Investigators probing the forced landing of an Austrian Fokker 70 near Munich on 5 January have found that ice-protection devices on both Rolls-Royce Tay engines had broken away from the cowlings.

The devices are panels mounted behind the engine fan, designed to protect the core from ice-fall while flying in freezing conditions.

The crew reported that both Tays lost power while on approach to Munich airport.

Flight OS111 had departed from Vienna and was around 10km (5.5nm) east of Munich at 08:08 when the crew made a mayday call.

Four minutes later, says German air navigation authority DFS, the pilots said the aircraft was experiencing "severe icing" of the engines.

A few minutes later, the twinjet landed in a snow-covered field 4.4km east of runway 26L, suffering severe damage to its undercarriage and coming to a halt resting on the underside of its fuselage. All 28 passengers and four crew members on the aircraft escaped injury.

"Why the panels broke away has not yet been established," says Austrian. German accident investigation authority BFU says the aircraft "could not hold the intended flight altitude during the approach procedure, for reasons not yet determined".

Source: Flight International