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explainer

Since March 10′s plane crash in Ethiopia, airlines and aviation authorities around the world have taken a popular model of Boeing airplanes out of the skies. On Wednesday, Canada and the United States announced both countries will be grounding the Boeing 737 Max 8. Transport Minister Marc Garneau said Canada made the decision after consulting with aviation experts who found similarities in the satellite-tracked flight paths of the two Max 8s that crashed. “Canadians expect and are entitled to a safe air travel system. I want them to be able to fly with confidence,” Mr. Garneau said at a news conference in Ottawa. The restriction also covers a variant of the 737 known as the Max 9. Here’s a guide to what we know so far about the Boeing 737 Max 8 and the controversy surrounding it.

Ethiopia refuses to send black box from crashed Boeing 737 Max 8 to United States for analysis

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


The plane at a glance

Length: 39.52 metres

Some other specifications:

Range: 6,570 kilometres

Wingspan: 35.9 metres

Maximum seats: 210

Engine: LEAP-1B from CFM International

 

 

THE GLOBE AND MAIL, SOURCES: GRAPHIC NEWS, BOEING

Length: 39.52 metres

Some other specifications:

Range: 6,570 kilometres

Wingspan: 35.9 metres

Maximum seats: 210

Engine: LEAP-1B from CFM International

 

 

THE GLOBE AND MAIL, SOURCES: GRAPHIC NEWS, BOEING

Length: 39.52 metres

Some other specifications:

Range: 6,570 kilometres

Wingspan: 35.9 metres

Maximum seats: 210

Engine: LEAP-1B from CFM International

 

 

 

THE GLOBE AND MAIL, SOURCES: GRAPHIC NEWS, BOEING

Since the 1960s, the 737 has been one of Boeing’s workhorse aircraft for short- to medium-range travel. In 2017, the Chicago-based aviation company introduced the Max 8, a modified version that flies farther and uses less fuel. Boeing says it’s the fastest-selling aircraft in his history. Air Canada aims to have 50 of the planes by 2021, according to company documents, making up a third of its narrow-body fleet.

But the model came under scrutiny last fall when a flight by Indonesia’s Lion Air crashed, killing all 189 people on board. A preliminary report on that crash found technical problems with airspeed and altitude displays in the days before the disaster. Questions about the 737 Max 8 intensified on March 10, when Ethiopian Airlines Flight ET 302 crashed minutes after takeoff from Addis Ababa, killing all 157 people (including 18 Canadians) on board.

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


publicly traded u.s. and canadian

airlines’ Exposure

737 Max series as percentage of total fleet

in service as of 2018*

Total aircraft

737 Max series

% 737

Max

Airline

Number of aircraft

391

Air Canada

4.6%

18

330

Alaska**

n/a

0

1,551

American

1.3%

20

750

Southwest

4.1%

31

1,329

United

0.7%

9

177

WestJet

6.2%

11

*Does not reflect current number of planes in service

**Has planes on order

Note: Delta, Allegiant, Hawaiian, JetBlue, Spirit, Mesa,

SkyWest and Volaris have no exposure to the 737 Max series.

JOHN SOPINSKI/THE GLOBE AND MAIL

SOURCE: cowen and company

publicly traded u.s. and canadian

airlines’ Exposure

737 Max series as percentage of total fleet

in service as of 2018*

Total aircraft

737 Max series

% 737

Max

Airline

Number of aircraft

391

Air Canada

4.6%

18

330

Alaska**

n/a

0

1,551

American

1.3%

20

750

Southwest

4.1%

31

1,329

United

0.7%

9

177

WestJet

6.2%

11

*Does not reflect current number of planes in service

**Has planes on order

Note: Delta, Allegiant, Hawaiian, JetBlue, Spirit, Mesa, SkyWest and Volaris have no exposure to the 737 Max series.

JOHN SOPINSKI/THE GLOBE AND MAIL

SOURCE: cowen and company

publicly traded u.s. and canadian airlines’ Exposure

737 Max series as percentage of total fleet in service as of 2018*

Total aircraft

737 Max series

Airline

Number of aircraft

% 737 Max

391

Air Canada

4.6%

18

330

Alaska**

n/a

0

1,551

American

1.3%

20

750

Southwest

4.1%

31

1,329

United

0.7%

9

177

WestJet

6.2%

11

*Does not reflect current number of planes in service

**Has planes on order

Note: Delta, Allegiant, Hawaiian, JetBlue, Spirit, Mesa, SkyWest and Volaris have no exposure to the 737 Max series.

JOHN SOPINSKI/THE GLOBE AND MAIL, SOURCE: cowen and company

Who’s grounded the plane

By Monday, aviation regulators in Ethiopia, China and Indonesia were among the first to ground their airlines’ fleets of Max 8s, also barring the model from flying in or out of their airports. Airlines across the Asia-Pacific region, Africa and the Caribbean followed suit, and by Tuesday major European buyers of the Max 8, notably Britain and France, also issued restrictions. Then the European Union’s aviation safety agency, EASA, suspended all flights in the bloc by the 737 Max 8 and Max 9 models. Finally, Canada and then the United States joined the ban, with U.S. President Donald Trump issuing a special order.

National regulators that have temporarily grounded the plane include those in Canada, the United States, Australia, Austria, Britain, the Czech Republic, Egypt, Ethiopia, the European Union, Fiji, France, Germany, Kazakhstan, India, Indonesia, Ireland, Lebanon, Malaysia, Panama, Poland, Singapore, Thailand, the United Arab Emirates and Uzbekistan. Not all of these jurisdictions have airlines with Max 8s in active service, though, and some airlines in countries who haven’t barred the planes have grounded their fleets anyway as a precaution.

Automated system in the spotlight

Though no cause has yet been established for the Ethiopian plane crash, one factor that experts are looking at is the Max 8′s automated anti-stalling system, called the Maneuvering Characteristics Augmentation System. Because the Max 8′s fuel-efficient engines are bigger than usual, the plane’s nose is more likely to pitch up after takeoff. The MCAS is designed to compensate for this by pointing the nose back down if sensors detect climbs that are too steep or too slow, either of which might cause a stall. Pilots who aren’t familiar with the system might make dangerous miscalculations in takeoff.

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

On Tuesday afternoon, U.S. President Donald Trump tweeted that airplanes have become “far too complex” to fly. “I see it all the time in many products. Always seeking to go one unnecessary step further, when often old and simpler is far better,” Mr. Trump tweeted. In a following tweet, he said the ecomplexity creates danger.

Watch: How does MCAS work? Here's a visual primer.


The fallout for Boeing

Boeing’s shares plummeted in the days after the crash, erasing billions of dollars in market value as more airlines grounded their Max 8 fleets. The company has defended its aircraft and said it has “full confidence in the safety of the Max.”



Compiled by Globe staff

Associated Press and Reuters, with reports from Brent Jang and Eric Atkins

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