I recently had the privilege of speaking in Manchester, England, at the National Safer Roads Partnerships Conference. The United Kingdom has some of the lowest road-user fatality rates in the world. While our annual vehicle miles traveled vary greatly, on a typical day, about 109 road users are killed on America’s roadways, while only 5 Britons lose their lives the same way. But, as I reminded the conference audience, even one fatality is still too many.
This was a unique opportunity to represent the NTSB because the audience was mainly British law enforcement officers, and the British tradition of “policing by consent” was tailor‑made for a prevention-focused discussion. Policing by consent means that, because most people want law and order, the goal should be to prevent crime rather than focus on punishing perpetrators. Our Safety Advocacy Division operates with much the same philosophy, working to prevent transportation accidents by encouraging stakeholders to implement the agency’s recommendations. We also explain road safety to vulnerable populations, such as young drivers, to bring lifesaving information to the traveling public, and we share our findings with colleagues.
We know that, as we face coming challenges in road safety, prevention opportunities abound. Our recent speeding study noted the value of a “safe system” approach, which depends on layers of safety in a given road environment and recognizes preventive uses of technology, such as automated speed enforcement. Our recent investigation into the fatal crash of a partially automated vehicle allowed us to consider the double-edged sword of automation. Our investigations have shown that, as vehicles rely more and more on automated sensors, they also collect more data, which should be gathered in a standard format and reported when vehicles with enabled control systems crash.
The world is changing, crash factors are changing, and our tools are changing. The data that cars themselves can provide about crashes is expanding. As I told the law enforcement officers in Manchester, the NTSB has learned that everything an accident can tell us is worth our attention. We are conscious that every safety lesson learned is worth retelling, both to spur acceptance of our recommendations and to prepare ourselves, our colleagues, and the public for the challenges of a fast-approaching future. By sharing lessons learned across borders, we improve our chances at reaching zero transportation fatalities worldwide.
Nicholas Worrell is Chief of the NTSB Safety Advocacy Division.
This week marked the 54th anniversary of the deadliest highway crash in US history. On September 17, 1963, a makeshift bus carrying 58 migrant farmworkers collided with a freight train near the city of Chualar, California (See Figure 1), killing 32 people and injuring 25. The workers on the bus were returning to a labor camp after a 10‑hour shift harvesting celery at farms in the Salinas Valley. The passengers were riding on two long board benches that ran the length of a canopy-covered flatbed truck.
Another deadly migrant farmworker crash occurred in the 1970s. On January 15, 1974, we investigated a crash involving 46 migrant farmworkers near Blythe, California. A farm labor bus traveling on a rural road failed to negotiate a curve in the roadway and vaulted into the bottom of a drainage ditch. The bus came to rest on its left side, partially submerged. Nineteen of the bus occupants, including the driver, died.
The last half century has seen many improvements in transportation safety, yet catastrophic crashes still occur, and the safe transportation of migrant farmworkers remains an issue. During the 8-month period from November 2015 through July 2016, we responded to three multifatality crashes in which 16 people were killed and 57 others were injured. Most of those killed and injured were migrant farmworkers being transported to and from farming locations. We investigate these crashes to learn from them and answer the important question: What can be done to improve transportation safety for migrant farmworkers?
Today, we released more than 1,100 pages of documents related to our ongoing investigation into the July 2, 2016, crash near St. Marks, Florida, involving a farm labor bus and a truck-tractor semitrailer combination vehicle. The bus, which was transporting more than 30 farmworkers from a farm in Georgia to Belle Glade, Florida, failed to stop at the intersection of State Road 363 and US Highway 98—which was marked by a stop sign and flashing red “stop” signal—and was struck by the truck-tractor vehicle. A postcrash fire ensued, and the truck driver and three bus passengers died (See Figure 2).
On November 28, 2017, we will hold a public Board Meeting to discuss the findings of the St. Marks crash investigation, its probable cause, and safety recommendations aimed at preventing future crashes. We will also review the circumstances of crashes in Little Rock, Arkansas, and Ruther Glen, Virginia (see Figure 2).
The Little Rock crash occurred on November 6, 2015, when a motorcoach transporting 20 farmworkers from Michigan to Texas departed Interstate 40 and collided with a concrete barrier. The collision resulted in the bus climbing up the side of the barrier, its roof impacting a bridge column that supported a freeway overpass. As a result of the crash, six bus passengers were killed.
The Ruther Glen crash occurred on June 18, 2016, when a 15-passenger van transporting 16 occupants, most of whom were migrant farmworkers, departed Interstate 95. The van swerved right across all lanes of travel and impacted another passenger car before overturning multiple times. Six of the van passengers were ejected and died.
By looking at factors such as federal and state oversight of motor carriers engaged in agricultural worker transportation, enforcement of safety regulations, outreach and education in the agricultural community, and individual states’ best practices, we hope to develop safety recommendations that will improve the transportation safety of migrant agricultural workers and prevent future tragedies.
Attend the November 28 meeting in person or watch via webcast as we attempt to determine, based on our findings from the St. Marks accident and similar crashes, what can be done to improve transportation safety for migrant farmworkers.
Jennifer Morrison is an Investigator-in-Charge in the NTSB Office of Highway Safety.
This is the fourth blog in a new series of posts about the NTSB’s general aviation investigative process. This series, written by NTSB staff, explores how medical, mechanical, and general safety issues are examined in our investigations.
As a National Resource Specialist for Aircraft Performance, which is government-speak for a technical expert in the aerodynamics and flight mechanics of aircraft, I work to determine and analyze the motion of aircraft and the physical forces that produce that motion. In particular, following an accident or incident, I attempt to define an aircraft’s position and orientation during the relevant portion of the flight, and determine its response to control inputs, external disturbances, ground forces, and other factors that could affect its trajectory.
I recently reviewed a 2009 cockpit video taken while I was testing a video recording device in a Bellanca Citabria. The footage called to mind recent NTSB cases that highlight the fallacies inherent in one of aviation’s oldest mantras—“see and avoid.”
The video from the camera mounted over my left shoulder reveals a hazy blue sky above and the Potomac River winding lazily below the Citabria’s plexiglass windows. It shows my head dutifully swiveling as I scan the practice area for traffic in preparation for a series of aerobatic maneuvers intended to test a prototype “portable flight data recorder” developed by a friend of mine. I’m flying in the Washington, DC, Special Flight Rules Area so I’m in contact with Potomac Approach, which helpfully keeps a radar’s eye on me and nearby traffic and conveys what I fail to see.
Images captured on the cockpit video during the testing of a video recording device in a Bellanca Citabria.
“Citabria 758, traffic about a mile southwest of your position. A Cherokee is in the practice area, altitude indicates . . . I’m not showing an altitude right now.”
On the video, my head moves around a little more as I respond, “758 looking, thank you.”
The controller then alerts the Cherokee. “Cherokee [call sign], traffic seems to be about 1-mile orbiting, altitude indicates 3,600, a Citabria.”
I’m still looking with no success when Potomac advises that the Cherokee is at 2,200 ft. The controller lets me and the Cherokee pilot know that we are getting close to each other.
“Cherokee [callsign], traffic just southeast of you, about less than 1 mile, Citabria in the practice area, altitude indicates 3,700.”
“Roger, we’ll keep our eyes open for that Citabria in the practice area.”
“Citabria 758, that traffic is just northwest of you, less than a mile now, and his altitude still indicates 2,300, appears to be eastbound.”
“758 still looking, thank you.”
The video now shows me craning my neck left and right, leaning forward, scanning the entire symmetrical view offered by an airplane with its seats on the centerline. The airplane banks left and right in gentle turns as I maneuver, trying in vain to spot the Cherokee. A little over 3 minutes after Potomac’s initial advisory, I give up.
“Potomac, Citabria 758 still looking for that traffic . . . is he still a factor?”
“758, now he’s about 5 miles north of you, no factor.”
I don’t know if the Cherokee pilot ever saw me, but if he did, he didn’t announce it. I imagine that most general aviation pilots don’t need to accumulate too many hours before they have an experience much like mine, or its more unnerving inverse: suddenly seeing an airplane that you had no clue about whiz by close enough to read the N-number. Both situations point to the inherent limitations of the “see-and-avoid” concept: the foundation of collision avoidance in visual meteorological conditions (VMC) under visual flight rules (VFR).
My flight was a personal one, unrelated to my duties as an aircraft performance engineer at the NTSB. However, my fruitless search for the Cherokee was consistent with conclusions the NTSB has drawn from investigating a number of midair collisions, and which call to mind what can happen when traffic remains unnoticed.
As detailed in the NTSB reports concerning two midair collisions that occurred in 2015, described further below, the see-and-avoid concept relies on a pilot to look through the cockpit windows, identify other aircraft, decide if any aircraft are collision threats, and, if necessary, take the appropriate action to avert a collision. There are inherent limitations of this concept, including limitations of the human visual and information processing systems, pilot tasks that compete with the requirement to scan for traffic, the limited field of view from the cockpit, and environmental factors that could diminish the visibility of other aircraft.
In a collision between an F-16 and a Cessna 150 near Moncks Corner, South Carolina, in July 2015, the F-16 pilot was unable to spot the C150, even though the Charleston Approach controller had alerted him to the presence of the airplane. The F-16, call sign “Death41,” was flying under instrument flight rules and communicating with air traffic control (ATC); the C150 was flying under VFR and not communicating with ATC.
“Death41, traffic 12 o’clock 2 miles opposite direction 1200 indicated type unknown.”
“41 turn left heading 180 if you don’t have that traffic in sight.”
“Confirm 2 miles?”
“Death41, if you don’t have that traffic in sight turn left heading 180 immediately.”
Even before the controller finished her last instruction, the F-16 had begun a standard-rate turn to the left. The F-16 was heavy and, at 240 knots, moving relatively slowly—for a fighter jet. Contrary to what one might think, it could not turn much faster in those conditions. Twenty-three seconds after the controller’s last instruction, the F-16 and the C150 collided at about 1,470 ft above the Cooper River. The crippled F-16 flew for another 2.5 minutes before the pilot ejected safely, and the jet subsequently crashed. The C150 crashed almost directly beneath the collision site, and both the pilot and his passenger died.
We determined the probable cause of this accident was the approach controller’s failure to provide an appropriate resolution to the conflict between the F-16 and the Cessna. Contributing to the accident were the inherent limitations of the see-and-avoid concept, resulting in both pilots’ inability to take evasive action in time to avert the collision.
Midair collisions can happen even when both aircraft are in communication with ATC. A month after the Moncks Corner midair collision, a North American Rockwell Sabreliner collided with a Cessna 172 in the busy traffic pattern at Brown Field in San Diego. Both aircraft were under Brown Tower’s control and on a right downwind for runway 26R, with the Sabreliner outside of and overtaking the C172. The tower controller intended to instruct the C172 to perform a right, 360-degree turn to position him behind the Sabreliner; however, he mistakenly instructed a different C172 to perform the maneuver, and immediately after instructed the Sabreliner to turn right base.
The Sabreliner and C172 subsequently collided, and all five people on the two aircraft died. The cockpit voice recorder on the Sabreliner indicated that both Sabreliner pilots were aware of and concerned about the busy traffic pattern, pointing out other aircraft to each other. One of the nonflying crew in the back of the plane is even heard asking, “see him right there?” presumably referring to traffic. Yet the collision still occurred.
We determined the probable cause of the accident was the local controller’s failure to properly identify the aircraft in the pattern and to ensure control instructions provided to the intended Cessna on downwind were being performed before turning [the Sabreliner] into its path for landing. Contributing to the accident were the inherent limitations of the see-and-avoid concept, resulting in the inability of the pilots involved to take evasive action in time to avert the collision.
My role in the investigations of the Moncks Corner and San Diego collisions was to reconstruct the motion of the airplanes based on radar data and other information, and to evaluate the resulting visibility of each aircraft from the cockpit of the other. In addition, it was my job to evaluate how new collision avoidance technology—such as cockpit displays that provide a radar‑like view of surrounding traffic based on automatic dependent surveillance-broadcast (ADS-B) information—could have averted each accident.
One objective of these visibility studies was to determine whether either of the airplanes involved in the collision were obstructed from the other pilot’s field of view by cockpit structures, or whether the pilots had an unobstructed view of each other but simply failed to see one another (because seeing other traffic from the cockpit is hard!). To find out, we measured the geometries of the window and other structures of exemplar airplanes with laser-scanning equipment, and the resulting measurements were used to determine where the windows were in each pilot’s field of view and whether the other airplane appeared within the windows or not. The results were most intuitively presented by creating computer animations of the collision from the point of view of each pilot using flight simulation software (Microsoft Flight Simulator X) to create the outside scenery and airplane models.
Readers can watch the animations we created for the Moncks Corner and San Diego collisions on our YouTube channel and judge the visibility results for themselves. The performance studies for these accidents provide technical details about the reconstructions, and they note that periods when airplanes are obscured from a pilot’s nominal field of view “underscore the importance of moving one’s head (and occasionally lifting and dipping the wings) so as to see around structural obstacles when searching for traffic.”
Readers can also watch animations of cockpit display of traffic information (CDTI) displays for each of the airplanes involved in these midair collisions. The animations depict the information that these radar-like displays, fed by ADS-B, could have presented to the pilots involved. Had the airplanes been equipped with CDTI, the pilots could have been made aware of the presence and relative locations of the conflicting traffic minutes before the collisions.
In general, the timely and information-rich traffic picture offered by a CDTI can greatly improve a pilot’s ability to detect traffic threats and avoid a collision without aggressive maneuvering. We issued a safety alert, titled, “Prevent Midair Collisions: Don’t Depend on Vision Alone,” to encourage pilots to learn about the benefits of flying an aircraft equipped with technologies that aid in collision avoidance.
Much of flying is an exercise in mitigating or engineering out risk. Pilots are trained, examined, and reviewed; aircraft are certified and maintained; checklists are used; flights are planned; weather is studied. Great effort is made to leave little to chance. However, when it comes to collision avoidance in VMC, we wink at risk management (“see-and-avoid!” “Keep your head on a swivel!”), when the reality is that we rely in great measure on luck. It’s a big sky, and it would be hard to hit somebody if you tried. The odds are against a collision, but on occasion, disaster strikes.
Technologies such as CDTI provide rational risk reduction for the VMC collision avoidance problem. Guardian angels will never lack for work, but tools such as CDTI can help us to make their jobs a little easier.
This is the second blog in a new series of posts about the NTSB’s general aviation investigative process. This series, written by NTSB staff, explores how medical, mechanical, and general safety issues are examined in our investigations.
The NTSB investigates every aviation accident in the United States. In each investigation, we look at the roles of the human, the machine, and the environment. By learning about the factors that cause an accident, we can make recommendations to prevent similar accidents in the future.
I am one of two medical officers (physicians) at the NTSB who work closely with investigators in all modal offices. When an investigator-in-charge (IIC) is concerned that operator medical issues, drugs, or toxins may have affected performance, he or she coordinates with us to study the medical aspects of the event. The medical officers review medical documents, toxicological testing results, and sometimes autopsy reports of those involved in accidents. In conjunction with the investigative team, we help determine if operator impairment or incapacitation contributed to the cause of the accident, then we help craft language to explain to the public the nature and significance of the medical issues and how they affected the operator and contributed to the accident’s cause. We also work closely with the Board’s biodynamics and survival factors experts to help evaluate accident-caused injuries and determine what changes could be made to prevent future injuries.
The resulting information is presented in a medical factual report, which documents all pertinent medical issues and any potential hazards that the medical issues posed. To ensure accuracy, these fact-based scientific reports are peer reviewed by the investigative staff before they are published as part of the public docket. The medical, factual, and operational details of each event are then analyzed by the investigatory team, which determines probable cause by consensus, peer review concurrence, and Board authority. The probable cause represents the most likely explanation for the event given all available evidence.
Two recent cases have garnered some attention in the general aviation (GA) community, both involving fully functional airplanes operating in manageable weather. In these cases, both pilot action (error or impairment) and pilot inaction (incapacitation) can lead to an accident. In these cases, we found that the pilots were operating in a relatively low-workload environment and had the skill and experience necessary to safely complete the flights. On the other hand, medical data showed that both pilots had severe heart issues that could cause sudden incapacitation without leaving a trace.
The first accident occurred on April 11, 2015, when an experimental Quad City Challenger II airplane crashed into terrain near Chippewa Falls, Wisconsin. The 77-year-old pilot died and the airplane was substantially damaged. The pilot had the skill and experience to operate the airplane in visual conditions. According to witnesses, while the airplane was on the downwind leg of the traffic pattern at the pilot’s home airport, it entered a steep dive that continued until it struck the ground in an open field. Investigators found no evidence of preexisting mechanical concerns and, based on the propeller damage, determined that the engine was producing power at impact. Operational evidence also strongly supported pilot incapacitation.
The pilot had a history of coronary artery disease, which was treated by multivessel bypass surgery. He also had high blood pressure, elevated cholesterol, and hypothyroidism, which were controlled with medications. The autopsy showed that the pilot had an enlarged heart; severe multivessel coronary artery disease (greater than 80-percent occlusion of all vessels), with coronary artery bypass grafts and complete occlusion of two bypass vessels; scarring of the ventricular septum, indicating he had had a previous heart attack; and active inflammation of the anterolateral wall of the left ventricle of his heart. These findings, particularly the large scar and active inflammation of the heart muscle, placed the pilot at high risk for an irregular heart rhythm, which can easily cause decreased blood to the brain and result in fainting without leaving further evidence at autopsy.
Additionally, according to the Chippewa County Coroner Death Report, the cause of death was blunt force trauma. However, the examining pathologist further stated, “the most likely scenario to explain [the pilot’s] death is that he suffered an arrhythmia secondary to myocarditis.” These findings are discussed in detail in the medical factual report. Based on the available evidence, we determined the probable cause of the accident to be the pilot’s incapacitation due to a cardiovascular event, which resulted in a loss of control and subsequent impact with terrain.
The second accident of note was the crash into terrain of a homebuilt Europa XL airplane on June 26, 2015. As in the previous case, the pilot died and the airplane was substantially damaged. In this accident, the 72-year-old pilot also had the skill and experience needed to successfully complete the flight, especially given that it was a clear day and he was operating under visual flight rules.
The airplane crashed under power in a steep, nose-down, slightly inverted attitude in an open field about a half mile from the end of the runway, slightly to the right of an extended centerline. According to the IIC, there was no evidence of preexisting mechanical concerns, the engine was operating at impact, and the operational evidence suggested pilot incapacitation.
The pilot had a history of severe coronary artery disease, which was treated with multivessel bypass surgery, stents, and medication. Additionally, he had elevated cholesterol and high blood pressure, which were treated with medications. Since his last medical certification examination, an exercise stress test showed no significant changes, but a cardiac catheterization report documented that his coronary artery disease had progressed, resulting in 90‑percent occlusion of the left anterior descending coronary artery and impaired blood flow to a part of the heart muscle. Additionally, the autopsy identified multivessel coronary artery disease treated with patent coronary artery bypass grafts, and documented up to 70-percent occlusion of the left anterior descending coronary artery.
These findings are discussed in detail in the medical factual report. The pilot’s severe progressive coronary artery disease and the impaired blood flow to an area of his heart muscle placed the pilot at high risk for an acute cardiovascular event such as a heart attack, anginal attack, or acute arrhythmia. Any such event would likely cause a sudden onset of symptoms such as chest pain, severe shortness of breath, palpitations, or fainting, and would leave no evidence visible on autopsy if death occurred in the first few minutes.
The Mahoning County Coroner Autopsy Report cited multiple blunt force injuries as the cause of death, with coronary artery disease and chronic hypertension contributing to the cause of death. Again, although the pilot died of blunt force injuries, the evidence supports our finding that the accident sequence was likely initiated by his incapacitation due to a cardiovascular event.
These cases illustrate how we integrate medical findings into our investigations. We also provide interested parties with links to publicly available, detailed information that supports our findings. In both of the cases described here, the medical factual reports document significant medical issues in pilots who were operating under sport pilot rules; however, we only determined the medically related probable causes after thorough, scientific, peer-reviewed analysis of all the available facts concerning the human, the machine, and the environment.
Our goal is to identify medically related hazards that may be causal to or resultant from the accidents we investigate, and then work with the experts on the investigative team to develop mitigation strategies, which take the form of safety recommendations, that target and eliminate these hazards and improve transportation safety.
This is the first in a new series of posts about the NTSB’s general aviation investigative process. This series, written by NTSB staff, will explore how medical, mechanical, and general safety issues are examined in our investigations. I hope you take time to read these posts and, in doing so, come away with a greater understanding of the NTSB, our processes, and our people.
It has been my ongoing honor and privilege to serve as a Member of the NTSB over the past seven years, and I’ve been impressed by the diverse professionals who make up the NTSB staff. They work in different modes—rail, highway, pipeline, marine, and aviation—and specialize in engineering, human factors, medicine, safety outreach, and recorders, to name a few, but they all share a common goal: to protect the traveling public through recommendations aimed at improving transportation safety.
The NTSB is made up of approximately 430 dedicated employees who have a wide range of educational backgrounds and relevant experience. Our ranks include MDs, JDs, and Ph.Ds. Among our investigators, we count former members of law enforcement, industry professionals, and technical experts. When we investigate an accident, a multidisciplinary team is selected to fit the needs of the investigation.
I’m often asked how the NTSB—particularly our crash investigation process—works. The NTSB is required by law to investigate every aviation incident in the United States, and our aviation safety staff investigate more than 1,200 aviation events each year. Our investigative process looks at three factors—human, machine, and environment—to determine the probable cause of accidents and incidents. This process has evolved during our 50 years, leveraging the skills, talents, and professionalism of our people, who use the latest investigative techniques and tools to find facts, analyze those facts, and determine why and how an accident happened.
Investigators consider what may have caused or contributed to the events of every accident. They look for issues in areas such as mechanical failures, operations, and weather conditions. They doggedly work to recover all onboard recorders and other sources of data, even when those recorders may be severely damaged. They also consider pilot performance, collecting evidence regarding possible fatigue, medical fitness, prior training opportunities, and specific aircraft experience.
Evidence is gathered through cooperation with pilots, witnesses, law enforcement officials, the FAA, airport officials, industry, and other stakeholders; in extreme cases, our staff can also issue subpoenas to obtain needed evidence. Investigations cannot and do not try to answer every question of why and how, but focus on questions of what caused the accident, or made it worse. Probable cause is the factor—or factors—that, based on all available evidence, the Board concludes most likely resulted in the accident. It generally takes around a year to produce a final report, which includes a probable cause and contributing factors.
Based on our investigations and special studies, we issue safety recommendations to regulatory agencies, industry, and other parties to an investigation who are positioned to implement our suggestions and improve transportation safety. The NTSB isn’t a regulatory agency, so we cannot compel compliance with our recommendations; however, of the more than 14,500 safety recommendations issued in our 50-year history, more than 80 percent are acted upon favorably. This is testimony to the NTSB’s diligence, investigative acumen, and commitment to transportation safety.
Looking back over the years and contemplating the NTSB’s contributions, I am proud to see that transportation safety has, in fact, improved greatly—especially in commercial aviation. We have seen significant improvements in aircraft crashworthiness; the introduction of life-saving technologies, such as collision avoidance and ground proximity warning systems; implementation of safety policies and regulations aimed at preventing pilot impairment, distraction, and fatigue; and emphasis on safety management systems and enhanced flight crew procedures. NTSB investigations identified the need for these advancements and helped incentivize remarkable safety improvements. Modern commercial aviation is safer now than ever before.
I often quote author Douglas Adams, who tells us that people are almost unique in their ability to learn from others, but remarkable for their resistance to doing just that. You may have heard the old saying, “knowledge is power.” We believe “knowledge is safety.” I hope you take a moment to learn about the NTSB’s investigative process in the next several blog posts, and that you come away with a greater understanding of how we at the NTSB strive to turn our knowledge into safer transportation.
One night, a couple feet underground outside an American home, the gas flowing in a service line began to escape through a puncture adjacent to a newly installed mailbox. A man and woman inside the home were watching the news. Their children were playing. Then, suddenly, without warning . . . nothing happened.
A simple and inexpensive device called an excess flow valve (EFV) kicked in, stopping the gas flow. There was no explosion, no fire, no injury or loss of life.
As a petroleum engineer and pipeline specialist for the NTSB, I know that the most important pipeline safety advance in recent decades has been the establishment of the national one-call 811 number. But EFVs may be the next most important life-saver, especially for homeowners.
Gas companies install an EFV in a service pipeline where it meets the main line. The EFV shuts off the gas flow in the service line when it exceeds the normal flow rate; excess flow often indicates that gas is escaping the service line through a puncture or sever, potentially leading to an explosion or fire.
I’ve been working a long time to encourage the progress that came to fruition late last year regarding EFVs. The Pipeline and Hazardous Materials Safety Administration (PHMSA) quietly completed an important achievement and, in the process, closed an NTSB recommendation. PHMSA issued a rule expanding the use of EFVs to new or renewed service lines leading to almost all small commercial businesses and multi-residence buildings.
It’s taken decades to achieve this result. In all, the NTSB has made 24 safety recommendations related to EFVs.
When I came to the NTSB in 1990, the agency had already been endorsing EFVs for 20 years, beginning with recommending a shutoff valve after research that came out of a 1970 safety study.
I worked on accident after accident that may have been prevented by EFVs. Most of my work between 1990 and 1994 involved single-family residences, but many multi-residence accidents were just as horrible, if not worse. The incidents occurred in large cities like Tulsa, Oklahoma, and St. Paul, Minnesota, and in smaller towns like St. Cloud, Minnesota; Montezuma, Indiana; and Cliffwood Beach, New Jersey. I can still remember my first NTSB supervisor expressing exasperation that this simple and elegant solution was not in wider use.
Then came June 9, 1994. At about 6:45 that evening, a 2-inch-diameter steel gas service line that had been exposed during excavation separated at a compression coupling about 5 feet from the north wall of John T. Gross Towers, an 8-story retirement home. The escaping gas flowed underground toward Gross Towers, passed through openings in the building foundation, entered the mechanical room through the floor vents, and migrated to other floors.
A resident smelled the gas, as did a workman onsite, who told his foreman. The foreman called the gas company and the housing authority, then had other employees locate and shut off the gas line valve inside the towers. But at 6:58 p.m., the built-up natural gas in the building ignited and exploded; a second explosion followed 5 minutes later. The accident killed one person and injured 66—and it could have been much worse. Many residents were not in the building on the early summer evening of the disaster.
A humble EFV could have shut off the gas flow into Gross Towers. After the explosion, the NTSB recommended that PHMSA’s predecessor agency require that all gas distribution operators inform all customers of the availability of EFVs. After many years, the agency did so. Meanwhile, fatal accidents continued—all potentially preventable with EFVs.
A man, woman, and their two children were spending their first night together in their new home. The family retired at about 10:30—the children to the upper level of the house, and, because not all of their furniture had arrived, the parents to the first-floor study. Shortly after midnight, the house exploded and was engulfed in flames. The children were thrown out of the house and onto the lawn, suffering minor injuries. The parents fell into the basement as the first floor collapsed. The father was able to crawl to safety, badly burned; the mother did not escape and died as a result of her injuries.
Again, an EFV could have prevented the tragedy.
Following this accident, the NTSB recommended that PHMSA require EFVs in all new and renewed gas service lines, regardless of customer classification, when operating conditions were compatible with readily available valves. PHMSA first required only that single-family homeowners be notified of the availability of the valve and be allowed to pay for it themselves. Then, in 2009, PHMSA changed the rule, requiring EFVs to be installed on almost all new and renewed service pipelines to single family homes. Finally, on October 14, 2016, PHMSA expanded the safety requirement to include most new and renewed service pipelines for multi-residential and commercial applications, closing one chapter in EFV history—and with it, an outstanding NTSB recommendation.
My first NTSB supervisor is no longer with us, but even years ago, he could imagine the broad use of EFVs that he did not live to see. Sometimes it takes a long time to normalize safety. Too often, it takes a highly visible accident—or several of them—to draw attention to a problem. Solutions often come a little bit at a time, or a long time afterward, without any fanfare.
But for now, and well into the future, for many businesses and homes nationwide, if a service line fails, nothing will happen. These homes and businesses are a little safer today because PHMSA and the gas industry acted on NTSB’s EFV recommendations.
Charles Koval is a Petroleum Engineer and Pipeline Specialist in the NTSB Office of Railroad, Pipeline and Hazardous Materials.
 The service line does not need an EFV if it: 1. does not operate at or above 10 psig all year, 2. has previously had contaminates, 3. could interfere with necessary operation or maintenance activities, or 4. is not commercially available to the operator.
Twenty five years ago, a crash occurred in Alton, Texas, that changed school bus safety forever. At 7:34 a.m., on September 21, 1989, a school bus carrying 81 students to school collided with a truck operated by the Valley Coca-Cola Bottling Company. After the collision, the school bus continued traveling and dropped into an excavation pit partially filled with water; the bus was totally submerged in approximately 10 feet of water approximately 35 feet from the nearest shoreline. Twenty-one students died. The NTSB investigated this tragedy to examine what occurred and made recommendations to improve school bus safety.
This tragedy allowed the NTSB to shed light on serious school bus safety flaws. In Alton, the children needed to escape through the windows, as the standard exits were either overcrowded or not working. But even with passengers shifting to windows, which were not designed as emergency exits, the exit options were insufficient. Moreover, the children were unprepared for how to react during an emergency. And during the evacuation, children and rescuers struggled to keep exits open. The NTSB issued several recommendations designed to address these gaps, including evaluating the feasibility of making the windows larger, establishing a requirement that floor emergency exits are designed to remain open during emergencies, and developing a comprehensive school bus evacuation-resource guide. Amendments to applicable federal regulations, issued in November 1992, addressed school bus emergency exits and a comprehensive guide was developed by early 1994.
Twenty-five years later, school buses are the safest mode of transportation for getting children back and forth to school. Every day, nearly 500,000 yellow school buses transport about 26 million school children nationwide safely. This week, school districts around the county will observe School Bus Safety Week. A week dedicated to engaging parents, students, teachers, motorists and school bus operators, and many others to address the importance of school bus safety.
As we reflect on the Alton crash twenty-five years later and the 21 young lives lost, we recognize that because of that loss and the changes that were made to buses lives have been saved.