Alitalia flight 404, a DC-9-30, struck a mountain crashed while on approach to Zrich-Kloten Airport, Switzerland, killing all 46 occupants. Flight AZ404 took off from runway 36R at Linate Airport in Milan, Italy at 18:36 on a scheduled passenger service to Zurich, Switzerland. After an uneventful flight, AZ404 was cleared to descend to 4000 feet and to make an ILS approach to runway 14 at Zrich-Kloten Airport. At 14 nm from the runway 14 threshold, the aircraft captured the localizer. At about 11,5 nm short, the aircraft descended through the cleared altitude of 4000 feet. Descent from 4000 feet was only allowed after intercepting the glide path at 8 nm. The aircraft descended about 1400 feet below the glide path until it struck trees on the Stadlerberg mountainside at an elevation of 506 meters, 5,2 nm from the runway. The aircraft crashed and broke up, killing all 46 on board. PROBABLE CAUSE: “False indication of VHF NAV unit No.1 in the aircraft; probable altimeter misreading by the PIC; no GPWS warning in the cockpit; pilots not aware of the possibility of incorrect indications in the NAV equipment in use (without flag-alarm); inadequate failure analysis by the pilots; non-compliance with basic procedural instructions during the approach; COPI’s initiated go-around procedure aborted by the PIC; the approach controller not observing the leaving of the cleared altitude of 4000ft QNH before the FAP.”