Crash et incident BAe Jetstream d'Airlink (AF Sud)

Airlink crash inquiry raises possibility of wrong engine shut-down
By David Kaminski-Morrow

South African investigators are trying to determine whether the crew of the crashed Airlink British Aerospace Jetstream 41 shut down the wrong powerplant after the aircraft experienced engine failure on take-off from Durban.

Preliminary evidence from the inquiry into the 24 September accident shows that the aircraft's right-hand engine failed on rotation, following an 18s take-off roll.

But as the aircraft climbed to around 450ft above sea level, there was a power reduction of the left-hand engine. The aircraft descended and hit the ground just 50s after starting the take-off roll.

South Africa's Civil Aviation Authority says smoke had been seen emanating from the right-hand Honeywell TPE331 powerplant. But while air traffic control advised the crew of the smoke, the call came during rotation - too late to reject the take-off.

Both flight recorders have produced "good quality" data, says the CAA, and analysis is under way.

It points out that the Airlink aircraft's weight should not have prevented it from climbing on a single engine and returning to land, as certification standards require. The CAA says its inquiry will therefore concentrate on the reasons for the power reduction on the left-hand engine.

This will include analysis of human factors "such as whether the power reduction on [the left-hand engine] resulted from an incorrect identification of the failed engine, or a decision to land the aircraft as soon as possible, or other factors unknown at this time". The pilots have yet to be interviewed.





Wreckage has been transported to a hangar in Johannesburg and the powerplants are to be sent to Honeywell for strip-down and examination, to verify that the left-hand engine was functional during the flight and to determine the reason for the right-hand engine's failure.

The CAA notably says that the investigation has not turned up any evidence for grounding Jetstreams or suspending approvals granted to the carrier.

Airlink flight SA8911 had been operating as a positioning flight with only a crew of three, all of whom sustained serious injuries. The airline has acknowledged the initial findings from the CAA.

"Our training and procedural systems have worked well over the past 17 years," it says. "But in the interest of enhancing safety and preventing a similar occurrence, we have begun revisiting our human factors and other training programmes for pilots to see if there are any things we could do differently."

Airlink grounds all Jetstream 41s over engine concerns
By David Kaminski-Morrow

Embattled South African regional carrier Airlink has grounded its entire British Aerospace Jetstream 41 turboprop fleet, after another safety incident.

The carrier has acted after a Jetstream yesterday aborted take-off from Nelspruit, in the northeast of the country, when it suffered a component failure in one of its engines.

Investigation of the incident has found that one of the Honeywell TPE331 engines suffered a failure of a turbine seal plate component.

Airlink says that the failure bore similarities to the engine problem which contributed to a fatal Jetstream crash at Durban on 24 September.

"The safety of our passengers, crew and equipment is our top priority," says the airline.

"While our crews are trained to deal with engine failures on take-off, we share the South African Civil Aviation Authority's view that - in light of two such failures in several weeks - this represents an unnecessary and unacceptable risk."

It claims, however, that the maintenance of the turbine seal plate is beyond its control because the component is selected and installed by Honeywell.

Airlink's accident at Durban was followed by two other serious events over the following weeks, which prompted a close inspection of its procedures and Government-level concern over the carrier's operations.

The carrier was permitted to continue flying earlier this month, on condition that it address issues picked up during the inspection.

Airlink has around a dozen Jetstreams and the grounding has forced it to shuffle its timetable and hire external capacity.

The airline's chief executive, Rodger Foster, says that the Jetstreams will stay out of service until Honeywell and the airframer, BAE Systems, have "identified and implemented a remedy".

Airlink points out that other types of aircraft in its fleet are unaffected and are operating flights normally.

Worn steering cable blamed for Airlink J41 runway excursion
By David Kaminski-Morrow

South African investigators have determined that slippage of a worn nose-gear steering cable led to an Airlink British Aerospace Jetstream 41's veering off the runway during take-off from Port Elizabeth last month.

The aircraft, bound for East London, had travelled around 400m along Port Elizabeth's runway 08 and reached a speed of about 70kt when it started heading to the left. It came off the runway and stopped about 35m from the left-hand edge.

In the early stages of take-off the aircraft is normally steered through a self-centring tiller, which connects to the nose-wheel through a gear and a steering cable.

Once the aircraft reaches about 70kt, the rudder gains sufficient authority to take over from the tiller as the primary steering control.

Inspection of the aircraft, says the South African Civil Aviation Authority, discovered that the steering cable was kinked - possibly during installation - and that it had worn against the steering gear, eventually resulting in intermittent slippage.

The CAA says the maintenance manual specifies that the tiller mechanism and cable is provided as a single unit, but adds: "However, as the vendor for the tiller mechanism is no longer able to provide it as a complete unit, industry practice has become to only replace the cable."

Wear on the gear teeth remains present, it states, and can only be detected once play appears with tiller movement.

None of the 29 passengers and three crew members was injured in the incident, on 18 November, but the event added to concerns over Airlink operations, which had already been under examination following a Jetstream accident in September.

Airlink has since grounded its Jetstream 41 fleet while it addresses a technical issue relating to the type's engines.

South African CAA starts clearing Airlink Jetstreams to fly

South African inspectors have cleared Airlink to resume services with a single aircraft from its British Aerospace Jetstream 41 fleet, two weeks after the type was grounded.
The regional airline's entire Jetstream fleet was taken out of operation after an engine problem on a 23 December flight, which bore similarities to the failure linked to a fatal Airlink accident three months earlier.
South Africa's Civil Aviation Authority says it will only allow the aircraft to fly again once they have undergone an inspection. The authority started examining the fleet on 1 January.
"To date, one Jetstream aircraft belonging to Airlink has successfully completed its recertification process and, as such, the commissioner for civil aviation has uplifted the suspension on this aircraft," it states.
Recertification, the CAA adds, also included a "thorough inspection" of all maintenance processes.
Two other Jetstreams, which are used by charter operator ExecuJet, have also been cleared by the CAA.