Event Details

Title:Flight into terrain, Final Report of the Aircraft Accident Investigation Bureau on the accident to the Saab 340B aircraft, registration HB-AKK of Crossair flight CRX 498 on 10 January 2000 near Nassenwil/ZH
Micro summary:Spatial disorientation results in a crash of this Saab 340B.
Event Time:2000-01-10 at 1656 UTC
File Name:2000-01-10-CH.pdf
Publishing Agency:Aircraft Accident Investigation Bureau (AAIB)
Publishing Country:Switzerland
Report number:1781
Site of event:near Nassenwil
Latitude/Longitude:N 47° 28’ 12” E 08° 28’ 17”
Departure:Zurich International Airport (Kloten Airport), Kloten, Switzerland
Destination:Dresden Klotzsche Airport, Dresden, Germany
Airplane Type(s):Saab 340B
Flight Phase:Climb
Type of flight:Revenue
Serious Injuries:0
Other Injuries:0
Executive Summary:On 10 January 2000, at 16:54:10 UTC, in darkness, on runway 28 of Zurich airport, the Saab 340B aircraft of the Crossair airline company, registered HB-AKK, began its scheduled flight CRX 498 to Dresden. Two minutes and 17 seconds later, after a right-hand spiral dive, the aircraft crashed on an open field near Au, Nassenwil ZH.

The ten occupants (three crew members and seven passengers) were fatally injured by the impact. The aircraft was destroyed. A fire broke out and there was damage to farmland.

The investigation has determined the following causes for the accident:

The accident is attributable to a collision with the ground, after the flight crew had lost control of the aircraft for the following reasons:

• The flight crew reacted inappropriately to the change in departure clearance SID ZUE 1Y by ATC.

• The first officer made an entry into the FMS without being instructed to do so by the commander concerning the change to standard instrument departure SID ZUE 1Y. In doing so, he omitted to select a turn direction.

• The commander dispensed with use of the autopilot under instrument flight conditions and during the work-intensive climb phase of the flight.

• The commander took the aircraft into a spiral dive to the right because, with a probability bordering on certainty, he had lost spatial orientation.

• The first officer took only inadequate measures to prevent or recover from the spiral dive.

The following factors may have contributed to the accident:

• The commander remained unilaterally firm in perceptions which suggested a left turn direction to him.

• When interpreting the attitude display instruments under stress, the commander resorted to a reaction pattern (heuristics) which he had learned earlier.

• The commander’s capacity for analysis and critical assessment of the situation were possibly limited as a result of the effects of medication.

• After the change to standard instrument departure SID ZUE 1Y the crew set inappropriate priorities for their tasks and their concentration remained one-sided.

• The commander was not systematically acquainted by Crossair with the specific features of western systems and cockpit procedures.

Learning Keywords:Operations - Crew Resource Management
Operations - Uncontrolled Flight into Terrain
Systems - INS/FMS/PMCS mis-entry
Other - Regulatory Oversight
Consequence - Hull Loss


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