Narrative:

At 35000 ft automatic pressurization controller failed. Cabin alert sounded a 10000 ft warning. I put my oxygen mask on and went to switch to my mask microphone. Captain was flying and initiated an emergency descent. He put his mask on and put the controller into manual to control cabin. We leveled at 22000 ft MSL with cabin under 10000 ft. We declared an emergency and diverted to cle instead of continuing on to mke. No damage, no injuries. Captain made all the decisions. Captain wrote up the pressurization automatic controller. Supplemental information from acn 370496: executed emergency descent. While descending with a sharp left turn away from the airway, a TCASII warning was generated due to a head on air carrier aircraft at 33000 ft. Flight was descending in a rate of approximately 6500 ft and went through 33000 ft in about 20 seconds. Reaching 22000 ft an emergency was declared. After consulting with dispatch, a diversion was made to cle hopkins airport to switch aircraft. According to ATC controller I spoke with the next day, few attempts made by ATC to warn me of the air carrier flight. While descending, I attempted to control the cabin and establish communication with my first officer and ATC while my first officer pulling the checklist to determine the pressurization problem. My observation from the whole event, is that ATC should have vectored air carrier immediately rather than trying to establish a verification whether I am descending or it is mode C error.

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Original NASA ASRS Text

Title: EMB145 FLC EXPERIENCE A LOSS OF CABIN PRESSURE AT FL350. AN EMER DSCNT IS STARTED, WITHOUT ADVISING ATC OF THE NATURE OF THE EVENT. A POTENTIAL CONFLICT ENSUES WITH ACR Y AT FL330. CREW DECLARES EMER AT FL220, HAD TURNED OFF COURSE DURING DSCNT. BOTH PLTS WERE LOW TIME IN ACFT.

Narrative: AT 35000 FT AUTOMATIC PRESSURIZATION CTLR FAILED. CABIN ALERT SOUNDED A 10000 FT WARNING. I PUT MY OXYGEN MASK ON AND WENT TO SWITCH TO MY MASK MICROPHONE. CAPT WAS FLYING AND INITIATED AN EMER DSCNT. HE PUT HIS MASK ON AND PUT THE CTLR INTO MANUAL TO CTL CABIN. WE LEVELED AT 22000 FT MSL WITH CABIN UNDER 10000 FT. WE DECLARED AN EMER AND DIVERTED TO CLE INSTEAD OF CONTINUING ON TO MKE. NO DAMAGE, NO INJURIES. CAPT MADE ALL THE DECISIONS. CAPT WROTE UP THE PRESSURIZATION AUTO CTLR. SUPPLEMENTAL INFO FROM ACN 370496: EXECUTED EMER DSCNT. WHILE DSNDING WITH A SHARP L TURN AWAY FROM THE AIRWAY, A TCASII WARNING WAS GENERATED DUE TO A HEAD ON ACR ACFT AT 33000 FT. FLT WAS DSNDING IN A RATE OF APPROX 6500 FT AND WENT THROUGH 33000 FT IN ABOUT 20 SECONDS. REACHING 22000 FT AN EMER WAS DECLARED. AFTER CONSULTING WITH DISPATCH, A DIVERSION WAS MADE TO CLE HOPKINS ARPT TO SWITCH ACFT. ACCORDING TO ATC CTLR I SPOKE WITH THE NEXT DAY, FEW ATTEMPTS MADE BY ATC TO WARN ME OF THE ACR FLT. WHILE DSNDING, I ATTEMPTED TO CTL THE CABIN AND ESTABLISH COM WITH MY FO AND ATC WHILE MY FO PULLING THE CHKLIST TO DETERMINE THE PRESSURIZATION PROB. MY OBSERVATION FROM THE WHOLE EVENT, IS THAT ATC SHOULD HAVE VECTORED ACR IMMEDIATELY RATHER THAN TRYING TO ESTABLISH A VERIFICATION WHETHER I AM DSNDING OR IT IS MODE C ERROR.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.