### 8.1 Helicopter Limitations

Quiz

##### Altitude Vs Gross Weight Limit Graph

Air density and weight is an important factor for a safe autorotation. If air density is low or you have a high density height (High Elevation) then you could expect poor performance while conducting an autorotation landing and hit the ground hard.

To ensure a safe autorotation landing for a gross weight refer to page 18 of the BELL 206L-1 Long Ranger II Handbook. Use the Altitude Vs Gross Weight Limit for Height-Velocity Diagram graphs to complete the following tables. For unit conversion refer to the ERSA.

##### To Find Gross Weight

First calculate the density height, then use the graph to find the maximum gross weight.

• First calculate density height for the elevation to land on using: QNH 993, Elevation 2000ft and OAT +25 degrees. (Refer to the beginning of this work booklet to understand how to calculat density height).
• Using the graph: Move from the density height line horizontally across to the line of the shaded area and drop vertically down to find the gross weight.
• "A" = 4400ft DHT
• 3700lb Gross Weight
##### To Find Chart Density Height

Use the graph to find the maximum safe autorotation density height for landing with a gross weight of 3600lb.

• To find Density Height start with gross weight at the bottom of the graph.
• Move vertically up to the line of the shaded area.
• From this line move horizontally across to find the density height.
• 3600lb Gross Weight
• "B" = 5300ft DHT
##### To Find Elevation Density Height

To find a safe density height for a HLS elevation, Chart verse Elevation, compare the two of them to determine if an autorotation landing is possible.

• First calculate the density height for the elevation using: QNH 1035, Elevation 5500ft and OAT +7 degrees.
• Then calculate the density height off the chart with 3600lb gross weight.
• If the Chart DHT is higher than the calculated DHT, a safe landing is possible.

Yes it is safe for landing.

• Chart 5300ft DHT
• Calculated 5080ft DHT