK DOWN FAILED. FOUND SMALL CUT ON BOTTOM OF AFT CARGO DOOR SEAL. REPLACED SEAL. RETURNED TO SERVICE.