The more difficult second level requires a flight of 180 seconds followed by a landing on simulated lunar terrain, complete with rocks and craters.
更困难的第二个级别，要求飞行180秒，接着在遍布岩石和陨石坑的模拟月球地形上降落。
2
This method can be applied to terrain correction point by point for the airborne gamma energy spectrum in cases of any flight ways and arbitrary topographic conditions.
该方法特点是适合于任意飞行方式(缓地形和水平飞行均可)和任意地形条件航空伽玛能谱的逐点地形改正。
3
The serious incident is officially classified in international aviation terms as "controlled flight into terrain only marginally avoided".