This is a condensed version of an in depth article published in the 19th August issue of Aviation Week and Space Technology.
Sean Broderick, Senior Air Transport Editor, looks into the Boeing 737 MAX crisis and asks:
what happened and what now?
Mid-August marked five months since the last Boeing 737 MAX fleet’s revenue flight and customer delivery as well as—most significantly—its second fatal accident. While Boeing is making progress on changes needed to convince regulators that the latest iteration of its venerable narrow body is safe to fly, the timing remains fluid. The road ahead is littered with unanswered questions. As for how one of the industry’s most successful and best-selling models ended up grounded less than two years after entering service, more is known. Following is a recap of how the MAX got here, where it is headed, and—to the extent known—what comes next. Some key issues related to the MAX crisis are not covered in detail. Among them: detailed breakdowns of the two accident sequences as revealed in preliminary investigative reports. While the MAX’s Manoeuvring Characteristics Augmentation System (MCAS) played a role in both accidents, other concerns—from maintenance practices to the adequacy of pilot training—will likely end up being identified as contributing factors. As with every major accident, the lessons learned go far beyond addressing the primary causal factors. With two accidents to learn from, the MCAS may be close to being updated, but the MAX story’s influence on aircraft design, certification and pilot training is only starting to be felt.
Why did Boeing develop the MAX instead of a clean-sheet successor to the 737?
As the 2010s began, Boeing was looking hard at developing an all-new narrow body to replace the aging 737, which first flew in 1967. The company’s leaders downplayed the belief that a rumoured reengining of the A320 by Airbus would force Boeing to follow suit. “Not if we’re convinced a new airplane will be coming at or near the end of the decade,” then-CEO Jim McNerney told Aviation Week in mid-2010. “I think our customers will wait for us.”
But with oil prices soaring, the 15% improvement in fuel efficiency the A320neo offered proved more attractive to airlines than waiting several more years for an even better airplane. By mid-2011, seven months after the Neo’s launch, Airbus had won more than 1,000 orders and commitments.
Boeing’s hand was finally forced by the prospect of losing one of its marquee customers, American Airlines. The carrier, previously an all-Boeing customer, split a record-setting order for 460 narrow bodies between the two companies—but only after Boeing agreed to launch the MAX. “The American Airlines A320neo deal was probably transformative,” John Leahy, Airbus’ long-time chief salesman, recalled last year. “Boeing threatened to sue [American] because it all happened before the end of a 20-year exclusivity agreement. But American said if Boeing wanted a share of the order, they would have to produce a [reengined 737]. So they did it, and did not even know what the aircraft was going to be like because they were so focused on the all-new single-aisle.”
Ironically, the A320neo was launched as a defensive move. Airbus leaders wanted to blunt the threat to the A320 from the C Series, the cutting-edge Bombardier aircraft program launched in 2008 with Pratt & Whitney geared turbofan engines. Even they had no idea the Neo would generate so many new orders.
“The Neo’s success in the marketplace did point out unmistakably that customers would embrace a lower amount of capability quickly,” McNerney reflected in 2012. “So that was a factor. We added it all up and decided to move with the MAX.”
The birth of the MAX took even its engine supplier by surprise. “Up until a few days before the American Airlines deal, Boeing was still saying they were going to do an all-new airplane,” said former CFM executive vice president,
GE general manager and deal broker Chaker Chahrour in 2013. “It was amazing how, literally within a few days, things had turned around.”
What happened with Lion Air Flight 610?
Like most accidents, several factors appear to have contributed to the crash of Lion Air Flight 610 (JT610) on Oct. 29, 2018. But a preliminary report issued in late November suggested that the accident sequence started when the MCAS activated based on faulty AOA data.
The report shows that the three-month-old 737-8, PK-LQP, was not airworthy when it pushed back to begin its trip to Pangkal Pinang, Indonesia. Something caused the aircraft’s left-side AOA vane to report a value that was 20 deg. higher than the right vane. This discrepancy, captured by the digital flight data recorder (DFDR) even as the aircraft was taxiing out, triggered a stickshaker stall warning on the captain’s side as soon as the aircraft took off.
Once the flaps were retracted, the left-side FCC, reading the faulty AOA data, triggered the MCAS. Nose-down trim was applied for 10 sec. The pilots countered with main electric trim nose-up inputs. At least 25 automatic stabilizer nose-down, pilot-directed stabilizer nose-up exchanges took place and then several nose-down inputs were not countered. The last automatic nose-down input precipitated a dive from about 5,000 ft. that ended with the aircraft hitting the Java Sea 13 min. after takeoff. All 189 people onboard were killed.
How did the key players react?
Lion Air was immediately concerned about the possibility of uncommanded stabilizer inputs playing a role in the accident. Within hours after JT610 disappeared, the airline issued a safety reminder to its 737 pilots, urging them “to review several procedures, including memory items of Airspeed Unreliable and Runaway Stabilizer,” the Indonesian National Transportation Safety Committee (NTSC) preliminary report released Nov. 28 says. Nothing in the report suggests that the JT610 crew followed the runaway stabilizer checklist.
It did not take long for Boeing to zero in on the accident sequence’s key elements. On Nov. 6, the manufacturer issued a Flight Crew Operations Manual Bulletin: “Uncommanded Nose-Down Stabilizer Trim Due to Erroneous Angle Of Attack During Manual Flight Only.” The bulletin explained that one source of faulty AOA data can trigger 10 sec. increments of nose-down stabilizer inputs. Electric trim input will stop the automatic nose-down stabilizer movement, but it “may restart” 5 sec. after the electric trim input stops. The only way to stop the cycle is to follow the runaway stabilizer checklist and toggle the console-mounted cut out switches. Boeing also warned that “higher control forces may be needed to overcome any stabilizer nose-down trim already applied.” It recommended that operators append the bulletin to flight manuals.
The next day, the FAA issued an emergency airworthiness directive mandating Boeing’s recommendation. Neither Boeing’s bulletin nor the FAA’s directive discussed procedural changes, and neither referenced the MCAS by name.
Did regulators or Boeing consider doing anything else?
Following the accident, both the FAA and the European Aviation Safety Agency (EASA) conducted risk assessments of the MAX fleet. They probed flight-safety databases and found no comparable incidents. Their conclusions: The risk was not high enough to take immediate action on the in-service fleet beyond the initial bulletins.
While it appeared, the fleet was not at immediate risk, PK-LQP’s problems and the JT610 accident sequence convinced Boeing that the MCAS needed improvement, and it began to work on a software upgrade. In early December, the company’s projected timeline for delivering the new software was 1-2 months. But the upgrade’s scope kept changing and has extended beyond the MCAS. It is still not done.
So when did the world learn about the MCAS?
A Nov. 10 message from Boeing to MAX operators shed more light on the system described in the earlier bulletin, using the MCAS’ name. Airlines disseminated bulletins to their pilots. For most of them, it was the first time they had heard of the MCAS.
Still, confusion persisted. Pilots at one U.S. major airline were told by their safety committee that the MCAS could be countered by applying opposite control-column input to activate the column cut out switches, which was not true.
How did the regulators react, and why was the FAA the last to ban the MAX?
Two fatal MAX accidents in five months were enough for many to take action. China was the first big mover, banning all MAX operations within 24 hr. of the ET302 accident. Other regulators and operators quickly followed suit. Notably, the FAA was not among them.
Late on March 12 Washington time, FAA Acting Administrator Dan Elwell said that the agency’s review of MAX in-service data, including what little was known about the second accident, “provides no basis to order grounding the aircraft, nor have other civil aviation authorities provided data to us that would warrant action.”
That changed overnight.
Working with Transport Canada, the FAA reviewed what it termed “refined” satellite data that helped map ET302’s flightpath. It showed altitude variations that were similar to those JT610 experienced as its crew countered the MCAS’ nose-down commands with nose-up inputs. The data was enough to convince the Canadians to ban the MAX. A few hours later, the FAA became the last regulator to issue a ban.
Elwell cited the flight data and a crucial piece of wreckage—believed to be a jackscrew showing that ET302’s stabilizer was in a specific position when it crashed—as the evidence that swayed the U.S. agency. The groundings—or, more accurately, operations bans that cover a regulator’s airlines and the airspace it governs—remain in place and must be removed one by one, at each regulators’ discretion.
How has the grounding affected Boeing’s production?
Boeing paused deliveries on March 14 and reduced 737 production—now mostly MAXs destined for airlines—from 52 per month to 42 per month as of April. Newly built aircraft are flown by Boeing production test pilots—many of them contributing to flight-testing the proposed software changes—and then stored.
Deliveries will resume after regulators lift their bans, which Boeing hopes will be sometime in the fourth quarter. If that happens, the OEM plans to ramp 737 production back up in 2020 to a rate of 57 per month—the planned target for 2019 before the second accident and groundings disrupted everything MAX-related. However, Boeing also says all production of MAXs could be temporarily halted if the return-to-flight timeline drags on into 2020.
When will the MAX return to service?
Boeing is targeting “the September time frame” for handing over the long-awaited changes to the FAA. They will include new MCAS software, related training and other changes to the flight control system that the FAA has requested.
If Boeing submits its package of changes to the FAA by mid-October, its current target of getting FAA approval sometime in the fourth quarter remains achievable. The FAA will be the first regulator to lift its ban, and at least some are expected to follow in short order—likely days.
Once a regulator clears the MAX to return to service, the process of preparing the aircraft for revenue service begins. In addition to routine work required to get any parked aircraft flying again, Boeing’s upgrades must be installed—a process the company says will take a few hours per airframe. Each aircraft will then be flight-tested.
For carriers with just a few MAXs, the return-to-service timeline could be just a few days. But for larger carriers, it will take a month or more—a function of their ability to take only so many aircraft in short order, Boeing’s available manpower to support the service returns, and—crucially—ensuring pilots have completed the latest training.
What about Boeing’s finances?
The longer airlines are without their MAXs, the higher the cost to Boeing will be. The company took a $4.9 billion second-quarter after-tax charge to cover anticipated customer compensation linked to the MAX grounding as well as development of the MCAS changes. That led to a record $2.9 billion quarterly loss.
But long-term damage to Boeing’s finances could be limited by the fact that current MAX customers don’t have a lot of options. They cannot simply switch orders to Airbus because the A320 family is largely sold out through 2022. And China’s new narrow body—the Comac C919—is unproven and behind schedule in flight-testing. “It’s like a world where there are just two car companies,” says Bank of America Merrill Lynch aerospace analyst Ron Epstein. “Boeing will come out of this.”
How much is the MAX grounding hurting airlines?
With affected airlines set to receive compensation from Boeing, the true impact of the MAX grounding is mixed—and the bite may end up being very little for some operators.
Parking the 385-aircraft MAX fleet with just hours’ notice created significant early disruption. Once airlines realized the aircraft were not coming back in short order, many began to adjust schedules to accommodate for the lost lift. They used every tactic available, from cancelling flights to cutting frequencies and shuffling aircraft around. Nonessential maintenance, such as cabin-refresh programs and inflight entertainment installations, were postponed to maximize aircraft availability. The few available aircraft on the lease market were snapped up, and many airlines with the flexibility to extend leases did so.
The grounding has taken an estimated 41 million seats out of the industry through late October, flight schedules specialist OAG says. That adds up to lost revenue of more than $4 billion. But the tightening of capacity has also allowed airlines to command higher ticket prices on some routes, boosting unit revenues. The delay in MAX deliveries has also allowed operators to postpone hefty capital expenditures. Despite the crisis, some MAX operators have reported robust quarterly profits.
According to OAG, China Southern Airlines, is the most affected MAX operator—with a loss of 3.6 million seats compared to its February schedule—followed by Air Canada and Southwest Airlines. Some carriers also have had their expansion plans interrupted. United Airlines, which was flying 14 MAXs and had planned to take delivery of 16 more by Oct. 1, has seen the grounding wreak havoc on its flight schedule, forcing it to cancel 1,290 flights in July, 1,900 in August, a projected 2,100 in September and 2,900 in October. The rising cancellations reflect a higher number of MAXs missing as planned deliveries are held up.
At Ryanair—an all-737 operator heavily dependent on a new, higher-capacity version of the 737-8 for expansion—major 2020 changes are already in the cards. It had planned on 50 new MAXs by next summer but now expects just 30. CEO Michael O’Leary says pilot and cabin-crew cuts as well as “some base closures” are inevitable.
While Ryanair is an extreme case—it planned to grow 7% next year, all using new MAX lift—other carriers will face increasing challenges if new MAXs are not flowing in before next year’s peak summer period. “If you get to the next summer schedule and the lion’s share of [the MAXs] aren’t available, I can’t imagine how that’s not a big problem,” says Epstein.
Another upcoming headache is how exactly the MAX will return to service once authorities have cleared commercial flights. Small airlines say their management resources are stretched so much during the peak summer season that they have no bandwidth to accept additional aircraft then. They will either take delivery in the winter or past the summer peak in the fall. They can also not take many aircraft at once. Boeing may very well be faced with many cases in which airlines disagree with its delivery plans that will likely emphasize clearing the backlog of parked aircraft as soon as possible.
Will the MAX situation change aircraft certification and global regulatory cooperation?
It already has. The FAA’s latest request to change flight control software beyond the MCAS came out of closer scrutiny of Boeing’s safety analysis and related assumptions, for example.
Boeing 777X development and certification already appear to have been affected. The company is taking a very cautious approach to flight-test of the large wide body, delaying the start to ensure fixes being put into the new General Electric GE9X powerplants are flying on all test aircraft.
In the long term, the FAA and other regulators will continue to collaborate and rely on each other’s analysis. But acceptance of each other’s work—a critical method of sharing resources and safely streamlining certification globally—will likely involve many more questions than in the past. Those seeking to validate will want to be walked through the analysis and, if needed, have the supporting data to justify their trust. Expect this not just for agencies dealing with the FAA, but any agency seeking to accept another’s technical analysis.
The FAA also faces scrutiny of its delegation program, which relies on industry’s engineering expertise to help validate that products meet certification standards. Several studies are reviewing certification, and the National Transportation Safety Board the is finalizing a set of recommendations.
