BELARUS NEWS AND ANALYSIS
DATE:
18/08/2009
Crash: Belavia CRJ100 at Yerevan on Feb 14th 2008, wing tip strike during takeoff
Crash: Belavia CRJ100 at Yerevan on Feb 14th 2008, wing tip strike during takeoff
| By Simon Hradecky, created Tuesday, Aug 18th 2009 12:45Z, last updated Tuesday, Aug 18th 2009 13:02Z  | | Theoretic and actual lift curves (Graphics: MAK) |
The Russian Interstate Aviation Committee (MAK) have released their final report in Russian concluding, that the most probable cause of the crash was:
- the asymmetric loss of aerodynamics properties of the wing during takeoff, which resulted in stalling the aircraft immediately after liftoff, the left wing contacting the runway and the subsequent destruction and fire.
- The reason for the loss of aerodynamics properties of the wing in the current weather conditions was frost contaminating the surfaces of the wings. The cause of the frost contamination was, most likely, the temperature difference of air and cold fuel in the tanks.
- Takeoff below the recommended safe speed for contaminated wings aggravated the situation.
- The current standard procedures to examine the aerodynamic surfaces before departure, along with the inefficiency, can not fully guarantee the preventions of similiar accidents during takeoff in the future because of the high sensitivity of the wing, that does not permit even a slight contamination of the leading edge.
- Deicing of the wings as required by an Airworthiness Directive by Transport Canada (Canada's Civil Aviation Authority) in the actual weather conditions released after another similiar accident most likely could have prevented the accident.
The airplane, a Canadair CRJ-100LR registration EW-101PJ, had arrived at Yerevan 2 hours before scheduled departure and was now preparing for departure as flight B2-1834 from Yerevan (Armenia) to Minsk 2 (Belarus) with 18 passengers and 3 crew. 2200 liters (1802kg) of Jet-A-1 fuel were added to the tanks, refueling was done in automatic mode 25 minutes after landing. Due to reported reducing visibility at the main alternate airport the crew decided to add another 400 liters of fuel about 30 minutes later during flight preparation.
The first officer - not the pilot in command although required in weather conditions, that are suspectible to frost contamination - performed the preflight check of the aircraft about 15 minutes after landing (and before refueling) and found all aerodynamics surfaces clean and dry by visual inspection as well as by touching the surfaces with the palm of his hand.
The weather at the time was: winds from 110 degrees at 2 knots, visibility 3500 meters (11500 feet) in light haze, clouds overcast at 2600 feet, scattered at 9800 feet, temperature -3 degrees Centigrade, dew point -4 degrees centigrade and QNH 1019 hPa.
The crew computed V1 at 137, Vr at 139 and V2 at 145 knots.
After engine start the crew activated the anti-ice systems of the engines, the wing anti-ice systems were not activated.
The airplane banked progressively left after liftoff until the left wing touched the ground with the airplane veering left of the runway, rolled right separating the right hand wing, crossed the runway rolling on its back and disintegrated coming to rest right of the runway. Leaking fuel triggered a ground fire, which was quickly brought under control by the airport fire fighters. 7 passengers received serious injuries, the other 11 passengers and the 3 crew remained unhurt.
The MAK performed a test employing a CRJ-900 registration D-ACKK to assess the accumulation and freeze of atmosperic moisture with large temperature differences between the ambient air and the remaining fuel in the tanks after landing. It was found, that ice accumulated on the underside of the wing immediately after landing and grew 25 minutes after landing upon refueling. The upper side of the wing showed dew accumulation after refueling. The fuel temperature at the time of arrival was measured at -21 degrees Centigrade, before departure at -12 degrees Centigrade with an ambient temperature of plus 8 degrees Centigrade.
At the time of the accident it can be assumed, that the temperature of the fuel in EW-101PJ never got above -12 degrees Centigrade with an ambient temperature of -3 degrees.
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First impact mark of left wing (Photo: MAK):
Tracks to the left of the runway (Photo: MAK):
Track across the runway (Photo: MAK):
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By Simon Hradecky, created Wednesday, Jun 24th 2009 16:26Z, last updated Wednesday, Jun 24th 2009 16:38ZThe General Director of Belavia reported today in a press conference, that the airplane took off without having been de-iced. However, it has not yet been determined, whether there had been ice accretion on the wings.
Ground personnel had recommended to de-ice the aircraft three times before departure, the crew however assessed based on temperature, humidity, dew point, the existing de-icing system of the aircraft and other factors, that de-icing fluid was not needed. The airplane reached a height of 13-16 feet, when the left wing struck the ground and the airplane rolled inverted.
He continued, that the manufacturer of the aircraft did not complete a system to protect the aircraft from icing.
The de-icing fluid including application, which could have saved the airplane, would have cost 600 US$, but now the plane is lost. "Aviation Law is written in blood", he said.
The final report has not yet been released.
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By Simon Hradecky, created Thursday, Feb 14th 2008 13:27Z, last updated Thursday, Feb 14th 2008 13:27Z
By Simon Hradecky, created Thursday, Feb 14th 2008 13:24Z, last updated Thursday, Feb 14th 2008 13:24ZWeather Data at the time of the accident:
MET UDYZ 140800Z 00000MPS 3500 -SN BR BKN020 M02/M05 Q1018 09190060 NOSIG=
MET UDYZ 140730Z 19001MPS 3500 -SN BR BKN016 M03/M05 Q1018 09190060 NOSIG=
MET UDYZ 140700Z 00000MPS 3500 -SN BR BKN016 M03/M05 Q1018 09010070 NOSIG=
TAF UDYZ 140750Z 140918 VRB02MPS 3500 BR SCT015 SCT100 TEMPO 0918 1000 SN OVC008=
TAF UDYZ 140450Z 140606 VRB02MPS 2000 BR SCT010 BKN100 TEMPO 0618 23006MPS 0600 SN OVC004 BECMG 1415 1000 BR TEMPO 1806 0200
SN FZFG VV001=
First picture of the crashed plane:
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By Simon Hradecky, created Thursday, Feb 14th 2008 07:08Z, last updated Thursday, Feb 14th 2008 07:08ZA Belavia CRJ-100, registration EW-101PJ performing flight B2-1834 from Yerevan to Minsk with 18 passengers and 3 crew, crashed on takeoff after a wing tip reportedly contacted the runway surface. After the wing tip strike the aircraft Russian Media report the airplane to have tumbled, departed the runway, turned over and broken in two parts. Thanks to quick reaction by rescue forces all people on board were recovered before the airplane exploded. All people survived, 4 were sent to hospital, the others treated on scene.
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Source:
http://avherald.com/h?article=4020f387/0018
