Why are liquids banned on planes?

More than ten years ago, the aviation industry – and long-suffering passengers – awoke to find the security rules for passengers had changed, literally overnight.

The Government announced that it had uncovered what was described as a terror plot to blow up transatlantic jets from Heathrow to North America, intended to kill even more people than 9/11.

The plan for the “Liquid Bomb Plot” was to take the ingredients for an improvised explosive device onto each aircraft and assemble the bomb on board before detonating it and blowing the plane out of the sky. The explosive, derived from hydrogen peroxide, was to be disguised in bottles of soft drinks. The perpetrators were later jailed for conspiracy to murder, though there is still debate about how far advanced the plot actually was.

Shortly before dawn on 10 August 2006, the top executives of Britain’s airlines were telephoned to be told their passengers would be banned from carrying anything more than a purse or wallet into an aircraft cabin. Even pens were banned from transatlantic flights, on the grounds that the ink they contained was a liquid. One concession was made, for nursing mothers: they could take milk for their baby through the checkpoint, but only if they tasted it first to demonstrate it was the real thing.

Predictably, the strict new rules immediately brought Heathrow airport almost to a standstill, and traumatised the flight network elsewhere in Britain.

Baggage systems simply could not cope with two or three times the normal number of items. Even mobile phones had to be checked in, and many went missing. At one stage, Paris- and Brussels-bound travellers who could not bear to be parted from their phones were switching to Eurostar trains at the rate of 10 a minute. In the ensuing week, British Airways alone cancelled over 1,500 flights. What should have been a very profitable week for Britain’s airlines ended up costing them around £50m.

What to do next became an international issue. Three months later, the near-total ban was eased; smaller items were allowed through, but there were new and draconian rules on liquids, aerosols and gels (LAGs, in the terminology).

The European Commission acknowledges: “This ban was envisaged as a temporary restriction to be lifted when suitable technology to screen liquids for explosives became readily available.” Yet the rules persist to this day, with everything from sunscreen to soft cheese ending up in the bins at security.

So the short answer is because three ounces of explosives aren’t enough to critically damage a plane. 3.4 ounces is the maximum amount of liquid that poses little to no risk to travelers. So while chugging a soda at the security checkpoint is nobody’s idea of fun, at least the TSA has a good reason for confiscating rogue beverages.

Be safe.

Check out my related post: Will Elon’s rocket take off?

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  1. I remember at around the same time we started to be asked to remove belts, shoes etc. My colleague and I were queuing patiently at Gatwick on the way back to Manchester when the security official called the man in front of us out for not removing his shoe. It turned out that this was because it was attached to his false leg!

    Liked by 3 people

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