Service difficulty report · Regulator · Dhav DHC8311

Difficulty date
September 28, 2011
Submitted
January 23, 2013
Operation
Air carrier
Make and model
Dhav DHC8311
Aircraft time
26,780 hours
Engine
Pwa PW123
Propeller
Hamstd 14SF*
Part
Regulator
Part number
900002411
Condition
Failed
Location
Oxygen Sys
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

(CAN) ON INVESTIGATING ON GOING O2 LEAK & DAILY CONSTANT OXYGEN DEPLETION, THE OXYGEN BOTTLE REGULATOR HAD BEEN FOUND TO BE PROGRESSIVELY, AND THEN EVENTUALLY HARD FAILING ALLOWING FULL BOTTLE PRESSURE THROUGH TO THE SYS. ALTHOUGH WE ONLY INADVERTENTLY HAD 500 PSI IN THE BOTTLE, WHEN TESTED WITH A CALIBRATED PRESSURE GUAGE THE LOW PRESSURE OUTPUT WAS MATCHING THE BOTTLE CONTENTS. WHICH ALSO LED US TO THE CONCLUSION THAT THE LOW PRESSURE RELIEF WAS NOT FUNCTIONING PROPERLY CONSIDERING IT WAS SUPPOSE TO VENT PRESSURE ABOVE 100 PSI. THIS OCCURENCE BLEW APART THE HOSE ASSY`S FOR ALL 3 CREW O2 MASKS, AND CAUSED THE SUPPLY LINE ASSY FROM THE BOTTLE TO THE AIRFRAME TO COME APART AT THE HOSE CRIMP NEXT TO THE O2 BOTTLE.