Chapter 10
Advanced Maneuvers
The maneuvers presented in this chapter require more finesse and understanding of the helicopter and the surrounding environment. When performing these maneuvers, you will probably be taking your helicopter to the edge of the safe operating envelope. Therefore, if you are ever in doubt about the outcome of the maneuver, you should abort the mission entirely or wait for more favorable conditions.
Reconnaissance Procedures
Anytime you are planning to land or takeoff at an unfamiliar site, you should gather as much information as you can about the area. Reconnaissance techniques are ways of gathering this information.
High Reconnaissance
The purpose of a high reconnaissance is to determine the wind direction and speed, a point for touchdown, the suitability of the landing area, the approach and departure axes, obstacles and their effect on wind patterns, and the most suitable flight paths into and out of the area. When conducting a high reconnaissance, give particular consideration to forced landing areas in case of an emergency.
Altitude, airspeed, and flight pattern for a high reconnaissance are governed by wind and terrain features.
You must strike a balance between a reconnaissance conducted too high and one too low. It should not be flown so low that you have to divide your attention between studying the area and avoiding obstructions to flight. A high reconnaissance should be flown at an altitude of 300 to 500 feet above the surface. A general rule to follow is to ensure that sufficient altitude is available at all times to land into the wind in case of engine failure. In addition, a 45° angle of observation generally allows the best estimate of the height of barriers, the presence of obstacles, the size of the area, and the slope of the terrain. Always maintain safe altitudes and airspeeds, and keep a forced landing area within reach whenever possible.
Low Reconnaissance
A low reconnaissance is accomplished during the approach to the landing area. When flying the approach, verify what was observed in the high reconnaissance, and check for anything new that may have been missed at a higher altitude, such as wires, slopes, and small crevices. If everything is alright, you can complete the approach to a landing. However, you must make the decision to land or go-around before effective translational lift is lost.
If a decision is made to complete the approach, terminate it in a hover, so you can carefully check the landing point before lowering the helicopter to the surface. Under certain conditions, it may be desirable to continue the approach to the surface. Once the helicopter is on the ground, maintain operating r.p.m. until you have checked the stability of the helicopter to be sure it is in a secure and safe position.
Ground Reconnaissance
Prior to departing an unfamiliar location, make a detailed analysis of the area. There are several factors to consider during this evaluation. Besides determining the best departure path, you must select a route that will get your helicopter from its present position to the takeoff point.
Some things to consider while formulating a takeoff plan are the aircraft load, height of obstacles, the shape of the area, and direction of the wind. If the helicopter is heavily loaded, you must determine if there is sufficient power to clear the obstacles. Sometimes it is better to pick a path over shorter obstacles than to take off directly into the wind. You should also evaluate the shape of the area so that you can pick a path that will give you the most room to maneuver and abort the takeoff if necessary. Wind analysis also helps determine the route of takeoff. The prevailing wind can be altered by obstructions on the departure path, and can significantly affect aircraft performance. One way to determine the wind direction is to drop some dust or grass, and observe which way it is blowing. Keep in mind that if the main rotor is turning, you will need to be a sufficient distance from the helicopter to ensure that the downwash of the blades does not give you a false indication.
If possible, you should walk the route from the helicopter to the takeoff position. Evaluate obstacles that could be hazardous and ensure that you will have adequate rotor clearance. Once at the downwind end of the available area, mark a position for takeoff so that the tail and main rotors have sufficient clearance from any obstructions behind the helicopter. Use a sturdy marker, such as a heavy stone or log, so it does not blow away.
Maximum Performance Takeoff
A maximum performance takeoff is used to climb at a steep angle to clear barriers in the flight path. It can be used when taking off from small areas surrounded by high obstacles. Before attempting a maximum performance takeoff, you must know thoroughly the capabilities and limitations of your equipment. You must also consider the wind velocity, temperature, altitude, gross weight, center-of-gravity location, and other factors affecting your technique and the performance of the helicopter.
To safely accomplish this type of takeoff, there must be enough power to hover, in order to prevent the helicopter from sinking back to the surface after becoming airborne. This hover power check can be used to determine if there is sufficient power available to accomplish this maneuver.
The angle of climb for a maximum performance takeoff depends on existing conditions. The more critical the conditions, such as high density altitudes, calm winds, and high gross weights, the shallower the angle of climb. In light or no wind conditions, it might be necessary to operate in the crosshatched or shaded areas of the height/velocity diagram during the beginning of this maneuver. Therefore, be aware of the calculated risk when operating in these areas. An engine failure at a low altitude and airspeed could place the helicopter in a dangerous position, requiring a high degree of skill in making a safe autorotative landing.
Technique
Before attempting a maximum performance takeoff, bring the helicopter to a hover, and determine the excess power available by noting the difference between the power available and that required to hover.