On May 4, 2015, at about 1410 UTC time, Mesa Airlines flight 5612, a CRJ900, N932LR, collided with a parked US Airways B757, while taxiing in the gate area of Phoenix Sky Harbor Airport (PHX). The left horizontal stabilizer of the CRJ900 was substantially damaged when it struck the left winglet of the B757. There were no injuries to the 81 passengers and crew onboard the CRJ900. The B757 received minor damage and there were no persons aboard. Flight 5612 was operating under 14 Code of Federal Regulations Par 121 as a regularly scheduled passenger flight from Albuquerque International Sunport (KABQ), Albuquerque, New Mexico, to KPHX. After landing in KABQ, the crew were notified via ACARS that their arrival gate had changed from B7 to B21. After arriving at the gate area, the crew inadvertently lined up with gate B23 and awaited marshallers. As the marshallers arrived, the crew noticed that they were aligned with the wrong gate and that a left turn to enter gate B21 was not possible due to ground obstructions. As a result, the flight crew decided to perform a right turn to return to the ramp area and then enter gate B23. The B757 was parked to the right of the CRJ900 at gate B25, and was aligned at about a 45 degree angle relative to the other parking configurations. As they reached approximately 90 degrees in the turn, the first officer (FO) advised the captain they were getting too close to the wing of the B757. The captain proceeded to slowly complete the right turn to exit the gate but the flight crew then felt a shudder and the FO noted possible damage to the winglet of the B757. The CRJ900 continued its taxi to the proper gate and all passengers deplaned normally. After engine shutdown, the captain exited the airplane to assess any damage to the CRJ900 and noticed the horizontal stabilizer leading edge was substantially damaged.