Reports of drone close encounters spiked in 2015, with no simple resolution in sight
The FAA released a report today detailing how pilots reports of dangerous drone activities that interfered with aircraft operations spiked in 2015. In 2014, pilots reported 238 such encounters, while this year that total rose to over 650 by August. In our previous reports on drones, many of you have questioned whether the issue is actually “that bad,” given that airplanes regularly suffer bird strikes without catastrophically falling out of the sky. Given that drone – plane interactions are skyrocketing, it’s useful to revisit the topic.
All modern aircraft engines are required to conform to the FAA’s minimum bird ingestion standards (Yes, that’s the actual term, and yes, it’s totally hilarious). Information on how much damage a drone would do to an aircraft on impact is difficult to measure: There are a great many different types of drones, they’re built from various materials as opposed to feathers and meat, and they have dramatically different weights. We can generally assume that heavier drones will do more damage than lighter ones, but that’s about it. There is, however, a great deal of information on how a jet engine reacts to the sudden intrusion of an avian, as demonstrated in the video below:
Bird strikes can cripple or destroy a plane, particularly if they occur during landing or takeoff. Multiple bird strikes in 2009 forced US Airways Flight 1549 to land in the Hudson river after both engines flamed out. It’s estimated that 65% of bird strikes result in no damage to the aircraft, but the cost of repairing the other 35% of planes is quite high, at $400 million in the United States and an estimated $1.2 billion worldwide.
Here are some of the more frequent comments we’ve seen on this topic.
Drones don’t weigh as much as birds: This depends on what kind of drone or bird you’re talking about, but the argument is based on a misconception. The overwhelming majority of the damage inflicted by an impact isn’t caused by weight, but by speed. A bird impact at 171 mph relative velocity has the same kinetic energy as a 220lb object dropped from a height of 49 feet. It should be noted, however, that while the kinetic energies are approximately equal, the force required to deflect the now-deceased bird is considerably less. Either way, it’s the speed of the collision that does the damage, not the mass.
Also keep in mind that existing aircraft built after 1960 were not designed to safety specifications that included impacts with flying drones. Smashing into a hard plastic or metal frame at several hundred miles per hour may do dramatically more damage to an aircraft that passes all existing safety standards concerning bird strikes.
People have a right to operate drones: The FAA is updating its current rules to cover drones and related aircraft, but the agency has already issued a preliminary set of guidelines. Drones shouldn’t operate above 400 feet, come within five miles of an airport without communicating with the airport and its control tower, or fly near people. According to the FAA, commercial airline pilots reported encountering 138 drones above 10,000 feet in June, and 137 in July. That’s up from 16 and 36 in June and July of 2014. The vast majority of hobby drones aren’t even capable of reaching that altitude, and many contain programmed limitations that prevent them from doing so.
The people causing problems, in other words, aren’t the guy who bought a $500 drone and wants to take some aerial photos of his house.
Planes can just get out of the way: This argument is often delivered alongside some variety of “Pilots should man up,” or a reference to the courage and bravery of Allied wartime pilots who flew bombing runs as opposed to modern cowards who aren’t willing to play chicken with an object that’s a fraction the size of their own aircraft. It’s a terrible argument, particularly given that it’s often made in situations where the aircraft in question was either fighting fires or trying to avoid drone intrusion on a landing or takeoff.
A firefighting aircraft isn’t cruising above the conflagration at 10,000 feet. The typical altitude for a retardant drop is more like 150-200 feet. At that height, the pilot has virtually no time to react if something goes wrong — and given that they’re already flying into a burning hellscape with all the smoke and heat attendant to such a situation, there’s already something wrong. Depending on the nature of the fire, a tanker may also be carrying smoke jumpers or rappellers, meaning the pilot is taking risks with more lives than just his own.
A drone strike that destroys a tanker aircraft would dump jet fuel into an already-blazing area, almost certainly kill the pilot and co-pilot (firefighting aviation disasters are nearly always fatal) and further hamper the efforts of the ground crew to combat the blaze. Telling the pilots to “man up” is simply ridiculous when the consequences of them doing so could dramatically worsen the very conflagration they’re attempting to stop. Discretion, at times, is the better part of valor.
Similarly, an aircraft in the midst of taking off or landing is at its most vulnerable. A drone strike in either situation could wreck the plane and possibly kill the passengers. According to United States law, the pilot in command (PIC) is the person who “Has final authority and responsibility for the operation and safety of the flight.” In a potentially dangerous situation, the last thing anyone needs is a pilot willing to risk the lives of his passengers and flight crew by taking risks.
No clear solution
There has to be a way to create a middle ground between outlawing drones and creating serious safety risks for pilots, but to date none have presented themselves. Requiring everyone to get a pilot’s license to operate a drone is, in my personal opinion, overkill — but drone pilots, in turn, need to have a way to be notified that the FAA has created no-fly zones over wildfires for safety reasons, or that an aircraft is approaching their vicinity. Whether this involves two-way radio communications (somehow), automatic piloting updates that prevent a drone from entering restricted airspace, or another method of resolving the situation is still unclear.
If the FAA’s report is any indication, planes and drones are going to continue encountering each other at an accelerating clip. Given this trend, it’s only a matter of time before that encounter involves significant damage to an aircraft. Hopefully we can take steps to resolve the issues at hand before that happens.