Refer to figure.
This graph is used to determine:

• The maximum mass to Hover In Ground Effect (HIGE) at a given pressure altitude with a given temperature (if entered in the graph with pressure altitude).
• The maximum pressure altitude to Hover In Ground Effect (HIGE) for a given mass at a given temperature (if entered in the graph with mass).

For this question, to determine the maximum helicopter mass to conduct a HIGE, proceed with the following manner:

• Enter with pressure altitude 8000 ft from the left side of the graph.
• Move horizontally to the right until the +20°C temperature line.
• Continue vertically downwards to read the maximum helicopter mass 2460 lbs.

The maximum helicopter mass extracted from the performance graph, 2460 lbs, is less than the maximum gross mass 2500 lbs and greater than the minimum gross mass 1600 lbs. Thus, it is valid.