How is the ELT activated when subjected to a prescribed force?

How is the ELT activated when subjected to a prescribed force?

• A. Perpendicular to the longitudinal travel
• B. Parallel to the longitudinal travel
• C. Along the vertical axis
• D. In the horizontal direction of travel

Answer: (B)

Activation is achieved by a crash sensor that detects a prescribed force along the aircraft’s fore‑aft axis. When the aircraft experiences rapid deceleration in the direction of travel, inertia of a small mass overcomes a spring and closes a circuit, triggering the ELT. This longitudinal (forward/back) axis is chosen because crashes commonly involve a strong deceleration along the travel direction, making this axis the most reliable trigger. Forces perpendicular to that axis or vertical deceleration are less likely to meet the trigger condition at the moment of impact, so they’re not the intended activation path.

Activation is achieved by a crash sensor that detects a prescribed force along the aircraft’s fore‑aft axis. When the aircraft experiences rapid deceleration in the direction of travel, inertia of a small mass overcomes a spring and closes a circuit, triggering the ELT. This longitudinal (forward/back) axis is chosen because crashes commonly involve a strong deceleration along the travel direction, making this axis the most reliable trigger. Forces perpendicular to that axis or vertical deceleration are less likely to meet the trigger condition at the moment of impact, so they’re not the intended activation path.