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Opinion Are the Boeing 737 Max jets safe? That depends on how you define safety

Ashley Nunes studies regulatory policy at MIT

An Ethiopian Airlines jet left Addis Ababa for what should have been a two-hour flight to Nairobi last Sunday. It ended up lasting just six minutes.

Air-traffic controllers lost contact with the jet – a Boeing 737 Max 8 – shortly after takeoff. Its wreckage was later found in a field outside a small village. Eighteen Canadians were among the 157 victims, including a nine-month-old infant and a 71-year-old grandfather. Prime Minister Justin Trudeau said he was “deeply saddened” by the news, expressing “heartfelt condolences to those who have lost family, friends and loved ones as a result of this tragedy.”

The last commercial jet crash occurred five months ago. Lion Air Flight 610 was flying from the Indonesian capital of Jakarta to the tin-mining islands of Bangka Belitung. Thirteen minutes after takeoff, air-traffic controllers lost contact with the jet; its wreckage was later found strewn across the Java Sea. All 189 passengers and crew on board were killed. The plane involved in that accident? A Boeing 737 Max 8.

ground altitude

In feet

6,000

Lion Air Flight 610

4,000

Both planes appear to have

lost altitude in the first few

minutes of their flights

2,000

Ethiopian Airlines Flight 302

0

0

200

400

600

SECONDS SINCE TAKEOFF

THE GLOBE AND MAIL, SOURCE: reuters

ground altitude

In feet

6,000

Lion Air Flight 610

4,000

Both planes appear to have

lost altitude in the first few

minutes of their flights

2,000

Ethiopian Airlines Flight 302

0

0

200

400

600

SECONDS SINCE TAKEOFF

THE GLOBE AND MAIL, SOURCE: reuters

ground altitude

In feet

6,000

Lion Air Flight 610

4,000

Both planes appear to have

lost altitude in the first few

minutes of their flights

2,000

Ethiopian Airlines Flight 302

0

0

200

400

600

SECONDS SINCE TAKEOFF

THE GLOBE AND MAIL, SOURCE: reuters

The fallout has been swift. On Wednesday, Hong Kong, Vietnam and New Zealand joined the United Kingdom, China and the European Union in banning Max jets from their skies. Canada eventually followed suit, though not before Toronto-based Sunwing Airlines announced it was pre-emptively taking sucFh action. Canada’s move – announced by Transport Minister Marc Garneau – effectively grounds 41 Max 8 and 9 jets across the country. Most of these planes are operated by Air Canada and Westjet.

The rationale for the move is safety. Given reports of similar problems on the Ethiopian and Lion Air flights – crew on both reported having trouble flying the plane – the aircraft are being labelled as unsafe to fly.

But is that really true? The answer has a lot to do with what we mean by safe in the first place and how we balance what we expect from the way we travel.

The plane is a marvel of modern engineering. It can – compared with many of its counterparts – fly faster for longer, all while burning less fuel. That matters to an industry that, in 2018 alone, spent more than US$170-billion on fuel-related expenses. However, eking out cost savings from the Max meant changing the airplane’s design. That in turn made the airplane less stable. Boeing’s solution? Technology. The jet maker introduced a feature (dubbed MCAS) which would prevent the airplane’s nose from rising too quickly.

Ethiopian Airlines crash: What we know so far about the disaster and the 157 victims

Who’s grounded the Boeing 737 Max 8 so far, and who hasn’t? A guide

key feature of boeing max

The Boeing 737 Max incorporates the Maneuvering

Characteristics Augmentation System (MCAS) – an

anti-stall feature introduced to compensate for the

heavier engines, which changed the aerodynamics

of the jet, tending to push the nose of the aircraft up

HOW MCAS WORKS

AOA sensor

Winglet aligns

itself with

airflow

Level flight: Normal angle of

attack (AOA) – angle at

which airflow hits aircraft

Aircraft trajectory

Air flow

CFM Leap-1B turbofan

Nose-up flight

A high AOA puts aircraft at risk

of stalling. MCAS is automatically

triggered, moving the horizontal

stabilizer trim counterclockwise,

which pushes the

jet’s nose down

Longitudinal

axis of aircraft

Angle

of attack

Aircraft

trajectory

Air flow

Measured angle of attack

System activates only when plane is being flown

manually, in flaps-up flight, and typically during

steep turns

the globe and mail, Sources: graphic news;

AP; JAO Aero Media LLC; the New York Times;

Seattle Times; the air current

key feature of boeing max

The Boeing 737 Max incorporates the Maneuvering

Characteristics Augmentation System (MCAS) – an

anti-stall feature introduced to compensate for the heavier

engines, which changed the aerodynamics of the jet,

tending to push the nose of the aircraft up

HOW MCAS WORKS

AOA sensor

Winglet aligns

itself with

airflow

Level flight: Normal angle of

attack (AOA) – angle at

which airflow hits aircraft

Aircraft trajectory

Air flow

CFM Leap-1B turbofan

Nose-up flight

A high AOA puts aircraft at risk

of stalling. MCAS is automatically

triggered, moving the horizontal

stabilizer trim counterclockwise,

which pushes the

jet’s nose down

Longitudinal

axis of aircraft

Angle

of attack

Aircraft

trajectory

Air flow

Measured angle of attack

System activates only when plane is being flown

manually, in flaps-up flight, and typically during

steep turns

the globe and mail, Sources: graphic news; AP; JAO

Aero Media LLC; the New York Times; Seattle Times;

the air current

key feature of boeing max

The Boeing 737 Max incorporates the Maneuvering Characteristics Augmentation

System (MCAS) – an anti-stall feature introduced to compensate for the heavier engines,

which changed the aerodynamics of the jet, tending to push the nose of the aircraft up

HOW MCAS WORKS

AOA sensor

Level flight: Normal angle of attack (AOA)

– angle at which airflow hits aircraft

Winglet aligns

itself with

airflow

Aircraft trajectory

CFM Leap-1B turbofan

Nose-up flight

A high AOA puts aircraft at risk

of stalling. MCAS is automatically

triggered, moving the horizontal

stabilizer trim counterclockwise,

which pushes the

jet’s nose down

Longitudinal

axis of aircraft

Angle of attack

Aircraft

trajectory

Air flow

Measured angle of attack

System activates only when plane is being flown manually,

in flaps-up flight, and typically during steep turns

the globe and mail, Sources: graphic news; AP; JAO Aero Media LLC;

the New York Times; Seattle Times; the air current

The problem, however, is that under certain conditions – such as those likely experienced during the Lion Air and Ethiopian Airlines flight – MCAS lowers the nose so strongly that pilots struggle to maintain control. This detail was largely omitted from the aircraft training regimen because it was considered unimportant. One airline executive said pilots don’t need to know how underlying systems are built because “they’re not engineers and their job is to fly the aircraft.”

However, as appealing as this reasoning is, it misses the mark. For one thing, more education doesn’t guarantee better decisions. History is filled with examples of seasoned pros making bad decisions. More importantly, getting proficient with complex systems isn’t cheap. Planes such as the Max rely on more than 350,000 parts – including nuts, bolts and screws – to fly, and more parts allow for more complex functions to be executed, giving the plane (and Boeing) a competitive advantage. But that advantage is lost if millions must be spent on first teaching pilots how every part works. Training takes time, after all, and time is money; that matters to an industry that has historically been a loss-making enterprise.

That’s the real irony of what has been called “the fastest selling plane in Boeing history.” Some pilots claim that the company opted – with cost savings in mind – to use a sticky design that raised safety concerns. Boeing alleviated those concerns using state-of-the-art technology. But it allegedly ultimately chose – once again, with cost savings in mind – to limit how much pilots were told about that technology. Unsurprisingly, Boeing disputes this characterization, instead emphasizing its commitment to safety.

Airplane crashes are, of course, a worst-case scenario – events that shake public confidence in what has become a nearly ubiquitous mode of transportation. In light of recent events, it may be tempting to call the jet unsafe. But improvements to the airplane will not result in the jet – or any jet – being perfectly safe. Whether or not the 737 Max 8 and 9 can be considered safe ultimately depends on how safety is defined.

If perfect safety is what you are looking for, you would do well to do as aviation pioneer Wilbur Wright once suggested: “Sit on a fence and watch the birds.”

Transport Minister explains Ottawa's reasoning for keeping the planes out of Canadian skies, effective immediately, in light of Wednesday's crash in Ethiopia. The Canadian Press
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