Seaplane Skiplane Flying Menu > Seaplane Operations ? Landings >Landing

Pilots performing glassy water landings may experience some difficulty in determining their altitude above the surface. The recommended procedure is to continue an approach to the surface with a slow rate of descent until making contact, avoiding any attempt to hover. The helicopter’s downwash creates a disturbance in the water as concentric ripples moving away from the helicopter. Although this provides the pilot with a visual reference, it may also cause the sensation of moving backwards or descending rapidly. A natural tendency is to apply too much collective pitch in an attempt to halt the perceived descent. To overcome the effects of these visual illusions, avoid staring at the water near the helicopter and maintain forward and downward movement until contacting the water. When making approaches to a landing on a large body of water when land areas or other fixed objects are not visible, occasionally glance to either side of the horizon to avoid stare-fixation. Another technique some pilots use when fixed objects are not available, and the water is glassy, is to make a low pass over the area to create a disturbance on the surface. This disturbance remains for a while giving the pilot a reference to help determine distance When landing on water with a slight chop, bring the helicopter to a hover and descend vertically with no horizontal movement. This procedure is similar to landing on a hard surface.

Make a running landing on water when high density altitude or a heavy load results in insufficient power to hover. Perform this type of landing when sufficient power is not available to reduce the speed to 5 knots or less. When approaching with greater than 5 knots of speed, hold a slight nose-high attitude to allow the aft portion of the floats to plane. Maintain collective pitch until the speed reduces to below 5 knots, and the helicopter settles into the water. At zero groundspeed,
slowly lower the collective into the full down position. Lowering the collective or leveling the helicopter too quickly may result in the floats tucking, which can cause the helicopter to capsize.

Caution: The following discussion deals with landing in heavy seas. Use these procedures only in an emergency.

Landing the float helicopter becomes risky when the height of short, choppy waves exceed one half the distance from the water to the helicopter’s stinger, and the distance from crest to crest is nearly equal to or less than the length of the helicopter. These waves cause the helicopter to pitch rapidly and may bring the rotor blades in contact with the tail boom or the tail rotor in contact with the water. In addition, avoid landing parallel to steep swells as this could lead to dynamic
rollover. [Figure 9-5]

Figure 9-5. Effect of landing heading relative to waves.

If landing on waves higher than half the distance from water to stinger, the following techniques apply:

• Land the helicopter 30º to 45º from the direct heading into the swell. This minimizes the fore and aft pitching of the fuselage, reducing the possibility of the main rotor striking the tail boom, or the tail rotor contacting the water. This also minimizes the possibility of dynamic rollover.

• When landing with power, maintain rotor r.p.m. in the normal operating range. This permits a quick takeoff if the helicopter begins to pitch excessively or when an especially high wave becomes a hazard.

• When landing without power in high wave conditions, hold the desired heading as long as directional control permits. As the rotor r.p.m. decreases to the point that the desired heading cannot be maintained, bring the rotor to a stop as quickly as possible to avoid rotor contact with the tail boom.