Approach Angle
~ a normal approach is considered to be a 10 degree approach
~ more than 10 degrees is considered to be a "steep"
~ less than 10 is considered to be "shallow"
~ we initiate maneuver by intercepting 10 degree approach angle
~ normally a collective pitch adjustment will be required to start helicopter descending on the 10 degree angle
~ the exact power setting will depend on things such as wind, density altitude, and helicopter weight
~ the way that a helicopter pilot judges whether he is maintaining the desired angle is similar to what an airplane pilot does
~ there are multiple cues which will tell you whether you are changing approach angle
~ shape of the landing area changes on different angles (shapes get distorted by perspective more at lower approach angles)
~ position of the landing zone in the windshield
~ LZ will be lower in the windshield on a steep aproach, higher on a shallow approach

Closure Rate
~ unlike an airplane, helicopters do not fly constant airspeed approaches
~ that's partly because they don't have to
~ if an airplane attempts to decelerate too much on approach, it stalls
~ a helicopter doesn't have that problem
~ normally, inside of a mile of the landing zone the helicopter is decelerating
~ at the same rate it is losing altitude so that by the time the altitude of the helicopter approaches zero,
~ the ground speed will also be approaching zero
~ one way for helicopter pilots to judge this is to look at apparent ground speed
~ from high up, the ground seems to be going by very slowly
~ as we descend, the ground appears to speed up
~ helicopter pilots simply hold the apparent ground speed to approximately a jogging pace,
~ and that will insure that as they approach the ground they will be moving forward at a jogging pace
~ the last few knots of ground speed can be killed as the helicopter transitions into a hover

Power Requirements
~ during deceleration from approach speed to minimum sink airspeed, less power is required as the helicopter slows
~ this will require helicopter pilot to be decreasing collective initially
~ however, from minimum sink airspeed until reaching the LZ, power required will be going up,
~ because the helicopter is on the back side of the power curve.
~ during the last portion of the approach, typically begining around 40 knots = 74 km/h of airspeed,
~ helicopter is on the part of the power required curve where power requirements are going up very quickly
~ pilot will normally notice a sudden tendency for the helicopter to sink below the approach angle
~ pilot will have to increase collective substantially to maintain angle
~ because the helicopter is in a slightly flared attitude,
~ this increase in thrust will increase the deceleration force (because the rearward component of thrust will be increased)
~ if pilot does not push forward on the cyclic at this time,
~ helicopter will generally come to a stop well short of the LZ, typically at a height of 25-35 feet
~ by adding forward cyclic, pilot will keep helicopter moving forward at a slowly declerating rate,
~ losing altitude at the same time, until the helicopter reaches the LZ at the desired hover height

Termination
~ maneuver can terminate either in a hover, which is the usual case, or can be flown right to the surface
~ approaches to the surface are typically used when pilot wants to minimize downwash,
~ or does not want to hover for one reason or another (poor visibility is one reason)
~ pilot will find that a large amount of left pedal is required to maintain skid alignment
~ as the helicopter decelerates through translational lift
~ whether maneuver is going to terminate in a hover or to the ground,
~ pilot should align skids with ground track at approximately 100' AGL
~ this prevents a rollover accident should the skids touch down with forward speed

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