Aviation Accidents Caused by Microbursts

Aviation Crashes: Delta 191 and USAir 1016

This paper examines two of the most devastating plane crashes in all of professional aviation, the crashing of Delta 191 and the crashing of U.S. Air Flight 1016.

To the lay person, these crashes might just look like isolated incidents that both involved the inability of technology to handle inclement weather. However, these crashes were related to a weather phenomenon known as a microburst -- a weather phenomenon that was not well understood at the times of the incidents and which neither the pilots nor the aircraft were well equipped to handle. This paper documents the elements of both crashes and the unique details that led to them both and how they could have been avoided. This paper also explores what a microburst is and how it functions and also scrutinizes why the field of aviation was so ignorant about this particular weather occurrence to begin with. Furthermore, a closer look at how the field of aviation changed in lieu of these accidents is also assessed and described.

As experts and journalists have noted time and again, the crashing of Delta Flight 191 is one of the most intensely examined crashes in all of history, and because there was so much evidence and so many recording devices that were uncovered after the accident, it really became a crash that people could get a full and nuanced understanding of as a result of all this real-time data. One of the main causes of this accident was the Delta crew and the decisions that they made. "The NTSB final report faults the Delta crew for continuing the approach through a cumulonimbus cloud from which they observed lightning, a lack of specific guidelines and training for avoiding and escaping from low-level wind shear, and a lack of real time hazard information" (Hirschman, 2012). One of the reasons why Delta 191 was considered to be such a landmark aviation accident which so completely shook the industry and shocked both professionals and civilians, was because the flight resembled any other airline flight, right up until the final 40 seconds, making the ultimate crash a shock to everyone (Flannigan, 2011).

Reasons for the Delta Flight 191 Crash

Like many instances in life, hindsight is often 20-20, particularly since the Delta crew almost averted disaster multiple times. If the captain had been able to push for a go-round just a few second earlier, the disaster would have been avoided (Hirschman, 2012). If the first officer hadn't unspooled the engines by minimizing power to near idle at the moment of the approach, or if the first officer had relaxed the back pressure on the main control yoke at the moment the stick shaker hit, it is likely that no one would have been killed.

"The first sign of trouble came at 800 feet AGL while on final approach into Dallas Fort Worth with a 24 knot increasing-performance wind shear. The crew rightly anticipated a loss of performance and pushed the trust levers "way up" as the airspeed dropped from 173 knots to 133 -- a 40 knot wind shear. Despite the L-1011?s nearly 160,000 pounds of thrust, the aircraft still slowed to 119 knots and rapidly descended to the ground where it bounced and skidded into water tanks killing 134 passengers and one nearby motorist" (Flannigan, 2011).

One of the main causes of the accident was connected to the fact that Delta Flight 191 had in fact entered a microburst: this was a weather related issue that would have been best for them to avoid, but which they didn't avoid, unfortunately. The crew was faulted repeatedly for continuing to approach the cumulonimbus cloud with visible lightning and for the overall absence of specific training and procedures for navigating past low level windshear; there was also a lack of real-time wind shear hazard information which was viewed as yet another probable cause for the entire circumstance. However, to play devil's advocate, there are professional in the industry who still assert that the crew managed to do a very good job. The most effective ways to escape windshear involve applying a maximum thrust and pitching thoroughly for the most superior climb possible (Flannigan, 2011). As Flannigan reminds us, one could still argue that the crew even did the absolute best that they possibly could, and that sometimes an aircraft lacks an adequate amount of power to recover from such severe manifestations of weather -- that in the case of the Delta 191, that particular plane just didn't have enough power to escape from the windshear -- regardless of the actions of the crew (Flannigan, 2011).

As experts have concluded, the crew's decision to engage in and continue the approach into a cumulonimbus cloud which they viewed as containing visible lightning, was one of the major reasons for the crash, and one which could have easily been avoided. Furthermore, there was an aggravated lack of specific guidelines, methods and education/training for avoiding and escaping from low-level windshears. Furthermore, the crew was dealing with a paltry amount of real-time information about the windshear. Essentially, as one journalist explains, the crew was fighting against a phenomenon that they never even knew existed (Philip, 2005). This was a manifestation of the times. The reality in fact was that aviation simply wasn't educated about microbursts and didn't consider them a very real threat.

In fact, recordings from the cockpit demonstrate exactly that: once one of the pilots made contact with the tower at Dallas-Fort Worth, the pilot acknowledged the storm cell they were looking at, and expressed his desire to go around it (Gibson, 1985). The tower replied as follows, "I've had about 60 aircraft go through this area out here 10 to 12 miles wide, getting a good ride, no problems" (Gibson, 1985). This represents not just a lack of education in this arena, but a failure to follow specific protocol for dealing with inclement weather. The controller essentially ignores the presence of the storm cloud that the pilot has observed.

During this time, John McCarthy, a meteorologist with the National Center for Atmospheric Research had fought and tried for years to persuade the U.S. Federal Aviation Administration that this was in fact a very real phenomenon and one which was a substantial threat to aviation, but the success that he was met with was only marginal at best (Philips, 2005). In reality, " several years before the crash of Delta Flight 191, a senior Federal Aviation Agency official declared McCarthy's theory unbelievable and walked out of his presentation" (Philips, 2005). In hindsight, it's apparent that the field of aviation just wasn't ready to accept these theories (which were actually facts) and viewed them as irrelevant and inappropriate fantasies of a phenomenon that had no pressing concern on reality.

This marked an all too significant cause for this dreadful crash: a lack of knowledge and a lack of education -- combined with an absence of willingness to try new techniques no matter how different or novel they might appear. "In the 1980s, Mulally and Higgins developed the pilot survival technique taught today. Pilots must perform a maneuver that seems counterintuitive: Go to full power and point the nose upward 15 degrees, or more, until the stall warning sounds. Then ride out the turbulence" (Philips, 2005). This technique was extremely different and extremely counterintuitive to what was being taught and used in cockpits at the time. As Mulally admitted very candidly in an interview, people were dying each year as a result of a refusal to adopt new methods which would be able to more precisely and more aggressively deal with these weather phenomena. Furthermore, anytime Mulally tried to pitch airlines on his new training program, he would be rebuffed and ignored.

Microbursts: About

Researchers who were discovering and explaining microbursts were considered radical thinkers. One of the thinkers who was on the forefront of microburst research was Ted Fujida, a researcher who as one of the first to propose their very existence: he discovered them while travelling in a helicopter over a remote forest in Siberia where there were thousands of trees blown around for hundreds of square miles; Fujida's guides told him that this wreckage was likely the result of a big tornado, but he knew that he had encountered a weather phenomenon that was extremely different than anything of that nature. He knew that he had encountered one which was distinct from a tornado as a tornado moves along a path, and this destruction was emanating outward from a single point (Philips, 2005). However, this knowledge and this discovery did not do a tremendous amount of good right away, as science and aviation really weren't ready to accept it. It really wasn't until 1982 after years of science and research had been conducted by the atmospheric research center located within the National Aeronautics and Space Administration, that meteorologists were able to provide hard evidence for a fact related to this phenomenon that they had always been suspicious about: that the phenomenon could be so powerful that it could even take down a large aircraft (Philips, 2005). "Unfortunately, shortly after McCarthy performed preliminary tests that proved this, another aircraft went down because of a microburst. On July 9, 1982, a Pan American 727 crashed near New Orleans, killing 145 people on the plane and eight on the ground" (Philips, 2005). This tragedy did provoke action, though it wasn't the right type of action and it was also very ineffective: ground sensors were installed around airports in major metropolitan centers but they weren't successful as they were not fast enough to pick up on the more rapid changes of weather: in fact one sensor issued a wind-warning in 1985, but this warning came just a few second after the plane had crashed (Philips, 2005). Thus, it's all too clear that the crash was more than avoidable; with a proper commitment to evolving research and technology, the crash didn't have to happen at all.

However, the minds of science and aviation at the time, were not ready to accept the notion of either this strange phenomenon in weather, nor the idea that there was a strong necessity for a change in practice.

Eventually however, in this case the urgency which sparked the winds of change in the field were really only as a result of a strange coincidence: weeks before the Delta crash a local news crew went to the meteorology lab in the Denver airport; during this time a massive microburst struck far from the airport, but it could be very visibly seen as a result of dust, and other particle which were caught up in it. (Philips, 2005). The cameraman, taking several minutes of footage of what was considered a bizarre phenomenon at the time, asked the correspondent what would occur if an airliner flew through the microburst; the meteorologist McCarthy replied "Very likely the plane would crash" (Philips, 2005). Thus, when the Delta 191 crashed at Dallas-Fort Worth, the news station new exactly what the significance of their film footage was: thus, they were the one news station that was able to show the dramatic and elusive footage of what had in fact caused the crash.

Recommendations for Delta Flight 191

One of the most basic things that this flight crew could have engaged in is the simplest and most tried and true aspects of what to do in severe weather: practice extreme and absolute avoidance. That day thunderstorms were in the area of approach of the runway and a thunderstorm shaft was in the direct path of approach. The crew should have practiced immediate and absolute avoidance: proceeding forward through this weather was the biggest mistake that they made.

However, because there was so much evidence post-crash, professionals in the field of aviation were able to learn tremendous amounts about how the crash could have been avoided and impose clearer changes and recommendations regarding safer and more effective procedures.

Better wind detection would have been an ideal solution for Delta Flight 191 and all subsequent flights of that decade. Today, American aviation still admits to its powerlessness over the weather, but what it has been able to adapt to is the fact that it can better predict the weather through precision forecasting instruments. Precision forecasting instruments would have been ideal in preventing this particular accident. This type of instrumentation can view the churnings that can lead to wind shear and microbursts via sophisticated systems that alert crew members to hazardous winds and comparable areas of danger. While Dallas Fort Worth airport now has the greatest and latest instruments today regarding weather forecasting and the detection of wind shears with 18 wind shear detection towers and two large Doppler radar arrays (Torbenson, 2010). The subsequent batch of air traffic control technology involves a range of projects which are driven to give even more intensively dimension forecasting so that airlines, air traffic controllers and pilots are able to engage in better decision making when it comes to inclement weather (Torbenson, 2010). The technology which is developing now is simply just vastly superior to the technology that was available in the mid-1980s when this crash occurred.

Technology today needs to better focus on time, through a network which updates faster and which is more accurately able to provide guidance for problems. The technology of the mid-1980s just wasn't able to allow pilots the ability to navigate through lines of storms; operations back then were simply less safe, which meant that more caution needed to be employed.

USAir Flight 1016 Causes

USAir Flight was a crash that was absolutely avoidable, like so many others. The media generally views this crash as the result of a series of errors which could have been prevented. However, this does not offer a comprehensive view of the realities of the crash. The blunders of this crash were of a specific variety: communication. Essentially, U.S. Air 1016 is a flight which crashed as a result of the fact that communication broke down when it was needed most and that the pilots were not provided with essential information that they absolutely needed to know. "The National Transportation Safety Board concluded today that USAir Flight 1016 crashed in Charlotte, N.C., last July 2 because air traffic controllers failed to pass along crucial weather information, the crew failed to recognize signs of wind shear and at the crucial moment the captain, apparently disoriented, told his first officer to push the nose of the plane down when the aircraft should have been climbing" (Wald, 1995). An unnecessary and completely preventable breakdown in communication is something which was the sole and utter cause of the crash.

Once the aviation safety board examined the wealth of evidence for why the crash occurred, it became all to shocking just how much weather information was available on the ground and in the air-traffic control tower, but which was not disseminated to the cockpit for unknown reasons. One example of this was that a departing plane had radioed the tower that there was a storm directly over the airport; a ramp in the USAir arena had been evacuated because of lightning and there was severe weather which showed up on the radar of air traffic control in the tower (Wald, 1995). The truly scathing fact is that none of these issues were ever communicated to flight USAir 1016 (Wald, 1995).

Upon examination of the plane's black box, it becomes apparent that the pilots simply do not hear a wind shear warning for all parts of the airport: however, this is not their fault. The warning was not blast over their radio frequency (Powell, 1994). Looking at the radar data retrospectively, it becomes apparent that the crew is flying directly into a sudden and aggressive thunderstorm that they only become aware of once they're in it. At: 27 seconds into the blackbox recording, a wall of water knocks against the plane, "the pilots decide to abort the landing, because they can no longer see the runway. They steer the plane to the right, despite instructions from the tower to fly straight and climb to 3,000 feet. 4): 15 The plane climbs as the pilots pull the plane's nose up and push the throttles to full power -- a standard procedure" (Powell, 1994).