South African investigators have concluded that an Airlink Embraer ERJ-135 overran at George Airport after a protective sealant, applied during pavement renovation, resulted in the runway surface becoming slick in wet weather.
The aircraft failed to stop after touching down at George on 7 December last year, and was substantially damaged in the overrun.
In an update to the inquiry, the South African Civil Aviation Authority expresses its certainty that application of a bituminous fog-spray, in October 2009, led directly to the accident.
The spray is used to seal runway surfaces to improve waterproofing and resistance to wear.
George Airport's runway 11/29 was sprayed along its entire length and width during the renovation.
"It appears that the application of the fog-spray sealant extensively degraded the surface friction coefficient of the runway surface," says the CAA, with the result that the ERJ-135 failed to gain enough braking traction to stop in time.
Use of the sealant, says the CAA, was the "primary probable cause" of the jet's aquaplaning.
Interim safety recommendations sought to prohibit large aircraft from using George Airport if the runway was wet.
In its inquiry update the CAA has recommended a ban on the use of sealants on runway surfaces.
It adds: "It is considered imperative, in the interest of aviation safety, that the service provider improve the runway surface at [George] and implement corrective actions to allow aircraft operations under wet conditions to return to normal."
Source: Air Transport Intelligence news
