When can additional shots, weights or both be added to the standard configuration of an E-5 barrier?

When can additional shots, weights or both be added to the standard configuration of an E-5 barrier?

• A. If the temperature drops below freezing
• B. If the aircraft weighs over 20,000 pounds
• C. If the runway length increases
• D. If the tower operator orders it

Answer: (B)

The barrier’s setup is driven by the load it must stop. Heavier aircraft carry more kinetic energy, so to keep the barrier’s energy absorption and deceleration profile within its design limits, you add mass to the barrier when the aircraft exceeds a certain weight. If the aircraft weighs more than 20,000 pounds, you can add extra mass—shots or weights—to the standard configuration to maintain the intended performance and safety margins. Temperature, runway length, or an operator’s instruction don’t change the energy the barrier must absorb, so they don’t justify altering the barrier’s mass.

The barrier’s setup is driven by the load it must stop. Heavier aircraft carry more kinetic energy, so to keep the barrier’s energy absorption and deceleration profile within its design limits, you add mass to the barrier when the aircraft exceeds a certain weight. If the aircraft weighs more than 20,000 pounds, you can add extra mass—shots or weights—to the standard configuration to maintain the intended performance and safety margins. Temperature, runway length, or an operator’s instruction don’t change the energy the barrier must absorb, so they don’t justify altering the barrier’s mass.