TM 1-1520-240-10
5-8-1
SECTION VIII. WATER OPERATION LIMITATIONS
5-8-1. WATER OPERATION LIMITATIONS.
5-8-2. Night Operation on Water.
Night operation on water is permissible provided:
a. Both AFCS are operational (ALT Hold and Heading
Select not required for night operation on water).
b. Pilot and copilot radar altimeter systems are operational.
c. A visible horizon is present at the landing site.
d. Two or more highly visible, stationary objects are
on the water surface to provide necessary visual cues for
landing.
5-8-3. Sea State Limits.
Operation on water is restricted to a maximum of Sea
State 2. Refer to table 5-8-1 for information on sea
states.
5-8-4. Operation Time Limit.
Operation on water is restricted to 30 minutes total flotation
time without draining the helicopter.
5-8-5. Gross Weight Limitations.
Maximum gross weight for water operations is as follows:
a. Normal operations — 36,000 pounds.
b. Emergency rescue missions — 46,000 pounds.
5-8-6. Taxiing Limitations.
Taxiing will not be conducted in water conditions above
Sea State 1 or in wind above 6 knots. Fast taxiing will be
conducted in a straight line only and to a maximum speed
of 10 knots when the lower nose enclosure is left in the
water.
5-8-7. Landing Limitations.
Water landings can be performed within the limitations
presented on fig. 5-8-1. The touchdown speeds presented
do not reflect indicated airspeed but actual forward
velocity at touchdown. Running landings will only be
conducted onto calm water. The ramp, lower rescue
door, and main cabin door shall be closed during water
landing. Water landings are prohibited when fuel in the
main tanks is less than 50 percent.
5-8-8. Rotor Starting and Shutdown Limitations.
Rotor starting or shutdown will not be conducted when
water conditions exceed Sea State 1 or wind exceeds 6
knots. maximum gross weight for starting and shutdown
is 28,550 pounds.
Figure 5-8-1. Water Landing Speed Limitations Up
To 46,000 Pounds gross Weight
Table 5-8-1. Description of Sea States
SEA
STATE
SEA DESCRIPTION WIND
DESCRIPTION
WIND
VELOCITY
(KNOTS)
AVERAGE
WAVE
HEIGHT
(FT)
Sea like mirror (calm) Calm Less than 1 0.0
0 Ripples with appearance of scales; no foam crests
(smooth)
Light Air 1-3 0.05
1 Small wavelets; crests of glassy appearance, not
breaking (slight)
Light Breeze 4-6 0.2
TM 1-1520-240-10
5-8-2
Table 5-8-1. Description of Sea States (Continued)
SEA
STATE
SEA DESCRIPTION WIND
DESCRIPTION
WIND
VELOCITY
(KNOTS)
AVERAGE
WAVE
HEIGHT
(FT)
2 Large wavelets;crests begin to break; scattered whitecaps
Gentle Breeze 7-10 0.6
3 Small waves, becoming longer, numerous whitecaps
(moderate)
Moderate Breeze 11-16 1.4
TM 1-1520-240-10
5-9-1/(5-9-2 blank)
SECTION IX. ADDITIONAL LIMITATIONS
5-9-1. Air-to-Ground Towing.
Air-to-ground towing operations are prohibited.
5-9-2. APU Operation.
APU operation in flight is prohibited except during emergencies.
5-9-3. Pitot Tube and AFCS Sideslip Port Anti-Icing
Limitation.
The PITOT switch shall not be on for more than 5 minutes
on the ground.
5-9-4. Windshield Heat.
Windshield heat shall not be used above 24C.
5-9-5. Single Point Refueling.
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