Incident at ST. JOHN'S INTL NL (CYYT)

2010-03-16: UPDATE TSB: A10A0024: COA1951, a Continental Airlines Boeing 757-200, was en route from Lajas, Azores Islands to Newark on a ferry flight with 13 company personnel and no passengers on board. At 2048 NST, the flight crew noted an air data computer ASI disagreement warning, a rudder ratio message, rudder speed trim message, and an elevator symmetry message. In addition, the autopilot was trimming and then disconnected after which it was noted that manual control of the aircraft was sluggish. The crew declared an emergency, initiated a descent, and requested and received a clearance to divert the flight to St. John's, NL. The aircraft landed safely at St. John's at 0921 NST without further incident. Previously on the 26 February 2010 on a passenger flight from Newark to Lisbon, the aircraft diverted into Lajas due to a similar problem. The operator dispatched five maintenance personnel to repair the aircraft. The right-hand air data computer was found to be faulty at which time it was replaced and the aircraft was returned to service. The aircraft was being ferried to Newark when the diversion to St. John's occurred. Maintenance personnel are conducting inspection and repairs at St. John's before further flight. UPDATE 5 March 2010: Maintenance inspection has revealed that the replacement air data computer installed prior to this flight was also defective. Another air data computer was installed and the aircraft has been returned to service without further incident. Both defective air data computers have been sent to the manufacturer (Honeywell) for a detailed analysis. It was suspected that there was atmospheric ice present at the aircraft altitude where the incident occurred, therefore, the operator removed and replaced the right-hand pitot tube in order to test for correct electrical input for de-icing.

2010-03-01: COA1951, Boeing 757-200, enroute from Lajes (LPLA) to Newark (KEWR), at 00:18Z, position 115 nautical miles south of St. John?s (CYYT), declared an emergency due to a flight control problem. The aircraft started descent and advised it was diverting to St. John?s. Air Traffic Control (ATC) cleared the aircraft as requested. The aircraft landed in St. John?s without incident at 00:51Z. TSB Case Closed.