federal government. The canton only had to make concessions for the commercial parts of the project, such as the restaurant wing. The dispatch of the Federal Council, submitted on 1 March 1965, requested a federal contribution of 23.1 million to the total costs of 129.4 million. Of this, 2.1 million was earmarked for the connection of the airport to the national road network and for the preparation of a connection to the planned (but never built) Zürich underground railway. The National Council and Council of States adopted the bill in October 1965, allowing construction work to begin the following year. The motorway loop was in operation from 1968. Finally, with the opening of the last new hall wing on 1 April 1971, the extension of the terminal building was completed. The first signs of noise mitigation for the airport were in 1972, when a night-time curfew was enacted, as well as in 1974 when new approach routes were introduced. Runway 14/32 was opened in 1976, and 16/34 began renovation. Attacks on El Al aircraft On 18 February 1969, four armed members of the Popular Front for the Liberation of Palestine (PFLP) attacked El Al flight 432, firing Kalashnikov assault rifles at the Boeing 720B whilst it prepared for takeoff. The Shin Bet employee Mordechai Rachamim fired back with his pistol and killed the terrorist Abdel Mohsen Hassan. The three remaining assassins were each sentenced to twelve years in prison. The aircraft's co-pilot subsequently died of his injuries. The attack marked the beginning of a discussion about airport security that had never been raised until then in Switzerland. On 21 February 1970 a parcel bomb exploded in Swissair's Convair CV-990 on flight SR330 (Zurich-Tel Aviv). In the crash near Würenlingen all 47 people on board were killed. Investigations revealed that a PFLP terrorist group had carried out the bomb attack. The actual target, however, had been an El Al flight from Munich to Tel Aviv, whose mail had been sent with Swissair to Zürich due to long delays. In 1970 the PFLP obtained the release of the three terrorists convicted in Switzerland and other comrades-in-arms imprisoned abroad through coordinated hijackings. Flights affected were SR 100 (Zurich-New York), TWA flight TW741, Pan Am flight PA93 and BOAC flight BA775. Third stage of construction In January 1969, the Zürich's Cantonal Council approved a loan for preparatory work for the third stage of expansion.