***Update - 08/26/21 @ 08:10 UTC: Since publishing this article, the FAA has confirmed that it was not a drone but a mylar balloon that the aircraft hit.***

An Envoy Air Embraer 175 reported striking a drone as it was departing Chicago O’Hare Airport this weekend. The flight, departing at 18:20 on Sunday, was passing through 2,500 feet when the pilots reported hitting something in the air. It safely returned to the airport, and no passengers or crew were injured.

Drone strike on departure

Envoy Air’s flight ENY3961, also operating as AA3961, is the regular evening departure from Chicago to Detroit. Operated by an E175, the flight takes off at just after 17:30, arriving in Detroit around 50 minutes later.

But Sunday’s flight took a whole lot longer than that after the E175 hit a drone on its way out of the airport. The aircraft, registered N252NN, took off around 40 minutes late at 18:20 local time and was expected into Detroit shortly after 19:00. However, as it was climbing out of the airport, it collided with a drone.

Recordings of ATC communications show that another flight had alerted the controllers to a possible drone sighting, with the tower asking the Envoy pilots if they saw a drone on departure. The Envoy crew said they think they hit something, to which the tower requested they contact departure. The pilot did so, stating,

“Departure, Envoy 3961, we just hit something. I believe we hit a drone about 30 seconds ago. We’d like to return to O’Hare.”

Pilots requested a short hold to burn fuel. Data: RadarBox.com

Having confirmed a return to the airport, the pilot requested a holding pattern for a short while in order to burn off some fuel. He stated that the aircraft was just slightly over its maximum landing weight. ATC asked if the crew required any assistance once back on the ground, to which the pilot replied,

“We might want someone to look at… to inspect the airplane when we get on the ground.”

The pilot later confirmed to ATC that the aircraft was about four miles northwest of the airport when the strike occurred. They were estimated to be at around 2,500 feet at the time of the strike.

Envoy E175
The aircraft was back in service the next day, suggesting the damage was minor. Photo: Envoy Air

N242NN is a four-year-old Embraer 175. It remained on the ground in Chicago that night and was ferried to Champaign/Urbana the next morning. It returned to revenue service later that day, suggesting the damage was not substantial. Passengers for flight AA3961 were accommodated on another E175, departing Chicago at just after 22:00. They arrived in Detroit just before midnight local time.

Drones at 2,500 feet?

Flying a drone near an airport is illegal, as is flying it at this sort of altitude. The FAA rules listed under Part 107 state,

“The maximum allowable altitude is 400 feet above the ground, higher if your drone remains within 400 feet of a structure. Maximum speed is 100 mph (87 knots).”

That’s not to say that drones are not capable of flying at higher altitudes, however. An article from Dronethusiast notes that the highest drone flight ever was a DJI Phantom 2, which made it up to 11,000 feet. In order to perform this stunt, the drone operator would have had to disable parts of the vehicle's software which cap the quadcopters at 1,500 feet.

Plenty of drones are for sale that have the ability to fly to altitudes where they could encounter aircraft. The DJI Phantom 4, for example, is capable of flying to almost 20,000 feet (6,000 meters) but would require all sorts of regulatory waivers to be legally allowed to do so.

Nevertheless, some drone operators seem to have very little respect for the rules, with multiple reports of near misses and even strikes by drones close to airports around the world. In 2016, British Airways reported a drone collision with an A320 on approach to Heathrow. In 2018 an Aeromexico 737’s nose was damaged after allegedly hitting a drone. And just last week, a police drone collided with a Cessna 172 at Buttonville Municipal Airport.

While civilian drones tend to be smaller and less weighty than some of the large birds aircraft occasionally strike, they behave very differently. Plastic and metal do not give way quite like flesh and bone, and can result in significant damage to the aircraft, as was demonstrated by The University of Dayton Research Institute in the video below:

Although the FAA and police will levy hefty fines and potentially even jail time on those who break the law when flying drones, it can be incredibly difficult to find and identify the perpetrator. For now, drones remain a significant risk to aircraft around the world.