BOSTON -- Model airplanes are suddenly on the public's radar as potential terrorist weapons.
A Muslim American from suburban Boston arrested Wednesday is accused of plotting to attack the Pentagon and the U.S. Capitol with remote-controlled model planes packed with explosives.
These are not balsa-wood-and-rubber-band toys investigators are talking about. The FBI said Rezwan Ferdaus hoped to use military-jet replicas, 5 to 7 1/2 feet long, guided by GPS devices and capable of speeds over 100 mph.
Federal officials have long been aware of the possibility someone might try to use such planes as weapons, but there are no restrictions on their purchase -- Ferdaus is said to have bought his over the Internet.
Counterterrorism experts and model-aircraft hobbyists said it would be nearly impossible to inflict large-scale damage of the sort Ferdaus allegedly envisioned using model planes. They are too small, can't carry enough explosives and are too tricky to fly, they said.
"The idea of pushing a button and this thing diving into the Pentagon is kind of a joke, actually," said Greg Hahn, technical director of the Academy of Model Aeronautics.
Rick Nelson, a former Navy helicopter pilot who is now a senior fellow at the Center for Strategic and International Studies, said Ferdaus would have had to hit a window or other vulnerable area to maximize damage, and that would have taken precision flying.
"Flying a remote-controlled plane isn't as easy as it actually looks, and then to put an explosive on it and have that explosive detonate at the time and place that you want it add to the difficulty of actually doing it," he said.
Ferdaus, 26, of Ashland, was arrested after FBI agents posing as al-Qaida members delivered what he believed was 24 pounds of C-4 explosive, authorities said. He was charged with attempting to damage or destroy a federal building.
Ferdaus has a physics degree from Northeastern University and enjoyed "taking stuff apart" and "learning on my own," court papers say.
The model planes he eyed were the F-4 Phantom and the F-86 Sabre, , investigators said. The F-4 model is the more expensive, at up to $20,000, Hahn said. The F-86, one of which Ferdaus obtained, costs $6,000 to $10,000 new.
Ferdaus' plan, as alleged in court papers, was to launch three such planes from a park near the Pentagon and Capitol and use GPS to direct them toward the buildings, where they would detonate on impact and blow the Capitol dome to "smithereens."
James Crippin, an explosives and anti-terrorism expert, said getting a stable explosive like C-4 to blow up at the right time would have been hugely difficult.
"Basically, I think he's suffering from delusions of grandeur," he said.