Cash was renowned for finding clues in the tapes. He knew the distinctive clicks of a flap lever and the grind of the landing gear. By studying the whines of the engines, he could tell if they were operating at full power. His office at the NTSB was a darkened room that was stacked high with audio equipment—amplifiers, tape players, audio mixers, and graphic equalizers. But the place where he worked his magic was a powerful Unix computer that ran a program called WAVES. It allowed him to translate sounds into squiggly lines that showed frequency, volume, and energy. When he wanted to identify a strange click or rattle, Cash compared that fingerprint with one from a known sound. He spent lots of time recording sounds on airplanes on the ground so he could match them with the mysterious noises. He was like a police fingerprint expert, always looking for a match.
It had been ten months since the crash, and the NTSB still had not identified the thumps heard on the 427 cockpit tape. Cash had taken the tape to the FBI’S sound laboratory in Quantico, Virginia, to see if they came from gunshots or an explosion, but the FBI found that the thumps did not have the unique signatures of sounds from a gun or a bomb. Since then, Cash had spent hours studying the thumps on his computer. He discovered that there actually were three distinct sounds, the first coming just as Emmett completed the sentence “Oh, yeah, I see zuh Jetstream.” But Cash had been unable to match the signature with any of the sounds from the stomping-slamming doors test conducted at National Airport a few days after the crash.
If the thumps had been heard at any other time on the cockpit tape, Cash would not have worried about them. Tapes often had sounds that couldn’t be identified. Human beings and airplanes made so many noises that it would be difficult to identify them all. But Cash thought it was important to find the source of the thumps because they occurred at the most crucial time, right before the plane rolled left and twisted toward the ground.
It was fortunate that he had four channels of sounds on the tape. Most 737 tapes had only three—one for each pilot and one from the area microphone in the ceiling. But someone on Ship 513 had mistakenly left the jump seat mike on, which meant there was a fourth source of sounds.
As he studied the squiggly lines on his computer one day, Cash noticed that the thumps were picked up by the microphones in the ceiling and the jump seat but not by the headset mikes that Emmett and Germano were wearing. That meant the sound was probably traveling through the frame of the airplane rather than through the air, which suggested it came from outside the cockpit. He also noticed an important difference in the sounds: the ceiling mike picked up the first thump 9/100 of a second before the jump seat mike did. He thought that was an important clue.
Late one summer night, Cash and a few helpers arrived at the USAir terminal at National Airport. They boarded a 737 parked at a gate and switched on the plane’s power. As the voice recorder was running, an FAA employee crawled through the baggage compartment and pounded on different spots with a rubber mallet.
They used two walkie-talkies. The FAA employee announced his location right before he pounded, so they could log where the sounds came from. When Cash got back to his office and examined the sounds in WAVES, he checked the timing of each to see which ones had the same 9/100 of a second interval. He found a match when the FAA employee pounded on the fuselage about twelve to sixteen feet behind the cockpit mike. That meant the sound came from Row 1 or Row 2 in first class.
He was halfway there. He knew the location of the thumps. Now he just had to figure out what caused them.
Every time a 737 burped, Vikki Anderson’s phone rang. It didn’t have to be anything serious. The usual hiccups of a plane—minor autopilot problems, rudder anomalies, or bumps from wake turbulence—were now being reported by 737 pilots as potentially serious incidents that might be related to the USAir crash. Many pilots had become jittery about the 737.
As the FAA’s lead investigator on the crash, Anderson provided technical help to the NTSB, to explain how the FAA certified the 737 and how it inspected USAir. She also had to help the FAA decide if there was any need to take action because of the crash. She had been a Braniff flight attendant for twenty-three years and had joined the FAA because she had grown weary of the vicious cycles in the airline business, when Braniff would go bankrupt and then reemerge to fly again. She talked about the airline like it was a movie with sequels, Braniff I, Braniff II, et cetera.
She started with the FAA as a cabin safety specialist, analyzing flight attendant training and evacuation plans, and then moved to the agency’s accident investigation office nine months before the Hopewell crash. This was her first major accident. As she was flying to Pittsburgh the morning after the crash, she wondered if she could handle the gruesome job. She wasn’t sure she could deal with body parts lying everywhere. She had done well in the months since then because she was forthright about her feelings. While many men in the investigation bottled up their emotions, Anderson was honest about what she was going through. She was a fun person to work for, easygoing, thorough, and well organized.
Only a handful of women were part of the tight fraternity of crash investigators, but Anderson had worked hard to learn the ropes. She read every crash book she could find, and she wasn’t bashful about asking questions. She would freely admit when she was baffled by an engineer’s mumbo jumbo. She kept the FAA team organized and made sure meetings didn’t drag on too long. A tiny woman with big brown eyes and a warm sense of humor, she could liven up the most dreary meeting. When they discussed the gurgling sound that Andrew McKenna had heard in Seat 1A, Anderson suggested it was someone sitting in 3A gargling. When she visited the Winston-Salem hangar, she said she was open to all theories about the crash, “even the one about Russian death rays.”
The FAA had declared the 737 safe. An independent team of FAA engineers and inspectors had conducted a Critical Design Review of the plane for six months and found no major problem that could be linked to the accidents in Hopewell and Colorado Springs. The team listed twenty-seven recommendations to improve the plane, everything from new screens in the wheel wells to a consistent definition of the word “jam,” but it found no serious problems with the plane.
Yet, despite the FAA’s assurances about the plane’s safety, pilots remained nervous. In cockpits and airport hallways, 737 pilots eagerly swapped gossip about recent incidents and discussed what they would do if their planes suddenly began to roll. At least once a month, Anderson would get a call from the FAA security guard saying there was a pilot at the front door who wanted to talk to someone about the crash. Sometimes the pilots had theories, other times they just wanted to find out the latest from the investigation. One young pilot—Anderson doesn’t remember his name or his airline—was surprisingly nervous about the 737. He needed reassurance that the plane he flew was not going to fall out of the sky. Talking to him was eye-opening. It made her realize that some pilots were truly scared.
Anytime a pilot reported a problem that sounded the least bit serious, the FAA and the NTSB quickly sent a team to check it out. A July 1995 incident in Richmond, Virginia, was typical. Anderson’s boss, Bud Donner, interrupted her during a meeting and said, “Vikki, I’m going to need you in a little bit. We’ve got another little adventure.”
A USAir plane carrying forty-eight passengers was making a left turn toward the runway when it suddenly rolled to the right. The captain shut off the autopilot, but the roll continued. He quickly turned the wheel and pushed the left rudder pedal to regain control of the plane. The rolling stopped, the plane leveled off, and they landed safely.