Sukhoi does not expect the Superjet 100 test accident in Reykjavik to delay Category IIIa certification for the twinjet type.

Prototype aircraft 95005 suffered serious damage in the 21 July accident after it made contact with the runway with its landing-gear retracted.

The circumstances of the accident have yet to become clear. But Sukhoi says the aircraft had been conducting Cat IIIa certification exercises at the time.

This level of certification allows an aircraft to conduct an automatic landing approach with a decision height below 100ft (30m) and a runway visual range of 200m (660ft).

Sukhoi had been testing the aircraft's ability to conduct Cat IIIa approaches in various configurations and weather conditions - including crosswinds at Keflavik - to secure the approval.

"Test flights to evaluate performance of the automatic landing system with strong crosswind conditions are the most complicated part of the trials," says the airframer.

"The test flights conditions are in close proximity with extreme flight regimes in order to identify limits of safe operations of the aircraft."

Sukhoi began carrying out Cat IIIa landings at the Moscow Zhukovsky test centre towards the end of 2011, initially with aircraft 95004 - the test aircraft subsequently destroyed in a terrain collision in Indonesia.

While the accident at Keflavik has interrupted the programme, the airframer's first president for certification Igor Vinogradov says it will not hold up the Cat IIIa approval because the company has achieved "sufficient volume" of landings.

"Information we have obtained so far allows [us] to finalise the certification programme on ICAO Cat IIIa in time," he adds.

None of the five occupants of the aircraft - three crew and two certification personnel - was seriously injured in the accident.

Source: Air Transport Intelligence news