SERVO FAILURE
Most helicopters certified for single-pilot IFR flight are required to have autopilots, which greatly reduces pilot workload. If an autopilot servo fails, however, you have to resume manual control of the helicopter. How much your workload increases, depends on which servo fails. If a cyclic servo fails, you may want to land immediately as the workload increases tremendously.
 

to the appropriate climb airspeed, adjust pitch gradually to climb attitude. As climb airspeed is reached, reduce power to the climb power setting and transition to a fully coordinated straight climb.
During the initial climbout, minor heading corrections should be made with pedals only until sufficient airspeed is attained to transition to fully coordinated flight. Throughout the instrument takeoff, instrument cross-check and interpretations must be rapid and accurate, and aircraft control positive and smooth.
COMMON ERRORS DURING INSTRUMENT TAKEOFFS
1 Failure to maintain heading.
2 Overcontrolling pedals.
3 Failure to use required power.
4 Failure to adjust pitch attitude as climbing airspeed is reached.

12-20

Flying at night can be a very pleasant experience. The air is generally cooler and smoother, resulting in better helicopter performance and a more comfortable flight. You generally also experience less traffic and less radio congestion. 
 

NIGHT FLIGHT PHYSIOLOGY
Before discussing night operations, it is important you understand how your vision is affected at night and how to counteract the visual illusions, which you might encounter.
VISION IN FLIGHT
Vision is by far the most important sense that you have, and flying is obviously impossible without it. Most of the things you perceive while flying are visual or heavily supplemented by vision. The visual sense is especially important in collision avoidance and depth perception. Your vision sensors are your eyes, even though they are not perfect in the way they function or see objects. Since your eyes are not always able to see all things at all times, illusions and blindspots occur. The more you understand the eye and how it functions, the easier it is to compensate for these illusions and blindspots.
THE EYE
The eye works in much the same way as a camera. Both have an aperture, lens, method of focusing, and a surface for registering images. [Figure 13-1].
Vision is primarily the result of light striking a photosensitive layer, called the retina, at the back of the eye. The retina is composed of light-sensitive cones and rods. The cones in your eye perceive an image best when the light is bright, while the rods work best in low light. The pattern of light that strikes the cones and rods is transmitted as electrical impulses by the optic nerve to the brain where these signals are interpreted as an image. The area where the optic nerve meets the retina contains no cones or rods, creating a blind spot in vision. Normally, each eye compensates for the other’s blind spot. [Figure 13-2]