Narrative:

Enroute at FL400. Received number 1 bleed trip off light approximately 100 NM west of where we had taking off from. Executed QRH procedures (light did not extinguish with trip reset button). We were now single pack operation. Continued to our filed destination with single pack. Pressurization ok. I was thinking about the single pack status and not feeling too comfortable with the fact I was one malfunction away from a possible emergency descent. Also; there would be some icing conditions possibly encountered enroute and I knew we were to 'avoid' icing conditions in that configuration. After about 10 minutes; I wondered if the Number1 bleed air would reset so we pressed the trip reset button. The light extinguished and we were two bleed source operation again and then brought the left pack on line again. Now; we had full capability if encountering icing. After another 10 minutes; the Number1 bleed tripped off again. This time; QRH was used and we did not attempt any further resets. We arrived at our destination single pack with no icing encountered enroute. When we arrived; I explained to maintenance what had transpired including the attempt to get the number 1 bleed back on line. He seemed to appreciate that this was a verified more than one time event; asked I write all that in the logbook; which I did; and the aircraft was taken out of service. I wanted to do the right thing by telling maintenance all my in-flight steps and; in doing so; realized I might be 'putting myself on report' by doing more than the QRH specifically authorized; hence this as soon as possible report. The QRH could be better amplified to tell us that we should not attempt a second reset of the system after waiting 10 minutes or so if it doesn't want us to do it. It is just too tempting given the situation we are put in with just single pack; long cruising requirements. I don't feel it is specifically (enough) prohibited; but better refinement could be warranted if in fact we should not be doing any extra resetting attempts.

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Original NASA ASRS Text

Title: A B737-700 Left Bleed tripped at FL400; but did not reset following the QRH. Ten minutes later a successful reset was accomplished but the bleed tripped again; so the flight continued single pack.

Narrative: Enroute at FL400. Received Number 1 Bleed Trip Off light approximately 100 NM west of where we had taking off from. Executed QRH procedures (light did not extinguish with trip reset button). We were now single pack operation. Continued to our filed destination with single pack. Pressurization OK. I was thinking about the single pack status and not feeling too comfortable with the fact I was one malfunction away from a possible emergency descent. Also; there would be some icing conditions possibly encountered enroute and I knew we were to 'avoid' icing conditions in that configuration. After about 10 minutes; I wondered if the Number1 Bleed Air would reset so we pressed the trip reset button. The light extinguished and we were two bleed source operation again and then brought the left pack on line again. Now; we had full capability if encountering icing. After another 10 minutes; the Number1 Bleed tripped off again. This time; QRH was used and we did not attempt any further resets. We arrived at our destination single pack with no icing encountered enroute. When we arrived; I explained to Maintenance what had transpired including the attempt to get the Number 1 bleed back on line. He seemed to appreciate that this was a verified more than one time event; asked I write all that in the logbook; which I did; and the aircraft was taken out of service. I wanted to do the right thing by telling Maintenance all my in-flight steps and; in doing so; realized I might be 'putting myself on report' by doing more than the QRH specifically authorized; hence this ASAP report. The QRH could be better amplified to tell us that we should not attempt a second reset of the system after waiting 10 minutes or so if it doesn't want us to do it. It is just too tempting given the situation we are put in with just single pack; long cruising requirements. I don't feel it is specifically (enough) prohibited; but better refinement could be warranted if in fact we should not be doing any extra resetting attempts.

Data retrieved from NASA's ASRS site as of July 2013 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.