Loss of control Accident Saab 340B HB-AKK,
ASN logo
 
This information is added by users of ASN. Neither ASN nor the Flight Safety Foundation are responsible for the completeness or correctness of this information. If you feel this information is incomplete or incorrect, you can submit corrected information.

Date:Monday 10 January 2000
Time:17:56
Type:Silhouette image of generic SF34 model; specific model in this crash may look slightly different    
Saab 340B
Owner/operator:Crossair
Registration: HB-AKK
MSN: 340B-213
Year of manufacture:1990
Total airframe hrs:21674 hours
Cycles:20587 flights
Engine model:General Electric CT7-9B
Fatalities:Fatalities: 10 / Occupants: 10
Aircraft damage: Destroyed
Category:Accident
Location:near Nassenwil, 1.5 km W of Zürich-Kloten Airport -   Switzerland
Phase: En route
Nature:Passenger - Scheduled
Departure airport:Zürich-Kloten Airport (ZRH/LSZH)
Destination airport:Dresden Airport (DRS/EDDC)
Investigating agency: BFU Switz.
Confidence Rating: Accident investigation report completed and information captured
Narrative:
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 17:56:14 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.

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:
cover
  
Investigating agency: BFU Switz.
Report number: No 1781
Status: Investigation completed
Duration: 4 years and 3 months
Download report: Final report

Sources:

SKYbrary 

Location

Images:


photo (c) Aviation Safety Network


photo (c) Harro Ranter; Zürich-Kloten Airport (ZRH); 31 August 1996; (CC:by-nc-nd)

Revision history:

Date/timeContributorUpdates
11-May-2024 16:23 RichT Updated [Location, Narrative]

Corrections or additions? ... Edit this accident description

The Aviation Safety Network is an exclusive service provided by:
Quick Links:

CONNECT WITH US: FSF on social media FSF Facebook FSF Twitter FSF Youtube FSF LinkedIn FSF Instagram

©2024 Flight Safety Foundation

1920 Ballenger Av, 4th Fl.
Alexandria, Virginia 22314
www.FlightSafety.org