Aircraft operators in the United Kingdom reported 23 near-misses with drones between April 11 and October 4 of last year, according to a new report from the UK Airprox Board.

One military helicopter had to take evasive measures to avoid a drone less than a rotor’s distance off its side in April, and several commercial flights have passed within a few dozen meters of drones. Pilots have reported the likelihood of a collision as “high,” and investigators are warning that “chance had played a major part” in avoiding a midair incident as of yet.

Pilots in the UK are now calling for research into what would happen if a drone did collide with a plane. They are also calling on stricter rules about flying near airports as well as mandatory insurance and drone registration.

“We must act now to protect passengers and flight crew and make sure a catastrophic crash does not happen,” Steve Landells, a Flight Safety Specialist from the British Airline Pilots Association (BALPA) told Vice News.

In the United States, the Federal Aviation Administration (FAA) compiled over 600 reports of pilots spotting drones while flying in 2015. Even commercial airliners have seen drones, at least once as high as 10,000 feet in the air.

Luckily, no plane on drone collisions have yet occurred. Last year, the internet went berserk over a video that showed a drone clipping the wing of a commercial flight, but it turned out to be a very convincing fake.

The FAA’s “Know Before You Fly” campaign may restrict drones from flying above 400 feet but also provides some vague instructions that could easily lead to these kinds of dangerous encounters. There are some criminal penalties in place as well, but only if you really screw up.

The current FAA rules require that operators:

Contact the airport or control tower before flying within five miles of an airport.

Remain well clear of and do not interfere with manned aircraft operations, and you must see and avoid other aircraft and obstacles at all times

No wonder these British pilots want to know what would happen if they hit a drone mid-fight — it seems like it might just be a matter of time until it happens. If drone operators are held to the same standards as pedestrians on a crosswalk, there will inevitably be a run in.

We really shouldn’t have to study what happens when a drone and a plane collide. Maybe it will help us save lives in the event that it does, but we should be focused on preventing it altogether. Admittedly, the likelihood of a collision is still small, but we’ve seen what happens when a plane collides with birds in mid-air, and it turns out that it’s nothing good.

Remember when Captain Sully had to land a commercial flight in the middle of the Hudson River? That was because the plane hit a couple of birds. And as Landells puts it: “Birds don’t have a big lump of lithium battery in them.”

That flight was carrying 150 people, and it was nothing but luck that a former fighter pilot with a sterling record of experience and leadership was at the helm to bring it down to safety (“We’re going to be in the Hudson,” went the quote). Birds remain enough of a problem. Let’s keep the drones way away.

Photos via Getty