Narrative:

After over an hour enroute at FL340 we received an EFIS comp mon caution. On the pfd there was an IAS amber box indication. Over the course of 5 minutes the captain's IAS steadily dropped from approximately 260 KIAS .75 mach to 40 KIAS. During this time we began completing procedures in the non-normal checklist. During this time we also received a boxed pit indication on the pfd. At the same time the mach trim caution appeared and the mach trim kicked off. At this point the captain's pfd changed to red boxed IAS; vs; and altitude. We continued the descent. At 14;000 we received an advisory message that press cont #1 and a caution message stall fail. Pfd #2 indications went to red boxed IAS; vs; altitude for approximately 5 seconds. The standby instruments remained unaffected from the pfd #1 and #2 indications failing. We requested an immediate decent to 10;000 ft from ATC. After the press cont message and feeling our ears popping; as per the checklist air data #2 was selected on the captain's side and both pfd's were displaying the flight instrument indications which also concurred with the stand by instruments. At around 10;000 ft once we had leveled off the autopilot began acting strangely. The yoke was oscillating forward and aft causing 20 to 50 ft altitude deviations. The autopilot was selected off and I hand flew the aircraft to a safe normal landing. Arff met the aircraft upon landing. We taxied off the runway and to the gate. No passengers were injured and we began notifications as per the fom.

Related reports:

Google
 

Original NASA ASRS Text

Title: CRJ-200 First Officer reports loss of the Captain's pitot static instruments at FL340. ADC number two was selected on the Captain's side and all indications returned to normal.

Narrative: After over an hour enroute at FL340 we received an EFIS COMP MON caution. On the PFD there was an IAS amber box indication. Over the course of 5 minutes the Captain's IAS steadily dropped from approximately 260 KIAS .75 MACH to 40 KIAS. During this time we began completing procedures in the non-normal checklist. During this time we also received a boxed PIT indication on the PFD. At the same time the MACH TRIM caution appeared and the MACH trim kicked off. At this point the Captain's PFD changed to red boxed IAS; VS; and ALT. We continued the descent. At 14;000 we received an advisory message that PRESS CONT #1 and a caution message STALL FAIL. PFD #2 indications went to red boxed IAS; VS; ALT for approximately 5 seconds. The standby Instruments remained unaffected from the PFD #1 and #2 indications failing. We requested an immediate decent to 10;000 FT from ATC. After the PRESS CONT message and feeling our ears popping; as per the checklist Air Data #2 was selected on the Captain's side and both PFD's were displaying the flight instrument indications which also concurred with the stand by instruments. At around 10;000 FT once we had leveled off the autopilot began acting strangely. The yoke was oscillating forward and aft causing 20 to 50 FT altitude deviations. The autopilot was selected off and I hand flew the aircraft to a safe normal landing. ARFF met the aircraft upon landing. We taxied off the runway and to the gate. No passengers were injured and we began notifications as per the FOM.

Data retrieved from NASA's ASRS site as of April 2012 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.