PROMOTION OF TRANSPORT AIRСRAFT FLIGHT SAFETY TAKING INTO ACCOUNT UPDATED CERTIFICATION REQUIREMENTS FOR ICING CONDITIONS

Abstract

Due to the implementation of new certification requirements for icing conditions provided in Annex О to CS-25, there is a necessity to analyze the impact of the requirements on the possibility of transport aircraft certification for flights under such conditions. The particularities of such certification requirements and their impact on three main directions of aircraft certification have been considered for icing conditions: icing annunciation system, air data system and anti-icing system. It has been shown that new requirements have no effect on certification of air data system sensors but they have an impact on icing annunciation and antiicing system. Timely annunciation of icing is important for safe operation of aircraft. The procedure providing timing annunciation was developed earlier in Annex C to AR/CS/FAR-25. It is highlighted that this procedure is also actual for new icing conditions but taking into account relevant updates in calculations of the growth of ice accretions on ice detectors, air inlets and lifting surfaces. One of the problems is to detect the moment of coming into icing conditions, determined by new requirements. It substantially determines the possibility of immediate escape from icing area if the airplane does not meet the safe operation requirements for such conditions. The techniques of removing ice accretions from lifting surfaces are described. The case of icing the wing surface behind the slats area with barrier ice accumulation was studied. The possibility of an aircraft limitless operation under icing conditions determined by new certification requirements was estimated.