January 30, 20255 min readHow Plane Accidents, like the DC Crash, Are InvestigatedThe accident that resulted in a commercial airplane crashing into the Potomac yesterday will require air safety investigators to dig deepBy Gary Stix edited by Dean VisserEmergency response units inspect airplane wreckage in the Potomac River near Ronald Reagan Washington Airport. Andrew Harnik/Getty ImagesA video camera at the Kennedy Center in Washington, D.C., captures a chiaroscuro image of the night landscape in the nations capital. A banking airplane approaches above. It moves toward the camera and then passes uneventfully out of view. Off in the distance, a bright blip in the sky moves slowly forward. A much smaller pinpoint of light approaches from behind at a quicker pace. Within a few seconds, the smaller aircraft overtakes the larger one and a brilliant flash illuminates the night sky hundreds of feet above the Potomac River.Last nights collision of a Sikorsky UH-60 Black Hawk helicopter with American Eagle Flight 5342 is feared to have resulted in the deaths of the commercial airplanes 64 passengers and crew, as well as the helicopters three U.S. Army service members. Understandably, the incident astonished both experts and the flying public. Traveling in U.S. airspace has generally been a remarkably secure experience for many years. The last domestic accident that involved a commercial airliner and resulted in major fatalities dates back to 2009.Ronald Reagan Washington National Airport remains a challenge for pilots, who must contend with both the heavy traffic and the restricted airspace near areas such as the White House and the Pentagon. The Potomac is the site of one previous major accident: in 1982 an Air Florida flight crashed into a bridge while taking off in a storm and then plummeted into the frozen river, killing 74 of the 79 people onboard and four motorists on the bridge. In recent years, near misses at Reagan National have occurred on the ground, with plane paths intersecting dangerously on the runway in multiple incidents recorded by the Federal Aviation Administration.On supporting science journalismIf you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.How do air safety officials proceed with investigating such a major accident? Scientific American put that question to Kristy Kiernan, associate director of the Boeing Center for Aviation and Aerospace Safety at Embry-Riddle Aeronautical University.[An edited transcript of the interview follows.]Accidents in commercial aviation are rare, and I think a lot of people are wondering how we will find out what really happened in yesterdays incident.There are very clearly defined processes for this. The NTSB [National Transportation Safety Board] has a go team that is launched immediately, and once the rescue and recovery operations are winding down, the attention turns to perishable evidencethings that might be affected by the environment or by the movement and recovery of the wreckage. So thats a very important thing, to collect the perishable evidence. Obviously, once the scene has been secured and its possible to operate safely, there are a lot of hazards at an accident scene, so protection of the people who are doing the rescue and recovery and the investigation is also an important factor.iSo what comes after that?Obviously, the so-called black boxes, the voice and data recorders, are very important to recover. Those would be present on the regional jets. I dont know what type of recording devices are on the UH-60 [helicopter]. But in general, the black boxes are a big focus. Then there are various groups that are convenedoperations, maintenance, air-traffic control, weatherand all of these groups, including human factors experts investigate their particular area.So, for instance, in air-traffic control, you would be securing all the air-traffic control radar and the tape of all the communications. Similarly, for operations, for both the Army and for PSA Airlines [the regional American Airlines subsidiary involved in the crash], there will be a collection of evidence related to the people involved in the operation of the aircraft, including their training records. If things are not as they should be, the effort in a particular area is proportional to the role that a particular fact plays in the investigation. So more and more resources will be deployed toward the areas where the investigation is progressing. All that takes time. We have a fast news cycle, and the public should get information as soon as they can, but its better to wait for good information than to give in to speculation and opinion, which frankly, have absolutely no place in aviation.Can you describe what has been learned from pursuing past investigations?I would say is that we have layers of safety that exist. And so, for example, there are procedures in terms of where airplanes are in the sky and what altitudes they are at. Then we have technologies. We have collision avoidance systems. We have whats called ADS-B, Automatic Dependent Surveillance-Broadcast. Thats another tool that is used to help in situational awareness of where other aircraft are in the airspace. We have highly trained air-traffic controllers, and in numerous instances in the past, theyve been instrumental in avoiding midair collisions. Then we have highly experienced pilots on the flight deck of the regional jet and highly trained and experienced aviators in the Army helicopter.But that isnt always enough, is it?So we normally have all of these layers. However, we also have to recognize that we ask a lot of our systems. We have that area in Washington, [D.C.], which is high-density, high-volume and has a high pace of operations. And while we have different margins of safetyso that when youre driving on a slick and snowy road in the dark, you can maintain safe operationsyour risk profile and your safety margin is different than on a beautiful Sunday afternoon. So there are areas where our safety margins are thinner, and those are the areas that we really have to be vigilant for.If people could see all of the activities that go into keeping the airspace safe, I think they would be reassured. But the last thing that I would say is that we should be comfortable where we are now. We should always, as aviation safety professionals, be uncomfortable. For the traveling public, I think they can take comfort because of all these activities that go on every single day. But even one accident, when there are 40,000 operations in the U.S. domestic airspace every day is too many.Air accidents with mass fatalities are rare. Doesnt that in some ways make them more difficult to investigate? I dont know that it makes [such accidents] more challenging to investigate. It definitely makes [them] more challenging to predict because there is a lot of modeling that is done in the industry to try and understand the different things that go into an accident. There is not a smoking gun; there is not just one causal factor. Even if you found one thing, there is a reason for that one thing, and that reason is more complicated. And if you just identify the one thing, youre really not solving anything. You have to go deeper and look at the why behind it. These accidents are very rare. So the likelihood of the same one recurring, especially after we take action, is extremely low. But we cant stop there. We want to use each thing we discover as an opportunity to examine all the factors that went into itso that we are not just being reactive but [are also] able to look forward and identify the risks and hazards that we have to mitigate.