Story ID: 
Study: Small Drone Flights Often Unsafe
By: Mark Huber
Caption: Operators Fly Too High, Close To Airports
Word Count: 1538
A significant number of all recreational drone flights sampled were conducted in ways that posed a hazard to navigation, according to a study released last month by Embry-Riddle Aeronautical University researchers and published in the International Journal of Aviation, Aeronautics, and Aerospace. The study used data collected between May 17 and May 29, 2018, that used an AeroScope deployed on an educational building adjacent to the Daytona Beach (Florida) International Airport (DAB).

The AeroScope detects, identifies, and tracks DJI drones, a company with an estimated 72 percent of the recreational sUAS market. The device tracked 192 separate flights by 73 separate platforms and recorded location, altitude, and time of day. Following the sampling period, the data was downloaded into electronic maps and UAS detection times were correlated with ADS-B data.  

Researchers also evaluated sUAS detections against the FAA’s UAS Facility Map (UASFM) established for the Daytona Beach. The UASFM shows the maximum altitudes for authorized Part 107 UAS operations around airports that do not require additional safety analysis. “At least 21.5 percent were determined to exceed the maximum defined altitude limits of their UAS Facility Map area,” the study noted. In one case, a sUAS was detected at 90 feet msl within 0.25 nm of the approach path of DAB's Runway 7L just seconds after an aircraft had approached. The researchers concluded, “Assuming the pilot was performing the published ILS approach, the aircraft would have crossed the Runway 7L threshold crossing at a height of 58 feet agl (88 feet msl). It is highly probable that the aircraft descended through the UAS altitude while on approach.” Eight drones were detected within one nautical mile of the DAB center point, including one at nearly 200 feet msl and 0.68 nm from the Runway 7L centerline. 

UAS detections ranged from as close as 0.83 statute miles (sm) to as far as 10.58 sm from DAB and even closer to other area airports and heliports. According to the study, “Unmanned aircraft operated as close as 0.50 nm to public airports and 0.35 nm to heliports. Of the 190 data points, 96.8 percent were detected within 5 sm of an aerodrome, with 84.2 percent detected within 5 sm of two or more aerodromes." 

UAS flights were detected significantly after local sunset, as early as 1:24 a.m. and as late as 11:49 p.m. local time. The most common times for flights were between the hours of 7 p.m. and 10 p.m. Altitudes ranged from ground level to 1,286 feet agl, with the mean altitude of 238 feet; at least 6.8 percent of platforms were detected above 400 feet, eight between 400 and 500 feet, two between 500 and 1,000 feet, and three above 1,000 feet (all altitudes agl).  

The majority of detections occurred within urban areas. Nearly 48.7 percent of detections occurred in residential neighborhoods; 28.3 percent near single-family homes, 20.4 percent near multi-family buildings, and 21.5 percent close to commercial, industrial, or public properties. Just 12.0 percent occurred near unimproved land and parks where drones could be operated relatively safely. One sUAS operated within 0.3 nm from the Tomoka Correctional Institution.

The researchers recommended providing drone activity information to pilots of manned aircraft to help reduce the danger of collisions, including making drone Low Altitude Authorization and Notification Capability (LAANC) request information available. 

FAA Oversight Under Scrutiny

To address the question of whether or not the FAA can control the swelling U.S. UAS market, the Department of Transportation (DOT) is conducting an audit. “Our prior and ongoing work has shown that [the] FAA is challenged to keep pace with the volume of requests for UAS to operate in controlled airspace near airports,” the DOT’s Inspector General said this week, announcing the audit on the FAA’s role in authorizing small UAS operations.

The IG said the purpose of the audit is to assess the impact of LAANC (Low Altitude Authorization and Notification Capability) on the FAA’s review and approval of UAS airspace requests and to evaluate the agency’s procedures for coordinating and communicating UAS airspace approvals and notifications between airports, ATC, LAANC service suppliers, and UAS operators.

The FAA has processed 1.1 million UAS registrations since December 2015, the IG noted. He added UAS sightings, reported primarily by manned aircraft to the FAA, increased nearly ten-fold between 2014 and 2017, from 238 to 2,185, and that year-to-date UAS sightings through October 26 were 2,085.

The audit is being conducted at FAA headquarters and various ATC facilities and airports across the country. 

Assessing Drone Collision Damage

Further study at the University of Dayton Research Institute’s (UDRI) Impact Physics group shows that impacts from small drones can be more damaging to manned aircraft than bird strikes. Researchers evaluated the damage a 2.1-pound DJI Phantom 2 quadcopter could level on the leading edge of a Mooney M20 wing compared to an identically weighted gel "bird."

The tests simulated the impact of both the drone and the gel bird on the Mooney wing at an impact speed of 238 mph. According to UDRI, “The bird did more apparent damage to the leading edge of the wing, but the Phantom penetrated deeper into the wing and damaged the main spar, which the bird did not do.”

“We wanted to help the aviation community and the drone industry understand the dangers that even recreational drones can pose to manned aircraft before a significant event occurs,” said Kevin Poormon, group leader for impact physics at UDRI. Poormon’s group routinely performs sponsored bird-strike testing of aircraft structures. “But there is little to no data about the type of damage UAVs can do, and the information that is available has come only from modeling and simulations. We knew the only way to really study and understand the problem was to create an actual collision.”

After calibration work to ensure they could control the speed, orientation, and trajectory of a drone, researchers fired a successful (drone) shot at the Mooney wing. The researchers then fired a similarly weighted gel bird into a different part of the wing to compare results. Poormon said his team is not aware of any other lab in the country performing controlled drone strikes on structures for research or data generation.

UDRI’s impact physics laboratory operates 12 gun ranges capable of propelling objects at velocities ranging from tens of feet per second to more than 33,000 feet per second. The laboratory is used for foreign object damage, light armor design and evaluation, penetration mechanics, hypervelocity impact testing and analysis, and dynamic behavior of materials.UDRI researchers collaborated with Sinclair College’s National UAS Training and Certification Center on the drone impact tests. 

Drone Maker Refines Geofencing

Facing tighter FAA regulation on recreational drone use, the world’s leading manufacturer of the vehicles, China’s DJI, recently announced improved geofencing technology to refine airspace limitations for drone flights near airports. DJI’s updated Geospatial Environment Online (GEO) Version 2.0 is being phased in as revised zones take effect for airspace around airports in the U.S. Upgrades in other parts of the world will follow, the company said.

DJI has selected PrecisionHawk to provide the data for the system, replacing the company’s previous geospatial data provider. DJI collaborated with the Aircraft Owners and Pilots Association and the American Association of Airport Executives in developing GEO 2.0. 

According to DJI, the new system creates three-dimensional “bow tie” safety zones surrounding runway flight paths and uses “complex polygon shapes around other sensitive facilities, rather than just simple circles.” The new restrictions better reflect the actual safety risk, while enabling more flights to the side of runways where the company says the risk is lower. 

DJI said its new geofencing incorporates the principles laid out in Section 384 of the new Federal FAA Reauthorization Act designating the final approach corridor to active runways at major airports to be "runway exclusion zones" for unauthorized drones and encouraged customers to update their DJI GO 4 flight control app and aircraft firmware to ensure these updates are implemented.

Its geofencing uses GPS and other navigational satellite signals to automatically help prevent drones from flying near sensitive locations such as airports and nuclear power plants. In certain instances, a DJI drone cannot take off or fly in a geofenced area without special authorization. 

GEO previously geofenced a five-mile circle around airports, with enhanced restrictions in a smaller circle around an airport. GEO 2.0 applies the strongest restrictions to a three-quarter-mile-wide rectangle around each runway and the flight paths at either end, where airplanes actually ascend and descend. Less strict restrictions apply to an oval area within 3.7 miles of each runway. This bow-tie shape opens more areas on the sides of runways to beneficial drone uses, as well as low-altitude areas 1.9 miles from the end of a runway, while increasing protection in the locations where traditional aircraft actually fly.

“DJI is proud to once again lead the industry in developing proactive solutions for safety and security concerns,” said Brendan Schulman, DJI vice president of policy and legal affairs. “This is an enormous step forward for safely integrating drones into the airspace based on a more finely-tuned evaluation of risks associated with aircraft approaching and departing different types of airports.”
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