Anti-handling device
Munitions fitted with anti-handling devices increase the difficulty and cost of post-conflict clearing operations, due to the inherent dangers of attempting to render them safe.
When a delayed-action bomb containing a ZUS-40 was dropped on a target, the impact when it hit the ground freed a ball-bearing inside the ZUS-40, thereby arming a spring-loaded firing pin.
[9] The time delay mechanism was simple but effective: after being dropped from the aircraft a small propeller at the rear of the bomb revolved, gradually screwing a metal rod into the fuze, crushing an ampoule inside it, which contained a solution of alcohol and acetone solvent.
The alcohol-acetone solution soaked into an absorbent pad next to a celluloid disk which held back a spring-loaded firing pin from a percussion cap connected to an adjacent detonator.
Because the lower end of the fuze was locked in place deep inside the bomb (where access was difficult) this posed major problems for enemy EOD personnel.
This action automatically triggered detonation by releasing the cocked firing pin in the lower fuze assembly, with lethal results for anyone nearby.
The second wave of bombers arriving a few minutes later would not face problems in identifying targets due to them being obscured by smoke and dust from previous explosions, and therefore could accurately drop bombs with instantaneous fuzes fitted.
[14] Unexploded bombs dating from World War II with chemical long-delay fuzes fitted remain extremely hazardous to EOD personnel.
One of these scenarios occurred in June 2010, when an unexploded 500 kilogram allied bomb fitted with a chemical long-delay fuze killed three German EOD personnel and wounded six others in Göttingen, whilst they were preparing to render it safe.
[15][16][17][18] Another allied bomb fitted with a chemical long-delay fuze was discovered in Munich during August 2012, and had to be detonated in situ (shattering windows over a wide area and causing major damage to surrounding buildings) because it was considered too dangerous to disarm.
[20][21] Since then, many nations have produced a wide variety of munitions with fuzes which incorporate some form of anti-handling function, including very small weapons such as cluster bombs.
[22][23] Alternatively, they have produced munitions with features which make it easy to add an anti-tamper function e.g. extra (but empty) threaded fuze wells on anti-tank landmines, into which the detonators on booby-trap firing devices (plus booster attachments) can be screwed.
The lower diagram shows two anti-tank landmines connected by a cord attached to the upper mine's carrying handle. The cord is attached to a pull fuze installed in a secondary fuze well in the bottom mine.
