The Boeing 737 Max is now one of the most controversial airliners of all time. Here are 4 others.

The Boeing 737 Max airliner has been grounded by regulatory agencies and airlines worldwide.
The action comes after two nearly-brand-new Boeing 737 Max 8 airliners crashed within a matter of months.
The crashes, the grounding of the fleet, and the public furor make the Boeing 737 Max one of the most controversial airliners in recent memory.
Other airliners that ran into trouble include the De Havilland Comet, McDonnell Douglas DC-10, and the Airbus A320.

The US Federal Aviation Administration grounded the Boeing 737 Max airliner on Wednesday. It was the last and arguably most significant regulatory body to take action against Boeing's state-of-the-art single-aisle jet.

The enforcement action against the Boeing jet comes after two 737 Max 8 airliners crashed under strikingly similar circumstances in a matter of months.

At the heart of the controversy surrounding the 737 Max is MCAS, the Maneuvering Characteristics Augmentation System. To fit the Max's larger, more fuel-efficient engines, Boeing had to redesign the way it mounts engines on the 737. This change disrupted the plane's center of gravity and caused the Max to have a tendency to tip its nose upward during flight, increasing the likelihood of a stall. MCAS is designed to automatically counteract that tendency and point the nose of the plane downward.

On Wednesday, Boeing announced that a software update to correct the shortcomings of MCAS is incoming. Until then, all 371 Boeing 737 Max airliners already delivered to customers remain grounded.

As a result of the crashes, the grounding of the fleet, and the public furor, the Boeing 737 Max has become one of the most controversial airliners in recent memory.

But the Max isn't the first plane to run into trouble, and many have been able to overcome their problems to have successful careers.

Here's a closer look at the at some of the most controversial airliners in recent history:

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