Narrative:

Taking off from runway 26; we were in the turn to assigned heading of 360 when the EICAS message ptrim main inoperative warning alert sounded. There were two additional messages that would appear periodically. I continued to finish the after take off check list. Then the captain called for the QRH. Departure assigned us the new heading and altitude. I checked with the captain to see if we wanted to accept those instructions. He decided that a block altitude would be best and to remain on our current heading. The controller assigned the block of 4;000 to 8;000 ft. Upon completion of the QRH checklist; it was discovered that the backup pitch trim still operated and the autopilot functioned correctly. We declared the emergency and informed the departure controller souls and fuel aboard. We began setting up the aircraft for the approach back into the departure airport. I notified the operations and sent a message to dispatch. The captain notified the flight attendant and the passengers. Before handing us off to tower control; arrival controller assigned us a speed of 190 KTS the initial approach fix and 170 KTS to final approach fix. Before contacting the tower controller; I suggested to the captain that we slow as practical to gain a feel for the aircraft at altitude instead of turning off the autopilot at a low altitude to find out what the aircraft will do. The captain agreed and when I checked on with the tower controller I made the request to have speed our discretion. Tower approved our request. We landed with no further incident. Pitch trim main inoperative.

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Original NASA ASRS Text

Title: An EMB145 EICAS alerted PTRIM MAIN INOP after takeoff but the autopilot trim remained functional so an emergency was declared and the flight returned to the departure airport.

Narrative: Taking off from Runway 26; we were in the turn to assigned heading of 360 when the EICAS Message PTRIM MAIN INOP warning alert sounded. There were two additional messages that would appear periodically. I continued to finish the after take off check list. Then the Captain called for the QRH. Departure assigned us the new heading and altitude. I checked with the Captain to see if we wanted to accept those instructions. He decided that a block altitude would be best and to remain on our current heading. The Controller assigned the block of 4;000 to 8;000 FT. Upon completion of the QRH checklist; it was discovered that the backup pitch trim still operated and the autopilot functioned correctly. We declared the emergency and informed the Departure Controller souls and fuel aboard. We began setting up the aircraft for the approach back into the departure airport. I notified the Operations and sent a message to Dispatch. The Captain notified the Flight Attendant and the passengers. Before handing us off to Tower Control; Arrival Controller assigned us a speed of 190 KTS the initial approach fix and 170 KTS to final approach fix. Before contacting the Tower Controller; I suggested to the Captain that we slow as practical to gain a feel for the aircraft at altitude instead of turning off the autopilot at a low altitude to find out what the aircraft will do. The Captain agreed and when I checked on with the Tower Controller I made the request to have speed our discretion. Tower approved our request. We landed with no further incident. Pitch Trim Main inoperative.

Data retrieved from NASA's ASRS site as of July 2013 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.