Narrative:

Upon selection of APU bleed at gate in [departure airport]; I noticed a flickering of the APU bleed switch light; then steady illumination. With a couple seconds; the smell of oil became so strong in the cockpit; you would have thought it was poured directly on the flight deck floor. As that subsided; the 'wet sock' smell became very prevalent. I notified line maintenance; and as a result of an investigation; the mechanics deferred the APU; as well as the left air conditioning pack. The flight proceeded without incident until top of descent into ZZZ. Once power came to idle; the wet sock smell again filled the flight deck. This time; I felt my eyes wanting to cross on two occasions and I told my first officer (first officer) that we may need to put the oxygen masks on. I could not switch off the right pack as the procedure would suggest as we would become unpressurized and still in the low 30s to high 20s flight levels. The smell did subside as we got closer to the ground; and after landing and clearing all runways; I requested my first officer to turn off the right pack. After parking; the flight attendants notified me the 'wet sock' smell began again on descent. By that point; I had already made another entry in the aircraft maintenance log. The rest of the evening I did have a headache and felt very lethargic; but as I awoke this morning I feel 100% back to normal.not much that I can suggest; but I would like clarification regarding our procedure as it stands to turning off packs. If I had done that; it obviously would have made the night much more interesting.

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Original NASA ASRS Text

Title: A320 Captain reported an APU and one pack had been deferred prior to departure but upon descent; fumes filled the flight deck strong enough that he considered putting on the oxygen masks.

Narrative: Upon selection of APU Bleed at gate in [departure airport]; I noticed a flickering of the APU bleed switch light; then steady illumination. With a couple seconds; the smell of oil became so strong in the cockpit; you would have thought it was poured directly on the flight deck floor. As that subsided; the 'wet sock' smell became very prevalent. I notified Line maintenance; and as a result of an investigation; the mechanics deferred the APU; as well as the left air conditioning pack. The flight proceeded without incident until Top of Descent into ZZZ. Once power came to idle; the wet sock smell again filled the flight deck. This time; I felt my eyes wanting to cross on two occasions and I told my First Officer (FO) that we may need to put the oxygen masks on. I could not switch off the right pack as the procedure would suggest as we would become unpressurized and still in the low 30s to high 20s flight levels. The smell did subside as we got closer to the ground; and after landing and clearing all runways; I requested my FO to turn off the right pack. After parking; the flight attendants notified me the 'wet sock' smell began again on descent. By that point; I had already made another entry in the aircraft maintenance log. The rest of the evening I did have a headache and felt very lethargic; but as I awoke this morning I feel 100% back to normal.Not much that I can suggest; but I would like clarification regarding our procedure as it stands to turning off packs. If I had done that; it obviously would have made the night much more interesting.

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.