TCAS RA on TAP A320 at Lisbon Due to Helicopter Maneuver (CS-TNL)

Incident Overview On 7 June 2008, during the opening period of Euro 2008, a TAP Portugal Airbus A320-214, call sign TAP873C, was on an ILS approach to runway 03 at Lisbon Airport. The aircraft had 8 crew members and 112 passengers on board. A HeliPortugal Eurocopter France AS 350 B2, registration CS-HFP, was operating in the vicinity to film football fans for a television station. ## Sequence of Events The helicopter had communicated with Lisbon Tower and indicated it would remain near the runway 35 alignment for about nine minutes. At 14:01:38 UTC, TAP873C was cleared to descend to 2,500 feet and intercept the ILS for runway 03. Lisbon Approach also advised the A320 crew that the helicopter was operating at 1,000 feet and below in the Marquês de Pombal area. The A320 crew acknowledged but could not visually locate the helicopter. At 14:02:40 UTC, the helicopter was east of the runway 03 ILS approach line while the A320 was descending through 2,300 feet. At 14:03:12 UTC, the tower issued landing clearance for runway 03. At 14:03:20 UTC, while the A320 was crossing 1,300 feet, the helicopter began a left turn. The A320 crew then reported “Overshooting due to TCAS RA” as the TCAS issued a climb resolution advisory. The crew stated they had not seen the other traffic and were climbing due to a TCAS RA with only about 100 feet of separation. ## Go-Around and Aftermath The A320 captain took the controls and executed a go-around. The crew reported on the Navigation Display that the traffic was climbing with continuously reducing vertical separation. The tower instructed the A320 to maintain 2,000 feet if possible, but the crew said it would stop the climb at 3,000 feet because it could not stop at the instructed altitude. The tower then instructed the A320 to maintain 3,000 feet, keep the runway heading, and remain on the tower frequency. At 14:04:12 UTC, the A320 was instructed to join the downwind for a new approach to runway 03, and it landed without further incident. ## Investigation Findings The preliminary investigation concluded that the direct cause was the activation of a TCAS climb resolution advisory on TAP873C due to the helicopter CS-HFP turning left to position itself head-on with the approaching traffic in an attempt to ensure visual separation. A contributory cause was the tower controller’s expectant posture that the helicopter would move east of the approach line, which did not occur. The report also noted phraseology issues: the A320 crew used “Overshooting” instead of the standard ICAO “Going Around,” and the controller did not use the standard “ROGER” response to the TCAS RA report. The A320 crew should have later reported “CLEAR OF CONFLICT, (assigned clearance) RESUMED” after completing the TCAS RA response. ## Outcome There were no injuries and no damage to the aircraft. The incident was classified as an ATM incident and investigated by Portugal’s GPIAA under procedure 17/SUM/08.