> Don't model rockets routinely go much higher than the 400 feet the FAA has traditionally limited hobby aircraft to?

Even if they do, they're mostly cardboard, whereas model airplanes have things like small engine blocks. I bet a 737 engine could ingest a model rocket without anyone noticing.

You'd be surprised. Jet engines are designed to be robust against some really crazy scenarios (I'm amazed a jet engine continues to function during the water injection tests I've seen), but all it takes is one blade failure -- with many to choose from in various places in the engine -- and it's game over. One can imagine many ingestions that might cause a blade failure, because the rotating fans in a jet engine are very high energy environments. With the right alignment of planets and hitting just right, a model rocket might cause a failure. It all depends and is hard to predict. Most people would predict modern engines as likely to survive ingestion of geese, but then we had US 1549 (and a USAF E-3 at Elmendorf before it).

Even though the FAA has engine manufacturers like GE test the hell out of engines, it's tough to predict what will happen in the real world. Birds are a huge threat to aviation, both engine ingestion and windscreen collisions, and birds are mostly organic. (It goes without saying to stand the hell away from an operating jet engine even at idle, too, because humans do get ingested with fatal results.) I can't imagine an operating engine ingesting a drone or anything else with non-organic components would go well, and this is why I always advocate very strongly for safe drone operation.

Here's an intentional intake blade failure to ascertain whether the engine can contain the failure without threatening the aircraft; this is useful to see what happens if something is ingested that causes a catastrophic blade failure: https://www.youtube.com/watch?v=WAhjSviYVr8

They can, but it's not routine, at least with the model rockets readily available to non-certified hobbyists (think Estes, maybe some of the G-motor Aerotech rockets).

Routine 400+ foot launches are more the purview of dedicated rocket launch events, which typically do go through extensive FAA clearance and such, and which have certification processes in place for those flying all but the lowest-powered rockets. Airspace is usually sanitized, and for good reason: these sorts of rockets tend to be much bigger than your ordinary backyard-launched Estes rockets, and very well could do significant damage to an airplane should a collision occur.

Actually, 1,000 ft flights are pretty routine. Any model rocket engine with a "-5" on the end is going to coast for 5 seconds after the fuel burns out. If the model is light enough to be near the top of its arc at that time, it will be about 1000 feet up. Flights with engines that end in "-3" (3 second coast) tend to end up about 300 to 400 feet up.

Tip: if you want to fly in a baseball field, and get your model back (not drift out of the park), stick with engines like "B6-4" or "C6-3" and models sized for those engines. If you fly a C6-5 or a D12-7, you had better have a good size farm to land in and a few friends to help spot :-)

http://www.hobbylinc.com/rockets/group/enginefacts.htm

Flying G size engines and up? Go to a special event in Nevada. Those can go a few thousand feet up. (or lift some heavy/dangerous frameworks)

I was just playing devil's advocate in light of an unreasonable position on the issue. I honestly don't know much about model rocketry specifics (build a few as a kid like 20 years ago, purchased as a kid, from a local hobby shop). I assume you can make them go more than 400ft into the air without much effort but you're probably not supposed to.