Regional Jet 900 (CRJ900)
Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument
Physiological - Other; Situational Awareness
Flight Deck / Cabin / Aircraft Event Illness / Injury; Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor
Flight Crew Overcame Equipment Problem; General Maintenance Action
Aircraft
During initial climb; the flight deck air conditioning vents began emitting a pungent wet socks smell; which lasted for approximately 5 minutes. We had departed in a bleeds open configuration; meaning the APU was off; and also meaning that the engine bleed air was feeding the air conditioning packs. The scent went away once we reached higher altitudes in the climb and did not recur in cruise. We cruised at FL230. Then again; during initial descent; the same scent began filling the flight deck; this time lasting for approximately 10 minutes.During this second occasion; I experienced a slight headache; which was followed by a minor; but persistent loss of focus. This loss of focus lasted for about an hour after the second wet socks smell event. Captain notified maintenance of the issue after we parked at the gate. Reading some literature online; I became aware that this may classify as a toxic fume event. The captain suggested; and I agreed; that we notify maintenance of the issue. The Captain then placed a write-up in the maintenance log.Cause: This event concerns a CRJ-900 where engine bleed air had been feeding the air conditioning packs. The issue was not noticed at the departure airport gate; during the outbound taxi; during the inbound taxi; or at the destination airport gate; which were all times that the APU was on and feeding the air conditioning packs. I believe the cause originates from an automated system; which when the APU is off; manipulates engine bleed air for use by the air conditioning pack system. Literature seems to indicate that the bleed air may become contaminated with certain oils and/or lubricants from the engine; creating the pungent wet socks smell.Suggestions: The only solution I am aware of at present would be to operate the APU throughout the initial climb and descent. Other solutions should be devised that allow the airplane to operate in its normal APU-off takeoff and landing configuration.
CRJ-900 First Officer reported a pungent socks smell during initial climb; which dissipated; then returned temporally during descent.