Environmental and Maneuvering Considerations

Question 1

Wind Envelopes

Answer 1

A1-H60CA-NFM-900
1. Are based on steady state winds measured by windward
mast-mounted anemometer. Limiting velocities indicated
on wind charts launch and recovery envelopes represent
maximums for steady state, nonturbulent winds. During
gusty wind conditions and/or large deck movement, if the
gust spread is 10 knots or more, reduce the maximum
winds allowed for rotor engagement and disengagement
by 10 knots in all quadrants.
2. Are defined relative to the ship’s centerline.
3. Are valid for a normal approach to the spot, with
the helicopter aligned with the ship’s line-up line at
touchdown.
4. Are valid for all certified lighting configurations.
5. Are shaded to distinguish day limits from night limits.
6. Are surrounded by a striped border when applicable to
emergency conditions resulting from a single failure of the
helicopter (ASE, hydraulic boost, or engine).
7. Are valid for PAC in either seat.
8. Are valid for all approved aircraft loading configurations,
provided power available exceeds power required to hover
out of ground effect.
9. Are valid for ships underway or at anchor.

Question 2

Salt Spray

Answer 2

Note
* The best indication of performance loss due to salt spray ingestion is the
relationship between TGT and torque.
* Establishing a torque/TGT relationship in level flight prior to commencing
low over water hover operations may aid in identifying saltwater encrustation
* Continued engine operation in clean air may dissipate some of the salt
buildup, but this cannot be assured. Flight through rain may also be
beneficial in reducing salt buildup, thereby improving performance.

The most significant factors in salt spray ingestion are wind velocity and hover altitude, as follows:
1. The probability of salt ingestion into the engine is greatest in winds of 8 to 12 knots. In this condition, there
are whitecaps on the water and moderately heavy salt spray is lifted off the water.
2. At wind velocities of 15 to 20 knots and higher, salt spray is generated, but it is blown aft underneath the
engines so that the rate of salt ingestion is small.
3. For a given wind condition, the rate of salt ingestion varies in a nonlinear manner with hover altitude. At 30
feet, there is generally no significant buildup regardless of wind condition. The change in rate of buildup
is moderate down to 15 to 20 feet. As the altitude is lowered further, the rate of salt buildup increases;
however, even at altitudes as low as 5 feet, the winds usually have to be in the range of 8 to 12 knots to
cause a deterioration of engine performance.

While operating in a salt spray environment for any period of time, a
TGT rise of 20 °C or more for constant torque is an indication of engine
performance degradation and possible salt encrustation. A TGT rise
of greater than 40 °C for a constant torque is an indication of engine
performance degradation, which may result in compressor stalls.

Question 3

Ceiling/Visibility (Shipboard Operations)

Question 4

Shipboard Maneuvering/Polar Plots

Question 5

Winds Abaft the Beam

Question 6

Shipboard Aircraft Tie-down requirements