Laydown delivery is a mode of deploying a free-fall
nuclear weapon in which the bomb's fall is slowed by
parachute so that it actually lands on the ground before
detonating. Laydown delivery requires that the weapon's case be reinforced so that it can survive the impact, and generally involves a time-delay
fuse for detonation. Laydown mode can be used to increase the effect of the weapon's blast on built-up targets such as
submarine pens, or to transmit a shockwave through the ground to attack deeply buried targets. It has the additional advantage of allowing the carrier aircraft to fly very low – in order to avoid enemy defences – and still get away without being destroyed in the detonation. This is particularly important where high-yield nuclear weapons such as the
B83 are concerned.
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