CH146493
Griffon
29 March 2004
In the vicinity of Goose Bay, Labrador
CH146493 was conducting a scheduled training mission for the co-pilot who needed simulated emergency practice. The emergency selected for the training was: "Governor Failure High Side". The co-pilot, flying in the left seat, was at the controls, with the pilot performing "non-flying pilot" duties. The emergency was briefed among the crew, followed by a simulation.
The emergency simulation was correctly initiated by the co-pilot raising the collective. The non-flying pilot then lowered the collective to regain single engine parameters in anticipation of switching the governor to manual. After identifying the governor switch and hearing "Confirmed" from the Flight Engineer (FE), the non-flying pilot selected the Governor switch to manual.
Shortly thereafter, the "Engine 2 Out" and the "Fire 2 Pull" lights came on and the aircraft experienced a power loss of the no. 2 engine. The pilot took controls and the crew executed a "No. 2 Engine Fire" emergency procedure successfully landing on a snowmobile trail just outside the Base.
Following shut down, the crew noticed extensive damage inside the no. 2 engine compartment consisting of burnt paint chips and metal discoloration caused by excessive heat.
The investigation later revealed extensive heat damage to the no. 02 stage of the Free Wheeling Turbine (picture). Nearly all the turbine blades were missing 20 to 50 % of their tips. Also, damage was observed on the inside of the exhaust duct, the air by-pass duct and both tail rotor blades had dents, nicks and scratch damage. The damage is consistent with Category C.
The likely cause of the occurrence is the failure to roll the no. 2 throttle to idle prior to moving the governor switch to manual. The investigation is on-going and will focus on crew procedures, crew communications and CRM.
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