On June 13, 2007, about 1240 mountain standard time, a Bombardier, Inc., CL-600-2B19 (CL65), N7264V, operated by Mesa Airlines as US Airways flight #2705, landed at the Phoenix International Airport (PHX), Phoenix, Arizona. Thereafter, upon taxiing to the terminal gate, the main passenger cabin door was found jammed and would not open. This event precluded passengers from immediately exiting the airplane via the main door. The incident occurred at the conclusion of a scheduled, domestic, passenger flight, performed under the provisions of 14 Code of Federal Regulations Part 121, which originated from the Los Angeles International Airport, Los Angeles, California. The airplane was not damaged, and there were no injuries to the three crew members or fifty passengers. The flight attendant (FA) was unable to open the door, and she summoned the First Officer (FO) for assistance. After the FA briefed the FO regarding her difficulty, the FO attempted to open the cabin door. He was similarly unsuccessful, and a mechanic was summoned. The mechanic entered the airplane via the galley service door on the opposite side of the airplane. He manipulated the passenger cabin door opening lever from inside the cabin, and he successfully opened the cabin door. A National Transportation Safety Board investigator who was on board the incident flight witnessed the event, and an investigation ensued. Initially, the operator's maintenance personnel examined the door, lubricated it, and indicated the door was functionally okay. The airplane, serial number 7264, was manufactured in 1998. It is commonly referred to as a "CRJ-200." On June 14, 2007, the airplane was ferried to Bombardier Regional Aircraft Services, Tucson Air Center (TAC), Tucson, Arizona, where it was examined. The airplane's door was found in need of repair. The Director of Maintenance at Bombardier TAC reported that the airplane's main cabin door was found completely out of adjustment (rig), which required mechanics to re-rig the door. Regarding the repair work order, maintenance records documented that the following actions were taken: (1) the door's pushrod and spring assembly were replaced with a new pushrod and spring assembly; (2) the release lever rod end was adjusted; (3) a new passenger door assist motor was installed to replace the inoperative motor; and (4) the lock/unlock indicators, which were not indicating properly, were repositioned. Safety Board investigators examined Mesa Airline's maintenance data for prior occurrences involving the incident airplane's door. The following discrepancy notations were found for the period between January 2006 and June 2007: Date Discrepancy 1/12/2006 PAX DOOR WONT FULL CLOSE 1/12/2006 PAX DOOR WILL NOT CLOSE AND LOCK 1/22/2006 PAX DOOR WILL NOT OPEN 4/01/2006 FA UNABLE TO CLOSE DOOR ACCT FOR DELAY 6/17/2006 PAX WILL NOT CLOSE 7/02/2006 MAIN CABIN DOOR HARD TO OPEN 7/12/2006 MAIN ENTRY DOOR W/N OPEN 7/15/2006 PAX DOOR HANDLE W/N OPEN 10/3/2006 PAX DOOR W/N OPEN OR CLOSE 5/10/2007 UNABLE TO OPEN PASS FROM INSIDE 5/17/2007 PAX DOOR WOULD NOT OPEN 6/09/2007 PAX DR W/N OPEN 6/15/2007 MAIN CABIN DOOR WILL NOT OPEN In addition, a review of the Federal Aviation Administration's (FAA) Service Difficulty Reports (SDR) database revealed one report, dated January 22, 2006, that involved N7264V. The discrepancy written in this report indicated that the airplane's main passenger door would not open or close. Thereafter, maintenance personnel inspected the door, were able to open it, and adjusted the door's proximity switch. A review of discrepancy data listed in the FAA's SDR database was also performed regarding the manufacturer's fleet of CL65 airplanes. The review indicated that since July 1994, about 58 reports involved CL65 jammed or difficult-to-open main cabin door events. Bombardier informed Safety Board staff that a search of pilot reports within the Canadian SDR database and Failure Reporting and Corrective Action System (FRACAS) records since 1995 listed 823 events regarding main cabin door jamming or difficult-to-open events on the CL65 model of airplane.