Category Archives: Inside NTSB

Recognizing Important Women Leaders at NTSB—From Yesterday and Today

By Chairman Robert Sumwalt

March is Women’s History Month, so it’s only appropriate to look at some of the American women who have helped influence and shape today’s transportation system, including those working at the NTSB today.

We have witnessed the extraordinary accomplishments of women like Bessica Raiche, the first female pilot in the United States to make a planned flight, and our very own Member Bella Dinh-Zarr, the first Asian American to become a Board Member at the NTSB. Member Dinh-Zarr has spent years advocating for and promoting safe and sustainable transportation. These women have reached great heights in their careers and are renowned nationwide for their successes.

Shannon Bennett (left), Sharon Bryson and Dana Schulze

Yet, there are many more women—perhaps not as nationally known but just as important to the NTSB’s critical mission—that we would like to recognize. In celebration of Women’s History Month, we recently sat down with some of the exceptional women who have emerged from the NTSB’s ranks to become leaders in management and safety. They inspire staff every day to work hard to improve transportation safety, sharing NTSB safety messages and encouraging us all to remember our mission to save lives. They are role models for many at the agency—men and women. We asked them to share their thoughts on leadership with staff last week at a special briefing, and we think their lessons are beneficial to all, even those outside our organization. Here’s what they had to say.

Dana Schulze is the deputy director of the NTSB’s Aviation Safety (AS) Office. As second-in-command of AS, she oversees all aviation accident and incident investigations in the United States and those involving US products or operations overseas. More than 50 air safety investigators and supporting staff within AS report directly to her. She approves information AS releases and routinely briefs Congressional staff and industry stakeholders on behalf of our agency. She began her career in the aircraft manufacturing industry as a mechanical engineer and has experience developing, manufacturing, and conducting failure investigations involving aircraft systems. From there, she rose through the NTSB ranks to her current position. She attributes her success to a continuous learning approach and her interest in improving aviation safety. Because of her critical-thinking skills and ability to lead others, she quickly rose to a leadership position at the agency.

According to Schulze, she did not initially set out to join management, but when the opportunity was offered, she recognized that she could add value and be a good fit. She believes a leader should be able to inspire and motivate others. Through integrity, consistency, and transparency, a leader “can instill a balance of vision and practicality,” she says. She says she has been inspired by thought leaders such as Steven Covey. Transportation has long been a male-dominated industry, and Schulze encourages women to get involved with transportation-related STEM programs that interest them, even those outside their comfort zones.

Sharon Bryson is the NTSB’s deputy managing director. She joined the agency more than 20 years ago after a career providing services to military families at Dover Air Force Base. When she arrived at the NTSB, the agency had just been given the responsibility for family assistance by Congress. Bryson took a lead role in setting up the NTSB’s first family assistance program. This program, now called Transportation Disaster Assistance, is still in place today and has served thousands of families over the years. Later, after serving as director of the Office of Safety Recommendations and Communications, Bryson became the agency’s deputy managing director, a position that involves assisting the Managing Director with managing the day-to-day activities of the agency.

According to Bryson, having the opportunity to mentor others and share what she has learned about leadership is very important to her.  She strives daily to engage with staff members and actively highlights their individual abilities, with the goal of seeing them thrive. “A leader is supposed to support and guide,” she says. By recognizing the strengths and weaknesses of the people around her, she puts value in their diverse opinions; there is no room for judgement or negativity. “When all of these are combined, it creates an environment where people feel engaged and encouraged,” she says.

Shannon Bennett came to the NTSB’s Office of General Counsel in June 2010 before becoming an advisory and special assistant to Board Member Dinh-Zarr in June 2015. She comes from a long military history, having enlisted in 1993 as an Air Force ROTC cadet during college, then serving 11 years on active duty as a judge advocate. She continued to serve in the Air Force Reserve and was assigned as a judge advocate in the Office of The Judge Advocate General at the Pentagon. According to Bennett, when she separated from active duty in 2010, she wanted to find a job where, as in the Air Force, she felt that she was serving her country and making a difference in people’s lives. That’s how she wound up at NTSB.

Leadership is “the art of influencing and directing people to accomplish the mission,” Bennett says, quoting the Air Force Pamphlet on Leadership she received as an ROTC cadet. She tries to live by the adage “saw the log in front of you,” meaning, do your very best in every job that’s given to you no matter how big or small, rather than seek the glory of a job you don’t have. Mentoring is also very important to her, and she encourages all leaders to guide others.

As we celebrate Women’s History Month, let’s all take the time to look around us and celebrate the unique and powerful women in our own lives. We are so grateful to have Dana, Sharon, and Shannon as members of our “Women Dream Team,” as well as all the other female employees at the agency who work daily to improve transportation safety and inspire those around them.

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Most Wanted List Progress Report: Highway Safety

By Member T. Bella Dinh-Zarr, PhD, MPH, and Robert Molloy, PhD

The NTSB is releasing a series of blogs highlighting the progress the transportation community is making in each mode to advance issues on our 2017–2018 Most Wanted List. This series sheds light on the progress made and what needs to be done going forward to improve transportation safety. This is the second post of the series. 


Member Dinh-Zarr talks with attendees during the highway session of the Most Wanted List midpoint meeting

We’re now midway through the 2017–2018 Most Wanted List cycle, and we’re eager to learn how this year will measure up to previous years. The past 2 years have resulted in an increase in highway traffic fatalities­­—from 32,000 roadway deaths per year in 2014 to more than 37,000 in 2016­­—so clearly, improvements are vital. We checked in with stakeholders on the progress they’re making to address the most pressing issues, and they’ve updated us on their successes and struggles. Here’s where we stand.

Install Collision Avoidance Technologies

Collision avoidance technologies can reduce the number of deaths and injuries on the nation’s roadways now. Today, automatic emergency braking (AEB) and forward collision warning systems already work to reduce rear-end crashes in equipped vehicles, and we’ve been working to encourage industry and vehicle manufacturers to adopt such systems. In 2017, we cohosted a roundtable with the National Safety Council on commercial vehicle (heavy-duty truck) use of advanced collision avoidance technologies and learned that truck manufacturers are beginning to see high customer demand for forward collision avoidance systems on their trucks. During the roundtable, one manufacturer indicated they were making the technologies standard on their trucks, while another mentioned that over 60 percent of their customers purchase vehicles with technology. In addition, the National Highway Traffic Safety Administration (NHTSA) is making progress on evaluation and testing collision avoidance technologies. We continue to advocate for connected vehicle technology because these technologies can further aid in collision avoidance, especially in situations where vehicle resident sensors are weak. Safety should never be considered a barrier to innovation, but rather, an integral component of it.

End Impairment in Transportation

In 2017, we saw progress on reducing alcohol impairment in transportation. Utah became the first state in the nation to pass a law setting a .05 percent blood alcohol content per se limit, and Nebraska and Oklahoma passed all-offender ignition interlock laws. The Federal Motor Carrier Safety Administration (FMCSA) published a final rule establishing the Commercial Driver’s License Drug and Alcohol Clearinghouse, and NHTSA developed training programs addressing the full range of responses to alcohol impairment, from enforcement through adjudication. Yet, we still need more states to strengthen their impaired driving laws and enforcement. We also need improved “place of last drink” (POLD) data to help law enforcement officers deter future violations, and we need better methods to measure impairment by drugs other than alcohol.

Require Medical Fitness, Reduce Fatigue-Related Accidents

In terms of medical fitness, we’ve criticized both the FMCSA and the Federal Railroad Administration because they have withdrawn their advance notice of proposed rulemaking regarding obstructive sleep apnea, which could have led to a rulemaking to address this important issue for people in safety-critical positions. In the highway mode, untreated moderate‑to-severe sleep apnea disqualifies drivers from operating large commercial vehicles because it affects driving safety, yet clear guidance is needed to assist medical examiners in identifying the condition. Nevertheless, the FMCSA has made notable progress by developing a National Registry of Certified Medical Examiners that lists all medical professionals who are qualified to certify drivers. This is a step in the right direction.

The FMCSA took another important step to improve safety when it implemented the electronic logging device (ELD) rule in December 2017. The rule requires the use of technology to automatically track driving and duty time. The NTSB advocated for such devices for many years because they enable better enforcement of hours-of-service regulations and can lead to reductions in drowsy driving among truck and bus drivers.

Eliminate Distractions

Our roundtable earlier this year, “Act to End Deadly Distractions,” brought together survivor advocates and experts throughout industry and government to discuss progress on state laws. We are beginning to see states consider legislation that would completely ban the use of hand-held devices, which highlight manual and visual distraction, but public awareness of the cognitive distraction that can result from hands-free device use remains very low.

Strengthen Occupant Protection

The good news this year on occupant protection is that motorcoaches are now built with lap and shoulder belts for all passenger seating positions. Now we’re focusing on all motorcoach passengers properly using those belts and using them every time they ride. We are urging primary enforcement of seat belt laws for all vehicles, including large buses equipped with belts, at every seating position, and we’re calling for safety briefings on motorcoaches similar to those delivered on commercial flights that explain seat belts and other safety features. As for passenger vehicles, some states, such as Massachusetts and New Hampshire, are considering joining the 34 states that already have primary enforcement of mandatory seat belt laws. Primary enforcement of mandatory seat belt laws is proven to increase seat belt use and, thereby, reduce the number of deaths and injuries on the roads. Regarding motorcycles, we are concerned that some states are repealing their helmet laws, because we know reduced helmet use will lead to more traumatic brain injuries and deaths.

Critical topics that touch on these highway safety issues are speeding and roadway infrastructure. Our recent safety study on speeding establishes what many of us already know but may not always apply: speeding increases the risk and severity of a crash. Here again, along with other safety recommendations, we’ve identified available technologies that can save lives but are not currently in use. The importance of infrastructure was highlighted recently by our highway accident report on a motorcoach collision that killed 2 people and injured 14 others. An unrepaired crash attenuator, an unmarked gore area, and out-of-compliance signage were cited in the report, in addition to the lack of seat belt use by most of the occupants.

Expand Recorder Use

Finally, we continue to urge all large highway vehicles be required to be equipped with recorders that capture a standard set of parameters. Event data recorders are vital investigative tools in every transportation mode—they help us do our job better and faster by providing valuable information after a crash so we can figure out what went wrong and make recommendations that prevent future injuries and deaths. Unfortunately, in crashes involving large trucks or buses, we are often left with limited data from the vehicle about the crash. We learn much more from passenger vehicles in crashes than from trucks and buses because of the standards NHTSA has developed (no such standards exist for trucks or buses). These standards are critical for large-vehicle operators, who can use recorders to train their drivers and increase safety.

The Most Wanted List midpoint mark allows us to reflect as well as plan and set new goals for the upcoming year. Although we have a long way to go to reach zero fatalities on our roadways, the efforts highlighted above, innovative partnerships and strategies, and bold actions to advance our recommendations are what we need to make America’s roadways fatality-free.


Dr. Robert Molloy is the Director of the NTSB’s Office of Highway Safety.

Most Wanted List Progress Report: Marine Safety

By Member Christopher A. Hart

 The NTSB is releasing a series of blogs highlighting the progress the transportation community is making in each mode to advance issues on our 2017–2018 Most Wanted List. This series sheds light on the progress made and what needs to be done going forward to improve transportation safety. This is the first blog of the series. 

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Member Christopher Hart and Brian Curtis, Director, NTSB Office of Marine Safety at MWL midpoint meeting.

It’s been just over a year since we released our 2017–2018 Most Wanted List (MWL) of transportation safety improvements, so we decided to check in with stakeholders on our collective progress toward addressing these important safety issues. I had the opportunity to join in the discussion with our Office of Marine Safety and representatives from the US Coast Guard (USCG), the American Pilots’ Association, and the Cruise Lines International Association, and I came away encouraged that progress is being made on the issue areas that most affect our Marine safety efforts: expanding recorder use, ending alcohol and drug impairment, requiring medical fitness, and eliminating distractions.

Expanding requirements for voyage data recorders (VDRs) remains of paramount importance to the NTSB, as underscored by the information obtained from the VDR in our recently-completed investigation of the sinking of the El Faro. We certainly appreciate the extensive and sophisticated resources that several government and non-government entities deployed to find the basketball-sized canister containing the data because it proved to be invaluable to our investigation. Operators can also use VDRs to track and monitor vessel and fleet routes, and to help them determine crew training needs. The marine representatives we spoke with at our midpoint meeting are similarly interested in moving forward with VDR requirements, especially as the technology becomes more capable, affordable, and available. We’re hopeful that our recent report on the El Faro sinking will further encourage stakeholders to take action on increasing the installation and use of VDRs.

Ending alcohol and drug impairment is another important issue that we are working with stakeholders to address. The biggest hurdle here, which we discussed at the midpoint meeting with United States Coast Guard (USCG) representatives, seems to be coordinating rulemaking between the military and civilian sectors. Civilian labor unions are reluctant to support some of the recommendations we’ve proposed, largely out of concern for the rights of their members. The USCG continues to work on this issue to coordinate and implement our recommendations aimed at addressing alcohol and drug impairment.

When our conversation turned to a related concern—requiring medical fitness—I was pleased to hear assurances that the USCG is also making progress. Since its last update, the USCG has stood up an office supporting medical fitness issues and now requires medical certificates in addition to piloting credentials.

The final marine issue we discussed at our midpoint meeting was eliminating distractions. The USCG representatives informed us that the Coast Guard has released our safety alert associated with an accident that tackles this issue (SA-059 November 2016), and it intends to continue to follow up on recommendations related to distractions.

We are always eager to hear feedback from our recommendation recipients, and this midpoint meeting was an excellent opportunity for us to make sure we fully understand the issues. We have recommendation specialists in each mode who help facilitate ongoing feedback, help with questions about our recommendation process, and discuss potential solutions.

At this 1-year mark, I’m encouraged and hopeful that we’re making progress on these important safety issues, and I look forward to seeing the NTSB and our recommendation recipients continue to work together to address them.

Thank You

SafetyCompassLogoBy Stephanie D. Shaw

We launched Safety Compass in March 2011 to provide you an inside-out view of the investigative and advocacy efforts we’re engaged in and the important safety issues we’re focused on. As we close out 2017, we want to say “thank you” to you, our readers. Thank you for your interest in the work we do and for sharing our safety messages and recommendations for improving transportation safety.

From teens and sleep to drones, autonomous vehicles to our investigative processes, we’ve given you an inside look at the NTSB and highlighted our comprehensive approach to improving transportation safety across all modes and for all people.

To wrap up the year, here’s a list of some of our most popular blogs of 2017:

Last month, we released data revealing that 2,030 more people died in transportation accidents in 2016 than in 2015. Of those fatalities, 95 percent occurred on the nation’s roadways. Many of those deaths were completely preventable! As we approach 2018, we call on each of you to help us reverse the trend of increasing transportation fatalities, especially on our roadways. Continue to read our blog, see the lessons we’ve learned through our investigations, and share the safety recommendations we’ve made to prevent transportation accidents and crashes, deaths, and injuries.

We encourage you to keep up not only with our blogs, but with other NTSB materials. Sign up to be on our Constant Contact list. Follow us on Facebook (@NTSBgov), Instagram (@NTSBgov), LinkedIn (@NTSB), and Twitter (@NTSB). And in case you missed it, we launched a podcast in 2017, too! Check out Behind-the-Scene @NTSB wherever you get your podcasts. If you’d like to suggest a blog topic, e-mail

As 2017 comes to an end, we again extend our gratitude to you for working with us to improve transportation safety. We wish you safe travels this holiday season and in 2018.

The Silver Bridge Collapse: Don’t Blame the Mothman!


By Don Karol

Rumor has it that, just before the December 15, 1967, collapse of the US Highway 35 Bridge in Point Pleasant, West Virginia, a 7-foot-tall monster with large, piercing red eyes and huge, mothlike wings was seen lurking nearby, warning of the impending catastrophe. This “Mothman” was soon blamed for the tragedy in which 46 people died and 9 were injured. Of the 37 vehicles on the bridge at the time of the collapse, 31 fell with it, many plunging into the Ohio River. Fifty years after the collapse of what was then known as the Silver Bridge, paranormal speculation still swirls around the event, perpetuated by movies (like the Mothman Prophecies), legends, and myths. As a civil engineer, though, I put my trust in the laws of physics, materials science, and the findings of the NTSB investigation completed five decades ago, which proved without a doubt that the Mothman wasn’t to blame.

Silver Bridge, Point Pleasant, West Virginia
Section of Silver Bridge, Point Pleasant, West Virginia, that collapsed on December 15, 1967 (source: Herald-Dispatch)

The Silver Bridge collapse was the first significant highway accident investigation in NTSB history. Working with experts from the Federal Highway Administration, the states of West Virginia and Ohio, and leading engineering consulting firms, we determined conclusively that the cause of the collapse was an eyebar fracture in one of the bridge’s suspension chains. The fracture resulted from stress corrosion and corrosion fatigue that had developed over the bridge’s 40-year lifespan. Not surprisingly, no evidence was ever found connecting the Mothman to the failure.

This catastrophic event prompted national concern about the safety of bridges across the United States. President Lyndon B. Johnson ordered all US bridges to undergo safety inspections. Congressional hearings resulted in mandates requiring the US Department of Transportation to develop and implement National Bridge Inspection Standards. In December 1970, landmark legislation was enacted that established national requirements for bridge inspection and evaluation. One would think that these rigorous new inspection standards would take care of bridge failures forever. Unfortunately, during the past half century, that’s not been the case.

1983 bridge collapse in Greenwich CT
A 100-foot-long section of the Interstate 95 bridge over the Mianus River in Greenwich, Connecticut, collapsed June 29, 1983 (source: Bob Child, Associated Press)

On June 28, 1983, a 100-foot-long section of Interstate 95 (Mianus River Bridge) collapsed near Greenwich, Connecticut. Two tractor-semitrailers and two passenger vehicles went down with it, resulting in three fatalities and three serious injuries. We determined that corrosion-induced forces led to lateral displacement of the suspension assembly, which went undetected by the state’s bridge inspection and maintenance programs and ultimately led to the collapse.

On April 5, 1987, tragedy struck again when two spans of the New York State Thruway (Interstate 90) fell about 80 feet into the rain-swollen Schoharie Creek. Four passenger cars and one tractor-semitrailer plunged into the creek, and 10 people were killed. We determined that the New York State Thruway Authority failed to maintain adequate support around the bridge piers, leading to severe erosion in the soil beneath the bridge footings. We also determined that the state’s bridge inspection program was inadequate. Not surprisingly, neither the Mothman nor the Loch Ness Monster was seen in advance of this collapse to forewarn of the impending catastrophe.

1987 bridge collapse near Amsterdam, New York
Divers search for victims in the Schoharie Creek after the New York State Thruway bridge collapsed near Amsterdam, New York, on April 5, 1987 (source: Fred McKinney, Times Union)

Other notable bridge failures we investigated in the late 1980s involved localized flooding and water scouring. One collapse occurred on April 1, 1989, near Covington, Tennessee, when two columns supporting three bridge spans collapsed, sending an 85‑foot section of the US Route 51 bridge 20 feet into the Hatchie River. Five vehicles fell with it, killing eight occupants. Again, our investigation identified deficiencies in the state authority’s bridge oversight. In response to our investigations of these events, additional requirements were developed for periodic underwater inspection of bridges.

Probably the most memorable bridge collapse we investigated occurred 10 years ago in Minneapolis, Minnesota, when a catastrophic failure occurred in the main span of the deck truss in the Interstate 35W highway bridge. As a result, 1,000 feet of the deck truss collapsed during rush hour, with about 456 feet of the main span falling into the river. A total of 111 vehicles were on the portion of the bridge that collapsed; 13 people died and 145 were injured. We determined that a design error in the gusset plates compromised the bridge’s load capacity, causing it to fail under substantial weight increases. Our investigation prompted the development of additional bridge quality assurance and improved bridge inspection requirements.

2007 bridge collapse in Minneapolis, Minnesota
Interstate 35W bridge over the Mississippi River collapsed in Minneapolis, Minnesota, on August 1, 2007 (source: Peter Matthews, Polaris)

On December 15, as we mark the 50th anniversary of the Silver Bridge collapse, let’s focus on the infrastructure improvements we need still need to make five decades later rather than try to place the blame on mythical creatures like the Mothman. Throughout the NTSB’s history, we have investigated catastrophic bridge collapses with one goal in mind: preventing future tragedies. Despite efforts to continually enhance the quality of bridge inspections, unforeseen disasters continue to occur, highlighting the need to thoroughly inspect and replace bridges before they collapse. Supernatural forces do not bring down bridges; neglect does.


Don Karol is a Senior Highway Accident Investigator and National Resource Specialist in the NTSB Office of Highway Safety.

Thank You for Your Service  

By Nicholas Worrell, Chief, NTSB Safety Advocacy Division

As we honor our veterans this week, I’d first like to acknowledge the many veterans who continue to serve the public here at the NTSB. Thank you for your service. I, too, began my public service in the armed forces as a member of the US Marine Corps. Like many of my NTSB colleagues, my focus then was—and remains—protecting American lives.

And to all American veterans, on behalf of the whole NTSB, thank you for your service. You were ready to stand your post and, if necessary, engage the enemy to protect your country.

A little more than a year ago, I had an opportunity to speak to sailors aboard the USS George Washington about road safety, which, I’ll admit, sounds strange. After all, why do sailors aboard a ship need to hear about road safety? The answer is because today’s military is working hard to stop an epidemic of vehicle crash deaths among its personnel, both off and on duty. For many years, the number of active duty personnel dying in crashes on our roads rivaled the number dying in our wars. Adding in American civilians, we lose over 37,000 Americans on our roads each year. Unintentional roadway injuries are the most likely cause of death for Americans, from childhood through middle age.

USS Washington
Nicholas Worrell talks with sailors about the USS George Washington

On the George Washington, I urged active duty personnel to “stay frosty” (alert) on US roads because, to me, something that kills tens of thousands of Americans a year must be seen as an enemy. This enemy’s three favorite tactics are impairment, distraction, and fatigue. Using the values drilled into me as a Marine—honor, courage, and commitment—I’m working to encourage others to counter these enemy tactics. I’m teaching my fellow citizens that it’s not okay to drink a six‑pack and get on your bike. It’s not okay to take phone calls—handheld or handsfree—while you’re behind the wheel. It’s not okay to drive without any sleep. If you do, you’re as good as collaborating with the enemy.

Body armor and up-armored vehicles keep soldiers and Marines safer, even when they’re in harm’s way. But what keeps you safe from the enemy on the roads at home?

A full FMVSS-218–compliant helmet.

Consistent use of your restraints.

Age-appropriate child car seats.

This is your body armor on the roads; your up-armor for your POV.

For many of us who have transitioned out of the military, our service values still drive us. We know that if there’s an enemy afoot, we are called to confront it. And, for Americans who never wore the uniform, improving road safety can be your chance to serve our country.

This Veterans Day, let’s thank our veterans by keeping each other safe on the roads that they served to defend.

Inside the NTSB’s General Aviation Investigative Process

The Nuts and Bolts

By Aaron Sauer

This is the sixth 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 public’s image of our agency is often based on the iconic blue and yellow NTSBNTSB Investigators Onscene jacket they see at accident scenes. What’s less well known is that examining and documenting on-scene evidence is just one step in an exhaustive process to gather all available information, determine a cause, and recommend any changes that can prevent similar accidents.

Since 2014, 12 percent of general aviation accidents—about three accidents every week—have involved a power plant malfunction. These malfunctions may include a fuel issue, component failure, or improper maintenance.  As an NTSB air safety investigator, I investigate such mechanical malfunctions, gather the facts of the investigation, and ultimately help determine the probable causes of accidents.

After the on-scene phase of the investigation is complete, the airplane wreckage is often recovered by professional recovery services and stored in a secure location until we determine if further NTSB investigation is needed. When circumstances, such as a large hole in the engine crankcase or the in-flight loss of a propeller, indicate that further examination is necessary, we work with the airframe, engine, and component manufacturers. These entities serve as parties to our investigation, providing technical expertise on their product. If required, we coordinate a follow-up plan to examine the aircraft wreckage in greater detail. At the accident scene or recovery facility, our investigators examining the machine determine the scope of follow-up based on any anomalies discovered.

In some accidents involving a reported loss of engine power, the initial examination (typically a 100-hour inspection) turns up no obvious anomalies. At this point, one of the best and most telling follow-up activities is to attempt an engine test run. Engine test runs may be performed at a recovery facility or at a manufacturer’s facility. A successful engine test run is a critical piece of information that may lead the investigation down another path.

When, upon initial examination, the investigator observes an engine issue consistent with an internal mechanical failure, it’s typical to disassemble the engine at the manufacturer’s facility or the recovery facility under NTSB supervision. Examining an engine at the manufacturing facility often provides the advantage of having available engineering staff, historical data and drawings, and proper test equipment for the engine components.

Once at the manufacturer’s facility, the investigation team (typically including NTSB, FAA, and airframe, engine, and component manufacturer personnel) determines the plan or approved test procedure for the detailed investigation. The scope of the investigation is determined based on the known facts and circumstances of the accident, the condition of the engine and components, and the work required to confirm the failure. It’s important to note that, although the parties work collaboratively, the NTSB has the final say if there is any disagreement in the investigation process.

Engine functional testing, partial disassembly, and full engine disassembly are the most common investigation techniques used to determine the cause of a failure or malfunction. Disassembly helps us identify fractured or broken parts, which are then documented and set aside for even further examination.

Most manufacturers have their own materials laboratory, metallurgists, and engineers. At this point and with the team present, our investigators may elect to use the manufacturer’s material laboratory for a preliminary examination to obtain a quick analysis of the failure mode, then forward the parts to our materials laboratory in Washington, DC, for a detailed metallurgical examination.

Even observers with a solid understanding of our processes beyond the on-scene images might not understand the many ways that NTSB investigations can improve safety. Even when all signs point to a mechanical malfunction, our investigative process still looks at two other factors: human and environment. When an accident involves reported loss of engine power, we gather information about the pilot and aircraft owner—documentation from the scene, aircraft records, and Federal Aviation Administration (FAA) records. We interview witnesses, visit and examine maintenance facilities, and meet with manufacturers. When necessary, we conduct follow-up examinations and interviews. If FAA inspectors handle the initial on-scene observations, we work hard to guarantee that our two agencies communicate effectively.

When the fact-gathering phase of the investigation is complete, our investigators compile all the relevant factual information, complete a detailed factual report, and create a public accident docket. For an engine failure accident, the docket may include engine reports, materials laboratory reports, aircraft records, and historical engine safety information in the form of service bulletins and airworthiness directives.

Many people understand that we may make recommendations at any point during an investigation, but sometimes our investigations also result in other actions to improve safety. For example, depending on the nature of the material failure, an NTSB investigator may work with the FAA or the manufacturer to issue a manufacturer service bulletin, service letter, safety notice, or a potential airworthiness directive. The safety action taken by the FAA or manufacturer depends on the failure’s cause, fleet exposure, and the potential safety awareness benefit of each product.

Over my 17 years as an NTSB investigator, I’ve investigated numerous engine-failure–related accidents that resulted from human error and material failure. Despite the varied causes and outcomes of these accidents, one fact stands out: proper maintenance is the best way to avoid catastrophic consequences. Following manufacturer-recommended maintenance practices and procedures and adhering to basic maintenance principles can prevent accidents.


All accident reports and public accident dockets are available on the NTSB website: