31/07/2011 | Last updated: 23:26 |  

As the airline industry continues to focus on liquid explosive threats, John Chisholm argues that far more efficacious substances could slip through with deadly consequences

Just 15 years ago, domestic air travel in the US was a relatively trouble-free activity. No more complex than getting on a Greyhound bus or a train, the ease and availability was symptomatic of the American dream. But, on 11 September 2001, the dream turned into a nightmare that has recurred in the minds of the population, politicians and the security services ever since.

The need to create a more stringent security system around air travel (beyond the necessary customs, excise and immigration requirements) can be traced back to the growth of hijacking. The first recorded instance of an aircraft hijacking was in 1931, when a Ford Trimotor was hijacked on the ground by armed revolutionaries during the coup in Peru. Between 1948 and 1957 there was about one incident a year, but the next decade saw that rise to about five per year. In 1968 the figure was 38, and in 1969 there were a bumper 82 incidents, including eight in January of that year that were forced to fly to Cuba. Between 1968 and 1971 the annual average increased to 41.

It has to be admitted that some of these were carried out by the security forces themselves; President Nixon did not stop the CIA from hijacking aircraft as an operational option until 1973. Also, the terrific expansion of air travel around the globe means that, statistically, we should undoubtedly expect some form of increase in incidents.

But things have changed. Overall attempts at hijacking have declined considerably for a number of reasons. The most direct has been the introduction of heavier security measures for passengers and a greater use and development of technology. Some airlines, such as el-Al introduced “sky marshals” as an on-board deterrent. But there is a broader picture: many of the groups who plotted airline atrocities have collapsed and their causes have vanished, such as the Red Army Faction or Black September. Added to this has been greater co-operation between countries in dealing with hijackers – even inveterate enemies such as Cuba and the USA have deals to refuse hijackers a safe haven, as well as an extradition agreement. Incidents such as Dawson’s Field (1970) or Entebbe (1976) now seem to belong very much in the past.

Airlines also had a fairly standard policy for dealing with a hijack if it had successfully gained control of the aircraft: put out by the FAA, this was termed the Common Strategy. In effect it advised co-operation by the passengers and crew until the plane was on the ground, after which the security services would handle things. The FAA had concluded, correctly, that the longer a plane was subject to control by hijackers the more likely a negotiated outcome was to take place. So, “no heroics” was very much the order of the day. 9/11 would change all of this, however.

The fact must be confronted that the Common Strategy endorsed by the FAA clearly made the jobs of the 9/11 hijackers easier, as they could expect no intervention from the crew or passengers. The extremely brave actions of the passengers on United Airlines flight 93 was only possible because they had been informed by mobile telephone that this was not a run-of-the-mill hijack, and that their captors were determined to die.

This was the fundamental flaw within the Common Strategy and virtually all orthodox counter-terrorism strategies that had been developed: the assumption that the terrorists wanted to stay alive. Generally, they either wanted to kill other people or they wanted to highlight their cause and make demands without doing so, although retaining the threat that they might. But incidence of suicide bombing had been growing, in Sri Lanka and the Middle East in particular, although there seems to have been little read-across to what might happen in the context of aviation. Indeed how, until the last minute, would you be able to tell the difference between a “classical” hijacker and one who wanted to immolate himself, passengers and crew?

One of the effects of 9/11 has been to make it unsafe for the traditional hijacker. Not prepared to take chances of a similar attack, governments have made it clear they are willing to shoot down aircraft rather than risk them plummeting into public buildings. Putting it ruthlessly, the passengers in that eventuality would be doomed anyway, and saving additional lives on the ground is the priority. India, Poland and Russia joined the US in declaring they would, dependent on circumstances, shoot down a hijacked commercial aircraft, although in 2008 the Polish government’s declaration was overturned by the country’s Constitutional Court. In any event it is clear that, among countries that would be potential targets, destroying a hijacked aircraft is now a very real option.

With ever-tighter security after 9/11, and with security forces taking an ever-greater interest in preventing a threat even reaching the airport, the would-be suicide bomber faces significant challenges to achieving his objective. Given the difficulties of taking an assembled device on board, the method that has for several years been mooted – and against which significant security precautions have been taken out – is that the bomber will carry on board a selection of harmless chemicals in his hand luggage and use them to mix up a bomb in the aircraft toilet. It all sounds pretty easy. It isn’t.

The usual suspect for a bomb is TATP or Acetone Peroxide, which was used by Richard Reid (the “shoe bomber”) as a trigger for his explosive heels. Nicknamed “The Mother of Satan” for its intense instability and twitchiness, TATP is only stable when it is pure. If not, it is extremely susceptible to early detonation from shock, friction or sparks. It is, on the other hand, very easy to make in an impure form, which has made it a favoured explosive for terrorist groups who have limited resources or knowledge of chemistry.

So far the incidents involving TATP on aircraft have involved small quantities taken on board in a finished state: Richard Reid was only in possession of small quantities as a trigger on American Airlines flight 63 in 2001, while the attempted destruction of Northwest Airlines flight 253 on Christmas Day 2009 involved a small amount TATP, but was primarily plastic explosive with the “detonator| being a syringe full of acid to inject into the mixture that was probably carried aboard the aircraft in a condom. In other words, there have been no successful uses of TATP on board an aircraft, and certainly none ever mixed on board.

This is because it is fiendishly difficult to do. First you need a concentrated form of Hydrogen Peroxide. You cannot buy this at the local chemist, so you would have to buy a lot of the highly diluted kind and fractionalise it by boiling off the water. This is hard enough in itself, and you could easily burn down your own lab before you have even got past stage one. That is assuming the chemist has not blown the whistle to the police already about you buying all of this diluted Hydrogen Peroxide in the first place. You will also need acetone and sulphuric acid, but they are less of a problem.

Now you will need to get them onboard your plane in separate bottles, kept nice and cool, along with a thermometer, a large beaker, a stirring rod, and a medicine dropper. You will need to think up ways to disguise these through the airport scanners or have a good excuse to have them. Let us assume this all happens successfully, you get on the plane and the time comes for you to start making up your bomb.

Flying first class is recommended as the ice bucket will come in handy and you will need plenty of ice to keep things cool. Then you need to lug all of this to the aircraft toilet. Assuming no one asks why you are taking an ice bucket and several kilos of ice into the toilet with you, along with the rest of the improvised chemistry set, you can set to work. You need to keep things cool, as the hotter the mixture gets the weaker the explosive; indeed, too hot and you would probably blow up yourself and possibly make a small hole in the aircraft fuselage but nothing more serious than that; in other words no virgins or servants on this trip. A long haul flight would probably be the best as you could do this while people are asleep and it is going to take you a good few hours ensconced in the toilet to make the stuff. If you have not been overcome by the fumes of the chemical reaction in the confined space (aircraft toilets are not known for their spaciousness or ventilation) and no one else has wanted to use the toilet in the meantime you are now, in theory, ready.

So, assuming you have not burned yourself alive before you get to the airport, got on board a long haul or night flight with your amateur chemistry set without being detected, wangled an upgrade to first class (if you could not afford the ticket), managed to commandeer a toilet for a few hours and get all your stuff inside with you, not gassed yourself or blown yourself up in the process of making TATP in sufficient quantities to bring down the plane and it is pure enough to do so, then you are ready.

So then you detonate it. Under the most favourable conditions possible you might succeed in killing a couple of people, blowing out some windows and depressurising the cabin. That is because you need really large quantities of it to make a real impact, and the amount of mixture you could smuggle onto an aircraft would not allow you to do this given restrictions on the amount of hand luggage you could carry.

Why not take it on board pre-prepared? The answer to that is, given TATP’s twitchy nature, it is unlikely to survive being tossed around, so just putting it through the scanner might see it go off. Even if it doesn’t, no operator is going to wave through a contraption that obviously has sufficient power to really damage a plane. Putting a large amount in the suitcase bound for the hold is almost certainly going to produce an interesting effect in the baggage screening area.

Terrorists have better options than this; they just have not got the wherewithal to manage it. A small group of highly motivated people bent on martyrdom, with a small but very stable neurotoxin that could be made by anyone with a working knowledge of chemistry, could launch a devastating attack; indeed, they could mix batch after batch until they got it just right. If they could make one that is absorbed through the skin as well as inhaled it would be even more effective, as no one on board would realise what was going on until it was far too late and the aircraft’s confined space and re-circulated air supply would do all the work for them. Certainly a small container, such as a perfume bottle, would fit the bill and sail past security personnel who are concentrating on looking for a TATP alchemist.

John Chisholm is intersec’s International Affairs Correspondent