Narrative:
A Hawker 850XP corporate jet was destroyed in an accident at Sulaymaniyah, Iraq. All seven on board were killed. Among the passengers were technicians and shareholders with Iraqi mobile phone company Asiacell.
An investigation showed that the airplane stalled before reaching sufficient speed, and descended, striking the ground almost 6900 feet from the runway 31 threshold, and 130 feet from the right-hand edge.
Prior to departure the crew did not remove accumulated snow on the upper surface of the wing.
Probable Cause
1- The flight crews failure to de-ice the aircraft prior to take-off resulted in the aircraft wings top surface, especially the right wing, being contaminated with ice and snow, leading the right wing to stall at a speed significantly below the clean wing stall speed.
a. There was a contaminated ice and snow on the wings, elevator and horizontal stabilizer top surface.
b. The pilot was in a hurry and didnt remove these contaminations.
Contributing Factors
1- The hurry up syndrome led the captain to disregard de-icing the aircraft, despite the physical evidence and confirmation of ice contamination by the F/O, as he was focusing his attention on the deteriorating visibility.
2- The F/O lack of assertiveness in insisting on de-icing the aircraft prior to take-off did not help the captain review his decision.
3- The Contamination of snow and ice on top of the wing, fuselage and tail will compromise the normal takeoff characteristics.
4- The stall warning did not activate as the wing stalling speed and AOA was well below the clean wing stalling speed.
ASN editorial note:
The Iraqi CAA final report writes that the speed "was well below the clean wing stalling speed." Given the context, the speed was likely *above* the clean wing stalling speed.
Loss of control
» Iraqi CAA Aircraft Accident Report No. 12/36/105
ORSU 041400Z 15006KT 1500 SN OVC035 03/00 Q1022=
Wind: 150 degrees at 6 knots; 1500 m visibility in snow; overcast 3,500 ft; Temperature 3°C; Dewpoint 0°C
accident date: 04-02-2011
type: Raytheon Hawker 850XP
registration: OE-GRS
| Status: | Accident investigation report completed and information captured |
| Date: | Friday 4 February 2011 |
| Time: | 17:49 |
| Type: |  Raytheon Hawker 850XP |
| Operator: | Sky Lounge Services |
| Registration: | OD-SKY |
| MSN: | 258804 |
| First flight: | 2006 |
| Engines: | 2 Garrett TFE731-5BR-1C |
| Crew: | Fatalities: 3 / Occupants: 3 |
| Passengers: | Fatalities: 4 / Occupants: 4 |
| Total: | Fatalities: 7 / Occupants: 7 |
| Aircraft damage: | Destroyed |
| Aircraft fate: | Written off (damaged beyond repair) |
| Location: | Sulaymaniyah International Airport (ISU) ( Iraq)
|
| Crash site elevation: | 753 m (2470 feet) amsl |
| Phase: | Initial climb (ICL) |
| Nature: | Executive |
| Departure airport: | Sulaymaniyah International Airport (ISU/ORSU), Iraq |
| Ankara-Esenboga Airport (ESB/LTAC), Turkey |
A Hawker 850XP corporate jet was destroyed in an accident at Sulaymaniyah, Iraq. All seven on board were killed. Among the passengers were technicians and shareholders with Iraqi mobile phone company Asiacell.
An investigation showed that the airplane stalled before reaching sufficient speed, and descended, striking the ground almost 6900 feet from the runway 31 threshold, and 130 feet from the right-hand edge.
Prior to departure the crew did not remove accumulated snow on the upper surface of the wing.
Probable Cause:
Probable Cause
1- The flight crews failure to de-ice the aircraft prior to take-off resulted in the aircraft wings top surface, especially the right wing, being contaminated with ice and snow, leading the right wing to stall at a speed significantly below the clean wing stall speed.
a. There was a contaminated ice and snow on the wings, elevator and horizontal stabilizer top surface.
b. The pilot was in a hurry and didnt remove these contaminations.
Contributing Factors
1- The hurry up syndrome led the captain to disregard de-icing the aircraft, despite the physical evidence and confirmation of ice contamination by the F/O, as he was focusing his attention on the deteriorating visibility.
2- The F/O lack of assertiveness in insisting on de-icing the aircraft prior to take-off did not help the captain review his decision.
3- The Contamination of snow and ice on top of the wing, fuselage and tail will compromise the normal takeoff characteristics.
4- The stall warning did not activate as the wing stalling speed and AOA was well below the clean wing stalling speed.
ASN editorial note:
The Iraqi CAA final report writes that the speed "was well below the clean wing stalling speed." Given the context, the speed was likely *above* the clean wing stalling speed.
Accident investigation:
 |
|
Classification:
IcingLoss of control
Sources:
» Canadian Press» Iraqi CAA Aircraft Accident Report No. 12/36/105
METAR Weather report:
14:00 UTC / 17:00 local time:ORSU 041400Z 15006KT 1500 SN OVC035 03/00 Q1022=
Wind: 150 degrees at 6 knots; 1500 m visibility in snow; overcast 3,500 ft; Temperature 3°C; Dewpoint 0°C
Follow-up / safety actions
CAA Iraq issued 8 Safety Recommendations
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Photos
accident date: 04-02-2011
type: Raytheon Hawker 850XP
registration: OE-GRS
Map
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 Sulaymaniyah International Airport to Ankara-Esenboga Airport as the crow flies is 1186 km (741 miles).
Accident location: Approximate; accuracy within a few kilometers.
Distance from Sulaymaniyah International Airport to Ankara-Esenboga Airport as the crow flies is 1186 km (741 miles).
Accident location: Approximate; accuracy within a few kilometers.
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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