Cleared to Collide: The crash of USAir flight 1493 and SkyWest flight 5569, or the Los Angeles Runway Disaster
Note: this accident was previously featured in episode 36 of the plane crash series on May 12th, 2018, prior to the series’ arrival on Medium. This article is written without reference to and supersedes the original.
On the first of February 1991, a USAir Boeing 737 touched down on runway 24 Left at Los Angeles International Airport, her passengers and crew believing that an uneventful flight was at its end. And then, just as the pilots brought the nose down, something terrifying materialized out of the night in front of them: another plane, its propellers glistening in the darkness.
There was no time to avoid it. With a sickening crunch, the 737 plowed into the smaller plane, a SkyWest Metroliner, and the two aircraft slid, locked together, off the side of the runway and into a building, where they burst into flames. The fiery collision would leave 35 people dead; some in the crash itself, and many more in the mad rush to escape as fire consumed the wreckage. The proximate cause of the disaster was apparent from the start: the tower controller at LAX had accidentally cleared both planes to use the same runway at the same time, a fact which the controller herself was quick to acknowledge. She would soon find herself caught up in an age-old debate: when a professional makes a mistake, who is responsible? On the surface, the sequence of events leading to the accident was remarkably simple, hinging on a single, regrettable human error. But investigators ultimately went far deeper, delving beyond the actions of a single controller to reveal how the structure of the air traffic control system at LAX allowed that single error to metastasize into America’s deadliest runway collision.
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Los Angeles International Airport, popularly known by its IATA code LAX, is one of the busiest airports in the world. Tens of millions of people pass through it each year, and over 1,000 planes land or take off on its four runways every single day. Operations at the airport are conducted according to a detailed and reliable set of procedures which keep planes safe and on schedule, a never-ending dance in which hardly anything ever goes wrong. Certainly the crew of USAir flight 1493, an utterly ordinary scheduled flight to LAX, could not have anticipated that out of all those hundreds of thousands of flights, theirs would be the one to buck the trend.
USAir flight 1493, a second-generation Boeing 737–300, had departed Syracuse, New York on the first of February 1991, then flew to Washington D.C. and Columbus Ohio, before continuing to Los Angeles and San Francisco on the west coast. The flight crew, who took over in Washington, consisted of 48-year-old Captain Colin Shaw, a veteran pilot with over 16,000 hours, and 32-year-old First Officer David Kelly, who was less experienced than his captain but was hardly a rookie. Along with four cabin crew, they flew without incident to Columbus, where 83 passengers boarded for the next leg to Los Angeles.
As far as anyone could recall, the flight to Los Angeles was completely normal from beginning to end. After over four hours in the air, flight 1493 began its descent amid gathering darkness, slowly making its way down through the complex airspace surrounding LAX. Approach control cleared them for an instrument approach to runway 24 Right, but at 25 miles out the crew reported that the airport was already in sight, and the controller let them perform a simpler visual approach to runway 24 Left instead.
Night fell over Los Angeles, and the lights of the runway could be seen slicing through the urban sprawl toward the black void of the Pacific Ocean. The approach controller’s job was now done, and they called to say, “USA fourteen ninety-three, thanks for your help. Contact Los Angeles tower one three three point niner at ROMEN. Goodnight.”
“Thirty three nine, goodnight,” Captain Shaw replied. He then reached over and dialed in the tower frequency, from which he expected to receive clearance to land at any moment.
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At that moment, everything was running smoothly in the LAX control tower, where several controllers were on duty to manage traffic on the ground and in the immediate vicinity of the airport. Responsibility was divided by both phase of flight and location, as one set of controllers handled the two southern runways, 25L/7R and 25R/7L, while a separate set managed traffic in the northern runway complex, consisting of 24R/6L and 24L/6R. Within the northern complex, Ground Controller Sheri Arslanian was handling taxiing aircraft, while takeoffs and landings were the responsibility of Local Controller Robin Wascher.
The local controller, often referred to as the “tower,” issues takeoff clearances, landing clearances, and clearances to enter or cross active runways. Her jurisdiction began where the ground controller’s ended, at the taxiway leading to the head of runway 24L.
At 17:58, five minutes before USAir flight 1493 first contacted the tower, the controllers made contact with SkyWest Airlines flight 5569, a commuter flight which had just left the gate in the southern complex and was making its way to runway 24L for takeoff. The plane was a Fairchild Metroliner, a 19-seat twin turboprop commonly seen at LAX in 1991. SkyWest had a large fleet of Metroliners feeding into the Delta Airlines network, as did rival commuter airline Wings West, which operated the type on behalf of American Eagle.
This particular Metroliner had recently arrived from Fresno, California, and was now scheduled to carry 10 passengers to Palmdale, a midsized city in the Mojave Desert some 60 kilometers north of LA. In command were 32-year-old Captain Andrew Lucas and 45-year-old First Officer Frank Prentice, who brought the total number of people on board to 12, as the plane was too small for a flight attendant.
Because the runways at LAX are very long and the Metroliner is very small, there was no need for the flight to taxi all the way to the end of the runway — it could take off just fine from the middle. On runway 24L, small planes usually performed these so-called intersection takeoffs from intersections 45 and 47, several hundred meters beyond the runway threshold. As such, when the SkyWest pilots contacted north complex ground controller Arslanian, they requested to be routed to intersection 45. In response, Arslanian cleared them to enter Taxiway Uniform, which ran parallel to runway 24L, and instructed them to contact the tower upon reaching Taxiway 45.
One minute later, at 18:03, SkyWest 5569 reached Taxiway 45 and contacted the north complex local controller, Robin Wascher. “SkyWest five sixty nine, at forty five, we’d like to go from here if we can,” the pilot said.
“SkyWest five sixty nine, taxi up to and hold short of two four left,” Wascher replied.
“Roger, hold short,” said SkyWest.
Meanwhile, Wascher continued to handle numerous airplanes in the vicinity of runways 24L and 24R. She cleared another SkyWest plane, flight 246, to cross runway 24L, enter 24R, and take off without delay. She then turned her attention to Wings West flight 5006, a Metroliner which had just landed on 24R and needed to cross 24L to get to its gate. “Wings five thousand six, taxi across runway two four left, contact point six five when off the runway, goodnight,” she said.
Six seconds went by without a response. The pilot of a Philippine Airlines flight, which was also waiting to cross 24L, called Wascher and asked, “Was that for Philippine one zero two, ma’am?”
“No, hold short,” Wascher replied. “Wings West five thousand and six,” she repeated, “taxi across runway two four left, contact ground point six five when off the runway.”
Eleven more seconds passed without a reply. A USAir flight took off, and she handed it over to departure control.
One second later, USAir flight 1493 called the tower for the first time. “USAir fourteen ninety-three, inside of ROMEN,” Captain Shaw said, reporting his position. The 737 was on final approach and needed landing clearance soon.
Wascher, however, was still busy trying to contact the Wings West Metroliner that was supposed to cross runway 24L. “Wings five thousand and six, ground — uh, tower?” she asked. Again, there was no reply.
Turning to SkyWest 5569, she said, “SkyWest five sixty-nine, taxi into position and hold runway two four left, traffic will cross downfield.”
“’Kay, two four left position and hold, SkyWest five sixty-nine,” the pilot replied. Flight 5569 entered runway 24L at intersection 45, assuming the takeoff position. Wascher planned to clear it for takeoff only once she had confirmed that Wings West 5006 had safely crossed the runway in front of it.
But before she could do that, she needed to find the missing Metroliner. “Wings West five thousand and six, tower?” she asked again. For the fourth time, there was no reply.
Up at the head of the runway, a Southwest Airlines Boeing 737 also wanted attention. “Tower, Southwest seven twenty-five’s ready in sequence,” the pilot said.
“Southwest seven twenty-five, roger, taxi up to and hold short of two four left,” Wascher instructed.
“Up to, hold short, Southwest seven twenty-five,” Southwest replied.
“You’ll follow the Metroliner,” Wascher added, referring to SkyWest 5569.
Of course, Southwest 725 couldn’t enter the runway until SkyWest 5569 had taken off, which couldn’t happen until Wings West 5006 had crossed the runway. And then there was USAir 1493, which was already on short final to land on that same runway. But Wings West 5006, the lynchpin of the whole sequence, was missing. Where had it gone? In hindsight, one can already see events beginning to spiral out of control, as Wascher struggled to keep track of each plane, its intentions, and the interlocking web of dependencies which those intentions created.
Finally, at 18:05, Wings West 5006 suddenly reappeared. “[Wings West five thousand six], on frequency again, changed radios, sorry ‘bout that,” the pilot said.
“Five thousand six, you’re back with me!” said Wascher.
“Yeah and we didn’t mean to switch radios, we’re now on,” said the Wings West pilot.
“Okay, I thought I lost you,” said Wascher. “[Cross] runway two four, contact ground point six five when off the runway, traffic will hold in position.”
“Great, and we thought we lost you, we apologize,” said Wings West.
“No problem, Sundance five eighteen, taxi across runway two four left, contact ground point six five when off the runway, goodnight,” Wascher repeated — although she accidentally referred to Wings West 5006 as Sundance 518, a flight which hadn’t been in her sector for over four minutes. This may a have been a sign that she was starting to lose the plot.
Sensing a gap, Captain Shaw on USAir 1493 jumped in again to try to get landing clearance. “USAir fourteen ninety-three for the left side, two four left,” he repeated.
But Wascher was busy with SkyWest flight 246, the plane which had earlier crossed runway, and was now taking off from runway 24R. “SkyWest two forty-six, heading two seven zero, contact Los Angeles departure, goodnight,” she said.
“Two forty-six, goodnight,” said the departing SkyWest pilot.
Now her thoughts turned to Southwest 725. “Southwest seven twenty-five, you’re holding short of two four left, correct?” she said. For several seconds there was no reply, so she said, “Southwest seven twenty-five, tower?”
“Ah, seven twenty-five, go ahead,” said the Southwest pilot.
“Yes sir, you’re holding short, is that correct?” Wascher repeated.
“Yes ma’am, we’re holding short,” said Southwest.
“Thank you.”
Wascher’s intention was to verify that the runway was clear for USAir 1493. Having confirmed that Southwest 725 was indeed holding short of the runway, she addressed the USAir flight, “USAir fourteen ninety-three, cleared to land runway two four left.”
“Cleared to land two four left, fourteen ninety-three,” Captain Shaw read back.
Wascher did not appear to realize that she had just made a critical error. Runway 24L was not, in fact, free — SkyWest flight 5569 to Palmdale was still sitting in the middle of intersection 45, waiting for takeoff clearance. Wascher had planned to clear it for takeoff once Wings West 5006 had crossed the runway, but somehow, amid the numerous overlapping communications, she had forgotten.
Nevertheless, the never-ending dance continued. Perhaps if she had had a moment of downtime, Wascher would have realized her mistake, but she did not. As soon as the last transmission from USAir 1493 was complete, another USAir flight called the tower: “Twenty-eight fifty-eight’s for the right, five miles,” the pilot said, requesting a landing on 24R.
“USAir twenty-eight fifty-eight, wind two three zero at eight, cleared to land runway two four right,” Wascher said.
“Cleared to land,” USAir 2858 acknowledged.
Seconds later, another Wings West Metroliner, which had just taxied into Wascher’s sector, came on the radio and said, “Tower, Wings West fifty seventy-two is ready for takeoff.”
“Wings fifty seventy-two?” Wascher asked.
“Affirmative,” said the pilot.
Wascher had no idea who was talking to her. Normally, she learned about aircraft which would enter her section via paper “progress strips” containing information about the flight and its intentions, which were filled out by the Clearance Delivery controller while the plane was at the gate. But nobody had given her a progress strip for Wings West 5072. Without this information, Wascher didn’t know where flight 5072 was or what it wanted.
“Wings fifty seventy-two, [are] you at forty-seven or full length?” she asked, trying to determine whether or not the flight wanted an intersection takeoff.
“We’re full length,” flight 5072 replied.
“Okay, hold short,” Wascher said.
“Roger, holding short,” said flight 5072.
“Wings fifty seventy-two, say your squawk,” Wascher said, asking for the transponder code assigned to the flight. If they didn’t have one, then the plane must have left the gate without clearance. If they did, then someone failed to give her the progress strip.
“Forty-six fifty-three,” flight 5072 replied, providing their transponder code. That meant the strip was missing, not the clearance.
Just then, yet another Wings West flight called and said, “Los Angeles tower, Wings West fifty-two twelve with you on the visual two four right.”
There was no reply from Wascher, who was busy asking the Tower Supervisor for help finding Wings West 5072’s flight progress strip. After a brief search, the strip was found in a stack of strips back at the Clearance Delivery station — the Clearance Delivery controller had forgotten to pass it on.
On board USAir flight 1493, all seemed normal as the pilots held the plane on course for landing on runway 24L. First Officer Kelly could see planes lined up on Taxiway Uniform, waiting to take off, but the runway appeared to be clear.
“Looks real good,” he said.
“Ahh, you’re coming out of five hundred feet, bug plus twelve, sink is seven,” said Captain Shaw, calling out flight parameters.
A few ATC transmissions passed in the background. “Lights on,” Shaw announced.
Flight 1493 descended out of the crystal clear night and alighted smoothly on runway 24L, its nose high as First Officer Kelly flared for touchdown. The main landing gear made contact perfectly in the touchdown zone, and Kelly began applying brakes and reverse thrust, slowing the plane as he pushed the nose down onto the runway.
And then, just as the nose was about to touch down, the pilots suddenly caught sight of another plane directly in front of them — a Metroliner, waiting for takeoff, its spinning propellers glittering under the glare of the 737’s landing lights. Kelly pushed the brake pedals to the floor, but there was no time to avoid it. In a flash, the 737 slammed into the back of the Metroliner at over 150 kilometers per hour.
In the back, passengers felt a sudden deceleration, followed a split second later by an mighty cacophony of twisting metal. The impact snapped the 737’s nose gear, sending the nose toppling to the ground, while the Metroliner’s right propeller sliced through the 737’s lower fuselage. The Metroliner’s fuel tanks immediately ignited, sending fire streaming past the windows. First Officer Kelly kept standing on the brakes, but they seemed to have no effect. With the Metroliner crushed underneath it, the 737 veered hard to the left, sparks flying, and skidded across several taxiways, consumed in flames, in full view of hundreds of people in and around Terminal 2.
In the end, the runway excursion was short. Despite Captain Shaw’s last-ditch efforts to steer away, USAir flight 1493 plowed into a disused airport fire station at about 100 kilometers per hour. With a terrific crunch, the plane stopped on a dime, surrounded by fire. In the badly smashed cockpit, Captain Shaw was killed near instantly — First Officer Kelly heard him draw a few ragged breaths, and then he was gone.
In the cabin, however, all the passengers and flight attendants had survived the crash. Desperate to get out of the burning plane, the 83 passengers undid their seat belts with a chorus of clicks and hurried into the aisles. In the back, both rear flight attendants had unfastened their seat belts too early and were thrown against the aft galley bulkhead on impact, but neither was seriously hurt, and they quickly opened both exits. The L2 exit was blocked by fire, however, and the flight attendant closed it again, forcing those in the back of the plane to use only the R2 exit, on the right side of the plane.
In the front, a flight attendant opened the R1 exit on the right side behind the cockpit, but within seconds heavy smoke poured into the first class cabin, making it difficult to see or breathe. One passenger staggered out of the choking cloud, and he pushed him out; another followed, jumping almost two meters down to the ground, as the slide had not deployed. The R1 flight attendant then tried to push into the first class cabin, but the heat and smoke were so intense that he couldn’t get past row one, so he fled.
For most of those on board, however, neither of these exits was the most convenient. The majority of the passengers immediately leapt for the overwing exits, but escaping through them would not be easy. The left overwing exit was almost totally blocked by flames; only two passengers managed to escape through it, crawling across the left wing before dropping to the ground. Meanwhile at the right overwing exit, the passenger seated closest to the hatch was frozen in fear, unable to rise from her seat or even to undo her seat belt, let alone open the door. Witness accounts vary regarding what happened next — according to one version, two men started fighting over who would open the exit door, as one accused the other of not knowing how to do it, before a third man climbed over them, opened the door, tossed one of them through it, and pulled the shell-shocked woman through after him. Other versions hold that the two fighting men managed to open the door themselves, or that someone else opened the door, and the fight was over who would get to go through it first. Regardless, it was an ugly display of tension amid a life-or-death race to escape.
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In the tower, controllers had caught sight of the explosion as the two planes collided, and an unidentified voice on the tower frequency exclaimed, “What the hell!?”
Witnessing the unfolding disaster, Tower Supervisor Francita Vandiver immediately activated the crash phone, and firefighters hurried to the scene. Despite this, however, traffic continued to build up, and Robin Wascher needed to deal with it. “Southwest seven twenty-five, just remain off the runway at this time,” she said.
“Helicopters PD eighty, do you need any help over there?” a helicopter pilot asked.
“Right now we don’t know,” said Wascher.
“Wings fifty-two twelve, we’re on a visual for two four right,” said the inbound Wings West flight, the same one who had tried to call Wascher earlier.
Her voice calm, betraying only the tiniest hint of emotion, Wascher replied, “Wings fifty-two twelve, wind two four zero at eight, cleared to land runway two four right — ah, use caution, we just had an aircraft go off the runway in flames.”
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By the time firefighters arrived around one minute after the crash, passengers were already streaming out onto the taxiway as flames threatened to consume the airplane. Some of the passengers were completely unhurt, but others had inhaled smoke and could scarcely breathe; a few were entirely engulfed in flames, suffering severe burns even as firefighters hurried to save them.
In the cockpit, First Officer Kelly tried to free himself from the wreckage, but his leg was stuck. Heat and smoke engulfed him, but just when it seemed he would not survive, he managed to pull his foot out of his shoe, and his leg came free. Moments later, firefighters pulled him out through the cockpit window. Even as they rushed him to safety, he urged them to go back in for Captain Shaw, but there was nothing they could do — Shaw was already dead.
Just behind the cockpit, firefighters pushed in through the R1 door to fight the flames inside the cabin, while others went around to the left side of the plane to tackle the fire between the fuselage and the building. It was here, near the seat of the fire, that they made a chilling discovery: a propeller.
Up until that moment, the controllers had assumed that USAir flight 1493 was the only airplane involved in the accident. Robin Wascher herself apparently had terrorism on her mind, as her first thought was that a bomb had exploded on board the plane. Only when the firefighters informed the tower about the propeller did they begin searching for a second missing flight. By then, Wascher had been relieved of duty, as was standard procedure after an accident — but as she was leaving the tower, a horrifying realization came over her. She immediately returned to the tower and asked the new local controller: had anyone been in contact with SkyWest flight 5569? A few inquiries were made, but no one had. Wascher took flight 5569’s flight progress strip, went to supervisor Francita Vandiver, and said, “This is what I believe USAir hit.”
It was a startling admission, one which took no small amount of courage. Wascher knew that she had forgotten to clear the Metroliner for takeoff, and that she had cleared USAir flight 1493 to land on top of it, causing the crash — and she admitted it immediately.
Shortly after informing the supervisor of her error, her veneer of calm finally broke down. In the controllers’ break room, her colleagues tried to comfort her as she sat there, crying and smoking a cigarette, mumbling “I’m sorry, I’m sorry,” over and over again. Every so often she would ask if everyone on the planes was okay — but her colleagues didn’t have the heart to tell her that dozens were dead.
Out at the crash scene, firefighters were instructed to follow the debris trail back to the point of impact to determine whether anyone on board the Metroliner may have survived after being ejected from the airplane. Numerous pieces of the Metroliner were found strewn throughout the area, and rescuers came across several bodies, but they found no survivors. Between those who were ejected and those who were crushed beneath the 737, it was clear that none of the 12 people on board SkyWest flight 5569 had survived.
By the time the fire was out, however, it had become apparent that loss of life about USAir flight 1493 was even heavier. Twenty-one people were found dead inside the plane, including Captain Shaw and one of the flight attendants, who had joined the line of passengers trying to escape through the overwing exit, only to succumb to the toxic smoke. She and ten other passengers were found collapsed in the aisle just short of this exit, unable to escape in time. In fact, only two bodies were found still in their seats, indicating that everyone else attempted to get out, but was unsuccessful. And not all of those who escaped pulled through either: two passengers who initially survived later died in hospital from extensive burns. In all, 35 people died, 23 of them on USAir flight 1493, while 66 survived.
Autopsies would later show that Captain Shaw and eleven occupants of the Metroliner died on impact. The remaining occupant of the Metroliner and the other 22 victims aboard the 737 were killed by fire, smoke, or both.
One of the questions facing National Transportation Safety Board investigators was why so many people died after surviving the initial collision.
One of the first things they noted was that only four of the plane’s six exits were usable at any point, and for the most part, passengers escaped through just two of them. Only three people used the R1 door, including a flight attendant and two passengers. One of these passengers happened to be David Koch of Koch Industries, a wealthy industrialist and political megadonor who gave a number of interviews about his experience. Koch was the only survivor out of the three people seated in First Class, apparently because the others went toward the back of the plane, while Koch went forward, towards the source of the smoke, which was streaming in through a hole in the forward cargo bay. Koch then claimed that he opened the R1 door, a story which he repeated numerous times over the years, but which appears to be, at best, a case of mistaken recollection, as the NTSB report states that the flight attendant opened this door, not a passenger.
In any case, despite the fact that the R1 door was the nearest exit for many, almost everyone in the forward section tried to get out through the right overwing exit instead, presumably because they wanted to move away from the smoke. Only 17 people, including two flight attendants, used the R2 door at the back, and only two used the left overwing exit. Everyone else used the right overwing exit, but they were slowed down by the exit row passenger who froze up and by the two men who got into a fight in front of the door.
For those who could not immediately exit, conditions in the cabin became hellish very quickly. Survivors reported that the entire plane filled with black smoke almost instantly after the crash. The 15 passengers who left via the rear said that they were only able to find the exit thanks to the track lighting in the floor — a handy feature installed as a result of the 1983 tragedy aboard Air Canada flight 797. Those in the front, however, reported that the track lighting didn’t come on, and it was in this area that virtually all of the victims were seated.
Unfortunately, there was little that could have been done to save them, as the smoke and fire entered the cabin much faster than certification requirements assumed. Although the 737’s fuel supply was never involved in the fire — all the fuel was later found unburnt — the rupture of the Metroliner’s tanks created a pool of burning fuel under the plane that entered the cabin almost immediately. The NTSB noted that the fire’s entry was accelerated by the rupture of the flight crew oxygen reserve cylinder during the crash, which fed the fire under the forward galley, and by the fact that some cabin furnishings, such as the overhead bins, had not yet been updated to meet the latest flammability standards.
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Another matter investigated by the NTSB was why the pilots of the two planes did not see each other in time to avoid the collision. Although the Metroliner didn’t have a cockpit voice recorder, rendering it impossible to say what the pilots were doing, it was hard to imagine that they could have seen a plane which was directly behind them. The USAir pilots, however, should have had an opportunity to spot the Metroliner. After all, it was a perfectly clear night, with at least 25 miles of visibility. But in his testimony before the Board, First Officer Kelly, the only surviving pilot from either plane, stated that the runway appeared perfectly clear — it was like the Metroliner wasn’t even there.
To understand why, investigators waited until a night with similar weather conditions, then positioned an identical Metroliner at intersection 45 on runway 24L at LAX. The investigators then flew several simulated approaches to runway 24L in a helicopter while the pilots of the Metroliner tested different lighting configurations. What they found was that if all of the Metroliner’s lights were turned on, it was possible to discern the aircraft, but in most configurations, it would blend almost perfectly into the runway lighting.
The Metroliner was equipped with an anti-collision beacon on the tail, navigation lights on the wingtips and tail, a taxi light on the nose, strobe lights on the tail and wingtips, and landing/recognition lights on the wings. However, normal Metroliner procedures called for the strobes, taxi light, and landing/recognition lights to be turned on only after receiving takeoff clearance. That left only the anti-collision lights and the navigation lights. An examination of the light bulbs confirmed that only these lights were illuminated at the time of the crash.
Testing showed that if these were the only lights on the Metroliner, it would have been very difficult to see. The navigation light on the tail blended perfectly with the runway centerline lighting, and the red anti-collision beacon was surprisingly dim. It was possible to spot the Metroliner if one knew it was there, but if one didn’t, it would have been a challenge. The findings therefore confirmed that it was unlikely that the pilots of USAir flight 1493 could have avoided the accident by seeing the Metroliner.
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The most important question, however, was why the planes were on the same runway in the first place. Sometimes, this type of question is quite difficult, but in this case, the answer was fairly obvious — from her very first interview, Robin Wascher explained that she had cleared both planes to use the same runway at the same time. She had originally cleared SkyWest 5569 to taxi into position and hold on the runway, intending to grant takeoff clearance once Wings West flight 5006 had crossed downfield, but this plane went AWOL for over a minute. It was at this point that Wascher began to lose situational awareness. The time spent trying to find Wings West 5006 caused other tasks to start piling up as more planes continued to request clearance to land, take off, or enter the runway. When she got back in contact with flight 5006 at 18:05, she told its crew that “traffic will hold in position,” suggesting that she was still aware that SkyWest flight 5569 was holding on runway 24L. But less than one minute after that, she cleared USAir flight 1493 to land on that same runway.
According to Wascher’s testimony, after Wings West flight 5006 crossed the runway, she saw a Metroliner moving up Taxiway Uniform near where SkyWest flight 5569 had been a minute or two earlier. Because the only Metroliner that was supposed to have been on Taxiway Uniform was SkyWest flight 5569, she thought that this unidentified aircraft must in fact be flight 5569, which, she assumed, must not have taxied into position on the runway because it was stuck in traffic. Flight 5569 was in fact sitting on the runway at intersection 45, patiently waiting for takeoff clearance, but it would have been hard to see it if she wasn’t specifically looking for it. Wascher noted, and other controllers agreed, that aircraft at intersection 45 were difficult to see at night because of glare from a set of four light poles installed on the ramp following the renovation of terminal 2 in 1989.
Thus having forgotten that she had cleared flight 5569 to enter the runway, and seeing a plane which she thought to be flight 5569 still on Taxiway Uniform, Wascher cleared USAir flight 1493 to land.
However, this second Metroliner was not SkyWest 5569, but Wings West 5072, a flight which Wascher was not expecting because the Clearance Delivery controller had inadvertently failed to pass her its progress strip. When flight 5072 identified itself to her, she was caught off guard. At this point approximately 50 seconds remained until the collision, but all of that time ended up being spent clarifying the identity of flight 5072 and searching for its progress strip. Almost as soon as she returned to her station, the planes collided.
In effect, Wascher’s mistake was caused by the untimely coincidence of two major distractions — the plane on the wrong frequency, and the missing progress strip — combined with a random memory lapse. The question which many observers now asked was a difficult one: did the source of the problem lie with Wascher, the system, or both?
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At the time of the accident, Robin Lee Wascher was 38 years old and had been working as a civilian air traffic controller since 1982. Even before the accident, however, her life had not been particularly easy. She served in the United States Air Force from 1971 until 1977, initially as a dental specialist. She transitioned to air traffic control in 1975, but less than two years into her new position, tragedy struck the Wascher family. In June 1977, Wascher’s parents flew their single-engine Aero Commander 112 to Eureka, California, to attend another daughter’s college graduation; but on the way back, controllers lost contact with their plane. The Waschers never arrived back home in Oxnard, and their plane was believed to have crashed somewhere in the rugged wilderness of far northern California. Despite extensive searches, however, neither the plane nor its occupants was found. The disappearance of her parents left Robin Wascher emotionally unable to continue working around airplanes, and in July 1977, she reported to a flight surgeon that she was no longer fit for duty. Two weeks later, she was honorably discharged from the military.
Wascher might never have gotten back into air traffic control were it not for the infamous PATCO strike of 1981, which ended with President Reagan’s mass firing of every striking controller. With so many controller positions now desperately seeking applicants, Wascher reapplied, and was accepted in 1982. Due to her background, the FAA subjected her to a special psychiatric evaluation, but she displayed no serious emotional problems and was found fit for duty.
In the subsequent years, Wascher slowly moved up to busier and busier airports, starting at Gulfport, Mississippi before moving to Aspen, Colorado. Colleagues at Aspen recalled that she took her job seriously, and she was said to “unflinchingly” reprimand pilots of private jets who knowingly landed after curfew.
After gaining several years of experience, Wascher was transferred to LAX in 1989. It was her dream to work a “big airport,” and LAX was ideal not only because of its size, but because its location on the west coast made it easier for her to spend time looking for her parents — a mission she had never given up, even though more than a decade had passed since their disappearance.
Although she cared deeply about her profession and clearly tried her hardest, Wascher did face some difficulties at LAX. One month after her certification as a full-performance controller at the Los Angeles tower, a supervisor conducted an over-the-shoulder evaluation and found several weaknesses in her performance, including the use of an incorrect callsign, two failures to complete control handovers, a failure to issue a required advisory to an aircraft, and a loss of awareness of aircraft separation. These were serious issues which, according to the examination protocol, should have prompted remedial training. But the supervisor, who appeared to be uncertain about the nature and purpose of the examination program, merely discussed the issues with Wascher instead of recommending more training. Six weeks later, the accident occurred.
All of this personal history made its way into hands of the media in the days and weeks after the crash, prompting members of the public to question whether Wascher was fit for duty. Her colleagues, however, were quick to her defense. For days after the accident they ensconced her in a hotel room and guarded the entrance to keep her away from journalists — she was certainly not in the right emotional state to talk to them. Instead of letting the media pile on, Wascher’s colleagues conducted their own interviews with journalists, in which they hammered home a salient point: it didn’t matter what past traumas she had experienced, and it didn’t matter that she probably wasn’t the best controller ever to work the LAX tower. What happened to Wascher, they said, could have happened to any of them.
It would have been easy to take all of the above and say that Wascher’s past explained her loss of situational awareness on the night of the accident. But the NTSB is not keen on that sort of moralizing. In the end, investigators indirectly backed the other LAX controllers: the cause of the crash wasn’t Wascher’s mistake, they argued, but the environment in which it occurred. Anyone could have made a similar error — who exactly was sitting in the local controller position was unimportant, because even the best controllers make mistakes, and only a deficient system would allow a single mistake to lead to disaster.
In the end, the NTSB identified numerous factors which came together to enable a fatal outcome on the night of February 1st, 1991. Most notably, there was a lack of redundancy in the procedures and staffing in place in the tower. Wascher was the only person responsible for ensuring separation between planes landing and taking off in the north complex, despite the heavy traffic in this area. No assistant controller position existed, even though it was considered best practice to have one. An assistant could have performed such tasks as managing progress strips and relaying questions to the supervisor, while helping to monitor the progress of aircraft on the runway surface. Instead, Wascher had to do all of these things by herself. Not only did this cause distractions which diverted her from her primary task of separating aircraft, it also reduced the number of eyeballs which were watching the airplanes at any given moment.
A second deficient area was the way the LAX tower handled progress strips. According to the Federal Aviation Administration’s standardized ATC regulations, ground controllers were required to be involved in the process of forwarding progress strips, but at LAX, managers had decided that progress strips should be sent directly from clearance delivery to the local controller, bypassing the ground controller. The purpose of this measure was to reduce the workload on the ground controller, but in practice it simply increased pressure on the local controller instead. Normally, pilots should tell the ground controller where they want to take off — at the runway head, or at a particular intersection — and the ground controller should mark this information on the progress strip before giving it to the local controller. This would provide the local controller with a written indication of every airplane’s intentions. At LAX, however, the local controller had to individually determine where each plane was going and then later recall this information from memory.
This issue played a subtle but important role in the sequence of events. First of all, it meant that the progress strip for SkyWest 5569 did not indicate whether the pilots intended to take off at intersection 45, intersection 47, or “full length.” After clearing it onto the runway, Wascher had to simply remember where it was. And second, under the system prescribed by FAA regulations, the problem of the missing progress strip for Wings West 5072 would have been discovered by the ground controller and dealt with at that position without Wascher having to get involved. She therefore would have received the progress strip on time, and would have known in advance that the Metroliner taxiing on Uniform was Wings West 5072, not SkyWest 5569. This would have eliminated the confusion between the two aircraft and the time spent looking for the progress strip, without which she might have remembered that SkyWest flight 5569 was on the runway in time to prevent the accident.
During the NTSB’s investigation, the LAX tower managers and FAA representatives both argued that the procedure in place complied with FAA regulations, which specified that progress strips should be forwarded to the “appropriate” position. In their view, this language was used so that towers would have leeway to modify the progress strip forwarding process according to their particular needs. However, the regulations also provided a description of the ground control position and listed handling progress strips as one of its required duties. In the NTSB’s opinion, the regulations were sufficiently clear about who needed to handle progress strips, and besides, the intent of the regulations was to standardize ATC practices across the country, so allowing individual towers to arbitrarily modify those practices would defeat the purpose.
Finally, in addition to a lack of human and procedural redundancy, the NTSB highlighted a lack of technological redundancy as well. Some readers may already be wondering: was LAX equipped with ground radar which could have revealed the presence of the Metroliner on the runway? The answer was yes — but it wasn’t working. Although LAX had an Airport Surface Detection system, as the technology was known, it had been custom built for the airport, and sourcing spare parts was difficult. As a result, it broke down frequently throughout the 1980s, sometimes for long periods of time. As early as 1987, ATC managers at LAX began telling the FAA that getting a new ASD system was of paramount importance, and installation of a new system was briefly scheduled for October 1988, but it became bogged down in development, and by 1991 it still wasn’t ready. As a result, the old ASD was still in use at the time of the accident, and on February 1st, the ground radar display at the Local Controller 2 position occupied by Robin Wascher was inoperative.
Although it was possible that the availability of ground radar could have prevented the accident, the NTSB expressed skepticism that it would have made any difference, because there was no point during the sequence of events when she would have been required to look at the display, nor was it clear when she would have found time to scan it thoroughly enough to spot an aircraft in an unexpected location.
Besides the problematic ASD, the NTSB also confirmed that the glare from the ramp lights on terminal 2 contributed to Wascher’s inability to see the Metroliner on the runway. During the first phase of construction on this terminal in 1988, controllers had complained about glare and the position of the lights was altered, but additional lights were installed during the second construction phase in 1989. These lights elicited the same complaints, but this time, a breakdown in communication occurred and personnel in terminal 2 were never told to modify them. Regrettably, this would have been an easy fix, and indeed the lights were modified to reduce glare shortly after the accident.
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Taken collectively, these factors made it clear that Robin Wascher made her mistake in an environment in which an error could be potentially deadly. In its final report, the NTSB wrote that “the expectation that controllers can perform for any length of time without error is unwarranted.” Quoting their own findings in an earlier runway collision between a Boeing 727 and a Beechcraft King Air in Atlanta, they then added that the cause of both accidents was “the failure of the FAA to provide air traffic control procedures that adequately take into account those occasional lapses in performance that must be expected. … The designers and operators of complex systems, such as the ATC system, who … allow a single individual to assume the full burden for safety-critical operations, must share responsibility for occasional human performance errors.” Consequently, in its probable cause statement, the NTSB cited the regulatory and procedural environment in which the mistake occurred, rather than the mistake itself, as the cause of the accident.
By forcefully expressing their stance on this issue, the NTSB thankfully prevented any movement to blame Robin Wascher for the crash. In fact, her behavior after the accident was outstanding — she admitted fault immediately, never tried to deflect blame, and answered the NTSB’s questions truthfully and thoughtfully. Some of her colleagues commented that they could not have been as brave had they been in her place.
As a result of the accident and the NTSB’s recommendations, a number of important safety improvements were made. Days after the accident, the FAA ordered all controllers in America to stop clearing aircraft to “taxi into position and hold” on a runway during nighttime or poor visibility, an order which was later made into a permanent rule. The FAA also modified aircraft design requirements, beginning in 1992, to mandate easier access to overwing exits.
In addition to these unilateral changes, the NTSB also issued a large number of recommendations. First, the agency urged airlines to upgrade older aircraft with less powerful lighting, such as the Metroliner, to meet the same standards as newer aircraft. Had the Metroliner been equipped with modern lighting, its anti-collision beacon would have been at least four times brighter. In this area, the NTSB also recommended that the FAA research ways to make planes more conspicuous while on the ground, and that allowable blind spots for anti-collision lights be reduced. To LAX, the NTSB recommended that major control positions be staffed with assistant controllers, and that different runways be used for takeoffs and landings, as was already being done at Dallas and Atlanta. And to pilots in general, the NTSB stressed the importance of vigilance when coming in to land at busy airports. In theory, the pilots of flight 1493 could have heard Wascher clear SkyWest 5569 onto runway 24L, prompting them to listen for its takeoff clearance, so that they could be sure that the runway was clear. However, maintaining such an awareness is challenging, so the NTSB hoped that a reminder of the benefits of doing so, backed up by the weight of tragedy, might prompt pilots around the country to listen to background communications a little more carefully.
And finally, the accident added urgency to ongoing efforts to develop technology which could provide advance warning of imminent ground collisions. In 1991, aural warnings could alert controllers if two planes were on a collision course in the air, but no similar system protected against collisions on the ground. Today, that has changed: Airport Surface Detection systems now incorporate aircraft data tags featuring identity information, and come with built-in alarm systems that can warn controllers if two planes try to use the same runway at the same time. In recent years, some airliners have even begun to be fitted with Runway Awareness systems, which can warn pilots prior to touchdown if another aircraft is on the runway.
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Looking back, the Los Angeles runway collision is noteworthy as a case of human error handled correctly. No one involved was found negligent, there was no angry recrimination, and where mistakes were made, they were acknowledged freely, and, apparently, forgiven. Although many safety systems broke down, others worked, saving lives that might otherwise have been lost. What happened that day was the result of an accumulation of random events, building upon one another until the system collapsed. Like rogue waves in the ocean, such events can take hold in any complex, moving system, turning a succession of normal occurrences into an error chain leading inexorably to disaster. The way to prevent such disasters is by adding redundancies, raising the “disaster ceiling” until even the mightiest waves rippling through the network can no longer touch it.
Because officials readily acknowledged this reality, Robin Wascher did not become the crash’s 36th victim. Although she doubtlessly lives with immense trauma, and she apparently declined offers to return to the control tower, she did remain in aviation, taking up a desk job at the FAA’s western regional office. She eventually found personal closure as well: her parents’ plane was spotted on a remote mountainside in 1996, and their bodies were found and laid to rest in 2005. Twenty-eight years after they disappeared, and sixteen years after Wascher moved to California to search for them, she was finally able to bring them home. As for whether she has found such closure for the trauma of the runway disaster, only she can say. But the rest of us, at least, can be thankful that safety has tangibly improved, allowing us the luxury of taking away a more philosophical lesson: that mercy is rewarded with honesty, and forgiveness is free.
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