Hatch locked in open position speeds (forward and sideward).

Hatch locked in open position speeds (forward and sideward).

• A. 70 KIAS forward, 25 KIAS sideward
• B. 60 KIAS forward, 30 KIAS sideward
• C. 80 KIAS forward, 35 KIAS sideward
• D. 85 KIAS forward, 20 KIAS sideward

Answer: (C)

Opening a hatch changes the aerodynamics around the helicopter and places additional loads on the hatch, its hinges, and the surrounding structure. To keep the aircraft within what the structure and latching can safely handle, speed limits are reduced when the hatch is locked in the open position. For this helicopter, the safe operating envelope with the hatch open is 80 KIAS in forward flight and 35 KIAS in sideward flight. The forward limit is higher because the airflow along the fuselage aligns with the hatch opening in a way that imposes somewhat lower lateral loading on the hatch, whereas sideward flight subjects the hatch to greater cross-flow and dynamic pressure on the opening, requiring a more conservative limit. Staying within these speeds helps prevent damage to the hatch and maintains controllability with the open door.

Opening a hatch changes the aerodynamics around the helicopter and places additional loads on the hatch, its hinges, and the surrounding structure. To keep the aircraft within what the structure and latching can safely handle, speed limits are reduced when the hatch is locked in the open position.

For this helicopter, the safe operating envelope with the hatch open is 80 KIAS in forward flight and 35 KIAS in sideward flight. The forward limit is higher because the airflow along the fuselage aligns with the hatch opening in a way that imposes somewhat lower lateral loading on the hatch, whereas sideward flight subjects the hatch to greater cross-flow and dynamic pressure on the opening, requiring a more conservative limit. Staying within these speeds helps prevent damage to the hatch and maintains controllability with the open door.