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Tuesday, April 9, 2013

■ SUDAN: SCAA releases final report on Sudan Airways A310 crash in Khartoum in 2008.

Sudan AirwaysThe Sudanese Civil Aviation Authority has released its final report on its investigation into the 2008 crash of a Sudan Airways (SD) Airbus A310-300 (MSN: 548 | ST-ATN) at Khartoum International Airport which killed 30 of 214 occupants on board. The Airbus had touched down on Khartoum's runway 36 at 20h26L before longitudinally overrunning the runway by some 200m and bursting into flames on its right side. The report blames the long flaring distance (900 meters from R/W  threshold) on a wet slippery runway and various piloting oversights as the primary causes of the crash.


Backround


Sudan Airways A310 ST-ATN
Sudan Airways A310 ST-ATN (unknown)
The aircraft had been operating as flight SD109 from Amman (Jordan)  to Khartoum (Sudan) via Damascus (Syria) with 214 persons on board, including 11 crew, and was inbound to Khartoum when inclement weather forced the pilot to divert to Port Sudan for 75 minutes where the aircraft was refuelled with 20 tons of Jet A1. After receiving clearance from Khartoum tower to resume his inbound leg, the flight continued to Khartoum later that night. However, the weather had once again deteriorated with thunderstorms and rain blanketing Khartoum.  

After entering a holding pattern over Khartoum due to preceding traffic, the captain commenced a normal approach to runway 36 as Pilot in Charge.

He  received clearance to land after the controller provided him with wind  information (320° / 7 Kt) and runway conditions (wet). The left engine thrust  reverser was unserviceable and inhibited as per Minimum Equipment List  (MEL) procedures. 

The aircraft landed smoothly at about 2026L on runway 36. However, after touchdown some 900 meters down range from the runway threshold, the  captain reported that he had experienced some difficulties in maintaining the aircraft  on the centre line just after setting both thrust levers in the reverse position.  

He did not succeed in slowing down the aircraft nor could he stop it before the end of the runway. The aircraft longitudinally overran the runway and came  to a stop 215 meters after the runway end before catching fire on its right side. 

The main fire occurred between the right hand engine and the right hand wing root. Neither engine core showed any traces of engine fire.  

The right hand slides could not be deployed so the crew and the passengers evacuated the aircraft from the left frontslide though in the process, twenty nine passengers and one cabin crew were fatally injured. 



Images courtesy AFP

Investigation

A subsequent investigation undertaken by the Sudanese Civil Aviation Authority established the following facts regarding the accident and its sequence of events:
  • The aircraft was dispatched to Amman with engine No. 1 thrust reverser deactivated
  • The captain was the pilot flying, he performed a R/W 36 approach
  • The crew got clearances for approach and landing.
  • Aircraft was fully configured for landing, checks completed.
  • The controller gave the following last wind information: 320° /07 kt.
  • The aircraft was actually supported by a tailwind (15 kt).
  • The controller advised the crew that the runway was wet.
  • Auto brake was not selected.
  • Touch down point was at about 900 meters beyond the runway 36 threshold.
  • The captain landed smoothly and set both thrust levers in the maximum reverse and No. 2 reverser deployed normally and No. 1 reverse remained stowed.
  • The ground spoilers deployed normally, except both spoilers No. 5
  • The aircraft skidded to the right after the thrust reverser was applied.
  • 10 seconds after touch down both reversers were stowed and thrust levers were set to idle
  • The captain put the aircraft back to the centre line by differential braking.
  • The wheels locked after the captain switched the anti-skidoff and applied full braking on both pedals.
  • The aircraft caught fire after stopping.It collapsed later on due to fire.
  • Most of the crew members and the passengers succeeded in escaping through the front left L1.
  • The fire fighting personnel could not provide a rapid and efficient service
  • The investigation could not find evidence of aircraft technical issues which could have contributed to the accident.
  • The ILS on Runway 36 was not calibrated.      

Conclusion

The accident was due to the excessively long flaring distance (900 meters from R/W threshold) on a wet slippery runway without selecting Auto brake and with one deactivated engine reverser in such rainy conditions. The remaining available landing distance turned out to be too short to allow the captain to stop the aircraft before the end of the runway.  Contributing factors:  The wind information was not appropriate as it was tail wind at time of landing.  The crew was not aware of the aircraft's ground speed and the tail wind.

Source [BEA]