Commentary. The Mercatus Center’s report released earlier this week stated that the real drone risk posed to aircraft was “minimal.” In a paper that was partly research and partly a pointed critique of the FAA’s overblown rhetoric on drone risk, researchers took bird strike data and made assumptions about the number of times (very, very few) that drones were actually likely to strike airplanes accidentally; and how dangerous it would be if they did. Their conclusion – that drones pose so little risk to aircraft passengers that the level is negligible – is in direct contrast to an earlier study performed by AeroKinetics, a defense firm based in Texas. That study, titled “The Real Consequence of Flying Toy Drones in the National Airspace,” also used bird strike data, and made broad estimates based on assumption of increased force. That study concluded that drones posed a “catastrophic threat” to aircraft passengers, and found a “huge risk” of collisions.
This argument might be amusing if it were not for the fact that a third study, produced in 2012 by the MITRE corporation, titled “A New Paradigm for Small UAS” was specifically cited by the FAA Registration Task Force as its reason for requiring registration for any drone over 2 kg. In the Task Force recommendations, the task force took one equation from the paper and reasoned out a mathematical risk scenario:
Referencing information from a 2012 MITRE report (which further references a United Kingdom Ministry of Defense 2010 study), an object with a kinetic energy level of 80 Joules (or approximately 59 foot-pounds) has a 30% probability of being lethal when striking a person in the head.
Solving for mass and velocity, this equates to an object weighing 250 grams traveling at a terminal velocity of 25 meters/second or approximately 57 miles per hour.
Using these results, it is reasonable to estimate the probability of such a lethal event occurring per sUAS flight hour…(For these purposes, we have used population density numbers reflecting a relatively densely packed urban environment. We have done so despite the fact that sUAS operations are prohibited over unprotected persons not connected to the operation).
You can find the math formulas by reading the original recommendations, linked above – but the task force, made up of a wide variety of attorneys, business people, and other industry “stakeholders,” started with a set of broad and questionable assumptions and ended by concluding that registration of toy drones weighing more than 2 kg was necessary to the safety of the National Airspace (NAS.) They handily ignored the rest of the MITRE study, which had this interpretation of the risk small drones pose:
In the event of a collision, the small size and frangibility of the small UAS may not result in a catastrophic loss.
In August of 2011, a US C130 collided with a RQ-7, Shadow, in Afghanistan. 12, 13 While there was some damage to the C130 and the RQ-7 was a total loss, the C130 was able to land safely with no injuries. The RQ-7 struck the wing of the larger aircraft. Perhaps if the impact occurred on the windscreen the collision may have had significantly greater consequences. However, the RQ-7, at maximum gross weight 460 pounds14, weighs significantly more than the small (20 pound or lighter) UASs which are envisioned to be operated under the new paradigm.
…A collision with a small UAS is likely to be less severe than a mid-air collision with even the smallest aircraft capable of carrying a human pilot (e.g., a 254 lbs ultralight). There are a number of documented incidents where remote control model aircraft have had mid-air collisions with a manned aircraft without a catastrophic result‡.
The “extreme risk” theory is one that the FAA has used over and over again as justification for heavy regulation and slow movement. They are supported in this by the powerful Airline Pilots Association union, who clamor for more heavy drone regulation. The” increasing number of near misses with airplanes” scenario was cited in FAA testimony about the missed September deadline for issuing Small UAS Rules, and has been cited in almost every discussion of drone regulation that the FAA has participated in since.
Last Wednesday, the Inspector General of the Department of Transportation acknowledged that the FAA has no real data or system of tracking to quantify accurately the number of truly dangerous interactions between aircraft and drones. In a prepared statement for his testimony about upcoming budget challenges, the Inspector General told lawmakers:
…FAA also has not established standard procedures for safely managing UAS in the same airspace as manned aircraft or an adequate UAS training program for controllers…. According to FAA, reported UAS sightings by pilots have increased significantly, with more than 1,100 reports in 2015, compared to just 238 reported in all of 2014. Some reports indicated safety risks, such as pilots altering the course of their aircraft to avoid UAS. Despite these risks, FAA does not have a formal system to track and classify the severity of UAS incidents. In addition, FAA inspectors still lack clear guidance on how to conduct UAS oversight.
A “lack of clear guidance” and no “formal system” would seem to be an inadequate data set to inform regulation that affects an entire industry, estimated to impact the US economy by billions of dollars in the next decade. While it may be convenient for both sides to manipulate data to provide “proof” to back up their policies, it serves neither government nor industry to produce laws on such scanty evidence.
The reason that bird strike data is used as a basis for assumption is because so much is known about the real impacts that birds have on airplanes. This is because manufacturers actually perform bird strike tests on airplane engines regularly to test for damage; these tests inform aircraft certification policies to ensure safety. An article in Wired Magazine described the testing of an aircraft engine:
The testing that goes into certifying the engines that power these aircraft—the engineering marvels that can send a 600,000-pound Boeing 777 over 500 mph—are no less extreme…manufacturers run tests that are as straightforward as they are awesome: They turn on the jets and start throwing things in there.
It’s time to throw some drones in there. As the US steadily falls behind other countries in the drone race due to overregulation or endless delays on the issuance of clear commercial guidelines, it is past time to stop guessing about how dangerous drones are to passenger aircraft. Missing in any FAA Reauthorization package so far is explicit direction to find out, but it is a gap that should be remedied. Instead of making comparisons between birds and drones, the FAA – or the drone industry – needs to fund research that can answer the question definitively: Do drones pose a “catastrophic threat” or “minimal risk”?
Miriam McNabb is the Editor-in-Chief of DRONELIFE and CEO of JobForDrones, a professional drone services marketplace, and a fascinated observer of the emerging drone industry and the regulatory environment for drones. Miriam has penned over 3,000 articles focused on the commercial drone space and is an international speaker and recognized figure in the industry. Miriam has a degree from the University of Chicago and over 20 years of experience in high tech sales and marketing for new technologies.
For drone industry consulting or writing, Email Miriam.
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[…] of which rely upon simulation, have evaluated the risk as anything from “minimal” to “extreme.” These studies don’t provide adequate information on which to base regulation. In fact, […]