Narrative:

Just prior to the top of descent I sensed a smoky odor in the cockpit. After a brief monitor of the sensation; the phenomena increased in intensity. I asked the first officer to confirm the presence of smoke; which he confirmed. At that point; as a precaution I commanded the first officer that we don oxygen masks and request ATC for a descent to 12;000 [feet] to prepare for corrective action in the event that the event became fully abnormal. The first officer communicated to ATC that we required an immediate descent due to the presence of smoke in the cockpit. ATC cleared us initially to 16;000 [feet]; then shortly after; to 12;000 feet. Subsequently; we were to become aware that ATC advised for us. Descending through 16;000 feet; we observed that the smoke didn't appear to intensify. I asked the first officer to remove his mask to assess the cockpit environment. After all appeared clear; we removed our oxygen masks and proceeded to run through the smoke abnormal checklist. From that point to landing; we monitored the situation and attempted to troubleshoot the source of the smoke. At the conclusion I contacted the chief pilot; maintenance and dispatch to describe our circumstances. A maintenance write up was entered in the aircraft flight maintenance log. A mechanic was dispatched to our location and after performing an inspection; returned the aircraft to service. Oxygen mask lenses should be cleaned or checked for hazing. It was very difficult to effectively observe cockpit instruments and switches because the mask lens was extremely hazed or dusty.

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Original NASA ASRS Text

Title: Air carrier flight crew reported a fumes event accompanied with smoke at top of descent. Flight crew executed an uneventful landing.

Narrative: Just prior to the top of descent I sensed a smoky odor in the cockpit. After a brief monitor of the sensation; the phenomena increased in intensity. I asked the First Officer to confirm the presence of smoke; which he confirmed. At that point; as a precaution I commanded the First Officer that we don oxygen masks and request ATC for a descent to 12;000 [feet] to prepare for corrective action in the event that the event became fully abnormal. The First Officer communicated to ATC that we required an immediate descent due to the presence of smoke in the cockpit. ATC cleared us initially to 16;000 [feet]; then shortly after; to 12;000 feet. Subsequently; we were to become aware that ATC advised for us. Descending through 16;000 feet; we observed that the smoke didn't appear to intensify. I asked the First Officer to remove his mask to assess the cockpit environment. After all appeared clear; we removed our oxygen masks and proceeded to run through the smoke abnormal checklist. From that point to landing; we monitored the situation and attempted to troubleshoot the source of the smoke. At the conclusion I contacted the Chief Pilot; Maintenance and Dispatch to describe our circumstances. A maintenance write up was entered in the Aircraft Flight Maintenance Log. A Mechanic was dispatched to our location and after performing an inspection; returned the aircraft to service. Oxygen mask lenses should be cleaned or checked for hazing. It was very difficult to effectively observe cockpit instruments and switches because the mask lens was extremely hazed or dusty.

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.