Narrative:

During cruise; noted several pressurization bumps - cabin vertical speed of 450 to 500 fpm. No faults or ECAM messages occurred. Selected bleed page and found cabin flow valve surging and engine bleed pressure varying between 10 and 38 psi. Bleed pressure then stabilized at 10 psi and 215 degrees. High pressure bleed valve never opened. Pack temps eventually stabilized at 0/0. Pack output was zero but no faults or ECAM message occurred.the only way to generate an ECAM was to turn on the wing anti-ice - during my ACARS messages with dispatch I verified that we would not encounter icing conditions during descent.during descent; when thrust went toward idle the hp valve opened and pack output resumed. We have far too much reliance on ECAM and fault messages and fail to train systems so that we understand the nature of problems and how to deal with them.

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Original NASA ASRS Text

Title: A321 pilot reported pressurization bumps in cruise and bleed page showed engine bleed pressure varying; but no ECAM alert. High pressure bleed opened during descent resulting in normal pack output.

Narrative: During cruise; noted several pressurization bumps - cabin vertical speed of 450 to 500 fpm. No faults or ECAM messages occurred. Selected Bleed page and found cabin flow valve surging and engine bleed pressure varying between 10 and 38 psi. Bleed Pressure then stabilized at 10 PSI and 215 degrees. High Pressure Bleed Valve never opened. Pack temps eventually stabilized at 0/0. Pack output was zero but NO FAULTS OR ECAM MESSAGE occurred.The only way to generate an ECAM was to turn on the Wing Anti-ice - during my ACARS messages with dispatch I verified that we would not encounter icing conditions during descent.During descent; when thrust went toward idle the HP valve opened and pack output resumed. We have far too much reliance on ECAM and Fault messages and fail to train systems so that we understand the nature of problems and how to deal with them.

Data retrieved from NASA's ASRS site 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.