On an American Trans Air flight in 1996, a mind-boggling sequence of events brought a Boeing 727 a hairbreadth from catastrophe. The miracle is that despite the lunacy in the cockpit, the plane landed safely.
ATA Flight 406 departed Chicago’s Midway Airport bound for St. Petersburg, Florida. At thirty-three thousand feet, a warning horn sounded because the altitude in the cabin was registering fourteen thousand feet. First Officer Kerry Green was flying. He immediately put on his emergency oxygen mask. Capt. Millard Doyle did not, opting to try to diagnose the problem. He instructed the flight engineer, Timothy Feiring, who was sitting behind and to his right, to silence the alarm. Doubtless already feeling the effects of altitude that was steadily increasing, Feiring could not find the control button, and more time passed.
As he looked around, the captain evidently thought he’d discovered the source of the problem, an air-conditioning pack switch that was off, and he pointed it out to Feiring. Then he turned his attention to the flight attendant in the cockpit, asking her if the passenger oxygen masks had dropped.
They had, she replied, and promptly collapsed in the doorway. Now Captain Doyle reached for his own mask, but it was too late. Disoriented and uncoordinated, he could not place it over his head, and he passed out, too.
Two of four people in the cockpit were now incapacitated, and Feiring was having trouble thinking. He mistakenly opened an outflow valve, creating a rapid and total decompression of the airplane.
He put on his mask and then got up to attend to the unconscious flight attendant, placing the flight observer mask on her face, but dislodging his own in the process. He passed out, falling over the center console between the two pilots’ seats.
Through all this, First Officer Green, with his mask on, was taking the plane down to a lower altitude at a speed of about four to five thousand feet per minute.
Back in the passenger seats, the cabin crew had not been given any instructions from the cockpit, but the flight attendant seated at the front of the plane made a pantomime with her mask to demonstrate what the passengers should do. Some travelers followed her example; others did not. Through it all, the flight attendants reported that the plane was pitching up and down and side to side, and there was a brief, incomprehensible announcement from the cockpit.
Passenger Stephen Murphy of San Diego thought he was going to die and remembers feeling a sense of peace as he recited his prayers. Then the woman seated behind him started having convulsions, and the man across the aisle began to claw at his ears.
“What bothered me was there was nothing I could do for him. It’s not like you see on TV; people don’t grab portable oxygen bottles and walk around the cabin helping people,” Murphy told me years later. “Had I had my full senses, I’d like to think I could have helped somebody. But based on what was going on, I didn’t. I knew I couldn’t.”
On the flight deck, Green was trembling, a common symptom of hypoxia. Something was wrong with the microphone in his mask, and he had to pry the compressible seal away from his face to contact air traffic control.
When the oxygen mask Feiring had placed on her face rejuvenated the flight attendant, she got up and returned the favor, replacing the mask that had come off him as he moved away from the flight engineer console. She also got a mask on Captain Doyle. Soon they both came to. American Trans Air Flight 406 landed safely in Indianapolis, but the episode could have ended in catastrophe.
The story, equal parts chilling and absurd, tells me that knowing what to do does not mean pilots will actually do it if their ability to think has begun to deteriorate.
Nine years after American Trans Air 406, on August 14, 2005, a Boeing 737 took off from Cyprus on a flight to Athens, but it never arrived. Helios Flight 522 ran out of fuel and crashed into a mountain south of the airport after flying on autopilot for more than two hours—long after the pilots and nearly everyone else on board had fallen into deep and prolonged unconsciousness. They had been starved of oxygen, presumably because the pilots failed to pressurize the aircraft after takeoff. The pilots were hypoxic before they realized what had gone wrong.
The Helios 522 disaster started about five and a half minutes after takeoff, as the plane climbed through twelve thousand feet. A warning horn alerted the pilots that the altitude in the cabin had exceeded ten thousand feet.
Less than two minutes later, the passenger oxygen masks dropped, but Capt. Hans-Jürgen Merten and First Officer Pambos Charalambous did not put on their masks, deciding instead to try to figure out what was wrong: a classic case of impaired judgment due to hypoxia.
For nearly eight minutes, Captain Merten, a pilot with five thousand hours of experience on the 737, conversed with the Helios operations center in Cyprus in an exchange that grew increasingly confusing to the men on the ground. One thing was certain. The horn warning of altitude did not direct the pilots to focus on the cabin altitude, and here’s why: the alarm’s insistent staccato is also used on the runway when an airplane is incorrectly set for takeoff. At that time in the flight, the same alarm is called a takeoff configuration warning. This case of one alarm for two hazards relies on the pilots’ knowing to which hazard they are being alerted.
On the ground, it seems straightforward. The takeoff configuration alarm will sound only prior to takeoff. The distinction is not so obvious, however, when the pilot’s ability to think is already fading. And we know this because, when the alarm on Helios 522 went off, Merten told his airline’s operations desk that the takeoff configuration horn was sounding. He did not associate the warning with cabin altitude. That mistake has been repeated on passenger flights around the world, including ten instances over ten years found in the files of the NASA Aviation Safety Reporting System, or ASARS.
“The simplicity of the error” is what struck Bob Benzon, an accident investigator with the National Transportation Safety Board at the time, who was helping the Greeks on the Helios accident. “There were one hundred twenty-one people who died on a modern airliner, and all through a simple error. That was the thing,” he said.
Six years earlier Benzon had been assigned to investigate a similar accident, involving a private jet and a popular American athlete. Payne Stewart was one of the most famous golfers on the pro circuit, beloved for the weird collection of tam-o’-shanters and knickerbockers he wore at tournaments. He suffered hypoxia on October 25, 1999, in the early stages of a four-hour flight from Florida to Texas.
Not long after departing from Orlando, the first officer, Stephanie Bellegarrigue, failed to respond to calls from air traffic control. She sounded fine in her last radio communication, but the plane failed to turn as planned, and no one on the ground could raise the crew as the plane passed thirty-two thousand feet.
“Somewhere west of Ocala, the crew became incapacitated. Maybe not dead, but they couldn’t answer the radio,” Benzon told me. The investigation never determined when or why the plane lost cabin pressure.
The plane continued straight from its last heading until it ran out of fuel and crashed in a field in South Dakota. From his office in Washington, DC, Benzon watched live news coverage of the runaway flight. Fifty years old at the time, he had worked nearly two hundred airplane accidents, but he had never seen one unfold before his eyes.
In the months after the Helios accident, aviation authorities in several countries shared their experiences with the investigators. Just eight months before the Helios accident, NASA had sent a special bulletin to Boeing and the FAA, concerned that several flight crews reported they had been confused by the dual use of the pressurization warning horn. Even earlier, in 2001, there had been an event in Norway when pilots disregarded the warning horn and continued to ascend. The Norwegian Air Accident Investigation Board sent a safety recommendation to Boeing also in 2004, calling for it to discontinue the dual-use alarm.
As Helios 522 ascended over Cyprus, Captain Merten’s thoughts were scattering, and his brain was going dim. He collapsed at his last position, checking a switch panel b
ehind his seat. First Officer Charalambous passed out against the airplane control yoke.
Using the experience of the survivors of American Trans Air Flight 406 as a reference, we can assume that the passengers on the Helios 737 were uneasy once their masks dropped, everyone waiting for news from the flight deck. But that uneasiness would not have lasted for more than twelve to fifteen minutes, because those masks have only a limited supply of oxygen; after that, the passengers would have passed out. This is why pilots quickly have to get the airplane to a lower altitude, but the pilots on Helios 522 were unconscious, and they weren’t going to recover. There was no one to initiate a descent, and the plane flew on, northwest past southern Turkey and high above the Greek islands.
The flight attendants had higher-capacity emergency oxygen bottles and portable oxygen masks. With more than an hour’s supply in each, they were likely conscious longer than the passengers. Twenty-five-year-old Andreas Prodromou was a flight attendant who also happened to be a private pilot. He may have waited for word from the cockpit, but at some point he got up from his seat by the back galley and took action.
What we know from this point comes from two sources: recordings in the cockpit documenting Prodromou’s arrival on the flight deck and the observations of two Greek fighter pilots who were dispatched to see what was happening with the airliner that had silently, and without contacting controllers, entered Greek air space.
Two air force F-16s were flying on either side of the airliner. It was just four years after terrorists had crashed four commercial jets into landmarks in New York and Washington, DC, and the Greek Air Force pilots expected to find something similar. Instead, they saw the first officer unconscious in the right-hand seat. One of the air force fliers saw Prodromou enter the cockpit. This means that Prodromou waited more than two hours after the depressurization.
He may have suspected the incapacitation of the crew, but the sight of the vacant captain’s seat and the copilot lifeless at the controls must have been terrifying. Captain Merten was partially on the floor and partially on the center console. Prodromou probably had to step over him to get to the left seat, where he removed Merten’s unused oxygen mask from the storage compartment and put it on. Lifting the mask activates the flow of oxygen through a thick gray umbilical cord that also contracts the face straps. This design keeps the mask fitted tightly to the head.
Prodromou put on the mask as the last of the left engine’s fuel was spraying into the combustion chamber. In moments, the engine would stop producing power.
Bank angle, bank angle. A computerized voice warned that the airplane’s left wing was losing lift. The Boeing 737 can fly with only one engine, but control surfaces have to be adjusted to compensate.
Prodromou searched the control panel for something familiar—something that connected this complicated aircraft to the small planes on which he had learned to fly. Then the control wheel in front of him started to vibrate. The stick shaker warning is as dramatic as it is urgent, an attention-getting, multisensory advisory that the plane is about to stall. For two and a half minutes Prodromou scanned the instrument panel while the airplane picked up speed in descent. The sound of rushing air joined the cacophony of warnings. Finally, hope extinguished, he called for help in a frail and frightened voice.
“Mayday, mayday, Helios Flight 522 Athens . . .”
And forty-eight seconds later:
“Mayday.”
“Mayday.”
Traffic, traffic. He heard only the mechanized voice of the 737.
The radio was not set to the proper frequency to transmit the message. Prodromou’s mayday would be heard only in the postcrash examination of the cockpit voice recorder.
As the plane approached the ground and ambient air pressure increased, the cabin altitude warning horn turned off and one contributor to the din in the cockpit subsided. It was then that Prodromou first noticed the fighter jet escort.
Years later, one of the fighter pilots explained that he gestured for Prodromou to follow him to a military airfield nearby. To this signal, the young flight attendant raised his own hand and, with weary resignation, pointed downward. Even if he could have figured out how to follow the F-16, it was too late. The right engine was shutting down. The plane was seven thousand feet above the ground with three and a half minutes left. Helios Flight 522 crashed into the countryside near Athens International Airport, not far from where it had been programmed to fly, killing the last of the travelers on this terrible journey.
When Prodromou’s role in the story made the news in Cyprus, many wondered: what if the young man had entered the cockpit earlier? Many factors could have changed the course of Flight 522. But at its heart, what claimed Prodromou and the others was a simple truth.
“Inherent in aviation is the exposure to altitude,” said Robert Garner, an aviation physiologist and director of a high-altitude training chamber in Arizona, “and the risk of hypoxia is always present.”
Emergency
In the early days of the Malaysia 370 mystery, I thought of these episodes. After all, it was an ordinary flight—under the command of an experienced and well-regarded captain—that suddenly turned baffling.
The Boeing 777 departed Kuala Lumpur International Airport on March 8, 2014, on an overnight trip to Beijing. There were 227 passengers and 12 crew members on board. In the cockpit, Capt. Zaharie Ahmad Shah, a thirty-three-year employee of the company, was in command. He had eighteen thousand flight hours. As a point of reference, that’s just fifteen hundred hours fewer than Chesley Sullenberger had in his logbook when he successfully ditched a disabled US Airways airliner into New York’s Hudson River, and Zaharie was five years younger than Sully.
Zaharie spent even more untallied time flying his home-built flight simulator. He took so much pleasure in this activity that he made videos and posted them on his Facebook page, offering tips and instructions to other simulator enthusiasts. Obsessed much? you might think when I tell you he also owned and flew radio-controlled airplanes. There just wasn’t enough flying, as far as Zaharie was concerned.
Professionally speaking, First Officer Fariq Abdul Hamid was everything Zaharie was not. Inexperienced on the Boeing 777, he was still training on the wide-body while Zaharie supervised his performance. The flight to Beijing would bring the young pilot’s total hours on the airplane to thirty-nine. Fariq had been flying for Malaysia for four years. From 2010 to 2012, he was a copilot on Boeing 737s. He was moved to the Airbus A330, where he flew as a first officer for fifteen months until he began his transition to the even bigger Boeing 777.
The moonless night was warm and dark with mostly cloudy skies when the jetliner lifted off at 12:41 a.m. on Saturday morning. Fariq was making the radio calls, so we can assume Zaharie was flying the plane.
On board were business travelers, vacationers, and students. There were families, couples, and singles from Indonesia, Malaysia, China, Australia, America, and nine other countries; a global community common on international flights. Because Kuala Lumpur and Beijing are in the same time zone and the flight was to arrive at dawn, many travelers were probably sleeping when things started to go wrong.
Flight 370 was headed north-northwest to Beijing. Twenty minutes after takeoff, at 1:01 a.m., the plane reached its assigned altitude, thirty-five thousand feet, and Fariq notified controllers.
“Malaysia Three Seven Zero maintaining flight level three five zero.”
Independent of what the pilots were doing, the twelve-year-old Boeing 777 was transmitting a routine status message via satellite with information about its current state of health. In the acronym-loving world of aviation, this data uplink is called ACARS, for Aircraft Communications Addressing and Reporting System. Messaging can be manual if the pilots want to request or send information to the airline. It can also be triggered by some novel condition on the plane requiring immediate notice. Absent either of these conditions, an automatic status report is transmitted on a schedule set by the airline. At Malaysia,
it was every thirty minutes.
Pilots may not be aware of when or how often the aircraft makes scheduled status transmissions, but they certainly know about them. They use ACARS often, for both the serious and the mundane things that happen in flight, from requests for weather updates to the latest sports scores. A pilot who needs a minor repair or a wheelchair on arrival can simply send a text through ACARS.
Neither Zaharie nor Fariq had anything to add to the 1:07 a.m. scheduled report, and the message showed nothing amiss. The engine performance indicated how much fuel had been consumed by the Rolls-Royce Trent 892 engines.
Around the time the ACARS message was being sent, it appears control of the flight was transferred to the first officer because Captain Zaharie was now making the radio calls. He confirmed to air traffic control that the plane was flying at cruise altitude. “Ehhh . . . Seven Three Seven Zero1 maintaining level three five zero.”
Eleven minutes later, as the airplane neared the end of Malaysian airspace, the controller issued a last instruction to the men in command of Flight 370, giving them the frequency to which they should tune their radio upon crossing into Vietnam’s area.
“Malaysian Three Seven Zero contact Ho Chi Minh one two zero decimal niner, good night.”
“Good night, Malaysian,” Zaharie said. It was 1:19. His voice was calm, according to a stress analyst who listened to the recording as part of the Malaysian probe. There was no indication of trouble.
Zaharie, fifty-three, had been in his seat since around 11:00 p.m., ordering fuel, entering information in the onboard computers, arming systems, checking the weather en route, and discussing the flight with the cabin attendants. He had also been supervising Fariq, who, after landing in Beijing, would be checked out on the Boeing 777. That was sure to be a heady and exhilarating new assignment for the young man, as Zaharie certainly recognized, having three children of his own around the age of Fariq, who was twenty-seven.
The Crash Detectives Page 2