Note: this accident was previously featured in episode 60 of the plane crash series on October 27th, 2018, prior to the series’ arrival on Medium. This article is written without reference to and supersedes the original.
On the 20th of December 1995, the crew of an American Airlines Boeing 757 lost track of their position on a nighttime approach to Cali, Colombia. Descending in darkness over the Andes, they became mired in a fog of confusion, errors building upon one another until the situation snowballed out of control. Only the sudden blare of ground proximity warning system stirred them from their paralysis, but despite a heroic attempt to avoid disaster, it was already too late: straining to climb, pitched up nearly to the point of stalling, flight 965 slammed into the darkened summit of El Diluvio, shattering the lives of 159 people upon the freezing mountainside. Just four passengers, spared by some twist of fate, would survive to see the morning light.
In the United States, the crash set off alarm bells throughout the aviation industry. How could a modern jet flying for a world class airline simply fly into the side of a mountain? How could a decorated flight crew, having graduated from one of the most rigorous training programs in the world, become so hopelessly confused? The lessons from the crash would be far-reaching, ushering in a new understanding of human interaction with automation, transforming safety at American Airlines, and convincing the industry to adopt technology that would save thousands of lives.
In 1995, Colombia was embroiled in a low-intensity civil conflict between the central government and myriad drug cartels, far-right paramilitaries, and communist rebels. Tens of thousands had died and the country’s infrastructure was in poor condition, its people terrorized and forced from their homes. Colombia’s national airline, Avianca, struggled with safety; in the 1980s and 1990s, it suffered a string of deadly crashes, including a flight which was blown up by drug lord Pablo Escobar. So for those who could afford to do so, the carrier of choice for the Colombian-American diaspora was American Airlines, which operated direct flights from Miami, Florida to several Colombian cities. With a modern fleet, well-trained pilots, and the latest technology, American Airlines should have been able to get passengers safely to and from Colombia. But on a dark night in December 1995, that assumption would be forever shattered.
The workhorse of American Airlines’ Latin American routes was the Boeing 757. As a part of the next generation of airliners that began to enter service in the 1980s, the 757 was outfitted with a so-called glass cockpit containing all the most modern navigational equipment, including an advanced flight management system integrating a global geographic database, an inertial reference system, and GPS technology. American Airlines knew that this type of guidance would be needed in South America, where infrastructure was often primitive and air traffic controllers were of little help. Pilots assigned to South American trips received extra training in which the dangers of operating on the continent were laid bare: these pilots were told that they would fly among mountains more than 20,000 feet high; that most airports lacked radar; that air traffic controllers would not speak English well and would not be able to help them; and that they must maintain the highest level of situational awareness at all times.
Among American Airlines’ routes into poorly-equipped South American airports was flight 965 from Miami, Florida to Cali, Colombia. In command of this flight on the night of the 20th of December 1995 were two highly experienced pilots. Fifty-seven-year-old Captain Nicholas Tafuri was a veteran aviator with 13,000 flight hours and a perfect safety record. He had a long history of performance commendations, received excellent marks in training, and was considered by all who flew with him to be an exemplary pilot. Joining him was First Officer Don Williams, himself a seasoned pilot with 5,800 flight hours and an equally impeccable record. Like Tafuri, Williams was a former Air Force fighter pilot, and a famous one at that: in 1985, he was named Air Force Instructor of the Year.
That night Tafuri and Williams were to take charge of 155 passengers. Nearly all of them were first- or second-generation immigrants returning to their old family stomping grounds in Colombia for the Christmas holiday. Dozens of them were children. Most were looking forward to seeing relatives; many were bringing their kids back to the homeland for the first time. All six flight attendants were also Colombian-born and had been working this route for years across three different US airlines; on the basis of seniority, they had been awarded this trip in order to go home to their families for Christmas, just like their passengers.
Flight 965 did not get off to an auspicious start. A heavy snowstorm had crippled air travel in much of the northeastern United States. At New York’s JFK airport, a Tower Air 747 slid off the runway and lost its nose gear, injuring 24 passengers. Like a domino effect, the delays spread across the United States. In order to accommodate a large number of passengers who had delayed connections, flight 965 was ordered to wait in Miami for two hours past its scheduled departure time, and by the time it took off at 6:35 p.m., night had already fallen.
Most of the approximately three-hour flight passed without incident, as the plane cruised south over the Caribbean Sea and into Colombia. In the cockpit, the pilots prepared the airplane for the approach to Cali. The plan was to perform an ILS approach to runway 01, which would involve flying past the airport before turning around to come in from the south. On the way in, they would navigate by tracking a series of radio beacons on the ground, a task which would be accomplished using the plane’s flight management system.
The city of Cali lies in the heart of the Andes, in a long, narrow valley which runs almost perfectly north to south for several hundred kilometers. To the west, the mountains average around 5,000 to 6,000 feet (1,500 to 1,800 meters), while on the east, they average 11,000 to 12,000 feet (3,350 to 3,650 meters), with some peaks stretching still higher. To guide inbound planes between the two ranges, a VOR (Very high frequency Omnidirectional Range) had been installed at Cali Airport, along with a a non-directional beacon (NDB) called ROZO, located a short distance north of the approach end of runway 19, and another VOR called TULUA, situated 61km (33nm) north of the airport. Flight 965 was to first fly to Tulua, then to Rozo, before circling around to the south side of the airport for the ILS approach to runway 01. They would have to do all of this without help from air traffic control, as guerillas had blown up Cali Airport’s radar system several years earlier.
At 9:34 p.m., already descending out of 23,000 feet, American Airlines flight 965 made contact with Cali approach control.
“Ah, buenos noches señor,” Captain Tafuri said, “American nine six five leaving two three zero, descending to two two zero. Go ahead sir.”
“The, uh, distance DME from Cali?” the controller asked.
“The DME is six three,” Tafuri replied, stating that they were 63 nautical miles (117km) from the airport.
“Roger,” said the controller, “is cleared to Cali VOR, uh, descend and maintain one five thousand feet. Altimeter three zero zero two, no delay expect for approach. Report, uh, Tulua VOR.” Because he had no radar with which to track the plane’s position, he needed the pilots to report to him upon crossing each of the navigational aids along the approach path.
“Okay, understood, cleared direct to Cali VOR,” said Captain Tafuri. “Uh, report Tulua and altitude one five, that’s fifteen thousand, three zero zero two. Is that all correct sir?”
It was at this point that a small misunderstanding occurred. In the United States, when a controller told a pilot that they were cleared direct to the VOR, that meant they could quite literally fly directly to the VOR, ignoring any intermediate reporting points. But in South America, no such understanding existed. In fact, the controller could not have conceived of a situation in which he would want the pilots to ignore passing over TULUA and ROZO, as these reports were the only way for him to track the plane’s position. By clearing flight 965 direct to the Cali VOR, he implicitly meant to clear them all the way to the VOR, including across all intermediate waypoints.
But in the cockpit of flight 965, Captain Tafuri had erroneously assumed that they could now fly directly to the Cali VOR as the crow flies. He reached down to the FMS and pressed the “direct to” button with Cali selected. Their projected flight path became a straight line to Cali, and TULUA and ROZO disappeared from the screen. “I put direct Cali for you in there,” he said to First Officer Williams.
“Okay, thank you,” Williams replied.
One minute later, the controller called flight 965 again. “Niner six five, Cali,” he said.
“Niner six five, go ahead.”
“Sir, the wind is calm,” the controller said. “Are you able to approach runway one niner?”
It was an intriguing proposition. Runway 19 pointed south, meaning that they could go for a straight-in approach, cutting out the time spent circling the airport to line up with runway 01. Considering that they were well behind schedule, Captain Tafuri probably saw this as a welcome opportunity to regain lost time. “Would you like to shoot one nine straight in?” he asked First Officer Williams, who was flying the plane.
“Uh yeah, we’ll have to scramble to get down. We can do it,” Williams replied.
Keying his mic, Tafuri said to the controller, “Uh yes sir. We’ll need a lower altitude right away though.”
In hindsight, this statement should have set off all kinds of alarm bells. The truth was that it was entirely too late to switch to runway 19: they were too high and too close to the airport to be able to brief the new approach and reconfigure the airplane before landing. In fact, it would be physically impossible to complete all the required tasks in time. They should never have accepted the offer — but under pressure to make up time, and perhaps overestimating their own ability to get it done, they agreed. Williams pulled back power and deployed the speed brakes to decrease lift and increase their rate of descent.
In response to Tafuri’s transmission, the controller said, “Roger. American nine six five is cleared to VOR DME approach to runway one niner. Rozo number one arrival. Report Tulua VOR.”
“Cleared the VOR DME to one nine, Rozo one arrival, will report the VOR, thank you sir,” said Tafuri.
“Report Tulua VOR,” the controller reminded him.
“Report TULUA,” Tafuri confirmed.
The request to report passing TULUA caught Captain Tafuri by surprise, as he had assumed they could ignore it. In fact, he didn’t even know where TULUA was because it had disappeared from their FMS display, along with ROZO, when he selected direct to Cali.
“I gotta give you TULUA first of all,” he said to First Officer Williams. “You, you wanna go right to Cal — er, to TULUA?”
“Uh, I think he said the Rozo one arrival?” Williams replied. Both pilots were apparently still under the impression that TULUA was not part of the approach they were flying, and they struggled to understand how to fit it into their mental model of where to go.
“Yeah he did,” said Captain Tafuri. “We have time to pull that out?” Answering his own question, Tafuri pulled out the chart for the approach to runway 19 via ROZO. “And TULUA one… ROZO… there it is,” he muttered. “Yeah, see, that comes off TULUA.” Now he had finally realized that TULUA was the initial approach fix for the approach they were flying, and that was why the controller wanted them to report passing it.
Jumping on the radio again, Captain Tafuri asked the controller, “Can American Airlines nine six five go direct to ROZO and then do the Rozo arrival sir?” Unsure where he was in relation to TULUA, he wanted to see if he could forget about it entirely and instead go directly to ROZO, the next waypoint after TULUA.
To the controller, this request made no sense. The official approach procedure began at TULUA and any plane flying the Rozo one arrival was obligated to cross it. ROZO was in fact near the very end of the approach, and under no circumstances could a pilot fly direct to ROZO and then land without crossing TULUA first. Furthermore, he had already cleared the pilots to fly the Rozo one arrival, so he was unsure why they were asking again. But he was unable to express any of this in English, so he simply said, “Affirmative, take the Rozo one and runway one niner, the wind is calm.”
“Alright, ROZO,” Captain Tafuri replied. “The Rozo to one nine, thank you, American nine six five.”
“Thank you very much,” said the controller. “Report TULUA, and eh, twenty-one miles, five thousand feet.” This was the closest he could get to explaining in English that they needed to go to TULUA before going to ROZO.
“Okay, report TULUA, twenty-one miles and five thousand feet, American nine six five,” said Tafuri.
“Okay, so we’re cleared down to five now?” Williams asked.
“That’s right, and off ROZO… which I’ll tune in here now. See what I get.” Continuing to ignore TULUA, which he seemed to have concluded was not worth the trouble, Tafuri again turned to the FMS to program a path to the airport via ROZO.
In order to select a navigational aid in the FMS, Tafuri needed to enter its ICAO code, which consisted of an identifier (in most cases simply the first letter of its name) followed by a country code. But in Colombia, authorities had given two beacons the same identifier. Both ROZO and ROMEO, a beacon near Bogotá, had been given the identifier “R,” and since they were both in Colombia, their ICAO codes were identical. In order to distinguish them, the designers of the FMS software — which contained a pre-programmed database of all the world’s published navigational aids — had given the identifier “R” to ROMEO, since it was located near a larger city with a busier airport, and changed the identifier for ROZO to the full name of the beacon.
Although this was the system’s standard way of distinguishing beacons with the same ICAO code, the pilots had no idea that such a distinction had been made, since their approach charts used the official Colombian identifier (“R”) rather than the identifier included in the FMS database (“ROZO”). So when Captain Tafuri wanted to select ROZO in the FMS, he typed in “R,” and a list of waypoints with that identifier appeared, with the nearest one at the top, which in this case was ROMEO. He didn’t spend enough time on the menu to notice that ROZO was not actually on the list — to bring it up, he would have had to type out the entire identifier, R — O — Z — O. Instead he immediately selected the navigational aid at the top of the list and pressed “execute” without stopping to confirm its identity. Little did he know he had just instructed the plane to fly to the ROMEO beacon near Bogotá, which lay some 250 kilometers behind them and to the left.
As soon as he instructed the plane to fly to ROMEO, the magenta line indicating their projected path on their FMS display changed to a sweeping U-turn to the left. Although both pilots were required to confirm the selection of the correct navigational aid and the resultant flight path, neither pilot said anything about this obvious discrepancy, and the autopilot began to dutifully turn the plane toward Bogotá. In their rush to get the plane configured for the straight-in landing, Tafuri and Williams had neglected to perform the cross-checks that should have caught the error.
As the plane turned away from Cali and toward the spine of the Andes, all references to Cali, TULUA, ROZO, or any other known location disappeared from their display. There was only the plane, the magenta line, and the black void of the mountains ahead of them.
“Uh, where are we?” First Officer Williams suddenly asked. “We goin’ out to…”
“Let’s go right to, uh, TULUA first of all, okay?” said Captain Tafuri.
“Yeah, where we headed?” Williams asked.
Captain Tafuri began trying to enter the identifier for TULUA to bring it up on their FMS display. “Seventeen seven, ULQ, uh…” he muttered. “I don’t know what’s this ULQ? What the — what happened here?”
In fact, ULQ was the identifier for TULUA. He was on the right track and he didn’t even know it. “Let’s come to the right a bit,” he said, making a minor and ultimately pointless correction to their trajectory. By this point they were flying east, not south, and yet somehow neither pilot had noticed this obvious problem.
“Yeah, he’s wanting to know where we’re headed,” said Williams.
“ULQ,” said Tafuri. “I’m going to give you direct to TULUA.”
“…Right now. Okay, you got it?”
“And… It’s on your map, should be.” Captain Tafuri had successfully entered TULUA into their FMS, although he had not yet instructed the plane to fly there. A dashed white line showed the projected flight path to TULUA, but it didn’t go where he expected. By this point they had passed TULUA and turned to the east, so the white line showed a left turn back to the northwest. This was not at all where Captain Tafuri expected TULUA to be. Most likely, he thought it was still ahead of them. He had fallen hopelessly behind his aircraft.
“Yeah, I gotta identify that fucker though, I…” Tafuri said. The projected flight path was all wrong, he couldn’t possibly be tracking TULUA. He listened in to the Morse code broadcast put out the by the beacon he had selected — it was clearly U — L — Q, the correct identifier for TULUA. “Okay, I’m getting’ it,” he said. “Seventeen seven. Just doesn’t look right on mine, I don’t know why.” Having confirmed that he really was tracking TULUA, the projected flight path to TULUA on the FMS display made even less sense.
“Left turn, so you want a left turn back around to ULQ,” First Officer Williams said, correctly reading the display. He began to turn left, heading towards TULUA.
“Nawwww, hell no,” said Tafuri. “Let’s press on to…”
“Well we’re — press on to where, though?” said Williams.
“TULUA,” said Tafuri.
“That’s a right, U… U…” Only it wasn’t a right, it was a left, as he had just said moments earlier. Williams began turning the plane back to the right anyway.
“Where we goin’? One two… come to the right. Let’s go to Cali first of all, let’s… we got fucked up here didn’t we,” said Tafuri.
“Go direct, C — L — O…” Tafuri said, entering the identifier for Cali. “How did we get fucked up here?” A few seconds later he continued, “Come to the right, right now, come to the right, right now.”
“Yeah, we’re, we’re in a heading select to the right,” said Williams.
By this point they had crossed over the first range of mountains and were in a high valley parallel to the main one. Upon making the right turn back to the south, they began tracking down this parallel valley, far to the east of the proper approach path. With their engines at idle and the speed brakes extended, they continued hurtling downward at 2,700 feet per minute, drawing ever closer to the mountains below. Hopelessly confused but mentally committed, they didn’t realize that they were digging their own graves.
Now Captain Tafuri again picked up the radio and called air traffic control. “And American, uh, thirty-eight miles north of Cali, and you want us to go to TULUA and then do the Rozo uh, to uh, the runway right? Runway one nine?”
The controller once again thought that something was strange about the request. Two minutes earlier they had reported that they were 38 miles from Cali, now they reported the exact same figure. Had they done some kind of loop? Where were they? The controller thought the crew seemed confused, but once again, he didn’t know enough English to express his concern. Instead he said, “You can [unintelligible] landed, runway one niner, you can use runway one niner. What is you altitude and the DME from Cali?”
“Okay, we’re thirty-seven DME at 10,000 feet,” said Captain Tafuri.
“Roger,” said the controller. “Report five thousand and uh, final to one one, runway one niner.”
Turning to his first officer, Tafuri said, “You’re okay. You’re in good shape now. We’re headin…”
In no universe were they in good shape. Perhaps Tafuri was simply trying tell himself that everything was okay, that he need not panic. In fact a healthy amount of panic might have been beneficial.
“We’re headin’ in the right direction, you wanna… shit, you wanna take the one nine yet?” said Tafuri. They were indeed going in the right general direction — south — but they were in completely the wrong place. “Come to the right,” he continued. “Come, come right to Ca — Cali for now, okay?”
“It’s that damn TULUA I’m not getting for some reason. See, I can’t get — okay now, no, TULUA’s fucked up.”
“But I can put it in the box if you want it.”
“I don’t want TULUA,” said Williams, who had perhaps realized that they passed TULUA ages ago. “Let’s just go to the extended centerline of uh…”
“Which is ROZO,” said Tafuri.
“ROZO,” Williams affirmed.
“Why don’t you just go direct to ROZO then?” said Tafuri. This was exactly the same plan that had taken them off course in the first place.
“I’m going to put that over for you.”
“…get some altimeters, we’re out of uh, ten now,” Williams finished.
The controller, becoming increasingly worried about the crew’s bizarre transmissions, called them again to ask for more information. “Niner six five, altitude?” he asked.
“Niner six five, nine thousand feet,” Tafuri replied.
“Roger, distance now?” the controller asked, perhaps trying to get a sense of whether the plane was too low. But he would never get an answer.
At that moment, the ground proximity warning system detected a mountainside rising rapidly beneath the plane. “TERRAIN! TERRAIN!” the warning blared. “WHOOP WHOOP, PULL UP!”
“Oh shit,” Tafuri exclaimed.
First Officer Williams immediately disconnected the autopilot, jammed the throttles to full power, and pulled the plane into a sudden climb. In the cabin, passengers screamed and held on for dear life as the plane pitched sharply upward, its engines roaring, panels shuddering. Heavy vibrations rocked the airplane as it climbed so steeply that it approached a stall.
“Pull up baby!” Tafuri shouted. Was he talking to his first officer or to the airplane itself? We will never know.
“PULL UP,” blared the GPWS. “WHOOP WHOOP, PULL UP!”
Airspeed decayed rapidly as they put everything they had into the climb. Sensing an impending stall, the stick shaker activated, warning the pilots that they were about to lose lift. The rapid-fire clack-clack-clack of the stick shaker joined with the GPWS to create a cacophony of terror.
“It’s okay!” Williams shouted.
“PULL UP,” said the GPWS.
“Okay, easy does it, easy does it!” said Tafuri.
For a moment the stick shaker stopped. “Nope,” Williams muttered.
“Up, baby!” Tafuri shouted. The stick shaker started clacking away again. The mountainside drew inexorably nearer, nearer…
“More! More!” Tafuri screamed.
“Up, up, up!”
“WHOOP WHOOP, PULL UP,” said the GPWS.
One second later, American Airlines flight 965, pitched steeply upward in a desperate attempt to escape, slammed into the side of a 9,000-foot mountain called El Diluvio. The plane plowed through the trees, breaking apart as it went. Debris careened over the top of the mountain and tumbled down the other side, rolling over and over, sliding, fragmenting, disintegrating. When the shattered remnants of the Boeing 757 finally came to rest, an eerie silence returned to the remote mountainside, penetrated only by the crackle of the flames.
For nearly everyone on board, the massive impact proved instantly fatal. Indeed, no one would have been surprised if the crash had left no survivors. And yet, by some miracle, the faintest glimmer of life held on amid the wreckage.
Dawn was approaching by the time the survivors began to regain consciousness. Among them were college students Mercedes Ramirez and Mauricio Reyes. Also alive was young father Gonzalo Dussan and his six-year-old daughter Michelle. They lay scattered across a vast debris field populated by the remains of over 150 passengers and crew who had not been so lucky.
It was cold up on the mountain, and the survivors were all gravely injured. Michelle Dussan’s legs were trapped in the wreckage and she couldn’t move to free herself. Mauricio Reyes and Mercedes Ramirez were both suffering from broken bones and internal injuries. Gonzalo Dussan had broken his back. He could hear his daughter crying out for help, and he managed to drag himself to the sound of her voice, where he saw her inside the mangled fuselage, still strapped into what was left of her seat. In the distance, he could also hear the sound of his 13-year-old son, Gonzalo Dussan Jr., calling out to him from outside the plane. But no matter how hard he searched, he couldn’t find him.
Back in Cali in the moments after the flight’s final transmission, an unsettling silence filled the control tower. No one could raise flight 965 on any frequency. Especially in light of the strange radio transmissions, everyone immediately feared that the plane had crashed.
As soon as the controller lost contact with flight 965, search and rescue operations kicked into gear. Families waiting to meet the passengers were told that the plane was circling over Cali because the airport had been closed. It wasn’t long before rumors began to swirl that the real story was that the plane was missing. An ambulance pulled up next to the terminal, and a team of rescuers hastily boarded. One of them wasn’t a rescuer at all: it was Mauricio Reyes’ older brother Juan Carlos, who had managed to talk his way on after telling the crew that he was a doctor. If his little brother was still alive, he was going to find him. “If you see a man who looks like me, it’s my brother,” he frantically told the rescuers. And so they set off.
At first nobody knew where to look for the plane. Witnesses had last seen it near the town of Buga, but where it flew from there was not clear. Locals reported rumors of a crash high on a nearby mountain, and the rescuers followed the rumors. Danger awaited them at every turn. The mountains were steep, the paths narrow, the night dark. The suspected crash site lay inside the so-called “Red Zone,” a region controlled by Marxist guerrillas. Military units had to move in to secure the area.
At first light, helicopters joined in the search, scouring the precipitous mountains around Buga for any sign of the plane. At 6:30 in the morning, shortly after sunrise, they finally found it: high on the slopes of El Diluvio, a terrible scar through the jungle marked the place where flight 965 had come to rest. No one expected to find any survivors. Officials had already told the media that there were none. But as the helicopter drew near the crash site, they came face to face with a miracle: someone was waving at them from the ground, crying out for help. Rescuers descended from the helicopter to find four survivors huddled around the wreckage, freezing and injured, but alive. Nearly nine hours had passed since the crash.
As paramedics hurried to stabilize the survivors, they finally found Gonzalo Dussan Jr., whose father had insisted his son was alive. “Gonzalito” had been thrown into a tree and had spent the entire night draped around a tree branch, completely exposed to the elements. He was alive, but unconscious and with only a faint pulse; he was airlifted immediately to a hospital, but soon died of massive internal injuries.
Meanwhile, those who had set out on foot began to reach the crash site. Juan Carlos Reyes was among those approaching the scene when someone called out, “Run, run, he looks like you!” And by some miracle, it really was his brother. After so much hoping against hope, knowing deep down that Mauricio was dead, it turned out he was alive all along — one of just four survivors out of 163 passengers and crew.
The weather soon took a turn for the worse, and after the evacuation of Mauricio Reyes it became impossible for helicopters to hover over the crash site due to low visibility. A decision was made to carry Michelle Dussan down the mountain on foot, because the little girl was in the gravest condition, while the others could wait for the weather to clear. A group of rescuers strapped Michelle to a makeshift stretcher made from airplane debris and began the long trek down through the jungle. But as it turned out, the weather cleared up rather quickly: helicopters were soon able to evacuate Gonzalo Dussan and Mercedes Ramirez to nearby hospitals, while Michelle Dussan didn’t arrive at the base of the mountain until nearly four hours later, the last of the survivors to be brought down from the crash site.
Save for these four lucky souls — as well as a dog which was found still in its kennel in the hold, virtually unscathed — no one remained to tell the story of flight 965. 159 people lay dead, including both pilots, making this the worst air disaster ever to occur in Colombia. The terrible crash and the incredible story of the survivors made headlines around the world. But one question baffled experts from the beginning: El Diluvio was nowhere near the approach path into Cali, so why was the plane there in the first place?
More so in this case than in almost any other, it was the cockpit voice recorder that revealed how the approach became so hopelessly derailed. Upon listening to the pilots’ conversation, investigators were left speechless. Over the course of seven and a half minutes, Captain Tafuri and First Officer Williams pushed ever deeper into an impenetrable fog of confusion. They had no idea where they were or where they were going, and yet they persisted, pushing onward toward inevitable disaster. How could two well-trained, well-regarded American Airlines pilots (as Captain Tafuri put it) get so “fucked up”?
A deeper analysis showed that much of their confusion began and ended with the flight management system. The FMS on the Boeing 757 was a highly capable alternative to traditional methods of navigation, but in 1995 understanding of its shortcomings was rather limited. The basic problem was that while the FMS could navigate with unprecedented reliability and accuracy, it was still just a computer that would do whatever the pilots asked it to do, even if what they asked it to do was wrong. At the same time, its very reliability encouraged pilots to depend on it to a worrying extent. Legendary American Airlines Advanced Aircraft Maneuvering Program instructor Warren Vanderburgh called these pilots “children of the magenta.” They had become so used to following the magenta line on their FMS that they lost their ability to question it, even if the magenta line led them to the gates of hell itself. For a long time, this tendency was promoted on an official level: far too many pilots during the 1980s were taught that they would always stay out of trouble if they just followed the magenta line.
Captain Tafuri and First Officer Williams were not exactly children of the magenta. The syndrome was more likely to take hold among less experienced and less competent pilots. But when pilots throughout the industry had received years of training that encouraged them to rely on automation, nobody was immune — not even the best of the best. So when Captain Tafuri encountered an unexpected exception in the FMS software architecture that led him to accidentally select a waypoint near Bogotá, he trusted the system so completely that he never even looked to see where it was taking him. The magenta line bent back to the northeast, away from their destination, and nobody said a word about it. By the time either pilot noticed anything was wrong, they had already rolled out on an easterly heading — a fact which, it seemed, neither of them ever truly appreciated.
The design of the FMS no doubt contributed to their confusion. Investigators felt it would be more intuitive if nearby navigational aids remained on the screen even when not directly selected, in order to help pilots orient themselves. When Captain Tafuri selected direct to Cali and the intermediate waypoints disappeared, he lost valuable reference points that could have later helped him figure out where he was. Instead, what he got was a magenta line slicing through a blank background, headed god only knew where. The disappearance of these waypoints was fundamental to Tafuri’s loss of situational awareness; in fact, he spent much of the rest of the flight trying to figure out where TULUA had gone, consuming valuable time which could otherwise have been spent not flying into the mountain.
Furthermore, one possible interpretation of the controller’s original clearance to fly “direct to Cali, report TULUA” would have been to report abeam TULUA while proceeding straight to the Cali VOR. But the design of the FMS didn’t allow for this perfectly reasonable interpretation, because TULUA disappeared upon selecting direct to Cali, making it much more difficult to comply with such an instruction. Frustratingly, FMS manufacturer Honeywell was well aware of the disappearing waypoint problem and had already introduced a fix on all new 757s, but the update was not retroactively applied to existing aircraft.
Another key link in the chain of events was the decision to accept the approach to runway 19 in the first place. The simple truth is that by the time the controller made the offer, it was too late for flight 965 to perform this straight-in approach. They were too high and too close to the airport and wouldn’t have enough time to perform all the required procedures. However, a number of factors compelled them to take this risky course of action with apparently very little forethought. One was the schedule: with the plane already two hours late, the pilots were keen to make up time, and not just to keep the company happy — they might have been looking forward to getting on the ground and relaxing in a hotel, given the hour. A second major factor, betrayed by the speed of their decision, was the fact that they had almost certainly done this before. There is a tendency among humans experienced in a particular field to rapidly choose a course of action if it is easily recognized as being similar to past situations, especially when under pressure. Thus, because they normally landed on runway 19 at Cali and had successfully handled late runway changes in the past, the crew accepted the offer without hesitation. As a result they did not adequately consider whether the approach was even possible, and were reluctant to alter their decision once it had been made.
This reluctance is also known as plan continuation bias. Closely linked to both confirmation bias and the sunk cost fallacy, plan continuation bias is the human tendency to stick with a plan despite mounting evidence that a new course of action is needed. Once the pilots became uncertain of their position, they needed to drop everything, climb to the minimum sector altitude, and fly in circles until they figured it out. However, making this decision can be surprisingly difficult. Choosing to abandon a plan — in this case, the plan to approach runway 19 — required a heightened level of situational awareness. It also would have required an admission that they were confused, which on the accident flight never occurred. Indeed, abandoning an approach due to navigational difficulties can feel like admitting to a failure unbecoming of an experienced pilot at a world class airline. Until the very end of the flight, Tafuri probably thought that he was perfectly capable of getting them back on course for a normal landing, if only he could get that damned FMS to work properly!
Investigators also looked at the pilots’ readiness for South American operations. Although both Tafuri and Williams had completed American Airlines’ training program for South American routes, a number of items suggested that they were not as familiar with the operating environment as they could have been. Captain Tafuri’s assumption that “direct to Cali” meant he could forget about all the intermediate waypoints was based on a very American understanding of the air traffic control system which did not appreciate the importance of hitting all the reporting points when in South America. Furthermore, although continuing to descend while unsure of one’s position is a bad idea anywhere, it’s an especially bad idea in the Andes. Numerous planes have been lost on South America’s high peaks due to navigational mistakes far smaller than that made by flight 965, including some American ones: for example, in 1985 an Eastern Airlines 727 crashed into the summit of a 19,600-foot peak in Bolivia, a location so remote that little wreckage was recovered and the cause is uncertain to this day. One would think that the pilots would be scared enough of the Andes to exercise heightened caution. So why didn’t they?
In addition to the biases already mentioned, investigators speculated that their awareness of the terrain might have been rather poor (as opposed to awareness of their altitude, which they clearly had, as routine altitude callouts were made right up until the end). One possible contributor was their approach chart, which marked high points but did not include any topographical shading or contour lines. Jeppesen, the company that designs aeronautical charts, had already begun producing approach charts with colorized relief, which is much more effective at instilling terrain awareness. However, it was only doing this for approaches to airports with an elevation change of at least 2,000 feet within six nautical miles of the airport, and Cali didn’t qualify, since the airport sat in the middle of a flat valley that was more than twelve miles wide. The result was that Captain Tafuri had flown to Cali 13 times, all of them at night, using an approach chart that did not provide the most intuitive picture of the surrounding terrain. Investigators speculated that he might not have known the position of the mountains with any specificity. But at the same time, Captain Tafuri didn’t need a perfect map of the topography to understand that Cali lies in the Andes! The more likely possibility is that he was so fixated on trying to “fix” the FMS that he never thought about the mountains at all.
All of these piloting mistakes and psychological traps led American Airlines flight 965 to the brink of disaster. But even after everything else that had happened, the ground proximity warning system kicked in, giving the crew one last chance to save the plane. The pilots performed the GPWS escape maneuver correctly, except for one overlooked detail: they forgot to retract the speed brakes. Having extended the speed brakes several minutes earlier in order to speed up their descent into runway 19, they never again touched the speed brake lever, and amid the confusion it simply slipped their minds. Heartbreakingly, investigators found that the speed brakes might have meant the difference between life and death. The speed brakes decrease lift, making the plane stall at a lower angle of attack. During a GPWS escape maneuver, the pilots must fly the airplane at the hairy edge of the stall angle of attack in order to extract maximum performance — that’s why the stick shaker stall warning kept going on and off during the final seconds of the flight. By making the plane stall at a lower angle, the effectiveness of this tactic was reduced. Investigators calculated that had the crew retracted the speed brakes within one second after beginning the escape maneuver, the plane would have had enough extra performance to clear the mountain.
Investigators noted that retracting the speed brakes was not part of the GPWS escape procedure that American Airlines pilots were required to memorize. Considering the number of distractions that affected the crew between the time when they deployed the speed brakes and the moment when they needed to retract them, it was rather unlikely that they would have remembered this step without having memorized it in training. Even so, the investigators had in mind a better solution: that the speed brakes should automatically retract when the pilots apply takeoff/go-around power. This would already occur if the plane was on the ground, but was inhibited while in the air, for reasons that in hindsight were difficult to fathom. This fact has been used in arguments in favor of Airbus, because the A320 and other fly-by-wire models were already capable of automatically retracting the speed brakes during a GPWS escape maneuver — therefore, had flight 965 been an Airbus rather than a Boeing, it probably wouldn’t have crashed.
The crash of American Airlines flight 965 struck doubt into the hearts of pilots and aviation experts across America. Captain Nicholas Tafuri and First Officer Donald Williams were two of the best pilots at American Airlines, which had one of the best pilot training programs in the world. Pilots learned the latest techniques in crew resource management, how to maintain situational awareness, and how to avoid controlled flight into terrain. Not long before the crash, the crew of flight 965 were given a case study examining Thai Airways flight 311, an accident in which a crew on approach to Kathmandu, Nepal became confused while trying to use their FMS and failed to realize that they had rolled out on the wrong heading and were flying into the Himalayas. The flight ended with a crash into a sheer mountain face that killed all 113 people on board. The similarities between this case study and the fate of flight 965 were not lost on anyone at American Airlines. The cause of both accidents was essentially the same: a stubborn refusal to forget about the FMS and go back to basics. Despite the case study, Tafuri and Williams were so focused on the problem in front of them that they never recognized that they were hurtling down the same deadly path as the Thai crew in Kathmandu.
Some pilots still have a hard time believing that such a highly regarded crew would act this way. One recently published book argues that the crew weren’t thinking straight because they were exposed to toxic fumes inside the plane, and that this possibility had been ignored by investigators to protect vested interests. While it could be true in theory, this alternative line of inquiry is based on the supposed impossibility of a well-trained crew at American Airlines behaving in such a manner, even though aviation history has shown us all too often that even well-trained crews are not immune to the psychological pitfalls that cause planes to fly into terrain over and over again. In fact, all the warning signs were there. Just over a month earlier, American Airlines flight 1572 nearly ended in disaster when it struck trees atop Metacomet Ridge on approach to Bradley Field in Hartford, Connecticut; although both engines failed after ingesting branches, the pilots managed to keep the plane in the air long enough to put it down just short of the runway. In the end, 78 passengers and crew were saved by the skin of their teeth. But if an American Airlines crew with a good record could hit a ridge during an approach in Connecticut, they could just as easily hit a mountain in Colombia, where the safety net is much thinner.
At first glance, this problem might seem unresolvable. But in the wake of the crash of flight 965, two main areas of improvement were identified: understanding of automation among pilots, and the development of new, more powerful ground proximity warning systems.
American Airlines flight 965 laid bare the fact that pilots needed to know more about how their automation worked, and when to decide that it would be better to do away with it. A new method of handling automation soon entered the mainstream: when in doubt, drop down a layer. When a situation is unfolding quickly and unpredictably, pilots ought to stop worrying about the FMS or other sophisticated computers and return to hand-flying the airplane. You wouldn’t mess around trying to program a new heading into the FMS to try to avoid a midair collision, so why should you do it while unsure of your position and descending at 2,700 feet per minute into the Andes? The correct response in both situations is to just fly the airplane. And while Tafuri and Williams would have told you that this was the correct response if you asked them, it evidently hadn’t been drilled into them hard enough.
Following the accident, and the near miss on flight 1572 one month earlier, American Airlines introduced new reforms intended to combat the risk of controlled flight into terrain. The FAA and American Airlines worked together to create a Safety Assessment Program that reviewed all of the airline’s operations and issued recommendations in seven areas. American Airlines created a Controlled Flight Into Terrain (CFIT) task force and a non-precision approach working group to provide guidance to crews on avoiding CFIT accidents. The airline also raised the minima for non-precision approaches by 100 feet and one half-mile visibility (1 mile on NDB approaches), and raised the threshold for the sterile cockpit rule to 25,000 feet while in Latin American airspace.
However, by far the most significant among the changes that came from the crash of flight 965 was the rollout of the Enhanced Ground Proximity Warning System, or EGPWS. Believe it or not, the original GPWS and the Enhanced GPWS were both the brainchild of a single man: Honeywell engineer Don Bateman. Bateman was known for his dogged efforts to prevent CFIT accidents, and for his unorthodox methodology when doing so. While searching for ways to improve his original GPWS design, Bateman learned that a secret Soviet terrain database had appeared for sale on the black market during the chaos following the collapse of the USSR in 1991. He convinced his superiors to give him enough money to buy it, and after successfully acquiring the database from god only knows who, it became the basis for the first iteration of EGPWS.
This next generation of ground proximity warning systems did away with the reliance on the radio altimeter and its inability to look ahead of the plane. Instead, the EGPWS would use GPS to track the position of the airplane against a global terrain database, allowing the system to predict a collision with terrain more than a minute in advance. The device also came with a moving map display that showed nearby terrain in colorized relief, greatly enhancing the pilot’s situational awareness. Gone would be the days of warnings that came too late to save pilots flying blithely toward darkened mountainsides.
Airlines were initially hesitant to test the devices, which one executive called “yet another box,” but following the disaster in Colombia, they changed their tune within days. American Airlines was the first to express a desire to try the new EGPWS, and United soon followed suit. With the help of these airlines, the FAA conducted a series of studies to assess the usefulness of EGPWS and the requirements it ought to meet, culminating in FAA approval of the device later in 1996. In 1998, the FAA proposed that such devices — which it referred to broadly as Terrain Awareness and Warning Systems, or TAWS — be installed on all aircraft with six or more passenger seats. The requirement to install TAWS went into effect in 2001, and all applicable airplanes had the systems by 2002.
Thanks to this technology, it’s hard to imagine a repeat of American Airlines flight 965 occurring today. In all but the most egregious cases, TAWS manages to cut through the confusion and save the day. Its brilliance lies in the recognition that humans will make mistakes, no matter how hard we train them not to — a fact best exemplified by the pilots of flight 965, whose long and storied careers now languish behind the long shadow of their final minutes. Indeed, it is sobering how quickly a lifetime of safe flying can go awry. The worst thing a pilot can do, therefore, is to look at what happened to Tafuri and Williams and think, “That would never happen to me.”
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