On Friday 27 September, at around 3:15pm, an Aer Lingus pilot flying over Howth is headed toward Dublin Airport. He makes a call to air-traffic control.
“Continued approaches, be advised: we’re at 3,000 feet and a drone just flew past our right wing to the north of us, less than 50 feet away from the aircraft, same level.”
His voice is clear and clipped. It stands out from the mumbled, routine calls and responses that come before it.
Air traffic control responds: “Ahh … large or small?”
“It looked fairly large from where we were, but it was literally about 20 feet outside of our wingtips. It was red and black,” said the pilot, in a conversation available online at ATC Live, an archive of radio transmissions.
“It was what? Red, was it?”
“Red and black. Quite large.”
“Okay, I’ll pass it on, thanks.”
There are rules in place to keep drones away from airplanes flying into and out of Dublin Airport. If this was a drone, someone was clearly breaking those rules. A spokesperson for the Irish Aviation Authority said they had referred the incident for investigation.
While questioning whether the pilot had really seen a drone so close to his plane, Fergal McCarthy, co-chair of the Unmanned Aircraft Association of Ireland (UAAI), said that people flying drones where they aren’t supposed to is a big problem around Dublin.
Howth is picturesque, McCarthy says. “People bring drones out there a lot. And unfortunately, they’re just not aware of the risks.”
Getting Too Close
It’s illegal to fly a drone within 5 km of any airport in Ireland, according to a spokesperson from the Dublin Airport Authority (DAA).
David Barry, a senior lecturer in aviation safety at Cranfield University in the UK, says that at 5 km from an airport, aircraft will typically be at about 900 to 1,000 feet.
“Well above any drones that are being flown legally,” says Barry. Which means, in that sense, the exclusion zone is “safe”.
In this case, the possible drone was spotted about 10 miles (16 km) away from the airport, the recordings suggest.
A few minutes after his first report, the pilot said: “Yeah Shamrock 165, that drone was at 3,000 feet at 10 miles just slightly north of the local line. There’s probably an issue for traffic behind us. It was very, very close to the local and central line.”
Air traffic control responded: “Yeah, approach is advising all traffic.”
This sighting was outside of the exclusion zone but still within controlled airspace around Dublin – within which there’s a cap on how high drones can fly.
Drone operators aren’t allowed to fly them higher than 15 metres, or 50 feet, around Dublin, says McCarthy, of the Unmanned Aircraft Association of Ireland (UAAI).
That’s unless they have a “specific operating permission” (SOP), something the Irish Aviation Authority can grant to professional drone operators, says McCarthy.
Even with an SOP, an operator has to apply for every job within controlled airspace, he says. “You have to submit a plan to air-traffic control and do a risk assessment, including where you’re going to take off from.”
When using an SOP, a drone still can’t be within 2 km of any plane, McCarthy says. “So if I’m in the flight path over Howth, although it’s more than 5 kilometres away from the airport, I still have to be 2 kilometres from that plane.”
The possible drone the Aer Lingus pilot said he spotted on 27 September was much, much closer than that.
Still, when the air-traffic controller can be heard advising other planes about the drone sighting, and asking whether they were okay to continue, they said they were.
“[Y]ou heard the report on the drone … Are you happy to depart?” air traffic control asks a pilot.
“Yeah, we’re happy.”
From the recordings, it doesn’t sound like any pilot refused to go ahead.
What Was It?
McCarthy, of the UAAI, is a bit sceptical that a pilot could have seen a drone that close to a plane travelling at high speed, at an altitude of 3,000 feet.
If the drone was 50 feet off the plane, it would get caught up in the backwash and wouldn’t survive, he says. “Most likely, it would tumble significantly, and, depending on the software, may be able to correct itself and keep going.”
The drone would be stable enough to be spotted for only a couple of seconds, he says.
“I’m not saying there wasn’t something there,” McCarthy says – various things have been mistaken for drones in the air: birds, plastic bags.
A spokesperson for the DAA confirmed they were notified that a pilot spotted a drone in the Howth area at around 16:30 on 27 September.
There are protocols in place to deal with drone sightings, she said, and the DAA works with Gardaí and other state agencies.
A spokesperson for the Irish Aviation Authority said that “Drone sightings near Dublin Airport are extremely rare.”
When they get a report about a possible illegal drone, they investigate, the spokesperson said. “We have noted the activity you mention and have sent this to our Flight Operations Inspection team to investigate further.”
They didn’t say when the investigation had started in this case. “We do not comment on individual incidents, as our reporting process is confidential,” they said.
When a pilot spots a drone in the vicinity of an aerodrome or when approaching one, the pilot has to report to air-traffic control straight away, noting the drone’s estimated location and height.
This allows air-traffic control to provide “safety advice to other aircraft”, the spokesperson says.
After that, an aircraft proximity report has to be filed “as part of the investigation process”.
Anything to Do?
Even if this particular sighting wasn’t actually of a drone, says McCarthy, of the UAAI, people flying drones in Dublin in places where they shouldn’t “is a huge problem”.
A lack of education and enforcement is at the heart of the problem, he says. New drones come with an IAA flyer setting out the rules, but there are cheap second-hand ones for sale too, he says.
Ireland recently adopted European Union-wide rules on drones, which means the EU will follow up with the IAA and the Gardaí if the rules aren’t being enforced, McCarthy says.
Barry, the Cranfield University lecturer, says the authorities can “raise public awareness, prosecute people who fly drones illegally, and investigate sightings like these”.
If someone still flies a drone near a plane, though, “There’s not much a pilot can do other than report the sighting,” Barry says.
The precautions the taken in this case – the pilot reporting the drone, the air-traffic controller passing that information along to other planes – were sensible. “[I]t’s difficult to think of any further practicable precautions.”
One technical solution could be restricting the height at which drones can fly, unless the operator has training and permission to go higher.
“I’m not aware of any restrictions on purchasing drones. Perhaps drones capable of flying at over 400 feet could be restricted in sale in some way,” he says.
Barry also says aircraft are tough, and it’s unlikely that hitting a drone “would have a catastrophic outcome”.
Helicopters and small planes are probably more vulnerable than airliners, he said. “It would be nice to see fewer drone encounters, but they are not amongst the biggest risks to aviation.”
A DAA spokesperson said they couldn’t talk about the method Dublin Airport uses to keep drones out of flight paths. “For operation reasons, I cannot comment on specific security matters relating to this issue.”