Reading The Wreckage
Air crash investigators train students to fit little pieces into the big picture.
- By Eric Adams
- Air & Space magazine, July 2001
An image of a wrecked U.S. Air Force C-119 transport flashes onto the screen.
“What do you see here?” instructor Ray Wall asks.
The students, sitting in a classroom cluttered with a variety of twisted and broken airplane parts, study the image. A few hands hesitantly go up.
“It looks like he overran the runway,” one student says.
“No,” Wall retorts, clearly ready for just that sort of response. “Describe factually what you are seeing, and leave your opinions at home. Your job is to gather the facts—the National Transportation Safety Board members make the interpretations.”
The rest of the hands go down. Wall helps them out: “The right side of the forward fuselage has compression buckling. The props are not feathered. There is substantial deformation with crushing. And see these people walking around? Have they touched anything? You now have a contaminated investigative area.” For this group of 33 aspiring air crash investigators, school has begun.
In a classroom tucked into the third floor of a boxy 1960s government building on the campus of the Federal Aviation Administration’s Mike Monroney Aeronautical Center in Oklahoma City, they are here to learn how to sort out the aftermath of aviation’s dark side. The class is offered to FAA investigators, airline and military aviation specialists, even new members of the NTSB—anyone who will be on a crash scene gathering evidence to turn over for the official NTSB review. During this six-and-a-half-day introductory course, which is conducted by the Transportation Safety Institute’s (TSI) Aviation Safety Division, the students will absorb lectures, view slides and videos, read radio transcripts, pass around failed engine parts and broken struts, and examine many cautionary case studies. Then, after five days of classroom work, they’ll break into teams and venture into the “boneyard,” a fenced compound containing the transported remains of a half-dozen real crashes that the students will investigate.
First, though, they have to learn the vocabulary. That’s what Wall, a retired NTSB accident investigator with more than a thousand investigations under his belt, is helping them do. When another image hits the screen a short while later—this time a single-engine Cessna—Wall asks the same question and gets a faster, better reply.
“The nose gear is collapsed, and both prop blades are bent,” the student says.
“Good. And what does that tell you?” Wall asks.
“The prop was rotating at impact.”
An hour later, the class has it down: They can spot bowed flanges, shorn bolts, torsion, and ground scars immediately. Learning how to accumulate such details and objectively assess their significance, Wall tells them, is the first step toward narrowing the possibilities for the cause of the accident. The real answers, after all, are often very far from what first impressions may suggest and usually include multiple failures, so investigators must have a comprehensive understanding of what the aircraft—and, ultimately, its crew—has gone through. Wall describes some of the analytical tools available. He tells them to document the site with videos, photographs, and grid sketches showing debris distribution lines. Another trick is vector analysis, drawing arrows on the wreckage that show the direction that forces are being applied. “You’ll get the big picture very fast,” Wall says.
Emphasis on the big picture is clear in the range of the course curriculum. It’s a general introduction, and it’s just one of many that investigators will take throughout their careers. The class, which is taught by TSI, NTSB, and FAA staff as well as aviation industry experts, covers all types of aircraft and gives equal weight to both clinical discussions of aircraft component failure modes and the human side, describing how to work with witnesses, survivors, and family members and what investigators might experience at the site. “When you arrive at a bad accident site, I guarantee you you will not sleep that night,” warns Frank Del Gandio, an FAA investigator who lectures on crash-scene biohazards, including blood-borne pathogens such as the hepatitis virus and HIV. “In fact, you might find you’re not sleeping for days. That’s normal. Don’t worry. But you need to focus on that investigation. Focus on the people you might be able to help in the future.”
That’s a virtual mantra for accident investigators, who must often work at remote and inhospitable sites and with a mind-numbing collection of variables. Their cause, though, is safety—to figure out precisely what happened at each accident so that the problem can be prevented from happening again. According to the NTSB, there are roughly 2,000 aviation accidents per year, most involving small general aviation aircraft and about 700 involving fatalities. All are thoroughly investigated with a variety of team configurations that can include representatives from the airline, if applicable, the aircraft manufacturer, and any part suppliers or airport personnel who might contribute useful records or data. If there are fatalities, the NTSB will lead the on-site investigation. If not, the board might delegate the investigation to the local FAA office. (The FAA, which is responsible for regulating the aviation industry and operations, always participates in investigations in support of the NTSB.) In all cases, the facts are reported to the five-member board, which will review the accident, develop a probable cause, and possibly issue recommendations for the FAA to enact.
The Transportation Safety Institute, a Department of Transportation division charged with training investigators of aviation, highway, and marine accidents, trains some 600 FAA investigators a year. It also opens its doors to tuition-paying military and commercial airline safety specialists. In the course I’m participating in, most of my classmates are these specialists, who oversee flight operations with an eye toward safety procedures, training, and maintenance and who might eventually participate in investigations that their companies or military units conduct in support of or in addition to an NTSB inquiry.
All training stresses that accident investigation is a team effort. After a crash is reported, the investigators, led by the Investigator In Charge, break into groups, each of which gathers evidence about the pilot, the powerplant, the aircraft structure, air traffic control, the weather, and other factors. They interview witnesses and begin sorting through debris. The students are taught that they must account for every component of an aircraft, if for no other reason than to rule it out as a contributing factor.
One of the biggest challenges in that respect is determining whether components were damaged before the accident or during it. Among the most thoroughly addressed subjects is fire. Wall passes around a small charred canister. It’s an oxygen container identical to the one that started the fire that brought down ValuJet Flight 592 in the Florida Everglades in May 1996, killing 110 people. This one was used to test whether such a fire could have occurred, and its presence silences the room. “Always suspect the possibility of in-flight fire,” Wall says. “When a fire is in the slipstream and fueled by lots of oxygen, such as in an engine, temperatures can exceed 3,000 degrees, whereas on the ground they will usually stay below 2,000 degrees.”
Materials leave distinctive signatures when subjected to certain temperatures, he continues, thus possibly revealing whether the fire occurred in the air or after the crash and where it originated. Rubber hoses, for example, will melt at 400 degrees, aluminum alloys at 1,000 degrees, and stainless steel at 3,100 degrees. Furthermore, when aluminum melts on the ground, it will puddle due to gravity, but when it comes apart in an in-flight fire, it produces the “broomstraw effect,” in which the points where the metal has come apart will look stringy.
Other damage might require closer inspection. Andy McMinn, a TSI staff instructor, briefs us on metallurgy and how to use it to determine what caused a part to fail. Throughout his talk, he refers to crystal structure—how atoms are arranged—and discusses the various ways parts can change, depending on whether they have been subjected to fatigue, violence, or some other stress. Parts usually fail by overload, the material can be ductile or brittle, and the failure will leave important clues. “Fatigue manifests itself in ‘beach marks,’ like tide marks in the sand,” McMinn says. “If a rectangular plate is pulled and compressed thousands of times, beach marks will indicate the direction of crack propagation. When the cracks reach a critical size, you’ll see progressive failure and then instantaneous failure.”
The course’s aggressive pace is relieved by breaks and lunches—but even then there’s something to see. Instructors show videos of airplanes crashing and documentaries about the accident investigation process. The classroom itself contains exhibits on investigation processes and equipment, examples of component failure, an enormous cut-away of a Teledyne piston engine, and framed, illustrated case studies showing the effects of inexperience, bad luck, aircraft neglect, and poor judgment. One shows an old Cessna sitting crushed, nose down, on the side of a mountain. The pilot, who had been killed, had only a student license that had expired five years before, and a list found in the cockpit showed about 30 repair items that needed attention, but there was no evidence that any of the repairs had been completed. The airplane had had its last annual inspection five years before the crash.
Mike Grimes, a Teledyne engineer who lectures on engines and propellers, knows that in accidents such as that any number of factors could have contributed. So he tells us to start at the front of the airplane and decide whether the engine was running when the airplane crashed—and then determine what might have caused the engine to stop. “Look for propeller damage that requires a lot of energy,” he says. “Are there massive chunks of aluminum torn out of the leading edge of the blade? Is the hub broken?”
But what if a propeller is missing? Why did it drop off?
“How do you find a missing propeller?” he asks. “You can’t use [FAA tracking] radar data because the propeller is too small, but you can use it to see where the airplane started coming down. That’ll give you a general idea. Then the insurance adjuster becomes your best friend. Why? He’s got the checkbook. Get him to place an ad and offer a reward. Everyone with an SUV is going to be out looking for that prop.”
The other side of crash investigation is, of course, the people—the investigators, the victims, and the survivors. The more harrowing aspects of crash investigation have to be addressed with care and sensitivity. Though the course stays away from graphic images in the classroom, there is a file of photographs that help prepare students for what they might see, and they can view them whenever they choose. “You never know how you’re going to respond,” McMinn says. “We’ve had students look at the pictures and say, ‘I’m in the wrong business.’ ”
One student, Ernest Menet, a technical operations safety manager at Delta Air Lines in Atlanta, is asked to talk to the class about his own experience at a crash site. He was one of the first on the scene when Delta Air Lines Flight 191 crashed at Dallas-Fort Worth International Airport in 1985, killing 134. The accident was attributed to wind shear. “I was really not prepared for what happened that day at DFW,” he begins. “We got a report of an aircraft down, and they thought it was one of ours. We drove out, but it was raining so hard we couldn’t see anything. So we just started walking around, and I began to see the wreckage. I saw some people strapped to their seats who looked just fine, but were dead. I also saw dismemberment, horrible burns, children. That struck home because I have two daughters.
“I felt responsible for what I saw,” continues Menet, who is taking the course to buttress Delta’s accident preparedness. “I looked at the wreckage and thought that these people trusted their lives in what I do. As the head of maintenance, I coordinated our participation in the investigation. I ran on adrenaline for the entire week. I got three hours of sleep each night. When it was over, it was almost a letdown. I started withdrawing into myself, I stopped talking to my family. I had to go through counseling. For those of you who haven’t seen it, I hope you don’t. But it changes you for the rest of your life.”
In the boneyard, we finally get to apply what we’ve learned. The team to which I am assigned confronts a mysterious accident involving a twin-engine Piper Aztec. The airplane crashed inverted in a pasture in Oklahoma after an engine and a large part of the wing fell off. Inside the wreckage, police found $35,000 and several dozen spotlights and motorcycle batteries.
While one team begins sifting through the wreckage, Keith Cianfrani, as Investigator in Charge, and I, as public relations chief, set about securing the site and talking to witnesses, local police, and gawkers. As they do at all of the crash sites in the courtyard, the TSI staff, playing these characters, do their best to challenge the investigators. A friend of one witness reveals that the witness took parts of the wreckage as souvenirs. McMinn comes over as an off-duty air traffic controller who saw the pilot working on the left engine the previous day. The local sheriff asks if she can keep the $35,000 found in the airplane so her department can buy a new squad car.
Then a television journalist and her cameraman—veteran Oklahoma City journalists Rick and Gwin Lippert—arrive and promptly begin aggressive coverage. They aim the camera over our shoulders to videotape our notes and use microphones to eavesdrop on conversations among investigators—both of which can lead to premature assessments or incorrect information being broadcast to the public. On air, Gwin gives me information I didn’t know: The airplane was flying along a known drug route. She also points out that the registration number on the fuselage is merely duct tape. “Don’t you find that fishy?” she demands. “Yes, that is fishy,” is the only reply I can manage.
Other team members are making substantial progress. They’ve noticed some broom strawing near the left engine, and conclude that an in-flight fire had torn the wing and engine from the fuselage, in spite of the pilot’s efforts to shut off fuel to the engine, as evidenced by switch positions in the smashed cockpit. Later in the classroom, we get the whole story: The pilot was flying to a rendezvous with other aircraft, transporting drugs from Mexico. The spotlights in the baggage compartment were to be used as runway lights at the secret airfield. While working on the engine the day before, the pilot didn’t tighten the fuel lines sufficiently, and leaking fuel ignited on the hot engine.
Accidents such as this are particularly frustrating for crash investigators and safety experts, more because the pilot was careless than because he was participating in illegal activity. “The bottom line is that the majority of these things are preventable through personal training or discipline,” Wall says. “So it’s frustrating when people make poor decisions, like taking off into icing conditions or not properly maintaining their airplanes.”
The students are no strangers to aviation, but they still come away impressed by the investigation process. “It was amazing to see the story unfold in the smallest of details,” says Friday, who monitors Boeing 757 maintenance for American Trans Air. Jack Combs, an Army Reserve helicopter pilot and safety officer at Fort Lewis, Washington, says he learned patience. “The TSI taught us to not form a quick opinion,” he says. “Just sit back, look, listen, and then carefully investigate.”