A lot of would-be terrorists are stupid or incompetent, and that's good. Sometimes, it thwarts their plans; it at least makes them easier to catch afterward.The recent bombing attempt at Times Square is an example. The Oklahoma City bombing utilized barrels of ANFO -- ammonium nitrate mixed with fuel oil. It's a powerful explosive commonly used in mining. Ammonium nitrate is also used as fertilizer. The Times Square bomber used fertilizer -- but it was the wrong kind.
Also, it was inside a metal gun locker, not mixed with fuel oil, and not exposed to the firecrackers and fuel canisters he also used.
He also removed the vehicle identification number (VIN) from the car's dashboard -- but not from its engine. That led to the car's original owner, which led back to him. He was caught in just a little over 2 days.
Others:
In a similar case in 2007, terrorists tried to drive a car with cans of gasoline and propane into the Glasgow Airport. Apparently, they failed to scout first, and didn't notice the bollards there, which kept them stuck at the door.
Also, fuel burns, but it doesn't necessarily explode, especially in small quantities. After the crash, they had nothing but a small fire. One got out and poured gas on the car, but all he accomplished was burning the other one badly enough that he died a month later.
- The prior day, two car bombs in London were stopped when one emitted a suspicious smell, and the other was towed away for parking illegally. Inside were found the terrorists' cellphones, holding the phone numbers of their associates.
- Also in 2007, men planning to attack Fort Dix were caught when they made a video of themselves shooting assault weapons and shouting incriminating things -- and took it to a Circuit City to be transferred to DVD.
- In January 2000, Al Qaeda members in Yemen tried to use a "boat bomb" against a U.S. Navy ship. However, they overloaded the boat and it sank.
- In 2009, a foreign student ordered $3,300 of aviation-related things online, including a map of a nearby air terminal, a flight jacket, and pilot education materials that included a DVD, "How an Airline Captain Should Look and Act." He used a bad credit card, which led him to be arrested for wire fraud.... and brought attention to the fact that his visa had expired 6 years earlier... and that he'd been using a fake SSN... not to mention the nature of the things he bought, and the fact that he wasn't a pilot.
- In 2009, Nicky Reilly's attempt to bomb a restaurant was bungled when got stuck in a toilet. He'd prepared three nail bombs while in the restroom, but then got stuck and one went off. He survived, and no one else was injured. (In fairness, he's said to have a mental age of ten.)
- Possibly beating him for the least competent: Two terrorists tried to bomb the U.S. Embassy in the Philippines. One set the timer in the dark, using only the light from a cigarette lighter (brilliant move #1). He set it to "500" -- five minutes, right? No, he had it upside down: it was "005" -- five seconds! The other one survived, though he staggered out stunned and covered in blood, and was arrested at the hospital. No one else was harmed.
References:
Why the Times Square Bomb Fizzled Rather Than Boomed, FastCompany magazine
Failed terrorist attempts, Wikipedia
The 5 Most Embarrassing Failures in the History of Terrorism, Cracked magazine
