October 29th, 2018
Jakarta – Soekarno Hatta International Airport – 06:20 Local Time
Lion Air Flight 610 with 189 souls on board takes off westwards into the clear skies before circling towards a north-east heading.
Few minutes into the flight
The stick shaker on the captain’s end begin to vibrate. What stick shakers are designed to do is to alert pilots of an impending stall. A stall could be extremely catastrophic and thus these shakers are extremely loud.
But the aircraft was flying normally, with no signs of an impending stall. This made the pilot decide to ignore the warning for the time being.
Thirty seconds later
The pilot notices a warning light on the cockpit – “IAS DISAGREE”. This warning light comes up when the computer system inside the aircraft has a malfunctioning sensor. This was a serious issue, and thus the pilot decided to investigate it while passing the control of the aircraft over to the first officer.
Every modern aircraft has redundancy measures taken for just these scenarios. The pilot decided to stop taking the input data from the sensors from his side of the plane, and instead, display the same data as obtained from the right side.
One Minute later
The aircraft reaches the altitude of 1500 ft, where officially the “Take Off” portion of a flight ends, and the first officer began his initial climb. And that’s when all hell broke loose.
The moment the First officer began the initial climb, the aircraft, instead of climbing up, lurched forward and plunged straight towards the ground.
The first officer instinctively counteracted on this, flicked a switch, and pitched its nose back up. 5 seconds later, it happened again, and this climbing and diving continued about 28 times, before finally plunging down into the water.
32 Kilometers into the flight, the Pilots requested heading back towards the airport.
Offshore Jakarta – 06:33 Local Time
The Air Traffic Control lost all contact with the Aircraft. The witnesses reported the Aircraft plummeting towards the water with a steep nose down angle. The aircraft crashed into the water, 34 Kilometers off the coast of the Island of Java. No one survived.
March 10th, 2019
Addis Ababa – Bole International Airport – 08:38 Local Time
Ethiopian Airlines flight 302 takes off onto the clear skies with 149 Passengers and 8 crew on board.
Just after the take-off, the stick shaker vibrated. The Altitude and other sensors on one side of the plane malfunctioned. A minute into the take-off, a “Flight Control” problem was reported by the pilot, but he decided to try to continue the flight.
90 Seconds later
Immediately after the First officer retracted the flaps of the aircraft as a post take-off procedure, the plane nosedived. The Ground proximity sensor started to warn “Don’t Sink.” Instinctively, the captain pushed the yoke skywards, and radioed back his intentions to return to the airport as soon as possible.
The diving down, followed by pull ups continued repeatedly, with aircraft crossing the redline and reaching about 500 knots of airspeed (926 Kmph) which obviously made the aircraft even less and less controllable.
Woreda District (Gimbichu Oromia region) – 08:44 Local Time – 6 Minutes after the take-off
The Aircraft at 9000 ft MSL (Mean Sea Level) disappeared from the Radar screens and crashes. Witnesses reported the Airplane trailing “white smoke” and making strange noises just before the crash. The Aircraft impacted the ground at roughly 700mph (1126 Kmph) around 62 Kilometers away from the Airport. There were no survivors.
What was in common between the two incidents?
• Both the flights were on the new Boeing 737 Max-8s.
• Both of these flights crashed just a few minutes after taking off.
• Both of the aircrafts plummeted straight downwards.
• Both these flights suffered “Flight control issues” before they crashed.
Looking at what’s common between the two crashes, it becomes highly suspicious that some fault was present in the model of the aircraft that was used. That’s what the investigation lead to and now, let us understand the concept behind the same.
Why does an aircraft Stall?
Before we understand what specifically was wrong with the 737 Max 8, let us first understand the underlying basis of an aircraft stalling.
In layman’s terms, a stall happens when the wing of the aircraft no longer creates lift. The loss in lift happens when the speed of the air above the wing decreases too much.
If we dive a bit deeper, an aerodynamic stall happens when the wing stops producing lift because the Angle of Attack is too high. This is usually caused by pulling back the yoke/stick without compensating for the power required to climb at that angle. The Angle of attack at with an aircraft can stall can be affected by various factors like the weight of the aircraft, the flaps and icing on the plane and such.
Maneuvering Characteristics Augmentation System (MCAS)
The Boeing 737 Max 8 were quite different from the previous aircrafts in the 737 family. The major difference was the fact that the Max-8 is powered by bigger engines than the previous generations which ended up providing up to 14% of savings in terms of Fuel consumption.
These larger engines are fitted further forwards under the wings, and thus, could potentially cause the plane to stall.
To avoid such a stall, Boeing implemented the MCAS system onto this generation. This software basically keeps looking at the Aircraft’s angle of attack continuously and any moment when it perceives a risk of stalling out, the system onto the computer initiates automatically, and no amount of pilot intervention can stop this system.
What happened in these two flights?
When the MCAS activates, it automatically tilts the horizontal tail at the back of the plane, lifting the rear of the plane and nudging the nose down. If the system gets triggered erroneously—and the plane dives for no reason—a pilot can pull back on the control column to lift the nose up again.
But every time a pilot straightens the plane out, the MCAS resets. That means the system can be triggered again, nudging the nose down and forcing the pilot to once again yank on the control column to set the plane back on track.
This tug-of-war between the pilots and the MCAS system can be seen repeatedly happening in both the Lion Air and the Ethiopian Airline crash.
Boeing – mistakes that shouldn’t have been
The first Mistake that Boeing did
The aircraft, just like every other system, for redundancy, had two separate flight sensors and Angle of attack sensors. The sheer “Stupidity” of Boeing came to play right here when they designed the MCAS to use only one of the sensors as the input.
The second mistake by Boeing
Boeing designed a warning light that would alert pilots when the sensors measuring their plane’s angle of attack differed widely, which would give notify them of a faulty MCAS activation.
Boeing doesn’t have that Warning light as a “standard” and instead has it as an “Option” for airlines to pay extra to have it installed.
Boeing treated an important piece of safety equipment, the lack of which could be catastrophic, the same as what vehicle manufacturers treat the sunroof of their cars as – An Option.
The third mistake by Boeing
According to Boeing, “Since it operates in situations where the aircraft is under relatively high-g load and near stall, a pilot should never see the operation of MCAS,” which basically meant, not all pilots were trained through its working and basically, the pilots were on a “Need to know” basis regarding the presence of this system. Which they didn’t even know about until the Lion Air crash.
The current situation
Beginning on March 11, 2019, airlines and regulators around the world grounded the Boeing 737 MAX passenger airliner. On Monday, March 11, Ethiopian Airlines announced it grounded its 737 MAX 8 fleet “effective yesterday March 10”. Also, on March 11, the China Civil Aviation Administration became the first government regulator to ground its aircraft, a fleet of 97, the largest in any country, based on its zero-tolerance policy for any safety hazards. In the next two days, dozens of airlines and regulators around the world followed in quick succession (Including the DGCA, the Civil Aviation authority in India) in grounding and denying airspace to the aircraft. The Federal Aviation Administration (FAA), the agency that certifies the safety of aircraft built in the U.S., issued a “Continued Airworthiness Notice” for the worldwide fleet of 387 aircraft, in which it said it had no evidence to order grounding. On March 13, Canada and the U.S. received new information from the investigations indicating the “possibility of a shared cause” for the accidents, prompting them to ground the planes.
There is no way I could word out a positive ending to this. The due negligence by Boeing, in addition to shoddy business practices came in the way of safety and led to a loss of a total of 346 lives in total. Here’s to a hope that the Aviation industry learns from this, the Aviation Authorities around the world employ even stricter safety measures and ensure this doesn’t repeat in the future.