时间:2012-06-08 09:45来源:蓝天飞行翻译 作者:航空 点击:次
To view this page ensure that Adobe Flash Player version 9.0.124 or greater is installed. Students should have had some exposure to Exercise Sloping Ground and Exercise Confined Areas before being sent on the first solo cross-country. This is to ensure that they are capable of landing at a suitable site in the event of any unusual circumstance when flying over inhospitable terrain. 25 HAZARDS The aerodynamic stresses to which the airframe and rotor system is exposed during the vortex ring state are virtually unknown. Emphasis should be placed on early recognition and avoidance rather than on practising a fully developed vortex ring state. Control of the rate of descent should be stressed in situations where vortex ring is likely to develop. Because of the unknown stresses put on the helicopter, many schools do not fly this as a full exercise, instead using classroom discussion and scenarios to cover the subject. Recovery can still be practised in the air by simulating vortex ring as described in Tips For Instructors over page. Theory of flight covering: Vortex ring LTE Retreating blade stall Mast bumping Recirculation Rotor stall For the student to learn the practical avoidance of, and recovery from, the vortex ring state Motivation It is preferable that the pilot altogether avoids the flight conditions that could result in vortex ring. It is nonetheless desirable that he or she recognises the symptoms of the incipient stage and can prevent it from developing into the full state, which in most operational situations will result in an accident. Airmanship ? Helicopter limitations ? Lookout Teaching Points Review the causes, conditions, and symptoms of vortex ring (see Tips for Instructors). Describe typical operational situations where the condition could be encountered, such as a steep approach at high all-up weight and density altitude conditions, with nil wind or a tail wind such as trying to continue with an overshoot. Review recovery action, discussing the advantages and disadvantages of: |