Narrative:

During climb approaching FL360; bld 1 leak and bld VLV1 clsd messages appeared on EICAS with red leak inscription on bleed one push button. Performed appropriate emergency checklist procedures; requested and received clearance to FL250. Began descent and referred to the manual for further checklist action items. Shortly after beginning descent; bld 1 leak message extinguished. At FL250 with message extinguished there were no further applicable checklist actions to accomplish. Shortly thereafter; the bld 1 leak message recurred. We returned to the checklist and continued down the applicable logic branch. Because the bleed one valve remained closed after selecting it open; we found the aircraft to be in an unpressurized condition with the cabin altitude rising slowly; so we decided to continue our descent to 10000 before the conclusion of the three minute wait specified in the checklist logic branch. Received clearance to 11000 (followed shortly by clearance to 10000) and began an expedited descent to minimize rise in cabin altitude. The captain donned his O2 mask followed by the first officer in anticipation of cabin altitude exceeding 10000 ft. During the descent the bld 1 leak message again cleared and then recurred without any change to the panel configuration. Reasoning that with the most recent occurrence of the bld 1 leak message it could not have been caused by bleed air from the number 2 engine side; the captain decided to open the bleed 2 valve momentarily to mitigate cabin pressurization loss. Once the aircraft leveled at 10000 ft we closed all bleed valves and continued flight unpressurized; consistent with checklist guidance. During the remainder of the flight the bld 1 leak message continued to present and clear repeatedly. Contacted dispatch and maintenance control and discussed actions already taken and jointly determined that a diversion was the most prudent course of action. The captain requested a change of destination with ATC and shortly thereafter made a formal declaration of the emergency with ATC. He then advised the flight attendants and passengers of the situation and planned course of action. Remainder of flight including landing was uneventful.

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Original NASA ASRS Text

Title: Malfunctioning engine bleed valves resulted in a slow depressurization of an EMB-145. The flight crew descended and diverted after consultation with maintenance.

Narrative: During climb approaching FL360; BLD 1 LEAK and BLD VLV1 CLSD messages appeared on EICAS with red LEAK inscription on bleed one push button. Performed appropriate emergency checklist procedures; requested and received clearance to FL250. Began descent and referred to the manual for further checklist action items. Shortly after beginning descent; BLD 1 LEAK message extinguished. At FL250 with message extinguished there were no further applicable checklist actions to accomplish. Shortly thereafter; the BLD 1 LEAK message recurred. We returned to the checklist and continued down the applicable logic branch. Because the bleed one valve remained closed after selecting it open; we found the aircraft to be in an unpressurized condition with the cabin altitude rising slowly; so we decided to continue our descent to 10000 before the conclusion of the three minute wait specified in the checklist logic branch. Received clearance to 11000 (followed shortly by clearance to 10000) and began an expedited descent to minimize rise in cabin altitude. The Captain donned his O2 mask followed by the First Officer in anticipation of cabin altitude exceeding 10000 FT. During the descent the BLD 1 LEAK message again cleared and then recurred without any change to the panel configuration. Reasoning that with the most recent occurrence of the BLD 1 LEAK message it could not have been caused by bleed air from the number 2 engine side; the Captain decided to open the bleed 2 valve momentarily to mitigate cabin pressurization loss. Once the aircraft leveled at 10000 FT we closed all bleed valves and continued flight unpressurized; consistent with checklist guidance. During the remainder of the flight the BLD 1 LEAK message continued to present and clear repeatedly. Contacted Dispatch and Maintenance Control and discussed actions already taken and jointly determined that a diversion was the most prudent course of action. The Captain requested a change of destination with ATC and shortly thereafter made a formal declaration of the emergency with ATC. He then advised the flight attendants and passengers of the situation and planned course of action. Remainder of flight including landing was uneventful.

Data retrieved from NASA's ASRS site as of April 2012 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.