The South African Civil Aviation Authority (SACAA) has lifted its restrictions on the use of George Airport’s runway during wet conditions following an incident in December during which a South African Airlink Embraer 135 Commuter Jet with 33 passengers and crew skidded off the runway during a rainstorm.
SACAA in a statement says the move follows tests that were witnessed by the regulator Tuesday to determine the compliance of the newly resurfaced runway. “This is certainly a welcome move for all concerned, especially following what was undoubtedly a trying time. The decision to lift the NOTAM (Notice to Airmen) was reached last night following a thorough assessment of friction and surface texture testing results,” SACAA General Manager: Air Safety Infrastructure Gawie Bestbier says.
Bestbier says the friction results were good and met International Civil Aviation Organisation standards. As part of the water drainage test, the previously problematic areas of the runway were flooded to determine the effect that the new runway surfacing has on the runway surface drainage characteristics. Due to the improved runway macro texture and levelling, water is now successfully dissipated via the open graded surface texture and to the side of the runway.
“The past several months, whilst working on this project, turned out to be a valuable learning curve for our team and stakeholders, adds Bestbier. More so as we soon discovered that there appears to be inconclusive global knowledge with respect to the exact relationship between runway friction and surface texture in terms of the nett effect on aircraft braking performance. The process has instantly led to South Africa being counted amongst the worldwide experts on the subject. We would not have gotten this far had it not been for the cooperation and support of all stakeholders, particularly the CAA’s investigation team, ACSA (Airports Company SA), its contractors and the airlines,” explained Bestbier.
Meanwhile, the authority has issued a new NOTAM on George Airport which informs pilots of the new state of the runway.
SACAA’s Accident and Incident Investigation (AIID) Division earlier this month fingered a fog spray sealant applied to the runway in November last year for the incident. “The use of the fog spray sealant can be considered to have been the primary probable cause of the occurrence of aquaplaning,” a report said. “In this regard it is considered imperative, in the interest of aviation safety, that the service provider (ACSA) improve the runway surface at George Airport and implement corrective actions to allow aircraft operations under wet conditions to return to normal.”
The regulator in February said it was perplexed by the incident. “A friction test was … performed on Monday, February 15 and the results indicated that the runway friction is within the prescribed limits,” SACAA said in a statement. “This presents a challenge when viewed against the fact that the data from the aircraft flight data recorder indicates that all systems appear to have functioned normally (inclusive of the brakes and the anti-lock braking system) and the approach and landing profiles and speeds were within normal limits. It is clear that something had to cause the overshooting of the runway at the time and the cause has to be identified in order to prevent a recurrence of the same accident.” George is the country’s sixth-biggest airport with 600 000 passengers a year.
As a result, the AIID has asked the Commissioner for Civil Aviation to issue a NOTAM (Notice to Airmen) restricting the use of runway 11/29, the runway concerned, at George by transport aircraft over 5700kg in weight when the runway is wet. It also recommended that the NOTAM remain in force “until such time as adequate friction/texture treatment, such as grooving, has been implemented over the entire runway length and width” and that ACSA be required to conduct a risk assessment on the lack of an end safety area on the runway, “and if found necessary, to incorporate some form of arresting mechanism.”
The AIID further recommended the Director for Civil Aviation consider banning the use of sealants on runway surfaces. “In this regard it is considered imperative, in the interest of aviation safety, that the service provider (ACSA) improve the runway surface at George Airport and implement corrective actions to allow aircraft operations under wet conditions to return to normal. A further suggestion was that the Aerodrome Department of the SACAA be strengthened to ensure adequate skills and knowledge to enable the comprehensive safety oversight over the certification of aerodromes and the maintenance of certification standards. “This should include the establishment of an office that deals primarily with runway safety,” the report said.
SACAA says a final report can now be expected in September.
“Notwithstanding the above, the SACAA holds the view that runways in SA are generally in a good state and compliant with the ICAO (International Civil Aviation Organisation) physical requirements,” the statement says. “The SACAA also wishes to reiterate that the objective of an accident investigation is to establish the cause(s) of the accident and to take steps to prevent a further occurrence. As such, the objective is not to apportion blame or liability. Moreover, the SACAA values accident reports as they serve as mechanisms that point to any shortcoming; and as such enables the Authority to continuously upgrade its oversight systems. In this regard, the SACAA will carefully study this Interim Report as well as the Final Report and where necessary introduce changes to address potential shortcomings.”