Boeing 737 Max: When will the doomed jet fly again after deadly crashes?

Exclusive: Experts analyse the likely return to service of a plane involved in two tragedies on the eve of the first anniversary of the Lion Air crash

Soon after dawn on 29 October 2018, Lion Air flight 610 took off from Jakarta airport. Its intended destination was the Indonesian city of Pangkal Pinang.

The 189 passengers and crew were aboard an almost-new Boeing 737. This is the world’s most successful jet aircraft in terms of sales, with more than 10,000 delivered and a further 5,000 on order.

Thirteen minutes later, the plane plunged into the Java Sea at 415mph. There were no survivors.

The final report into the tragedy found serious shortcomings in pilot training and maintenance procedures at the Indonesian airline. But the primary cause of the crash was Boeing’s flawed installation of an anti-stall system known as MCAS – compounded by a failure to tell pilots about its existence, purpose and potential problems.

The twin-jet 737 first flew in 1967. Half a century on, the latest version of the plane entered service: the “Max”.

For frequent flyers boarding Lion Air 610, the interior of the Boeing 737 Max looked the same as earlier editions. But aerodynamically the 737 Max is significantly different.

The Max has much larger engines, improving the fuel efficiency of the aircraft. But the undercarriage of the Boeing 737 is short, and it sits much lower on the ground than its more modern counterpart, the Airbus A320.

Had the latest large engines been hung from the wings, as on previous versions, there would have been insufficient ground clearance.

Instead, the engines were moved further forward and blended into each wing. While intuitively this sounds as though it should have made the aircraft “nose-heavy”, in fact the aerodynamic consequence was that the engine housing themselves generated lift and could tilt the aircraft upwards.

The designers concluded this characteristic increased the risk of a stall, in which the wings do not generate sufficient lift to keep the plane flying safely.

So they installed software called the Maneuvering Characteristics Augmentation System (MCAS).

The anti-stall system monitors the angle between the wing and the airflow, known as the “angle of attack”. This is measured by a vane on the outside of the aircraft. If the system detects that the angle is getting dangerously steep, it operates an elevator in the tail to nudge the nose downwards – and does so repeatedly, even overriding the pilots’ commands.

It was installed, says Boeing, “to enhance the pitch stability of the airplane – so that it feels and flies like other 737s”.

The Indonesian accident report spells out: “MCAS was needed in order to make the Boeing 737 Max handling characteristics so similar to the [previous] versions that no simulator training was needed for type rating.”

As airlines updated their fleets, a more economical version of an old favourite, with no additional training required, was an appealing prospect.

But the Indonesian accident report, published almost a year after the tragedy, revealed that a faulty sensor caused MCAS to intervene repeatedly to force the nose of the aircraft down – even as the plane was falling at 10,000 feet per minute.

Nine days after the crash, the US safety regulator took action. The Federal Aviation Administration (FAA) issued an Emergency Airworthiness Directive about MCAS, saying its erroneous deployment “could cause the flight crew to have difficulty controlling the airplane, and lead to excessive nose-down attitude, significant altitude loss, and possible impact with terrain”.

But four months later, another 157 people lost their lives in a similar accident. The pilots of Ethiopian Airlines flight 302 from Addis Ababa to Nairobi were aware of the possible problem. But when MCAS was triggered, again because of a faulty sensor, they could not overcome the pressure with which the system forced down the nose of their Boeing 737 Max.

Within days, all Max aircraft were grounded worldwide. In total, 387 of the plane type had been delivered to 48 airlines since the plane entered service in May 2017.

For passengers, flight crew and airlines, there are three crucial questions. When will the Max fly again? What will be different about it? And how will readily will travellers step aboard the jet?

Boeing assumes the Boeing 737 Max will be approved to fly again by the end of the year. It says: “This assumption reflects our best estimate at this time, but actual timing of return to service could differ from this estimate.”

But Sean Broderick, senior air transport and safety editor for Aviation Week, warns that even if the plane is given the green light, it will be “late winter or early spring” before it is back in commercial service.

“The best guess right now – and it is a guess – is that the US FAA and likely a few other regulators will clear the Max to return sometime in December,” he said.

“Regulators are still awaiting some final bits from Boeing to round out the entire package, which includes software updates and documentation.

“The changes have to be flight-tested by regulators and some airline pilots, and training also must be finalised.

“Delays in any of this, or discovery of any other issues during final testing could push initial approvals into 2020.”

But Tim Jeans, former managing director of Monarch Airlines, believes there may be more fundamental flaws. He said: “We’re now seven months into the grounding with no clear timetable for a reintroduction to service.

“That says to me, it isn’t just software. You can see regulators being uncomfortable with an aircraft that tends to go nose-up.

“It may be that regulators say ‘you have to get rid of the root cause’.”

A redesign of the engine mounting to eliminate the nose-up effect would require far more time and money than a software fix.

Even when the US FAA is satisfied with Boeing’s changes, other safety regulators may withhold approval until they have conducted their own investigations into the changes.

The UK’s Civil Aviation Authority (CAA), Europe’s EASA and many other regulators were appalled by the FAA’s insistence that the Boeing 737 Max was safe, even after the loss of the Ethiopian Airlines jet.

Britain banned the plane on 12 March 2019, and on the same day the FAA said: “Our review shows no systemic performance issues and provides no basis to order grounding the aircraft.”

Within two days, though, the Max was grounded worldwide.

As a result, said Mr Jeans, the normal “lockstep”of safety regulators, in which they agree internationally, may not apply.

Mr Jeans said: “While the bond of trust between regulators has not been broken forever, foreign safety bodies won’t want just to take the FAA as received wisdom.

“The FAA has blown that for the time being.”

But Mr Broderick said divergence between Europe and the US may not last for long: “I would be surprised if EASA’s timeline is more than a few weeks off from the US.

“The FAA and EASA work together very closely, and have forged a very strong relationship that includes having high confidence in each other’s work as part of a larger effort to unify, and improve, global aviation safety standards.”

Asian regulators may behave differently. India’s Spicejet has been badly affected by the grounding, but the director of India’s Directorate General of Civil Aviation has said he will be “conservative” about allowing the plane back in service. China and Indonesia may also insist on their own investigations.

Dr Rob Hunter, head of flight safety for the British Airline Pilots’ Association (Balpa), said: “Some regulators may have accepted the certification decisions of the FAA without substantial scrutiny because they have trusted the FAA. Regulators may now not automatically accept FAA certificatory decisions.”

Mr Broderick warned: “A split between FAA and EASA now risks a larger breakdown in global aviation safety confidence and leadership.

“Regulators should be striving for common standards, not competing views of what is acceptable and what is not.”

Were the Boeing 737 Max to start flying in North America before it is allowed back in the skies of Europe, it could cause consternation.

British Airways and Virgin Atlantic could find themselves selling “codeshare” tickets on their partners American Airlines and Delta respectively, for flights on an aircraft type that the UK CAA does not officially recognise as safe.

Returning the Boeing 737 Max to commercial flight will not be a smooth process. Mr Broderick said some airlines are maintaining their Max aircraft as if they never left the fleet, running engines and systems frequently, and performing routine maintenance.

“These aircraft would be ready to go in a matter of days, with their return likely governed by how quickly airlines can work the Max back into its flight schedules.”

But he added: “Some airlines have their Maxs in long-term storage – mothballed, if you will.

“Getting these aircraft ready will take considerable man-hours. One US airline has estimated 100-150 per aircraft.”

Pilots will also demand more training. Dr Hunter of the pilots’ union, Balpa, said that pilots “were tragically let down” by the way that the Boeing 737 Max was certified, and will be very involved in the return to service of the aircraft.

He said: “There needs to be comprehensive training in the simulator and thereafter a further programme of training oversight once the pilots are flying in commercial operations.

“In practice this involves specially trained captains that sit on the third seat on the flight deck. These captains monitor and give advice and guidance to crews in their early days of flying the aircraft.

“With these arrangements in place the public should be reassured that it is safe to fly in this aircraft.”

But whether the public will feel reassured is another matter.

In June 2019, a Twitter poll by The Independent found that more than half of passengers would not want to fly on a Boeing 737 Max.

A Boeing spokesperson said: “The confidence of the flying public is very, very important to us.

“We’re listening to the flying public to ensure we consider their feedback about our communications as we finish up the certification process on the software update and return the 737 Max safely to flight.”

Mr Broderick said that US airlines are attuned to concerns: “The smartest ones are permitting passengers no-fuss, no-charge changes from flights operated by Maxs to other flights.

“Some are even planning mandatory training for pilots, cabin crew, and other frontline staff on how to address concerns expressed by nervous customers.”

But there is no legal obligation to offer alternative flights if passengers are concerned about an aircraft type. European airlines such as Ryanair – which was due to start flying a specially designed Boeing 737 Max, the -200 version – may adopt a “take it or leave it” attitude.

The veteran aviation journalist Malcolm Ginsberg reaches back into history – and the Comet disasters of the 1950s. “There was no public resistance about the Comet 4 being the first jet across the Atlantic.

“The DC10 remained popular even after it was temporarily grounded, with Laker Airways using it for cheap transatlantic flying.

“However we now live in powerful social media age and this will certainly have an effect. It only takes for one person to give a plausible ‘don’t-fly story’ for it to go viral and everything will stop.”

Former Monarch boss Tim Jeans said: “I think this will blow over faster than many people think.

“There’s little doubt that the Boeing 737 Max will be as safe as any aircraft has ever been.”

Dr Hunter of Balpa said: “We think that the aircraft will be successfully returned to service because the penalties for further failure will be so great.”

Sean Broderick said the travelling public should focus on aviation’s remarkable safety record: “As the Max tragedies show, the industry is not perfect, and it never will be.

“Yet it remains incomprehensibly safe compared to other modes of mass transportation, and efforts to make it even safer will never stop.”

The harsh truth is that aviation safety is built on the painstakingly investigation of past tragedies. The report into the Lion Air loss on 29 October 2018 is dedicated to those who lost their lives in the crash.

“Their sacrifice will not be in vain. They will be forever missed and never forgotten.”