直升机飞行训练手册 HELICOPTER FLIGHT TRAINING MANUAL(7)

曝光台 注意防骗 网曝天猫店富美金盛家居专营店坑蒙拐骗欺诈消费者

THE INFLUENCES OF C OF G IN FLIGHT
CG AFT LIMIT (TAIL-LOW)
When the CG is aft, the cyclic is in the forward position. With a tail-low attitude, you need even greater forward displacement of the cyclic while hovering into the wind. If the helicopter exceeds aft CG limits, hovering is not possible. Takeoff and landing in the strong headwind conditions may be critical, because you need greater forward cyclic to hover as well as levelling off after  a flare on an autorotation approach. 
CG FORWARD LIMIT (NOSE-LOW)
When the CG is forward, the cyclic is in the aft of the neutral position. With a nose-low attitude, you need excessive rearward displacement of the cyclic control to maintain a hover in a no-wind condition. You should not continue flight in this condition, since you could rapidly run out of rearward cyclic control as you consume fuel. In the event of engine failure and the resulting autorotation, you may not have enough cyclic control to flare properly for the landing.
LATERAL OFF-BALANCE
The cyclic will be displaced opposite to the position of the load. This is more noticeable if  litters are being used. For slope operations, care must be taken and you must prevent the static/dynamic roll over situations.
 

 
Figure 2-2 Centre of gravity
INSPECTION OF THE AIRCRAFT
It is the responsibility of the pilot-in-command to ensure that an aircraft is safe and fit in all respects for the intended flight. The pre-flight external inspection determines, from the pilot’s point of view, that the aircraft is serviceable and that it has sufficient fuel and oil for the intended flight. Your pre-flight inspection should follow a set pattern and sequence. In this way, no items will be forgotten and your sequence will be similar no matter what type of helicopter you fly in the future. Most manufacturers recommend that you begin at the nose, on the right hand side to finish at the point you started. (Fig 2-3). Having completed the external inspection in this fashion you are ready to enter the cockpit. A recommended method of conducting this inspection is found in most helicopter flight manuals.
 

 
Figure 2-3: Pre-Flight Inspection 
 
While walking out to the helicopter you should take note of the strength and direction of the wind, and the presence of any other aircraft, or obstacles, which may affect the starting procedures or the subsequent takeoff.
Your instructor will teach you the correct procedures for briefing your passengers at this stage.
Where possible, the helicopter should be positioned into wind, clear of any obstructions to main and tail rotor blades, with a fire extinguisher available. It is discourteous and may be hazardous to start a helicopter close to buildings or vehicles, as damage may be caused by the rotor downwash as the helicopter lifts into a hover. Light aircraft parked nearby may suffer substantial damage to their control surfaces.
Your instructor will demonstrate a pre-flight inspection and explain what you should look for to determine the airworthiness of the helicopter. If during this inspection you discover an un-serviceability, or have any doubts about the helicopter’s airworthiness, then it should not be flown. All schools have a system of reporting defects. It could well be just to inform your own instructor, but do not be afraid to express your doubts to an engineer.
Before starting the engine, a thorough cockpit and “pre-start” check utilising a checklist shall  be performed. Completion of these checks using the checklist is very important, and should be conducted in accordance with the recommended procedures contained in the helicopter flight manual. This pre-flight check will ensure that components are not damaged through incorrect starting procedures. Using the appropriate checklist, all further checks, such as starting,  warm-up and run-up, if applicable, should likewise be performed in accordance with the manufacturer’s recommendations.
　
中国航空网 www.aero.cn
航空翻译 www.aviation.cn
本文链接地址：直升机飞行训练手册 HELICOPTER FLIGHT TRAINING MANUAL(7)