Certification of the Sikorsky S-92A™ Helicopter to the EASA Limited Icing Special Condition

Sikorsky Aircraft certificated the Model S-92A™ helicopter for flight in icing conditions in 2005. Since that time, the aircraft has flown in icing conditions throughout the world and the approval to launch a flight when icing conditions are forecast or reported has been valuable to operators. However, when the rotor ice protection system was inoperative due to a system failure, use of the aircraft on days of forecast icing was prohibited. Sikorsky Aircraft, therefore, elected to obtain certification of the S-92A helicopter to an EASA limited icing Special Condition so that UK and Norwegian operators in the North Sea sector could complete a mission when icing conditions were forecast, should the RIPS be inoperative on that day. A review of previously available icing data indicated that the S-92A helicopter could meet the requirements of the EASA Special Condition, but that additional flights were required to demonstrate full compliance. The S-92A demonstrated compliance with the Special Condition for ambient temperatures equal to or greater than -5°C, liquid water content equal to or below 0.5 g/m₃, and pressure altitudes equal to or below 8,000 feet. The S-92A helicopter is now allowed to operate with RIPS inoperative in known or forecast icing in the North Sea sector within these conditions.