Siberian Tragedy: The crash of S7 Airlines flight 778

S7 Airlines flight 778 burns after skidding off the runway in Irkutsk. (Ne svezhie novosti)

On the 9th of July 2006, an S7 Airlines Airbus A310 was landing in the Siberian city of Irkutsk when something went terribly wrong. The wide body jet with more than 200 people on board refused to slow down, hurtling down the full length of the runway at terrific speed despite the pilots’ attempts to stop it. The plane ran off onto the grass, struck a concrete wall, and careened into a storage cooperative, igniting a massive fire which quickly consumed the plane. Of the 203 passengers and crew, 125 perished in the inferno. But the plane should have had plenty of room to slow down — so why didn’t it? The answer turned out to be shockingly simple: during the entire landing rollout, the left engine was still producing forward thrust! This colossal error should have been obvious, but instead the pilots flailed in helpless confusion, unable to discern the problem. The investigation found one tiny mistake that set the whole thing in motion — along with a host of troubling maintenance practices, a breakdown in communication, and a psychological phenomenon which left the pilots unprepared to react.

F-OGYP, the airplane involved in the accident, pictured one month before the crash. (Gennady Misko)

S7 Airlines, formerly known as Siberia Airlines (and still popularly known as Sibir), is the largest domestic airline in Russia, with over 100 airplanes and 150 destinations. One of Sibir’s most popular routes is the 4,200-kilometer trip from Moscow to the airline’s operational base in the Siberian city of Irkutsk, near the shores of Lake Baikal. In the mid-2000s, Sibir operated this route using a wide-body Airbus A310 capable of seating more than 200 passengers, and it regularly filled the plane to capacity.

On the 9th of July 2006, the A310 operating this flight was F-OGYP, a 19-year-old jet previously owned by Pan Am, Delta, and Aeroflot. Although this was a cross-country red eye flight, the plane was almost full, with 195 passengers and eight crew on board. In command were Captain Sergei Shibanov, a highly experienced pilot who had upgraded to the A310 the previous year; and First Officer Vladimir Chernykh, who was almost as experienced as Shibanov but had only recently started flying the A310 and had only 158 hours on the type.

The route of flight 778. (Google)

F-OGYP departed Moscow’s Domodedovo International Airport for flight 778 to Irkutsk at 10:17 p.m. local time. The entire five-hour flight proceeded normally, and after crossing four time zones without leaving Russia, the crew began their descent into Irkutsk shortly after dawn. By that point, nothing untoward had occurred, although Captain Shibanov had commented to an air traffic controller that “it’s night and we’re not getting enough sleep.”

The plane was also not in sound mechanical condition. In the preceding 111 flight hours, no less than 50 different malfunctions were recorded, and by the day of flight 778, 15 of these had still not been fixed. The broken items included the left thrust reverser, the №2 autopilot, the auxiliary flap actuation system, and one of the toilets. But at Sibir, flying like this was business as usual. In fact, just three days earlier, this very plane had been landing in Irkutsk with an inoperative right thrust reverser when the left reverser also failed, leaving the plane with no thrust reversers at all. Because reverse thrust is important to helping slow the plane on landing, the concurrent failure of both reversers was serious enough to be classified as an “incident” by Russia’s transport agency. To correct the problem, Sibir’s maintenance division replaced the broken flexible drive shaft from the right reverser with the serviceable drive shaft from the left reverser, labeled the left reverser inoperative, and cleared the plane to fly.

Shibanov and Chernykh were well aware that they would be landing with only one thrust reverser, and the procedure for doing so was so simple that it hardly needed to be stated: they would simply activate the right thrust reverser without touching the left one.

As flight 778 approached Irkutsk shortly before 7:40 a.m. local time, the runway was covered with water, but the storm that dumped it had already passed, and a normal landing seemed imminent. At 7:43 and 40 seconds, the plane touched down on Irkutsk International Airport’s runway 30. The spoilers deployed to force the wheels onto the pavement, and the autobrakes activated. Now Captain Shibanov reached over to engage the right thrust reverser. The thrust reversers are activated using secondary thrust levers attached to the forward sides of the main throttle levers; while pushing the main throttle levers forward increases forward thrust, pulling the reverse levers backward will increase reverse thrust. As expected, Shibanov pulled back only the right reverse lever, and the right reverser came alive with a thunderous roar.

How the throttles levers and reverse levers work on the Airbus A310. (John Kelley)

As the plane decelerated through 185 km/h, Shibanov began to slowly reduce power to the reverser in order to smooth out the landing roll. But as he pushed the right reverse lever forward, his palm caught against the left throttle lever and began to push it forward as well. The left engine consequently began to accelerate, spinning up even as the right engine was spinning down. Within 20 seconds of touchdown, the right reverser was totally stowed and the left engine had reached 60% of takeoff thrust. The plane stopped slowing down, and 10 seconds later it began to gradually speed up instead.

Animation of the landing with the position of the throttle and reverse levers — watch their positions closely. Animation plays at double real speed. (ChilloutJr’s Animations via YouTube)

The pilots had thought the landing was essentially over, yet now something seemed off— but what? At that same moment, the takeoff configuration warning sounded in the cockpit, catching the pilots completely by surprise. They were landing — so why was the plane telling them they were not configured for takeoff? In fact, when the left engine accelerated beyond a certain threshold, the system determined that they were taking off and was attempting to warn them that they had not properly set the flaps, slats, or stabilizer. However, instead of trying to figure out why the warning had activated, First Officer Chernykh concluded that a technical glitch must have occurred, and he simply deactivated the alarm. He then reported to the controller that they had landed successfully, as yet unaware that something was terribly wrong.

Another effect of the high forward thrust on the left engine was that the spoilers, which help force the plane down onto the runway, automatically retracted. This in turn deactivated the auto-braking system. By this point, having used up 1,600 meters of the 2,450-meter runway, Captain Shibanov observed that they were no longer decelerating and finally asked, “What’s wrong?”

“RPMs increasing,” said Chernykh.

“Reverse again,” Shibanov ordered, applying maximum manual braking power as he did so.

Chernykh attempted to reactivate the right thrust reverser, but because the left engine was providing significant forward thrust, the reverser could not activate — a safety feature designed to prevent reverse thrust from being engaged in flight or on takeoff.

The speed of the plane stabilized as Captain Shibanov’s heavy braking cancelled out the thrust from the left engine, but the end of the runway was rapidly approaching, and the pilots still had not figured out why they weren’t slowing down.

“We’re rolling out,” Chernykh exclaimed. “Why!?”

“I don’t know!” said Shibanov, desperation in his voice. As he fought against the asymmetric thrust, the airplane slid to the right, back to the left, then hard to the right again, skidding off the end of the runway at 180 kilometers per hour.

Path of flight 778 after leaving the runway. (Google)

As the plane hurtled off onto the grass, Shibanov shouted, “Shut down the engines!” But, frozen in fear, First Officer Chernykh didn’t react. Seconds later, the plane slammed headlong into the airport’s 3-meter-high concrete perimeter wall, ripping off the landing gear and most of the left wing. Flames erupted from the ruptured fuel tanks as the jet grazed a parking lot and plowed into a private storage cooperative, flattening twenty garages in a hail of flying bricks and rending metal. The plane finally came to a stop leaning to one side, its cabin broken into two pieces with the wings resting on top of nearby buildings. Inside the A310, the jarring impact had thrown numerous passengers out of their seats, and one woman was dead after suffering a grievous head wound. The other 202 people on board had survived the crash with varying degrees of injury — but now they had to escape before fire consumed the plane.

My sketch of the moment flight 778 crashed through the perimeter wall. (Own work)

Almost immediately, flames erupted on all sides of the airplane, and noxious, black smoke began to pour into the cabin. Passengers screamed in terror, pushing and shoving against each other to escape the inferno. “Doors! Open the doors!” they shouted, as the crew sprang into action. Flight attendant Viktoria Zilbershtein forced open the right overwing exit, and people began to pour across the right wing and onto the roofs of the garages. Meanwhile, another flight attendant in the front of the plane found that the floor had collapsed, leaving her dangling upside down by her seat belt in the cargo hold. Flames and wreckage prevented her from reaching the passengers, so she undid her belt and dropped down to the ground, where she suffered burns to her arms and legs but managed to escape with her life.

The A310 burns shortly after the crash. (Aviation Accidents Database)

In the back of the plane, a cabinet full of packaged airline meals had burst open during the crash and spilled its contents onto the right rear flight attendant. After digging herself out of the pile of food containers, she tried to open her assigned exit, but the containers were in the way, and the door wouldn’t budge. The left rear flight attendant managed to open his exit and inflate the slide, but a piece of wreckage sliced it open and it immediately deflated; passengers queuing for the exit were forced to jump four meters down to the ground, resulting in numerous broken bones. But they were the lucky ones: none of the plane’s other four exits could be opened due to the fire, and none would live to tell of the fate of those who were seated near them.

Firefighters attempt to douse the flames after the end of the evacuation. (Ne svezhie novosti)

The crew of an airport fire truck had seen the plane streak by with excessive speed and, sensing that something was wrong, began to follow it even before the alarm was raised. This fire engine arrived at the scene one minute after the crash, followed 20 seconds later by three more engines. By the time the fire crews arrived, the flight attendants had succeeded in evacuating 67 people (including themselves) in just 55 seconds, but no more passengers were coming through the emergency exits. Firefighters broke in through the right rear exit and entered the smoke-filled plane, where they dragged 11 more people to safety, but they were soon forced to retreat as the fire ripped from one end of the cabin to the other. It was clear that no one else would be coming out alive.

Firefighters work near the still-smoldering tail section of the A310. (AP)

As authorities took stock of the dead and wounded, the true toll of the disaster became apparent. Of the 203 people on board, 125 were killed, including both pilots and three of the six flight attendants, while 78 people survived. All but one of those who perished died of smoke inhalation; heavy concentrations of carbon monoxide inside the cabin rendered them unconscious before they could escape the inferno. From her hospital bed, flight attendant Viktoria Zilbershtein described the harrowing scenes inside the plane, bringing to light much of what is known about that first terrible minute after the crash. Although she was hailed as a hero for saving 20 passengers, she broke down upon learning that so many others had not escaped. “If they only managed to open two exits before the explosion — one on the side and one in the tail, then…” She paused. “Then only 30 people could have escaped through the far exit! And the rest? This can’t be!”

Investigators walk along the wings, examining the wreckage. (Ruspekh)

As Russia mourned the victims of the crash, investigators from the Interstate Aviation Committee (MAK) arrived to determine the cause. Officials initially told journalists that they suspected a mechanical failure of the brakes, but an exhaustive analysis of the plane’s systems disproved this possibility. Instead, the left engine somehow accelerated to 60% of takeoff thrust during the landing roll, and the pilots never attempted to shut it off. The high power setting not only propelled the plane forward but caused the spoilers and autobrakes to disengage automatically, sending the plane off the runway with incredible speed. How could this happen?

After ruling out all other possibilities, the MAK was forced to conclude that the captain, while pushing the right reverser lever toward the stowed position, had accidentally pushed the left throttle lever along with it. Tests showed that it was possible to do this by applying relatively little force; it was entirely conceivable that Shibanov might not have noticed, particularly on a rough runway with heavy vibrations, as was the case in Irkutsk. The MAK also found three previous incidents in which Airbus A310s had overrun the runway after the pilots accidentally accelerated one or both engines during landing. (None of these incidents resulted in damage to the airplane, because in each case the pilots noticed the problem and shut the engines after an average of 30–35 seconds.) Clearly this was something that, while not common, nevertheless happened from time to time.

The tail section was the only part of the plane that was not completely burnt. (Zhurnal “Itogi”)

The bigger question was why neither pilot ever figured out that the power on the left engine was increasing. The MAK calculated that, had the pilots shut off the left engine at any point during the first 25 seconds after it began to accelerate, the spoilers and autobrakes would have come back on by themselves, and the plane would have stopped on the runway. The solution was incredibly simple, and they should have had plenty of time to come up with it. Although it remains hard to understand how a trained crew could miss something so basic, the MAK expended a considerable amount of effort to explain this seemingly inexplicable mistake.

The first point of focus was First Officer Chernykh. As the pilot not flying, it was his job to monitor engine parameters and call out any changes in the plane’s configuration during the landing roll. But he missed all of these callouts — he didn’t announce the deployment of the reverser, the increase in thrust, or the automatic retraction of the spoilers. One factor possibly contributing to this was his limited experience. He had only spent 92 hours in the cockpit since finishing training on the A310, and his training did not heavily drill after-landing callouts; as a result, he had not yet ingrained these items into his routine, and he might have simply forgotten about them. Investigators also noted that Captain Shibanov’s hand was still on the right reverse lever, which would have blocked Chernykh’s view of the throttles.

Recovery crews prepare to remove the A310’s tail section using a crane. (Bureau of Aircraft Accidents Archives)

However, another factor might have played a bigger role: the psychological phenomenon known as premature mental demobilization. When the abnormal situation began, the plane was already well down the runway and had decelerated considerably, generating a false belief that the flight, and therefore all sources of danger, were already over. The pilots relaxed their guard even though their primary task (stopping the plane) was not yet completed, adding significantly to the time required to assimilate information suggesting the onset of an emergency. This could explain why the first officer was not monitoring engine power: he had already mentally moved on to the taxi phase, as evidenced by his delivery of the landing report to the controller, something which is normally done only after decelerating to taxi speed. Contributing to the pilots’ premature mental demobilization is that they had just arrived back at the company base after a long overnight flight and were emotionally ready to call it a day. Although the MAK did not discuss it, it is also likely that the pilots were suffering from fatigue.

After the initial discovery that the plane was not slowing down, confusion and stress prevented the pilots from adequately reacting to the situation. Fear set in so quickly that the pilots lost the ability to think rationally. Had they been able to remain calm, they might have run through all the things that could possibly cause the plane to speed up, and eventually noticed the position of the throttle lever; or perhaps the first officer would have reverted to his instrument scan and eventually seen that the left engine was generating power. Instead, they failed to communicate, acted confused, and never made a concerted attempt to figure out what was going on. Captain Shibanov ordered First Officer Chernykh to shut down the engines only seven seconds before the crash, far too late to have made any difference. Chernykh never complied with the order anyway — apparently, he was either too terrified to respond, or in his highly agitated state he reverted back to his memories of flying Russian aircraft, and thought that the non-existent flight engineer would handle the engines.

Mangled debris was all that remained of the airplane’s forward section. (Bureau of Aircraft Accidents Archives)

The MAK also looked into Captain Shibanov’s training history to search for clues which could explain his failure to act. They discovered that he had been promoted to A310 captain directly from his former position as captain on the Tupolev Tu-154, without undergoing first officer training or gaining line experience as an A310 first officer. In fact, he became a captain on the A310 with only 43 flight hours on the aircraft type — a shockingly low amount, even by Russian standards, which are lower than those in the United States. By contrast, Aeroflot, which also operated the A310, required 3–5 times as many flight hours to earn promotion to captain, and only allowed pilots to skip serving as a first officer if they had previous experience on a similar airplane. (The Tu-154, a Soviet-built jet with a four-person cockpit crew, would not have qualified as similar.) The training did include crew resource management (CRM), the set of principles underpinning effective cockpit communication, but no transition training existed to demonstrate the difference between CRM practices on the four-pilot Tu-154 and the two-pilot A310. This could have rendered the training ineffective and contributed to his lack of communication with the first officer during the fatal landing. Taking all of this together, it could be said that although Shibanov had accumulated about 1,000 hours on the A310, the adequacy of his initial training needed to be called into question. Given the limited amount of training time, it was also not surprising that landing with only one thrust reverser was not part of the curriculum.

The plane’s landing gear lies amid a pile of charred debris. (Bureau of Aircraft Accidents Archives)

A line of inquiry which proved to be even more illuminating was the captain’s history of psychological examinations. The MAK provided the data and observations from these exams to independent aviation psychologists, who concluded with a high degree of confidence that Shibanov was emotionally excitable, anxious, and possibly prone to panic in unexpected situations. Such traits indicate that the pilot needs additional training in order to bring more possible events out of the “unexpected” category and into their main body of knowledge where a rational, automatic reaction can take place. (Notably, his rather brief training on the A310 meant that few scenarios were given this treatment.) However, the psychologist either missed these cues or ignored them, despite neuropathologists repeatedly referring Shibanov to psychologists after discovering that, during simple examinations, he had a heart rate which was so high as to be hazardous to his health. The MAK felt that these findings should have been sufficient for the psychologist not to recommend him for the an upgrade to an unfamiliar aircraft. Most likely, the psychologist was more focused on some of Shibanov’s many positive traits, such as good self-control and a strong intellect, along with his successful training history. It is important to note, however, that the decision to recommend or not recommend a pilot for promotion based on psychological examinations is a subjective art, not an objective one.

A crane begins the process of debris removal. (Kommersant)

The MAK also looked into why the plane was flying with only one working thrust reverser, and discovered that this was a rabbit hole all of its own. It turned out that when A310 mechanics requested parts for repairs, Sibir had the parts in stock only 25–30% of the time. The company had difficulty getting spare parts through Russia’s customs clearance process, and consequently most defects were deferred for at least 10 days while replacement components trickled in through a sea of red tape. This spotty maintenance resulted in an astonishing defect rate of one failure per plane per 23 flight hours. Sibir was also having incidents with its A310 fleet four times as often as Aeroflot did when it operated A310s. Sibir never violated regulations with its maintenance practices — it only dispatched planes in accordance with the Minimum Equipment List (MEL), the document which describes what systems must be working in order for a plane to legally take off. However, the routine operation of airplanes with numerous broken items, even if they are exempted by the MEL, necessarily increases the stress placed on the crew and negatively impacts safety. In hindsight, it was not surprising that Sibir eventually suffered an accident in which a deferred maintenance item was a contributing factor.

The A310’s tail looks decidedly out of place, sticking up between the rooftops of Irkutsk’s Svetlyi district. (NTV)

The root of Sibir’s problems with both maintenance and pilot training was the fact that the airline was expanding faster than its own infrastructure could handle. In order to meet demanding new schedules and service its ever-growing fleet, the airline had to fast track pilots onto new aircraft types and make do with limited supplies of parts. Numerous crashes throughout history have shown that this kind of growth is detrimental to safety. Airlines run thin margins, and the urge to seek profit is compelling, but a major accident is always more expensive than slowing down growth to make sure that the safety net can keep up.

Firefighters battle the flames an hour or two after the crash. (IrkutskMedia)

In its final report, the MAK recommended that A310 pilots not use reverse thrust at all if one reverser is deactivated; that the training courses for the same aircraft at different airlines be unified, in order to increase standards across the board; that CRM courses be developed to help the transition from three- or four-person crews to two-person crews; that the federal government speed the customs process for aircraft parts being imported to Russia; that Sibir train its crews to consult the MEL to learn special procedures for flying with mechanical defects, stop promoting pilots of Russian aircraft to captain on Western aircraft without gaining experience as copilot first, and discuss with pilots the causes of incidents which occur at the airline; that Airbus prevent the takeoff configuration warning from sounding on landing, or explain in the manual why it might do so; that cockpit video recorders be introduced (something investigators have wanted for years but has never been implemented); and that Russian authorities examine the construction of buildings near runways, among many other suggestions.

The burnt-out interior of the tail section. (Anatolii Markusha)

One of the key lessons of the crash of flight 778 is that while Captain Shibanov was by all accounts a competent and diligent pilot, in his final moments he was nevertheless caught by surprise. How could he have made such an elementary mistake? His wife insists to this day that he was framed, that the MAK always “blames the pilot” because it’s convenient. For her own sanity she must believe this, but other pilots do not have the luxury of this innocent naïveté. The best way to avoid ending up like Shibanov is to read about what happened to him and countless other pilots throughout history. It would be a shame to die because one’s palm accidentally pushed against a throttle lever, especially after the flames of tragedy have already illuminated the danger.

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Analyzer of plane crashes and author of upcoming book (soon™). Contact me via @Admiral_Cloudberg on Reddit or by email at kylanddempsey@gmail.com.

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