ASN Aircraft accident Saab 340B HB-AKK Nassenwil
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Status:Accident investigation report completed and information captured
Date:Monday 10 January 2000
Type:Silhouette image of generic SF34 model; specific model in this crash may look slightly different
Saab 340B
Registration: HB-AKK
MSN: 340B-213
First flight: 1990
Total airframe hrs:21674
Engines: 2 General Electric CT7-9B
Crew:Fatalities: 3 / Occupants: 3
Passengers:Fatalities: 7 / Occupants: 7
Total:Fatalities: 10 / Occupants: 10
Aircraft damage: Destroyed
Aircraft fate: Written off (damaged beyond repair)
Location:near Nassenwil (   Switzerland)
Phase: En route (ENR)
Nature:International Scheduled Passenger
Departure airport:Zürich-Kloten Airport (ZRH/LSZH), Switzerland
Destination airport:Dresden Airport (DRS/EDDC), Germany
At 17:00 Saab 340 HB-AKK arrived at Zurich, Switzerland following a flight from Guernsey. The aircraft was then prepared for Crossair flight 498 to Dresden. Germany.
Taxi clearance was given at 17:50 and the crew taxied to runway 28. The crew expected to be cleared for a standard instrument departure SID ZUE 1Y. This procedure calls for the aircraft to climb straight ahead heading 280 and then make a left turn to cross overhead the airport at the KLO VOR and then assume a heading of 054° onto airway R234 to the Zurich East (ZUE) beacon.
At 17:54 the aircraft was cleared for takeoff. Takeoff and climb were conducted with flaps at 0 degrees, which is normal for a Saab 340 departing from runway 28. The aircraft climbed normally at 136 knots IAS. After retracting the gear the Flight Director was switched on. While climbing through 2500 feet QNH the crew switched to Zurich Departure Control and were recleared to climb to FL110. At 17:55 the crew were cleared to make a left turn to intercept airway R234. A left turn was initiated, during which the first officer entered a command in the Flight Management System (FMS) to ZUE.
The command "direct to (DTO) – left – ZUE" however was programmed only as "direct to – ZUE". The programming was performed by the first officer alone, without the prescribed monitoring and checking by the captain. The latter was absorbed in manually flying the aircraft.
After having turned left for 7 seconds the captain started a right turn, consistent with Flight Director commands generated by the FMS for a 'direct to ZUE' as the right hand turn was the shortest.
In clouds the aircraft continued a right roll, which at 16:56:14 reached a right bank angle of 65.8°. The first officer advised the captain that the aircraft should actually turn to the left. This was also noted by the Zurich departure controller at 17:56:20, who asked the crew about the direction of the turn. The first officer replied: "Moment please, stand by". Upon which the Departure controller recleared the flight to continue the right turn direct to ZUE. By then the pitch had also decreased rapidly, accompanied by a marked speed increase and the Saab entered a high speed high-rate spiral descent. At 17:56:28 the aircraft crashed in an open field.

Weather reported included temperature 2deg C; dew point 1deg C; 1032 mB wind WNW/3 knots and light drizzle.

Probable Cause:

CAUSES: "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 co-pilot made an entry in the FMS, without being instructed to do so by the commander, which related to the change to the SID ZUE 1 standard instrument departure. 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."

Accident investigation:

Investigating agency: BFU Switzerland
Status: Investigation completed
Duration: 4 years and 3 months
Accident number: No 1781
Download report: Final report

Loss of control

» SKYbrary 

Follow-up / safety actions

BFU Switz. issued 11 Safety Recommendations

Show all...


photo of Saab-340B-
photo of Saab-340B-HB-AKK
accident date: 10-01-2000
type: Saab 340B
registration: HB-AKK

This map shows the airport of departure and the intended destination of the flight. The line between the airports does not display the exact flight path.
Distance from Zürich-Kloten Airport to Dresden Airport as the crow flies is 552 km (345 miles).
Accident location: Exact; as reported in the official accident report.

This information is not presented as the Flight Safety Foundation or the Aviation Safety Network’s opinion as to the cause of the accident. It is preliminary and is based on the facts as they are known at this time.
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