By Clive Irving (Credit Daily Beast)
There is no case in the recent history of commercial aviation where within the first year of introducing a new model jet there have been two serious fatal accidents involving that model. But that is now the record of the Boeing 737 MAX-8, the newest version of the most widely used single-aisle jet in the world.
The crash of Ethiopian Airlines Flight 302 shortly after taking off from Addis Ababa occurred little more than four months after the crash of Lion Air Flight 610 in Indonesia. A total of 346 people died in the two crashes, 157 in Ethiopia and 189 in Indonesia.
Eight Americans, 18 Canadians, and passengers from at least 35 countries died in the crash of Flight 302, bound for Nairobi, Kenya.
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A conclusive explanation for the Ethiopian crash cannot be reached without recovery of the data from the airplane’s black box. And, even though there are striking similarities between the two disasters, it is too soon to conclude that the cause was exactly the same.
Nonetheless it must be of great concern that at a time when the rate of fatal air crashes has been reduced to record low levels two such catastrophes can occur involving a new model jet that has only recently joined airline fleets: the Lion Air 737 was delivered in August 2018 and the Ethiopian 737 in November 2018.
The most pressing question for investigators is whether the Ethiopian pilots confronted the same sudden emergency that doomed the Lion Air flight.
Within a few minutes of takeoff the Lion Air pilots encountered a problem that made it difficult to control the climb. Due to a faulty instrument, the 737’s automatic flight controls system detected an aerodynamic stall and forced down the airplane’s nose to correct it.
In fact, the jet was nowhere near to stall speed and for the rest of what was only an 11-minute flight the pilots struggled to overcome the automated commands that continued to force down the nose. They lost that struggle and the jet nosedived into the Java Sea.“At the heart of the concerns about the MAX-8 is a change in the automatic flight controls.”
The Ethiopian 737 was in the air for far less time, around six minutes. But in that time the captain, like the Lion Air captain, reported difficulties and requested a return to the airport. Unlike the Lion Air flight there is no evidence that the Ethiopian crew was able to maintain altitude and begin to make a turn back toward the runway – the jet’s end was very sudden and it appears to have impacted the ground at high speed.
Addis Ababa airport operates at what is technically called “hot and high” conditions – the runway is at a height of more than 7,600 feet above sea level and in a location where temperatures are often high. This means that the air is thinner than at usual ground levels and airplanes need a longer takeoff run.
So although Ethiopian Flight 302 reached a height of around 9,000 feet above sea level its actual height when it hit trouble was around 2,500 feet above the ground – the Lion Air jet first encountered a control problem at 1,000 feet, when it fell suddenly about 600 feet, and never rose above 5,000 feet.
There is a difference in the immediate history of the two flights. Pilots who flew the Lion Air jet on its previous flight had reported problems with the controls. While that airplane was between flights the airline’s maintenance crew checked it and reported it safe to fly – without, apparently, detecting the fault in a sensor that triggered the computers to force down the nose.
According to a press conference held by Ethiopian Airlines’ CEO, Tewolde Gebre Mariam, the airplane had undergone normal safety checks after a flight from Johannesburg, South Africa, in preparation for the flight to Nairobi, and no problems had been reported.
At the heart of the concerns about the MAX-8 is a change in the automatic flight controls. Boeing is facing a lawsuit on behalf of the family of a victim of the Lion Air crash that focuses on changes made to the flight controls in a few lines of new software.
The change, called Maneuvering Characteristics Augmentation System, MCAS, initiates the nose-down command without input from the pilots. The introduction of this system was not included in the flight manuals issued to pilots nor was it included in the training given to pilots who transferred to the MAX-8 series from earlier model 737s.
Boeing has responded to the suit by maintaining that pilots should recognize they were facing a “runaway stabilizer” problem for which they are prepared, both in training and by instructions in the manual. Using those procedures, Boeing argues, they can override the computer commands.
However, given the stress in the cockpit when an emergency of this magnitude strikes without warning at a critical time immediately after takeoff, recalling and executing the required moves is demanding. Switches have to be flipped to de-activate the computer commands and the pilots have to manually reset the horizontal stabilizer.
In the Ethiopian emergency the demands on the captain were probably made more demanding because his copilot was a rookie – with only 200 hours of experience, an unusually low number. The captain, in contrast, had 8,000 hours of experience.
The Chicago lawyers bringing the suit against Boeing said that introducing the MCAS without a specific warning of its actions was “like Boeing first blindfolded and then tied the hands of the pilots.”
The U.S. National Transportation Safety Board is sending a team to join investigators in Ethiopia, and the FAA is also monitoring developments. But this is by no means a normal investigation situation. The Ethiopian investigation has to begin by taking into account the lethal chain of events that led to the Lion Air disaster – and the unusual sequence of two such serious accidents happening within such a short time involving the same airplane type.
Thomas A. Demetrio, the Chicago lawyer leading the suit against Boeing, told The Daily Beast that regulators should be considering a grounding of the MAX-8 until a definitive cause of both crashes is established.
“We have to discuss as a society whether we are going to place the value of a human life over the loss of revenue to airlines involved in a grounding. The value of a life is more important than the cost of a round trip to anywhere,” he said.
The last time a new jet was grounded was in 2013, when the Boeing 787 Dreamliner was grounded for three months following a series of fires originating in lithium-ion battery packs that supplied power to the airplane’s systems. (One of those fires occurred in an Ethiopian Airways 787 while parked at London’s Heathrow Airport.)
The installation of the battery packs was revised and no more fires occurred. The 787 has a flawless safety record.