Alitalia Flight 404
McDonnell Douglas DC-9-32 · Controlled flight into terrain due to NAV receiver failure and pilot error
From Milano Linate Airport (LIN) to Zürich Airport (ZRH)
Event
- Event typeAccident: someone killed or seriously injured, or the aircraft substantially damaged (NTSB definition). Incident: an occurrence that affected or could have affected safety, short of that. Glossary
- Accident
- Event fatalities
- 46 · all aircraft and ground
- Ground fatalities
- Unknown
- Occupants
- 46
- Survivors
- 0
- InjuriesFatal: death within 30 days. Serious: over 48 hours in hospital within a week, most broken bones, severe bleeding, nerve or organ damage, or serious burns. Minor: anything less. Glossary
- Unknown
- OperationWhat kind of flying it was, grouped by the rules it flew under: airline (US Part 121), air taxi and commuter (Part 135), general aviation (Part 91 and similar), military or government. Glossary
- Airline
McDonnell Douglas DC-9-32
- Flight
- AZ404
- Aircraft type
- McDonnell Douglas DC-9
- Category
- Airplane · from aircraft type
- RegistrationThe aircraft's tail number, such as N12345 or G-ABCD. Registrations are reissued, so the same one years apart can be a different aircraft. Glossary
- I-ATJA
- Operator
- Alitalia
- Onboard fatalities
- 46
- Route
- From Milano Linate Airport (LIN)To Zürich Airport (ZRH)
Cause areas
- Aircraft › Aircraft systems
- Personnel issues › Psychological
- Personnel issues › Miscellaneous
- Environmental issues › Physical environment
- Environmental issues › Task environment
From the investigation findings the Wikipedia article reports, sorted into the NTSB's cause areas with AI assistance.
Approximate · Coordinates from the Wikipedia article; not checked against an investigation report.
From the Wikipedia article
Alitalia Flight 404 (AZ404/AZA404) was an international passenger flight scheduled to fly from Linate Airport in Milan, Italy, to Zurich Airport in Zurich, Switzerland, which crashed on 14 November 1990. The McDonnell Douglas DC-9-32, operated by Alitalia, crashed into the woodlands of Weiach as it approached Zurich Airport, killing all 46 occupants on board.
A Swiss investigation concluded that the accident was caused by a short circuit, which led to the failure of the aircraft's NAV receiver. The malfunction went unnoticed by the crew, who likely believed they were on the correct flight path until the crash. Swiss authorities also blamed inadequate crew resource management, exemplified when the captain vetoed the first officer's attempted go-around, along with the absence of lighting on Stadlerberg Mountain and a known problem with errors in reading the drum pointer altimeter of the aircraft.
The final report by the Federal Aircraft Accidents Inquiry Board requested several major changes and made further recommendations.
Accident
During the approach to runway 14 of Zurich Airport, the captain's instrument landing system (ILS) display gave incorrect values due to a faulty receiver. It falsely indicated that the aircraft was about 1,000 feet higher than it actually was, which also prevented the Ground proximity warning system (GPWS) from reading the situation and sounding a warning. The ILS receiver of the first officer was working correctly and displayed the dangerously low approach. Without thoroughly examining which value was correct, the captain decided to ignore the second device, aborting a go-around maneuver initiated by the first officer. Shortly afterward, at 20:11 CET, the plane struck Stadlerberg Mountain at 1,660 ft, killing all 40 passengers and six crew.
The aircraft's first impact was with trees on the right side of the aircraft, causing several essential parts on the right side of the aircraft, such as the right-wing flaps and the outer right wing, to detach. As a result, the aircraft produced an asymmetric lift force and began to roll to the right, finally slamming into the mountain in a nearly inverted position.
Firefighters and police were immediately dispatched to the accident site but the fire was so intense that it took an entire day to put out. Eyewitnesses stated that "the plane was burning like a volcano." Linate Airport immediately set up a crisis center to handle the relatives of the victims aboard the flight.
Investigation and cause
Investigation
Swiss officials were informed of the accident approximately one hour after it occurred, and at least 80 Swiss investigators were involved in the inquiry. Additionally, Italian Interior Minister Vincenzo Scotti sent a team of investigators to the accident site along with the United States' NTSB and FAA. Both the Flight Data Recorder and the Cockpit Voice Recorder were recovered from the accident site.
In the initial hours after the accident, several witnesses claimed that the aircraft was on fire before it hit Stadlerberg while others claimed that the aircraft had exploded before it impacted terrain. Josef Meier, a spokesman for Swiss air traffic control authorities stated in a news conference that all possible causes, including terrorism, were being evaluated by the investigators.
Italian news media reported that the mountain was covered with cloud and that there was heavy rain in the area, while Swiss investigators claimed that visibility was good during the accident with light showers occurring at the airport.
On 16 November, an official from the Swiss investigation team stated that the aircraft was flying at a lower altitude than it should have been: "The plane was 300 m too low on its approach, and was slightly off course. [The captain] was not following the radio beacon signals." The statement did not say why the plane was too low.
Text from the Wikipedia article “Alitalia Flight 404” (revision 1372834312, retrieved 2026-09-18) by its authors, under CC BY-SA 4.0. Extracted as plain text: references, tables, images and some sections are left out. Read the article
Sources
Wikipedia article: Alitalia Flight 404
- Article
- Alitalia Flight 404
- Revision
- 1372834312 · 2026-09-02 · retrieved 2026-09-18
- Wikidata
- Q2647284
- Licence
- Text CC BY-SA 4.0, by the article's authors; Wikidata CC0; town positions GeoNames (CC BY 4.0)
Where each value comes from
- Record
- Wikipedia article "Alitalia Flight 404" (page 21950330, revision 1372834312)
- Date
- Wikipedia infobox: date
- Place and country
- Wikipedia infobox: site
- Map position
- Wikipedia article coordinates
- Aircraft, operator and route
- Wikipedia infobox: aircraft type, registration, operator, origin and destination; route airports from the linked airport articles' Wikidata codes (OurAirports)
- Operation
- airline flight number in the infobox
- Fatalities
- Wikipedia infobox: aircraft fatalities
- Ground fatalities
- not stated in the Wikipedia infobox
- Summary
- Wikipedia infobox: summary
Source notes (1)
- Wikipedia · Facts from the Wikipedia article's infobox and coordinates, not checked against an investigation report. Independent review pending.