The following YouTube clip from the movie Blue Thunder kinda conveys the awesomeness of chasing a light aircraft between high-rises in a city, as well as the collateral damage when military ordnance goes awry…
To answer the OP, I agree with those that stated the powers that be would probably wait to apprehend the terrorists until the aircraft landed. First on the scene probably would be National Guard, and I think they’d have very little diffculty killing the aircraft. The hard part would be clearing the airspace around the aircraft and making sure shrapnel/aircraft bits didn’t land on any civilians. Or, you could just wait 'til he ran out of gas. Even an Extra 300 is only taking our terrorist ~500 miles or three hours of flight time, less if he’s making frequent +10 g break turns.
One advantage a cropduster has over a ground-based system is aerosol creation and dispersion. I’ve not looked at the math, (and truthfully, wouldn’t know where to start) but I would imagine the aerosol footprint beneath a cropduster at low altitude is considerably wider than that of a truck.
One thing to notice about crop-dusting aircraft is that they operate very close to the ground – like 10 or 20 feet AGL. The reason is that they want to lay down an effective amount of pesticide (or whatever). The higher you go, the more dispersed the aerosol. I van on a crowded street can provide concentrations of toxins to large numbers of people better than an aircraft can, when there are many obstacles that are higher than a crop-duster needs to fly for an application of maximum effectiveness.
What sort of weapon would a crop-dusting terrorist use? The first one that comes to mind is Sarin. According to results of a quick google search, the 50% lethal dose is 75-100 mg-minute/cubic meter. (i.e., 50% of people exposed to that does will die.) How much Sarin is that?
A crop-dusting airplane carries anywhere from 100 to 800 gallons of payload. The Air Tractor AT-502 is (according to the linked page) the company’s most popular model, and it has a 500-gallon hopper. I’m too lazy to figure out the maximum altitude at which the plane can fly wherein an area can be sprayed to result in 75-100 mg that will be inhaled or otherwise absorbed in a minute’s time.
Of course, the OP is talking about dropping pipe bombs and shooting at people. In that case, I still think a van is better. Especially if the van is loaded with explosives for a grand finale.
Rob Holland, the pilot in that link, taught me to fly aerobatics.
I have a slightly skewed opinion on this question. Not sure about the technical aspects of shooting him down. But I will say that the aerobatic pilot in this scenario need not actually cause any damage.
It would be sufficient for him to do some low level maneuvering say, 10 feet over the runways at JFK airport, ziz-zag among the buildings of New York City, and perhaps land on the great lawn in Central Park to make the point that he can do whatever he wants with impunity before anyone could shoot him down.
I wonder if you could kill a small plane with a fire hose? Some of the high pressure ones have decent range…if you happened to hit a wing or the tail, at low altitude, maybe you could put him out of control? Again, even getting a shot would be mostly luck…
I had a (Revell) model of the F4U Corsair when I was a kid. As I recall, the historical information on the instructions said that during WWII Corsair pilots ‘shot down 1,239 Japanese aircraft – and sawed down one.’
