Narrative:A Embraer RJ135LR passenger jet, registered ZS-SJW and operated by SA Airlink, sustained substantial damage when it suffered a runway excursion on landing at George Airport (GRJ), South Africa. Three crew members and seven passengers sustained minor injuries.
SA Airlink flight SA 8625 departed Cape Town International Airport (CPT) on a domestic scheduled flight to George. The aircraft was cleared for an instrument landing system (ILS) approach runway 11. The prevailing weather conditions at the time were overcast in light rain. The aircraft touched down in the area of the fourth landing marker. At the end of the runway veered to the right and went past the ILS localizer. The aircraft collided with eleven approach lights before it burst through the aerodrome perimeter fence, with the aircraft coming to rest in a nose down attitude on a public road.
Runway 11 is a 2000 x 45 meters asphalt runway. At the time of this accident it was the first time that the George area had received a proper rain shower following the rehabilitation of the runway, which was concluded on 6 November 2009. It would appear that the application of the fog spray sealant extensively degraded the surface friction coefficient of the runway surface during wet conditions, thereby allowing the onset of aquaplaning and thereby inhibiting the application of adequate braking pressure by the anti-skid system to stop the aircraft within the certificated distance.
Weather reported at the time of the accident (about 09:06 UTC / 11:06 local):
FAGG 070900Z 08007KT 040V130 9999 -RA BKN080 19/18 Q1011= [Wind 080 degrees at 7 knots variable from to 130░ ]
The crew were unable to decelerate the aircraft to a safe stop due to ineffective braking of the aircraft on a wet runway surface, resulting in an overrun.
1. The aircraft crossed the runway threshold at 50 ft AGL at 143 KIAS, which was 15 kt above the calculated VREF speed.
2. Although the aircraft initially touched down within the touchdown zone the transition back into air mode of 1.5 seconds followed by a 4 second delay in applying the brakes after the aircraft remained in permanent ground mode should be considered as a significant contributory factor to this accident as it was imperative to decelerate the aircraft as soon as possible.
3. Two of the four main tyres displayed limited to no tyre tread. This was considered to have degraded the displacement of water from the tyre footprint, which had a significant effect on the braking effectiveness of the aircraft during the landing rollout on the wet runway surface.
4. Non-compliance with ICAO Standard 2.9.5 of ICAO Annex 14, volume I, Aerodromes: "Information that a runway or portion thereof may be slippery when wet shall be made available."
5. Non-compliance with ICAO Standard 2.9.6 of ICAO Annex 14, volume I, Aerodromes: "A runway or portion thereof shall be determined as being slippery when wet when the measurements specified in 10.2.3 show that the runway surface friction characteristics as measured by a continuous friction measuring device are below the minimum friction level specified by the State."
6. Although ICAO Standard 10.2.3 of ICAO Annex 14, volume I, Aerodromes: "Measurements of friction characteristics of a runway surface shall be made periodically with a continuous friction measuring device using self-wetting features" were met, no corrective action in the form of NOTAM was issued timeously to ensure aircraft safety was not jeopardised as called for in ICAO Annex 14 even though the test data was available.
7. Non-compliance with ICAO Standard 10.2.4 of ICAO Annex 14, volume I, Aerodromes: "Corrective maintenance action shall be taken when the friction characteristics for either the entire runway or a portion thereof are below a minimum friction level specified by the State."
8. There were inadequate procedures within the regulating authority to prioritise and analyse the results of the runway friction test conducted 30 days prior to the accident in question by an external service provider.
9. A significant contributory factor to this accident was the failure by the appropriate role-players to take immediate remedial action following the 6 November 2009 CFME test results. These results were found to be below the minimum friction level of 0.43 as called for in ICAO Annex 14, volume I.
Official accident investigation report
|investigating agency: ||Civil Aviation Authority (CAA) - South Africa |
|report status: ||Final|
|report number: ||CA18/2/3/8719|
|duration of investigation:||983 days (2 years 8.4 months)|
|download report: ||
Aircraft accident report ZS-SJW
(S.A. CAA CA18/2/3/8719)
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 Cape Town International Airport to George Airport as the crow flies is 347 km (217 miles).