Boeing’s 737 Max, the jetliner grounded for 20 months after two international crashes that killed 346 passengers and crew, was cleared to fly again Wednesday by the Federal Aviation Administration.
The troubled airliner’s return to the skies won’t be immediate, even with the ungrounding order. The planes will need to be refitted with improvements ordered by the FAA, and pilots will need to be retrained in procedures.
In 2011, Boeing believed an upgraded 737 jet, the favorite child in its aircraft family, would help it retain market share in the fiercely competitive aviation industry. In 2017, the 737 MAX entered service.
Since then, 346 people have died in two 737 MAX crashes. Nearly 500 MAX jets remain grounded and orders for thousands more are in limbo. Boeing faces fines, lawsuits, and accusations of rushing the aircraft into production.
How did the 737 MAX become a poster child for corporate error? Here is what we know:
The MAX was born when rival Airbus said in 2010 that it would build the A320neo to capture narrow-body aircraft sales in a jet with more efficient engines to lower operating costs. Boeing came back with the 737 MAX.
Airlines use narrow-body aircraft for short- and mid-range flights. They’re built relatively low to the ground, which makes it easier to work on engines and load and off-load baggage, especially at smaller airports. Turnaround times at airport gates are faster than those of wide-bodies.
The narrow-body 737 is Boeing’s best-selling airplane. Introduced in 1967, it’s now in its fourth generation. Airlines have embraced it since the 1980s. Boeing hoped for similar success with the MAX.
Southwest Airlines called it the future of its all-Boeing 737 fleet when it introduced the plane in October 2017.
Instead, the MAX, and its flight-control system, grabbed public attention after the two high-profile air crashes five months apart, in October 2018 and March 2019.
Investigations cited the MAX’s Maneuvering Characteristics Augmentation System, or MCAS, as one of several factors. MCAS is an onboard flight-control system designed to compensate for larger engines and make the MAX feel like previous 737 generations to pilots.
MCAS was intended to help Boeing in two ways:
1. It allowed the company to use an existing airframe to retrofit a higher-performance engine, instead of building a completely new plane. That would have taken more time at higher cost.
2. It allowed Boeing to sell the MAX to airlines by presenting it as a re-engined, but comfortably familiar, 737. That reduced training time for pilots.
Boeing’s position is that MCAS was designed to operate in the background and became operational only when needed. Some pilots have said they were not aware MCAS was part of the aircraft’s systems.
The larger engines were CFM International LEAP-1Bs. CFM, a partnership between GE and Saffron Aircraft Engines, claims the LEAP is 15% more fuel efficient the previous CFM56-7 model.
That gives planes longer ranges and new options for budget flight routes, which piqued interest from overseas airlines. Lion Air, the largest service in Indonesia, became one of the first to buy the MAX with an order of 201 models in November 2011.
Beginning of the downfall
On Oct. 29, 2018, a Lion Air 737 MAX was the first of two passenger jets to crash. All 189 people aboard were killed.
A typical flight reaches an altitude of 25,000 feet in about 10 minutes. The Lion Air flight climbed, struggled to maintain altitude, then descended. It never reached 6,000 feet before it crashed into the Java Sea.
A year after the crash, Indonesia’s National Transportation Safety Committee released a report that listed multiple factors, including design flaws in the 737 MAX, a lack of maintenance by the airline, and pilot confusion.
The design defects focused on the aircraft’s angle-of-attack sensors, two small winglets on each side of the plane below the cockpit windows. Investigators said a sensor malfunctioned and sent false data to a flight computer, telling it the plane’s nose was too high and that the aircraft would stall.
MCAS responded by pushing down the plane’s nose, forcing the pilots to fight for control. Pilots attempted to manually override the system more than two dozen times, investigators found.
While the report said more than one factor contributed to the crash, it criticized MCAS and lack of pilot training: “The investigation considered that the design and certification of this feature was inadequate. The aircraft flight manual and flight crew training did not include information about MCAS.”
The report also blamed Boeing and the FAA for not considering “the likelihood of loss of control of the aircraft” if MCAS failed.
Lion Air had the plane in service for about four months. Investigators reported the jet experienced similar problems on previous flights. On the inbound flight to Jakarta, pilots experienced difficulty and were able to shut off the system.
After the initial crash report, Boeing said it was “deeply saddened by the loss of Lion Air Flight 610,” but said the MAX was “as safe as any airplane that has ever flown the skies.”
However, just 132 days after the Lion Air crash, another MAX jet, Ethiopian Airlines Flight 302, crashed six minutes after takeoff on March 10, 2019. All 157 people aboard, including 8 Americans, were killed.
Review of the Ethiopian crash showed its pilots also struggled with MCAS shortly after takeoff. Investigators found the two angle-of-attack sensors sent conflicting data to the flight computer.
That activated MCAS, which pushed down the nose of the plane. The pilots shut off the system, but then turned it back on, putting MCAS back in control.
The BBC reported the plane crashed 30 miles southeast of the airport, near Bishoftu. The impact left a crater 92 ft. wide and 131 ft. long. The engines were found buried 32 ft. deep.
Investigators said the plane had been in service for less than three months. It had last been in for routine maintenance on Feb. 4.
In response to the Ethiopian crash, the FAA grounded 737 MAX jets in the U.S. on March 13, 2019. A worldwide ban was in effect by March 18.
Since then, the 737 MAX and Boeing itself has undergone intense federal scrutiny into how the jet was developed, how MCAS could fail, and how Boeing convinced airlines that its pilots did not need additional training.
737 MAX production remains halted. Boeing must pay FAA fines and deal with lawsuits from families, airlines and pilots, a fall in stock value – and public backlash over a perceived culture of profit over safety.
Wiring problem discovered
On Jan. 5, the New York Times, reported discovery of another possible MAX flaw. Engineers found two bundles of wiring leading to the tail may be placed too close together, threatening a short circuit. An electrical short could cause control problems and a crash if pilots did not respond quickly enough.
In addition to the wiring problem, internal Boeing communications released Jan. 9 show employees mocking safety regulators, pushing back against suggestions of simulator training, and expressing contempt, disbelief and fear over the MAX’s rapid development.
David Calhoun, Boeing’s new CEO, is under pressure to get 737 MAX jets recertified and back into the air. The company is making software changes and other fixes to MCAS and has agreed to more pilot simulator training.
As scrutiny of the aircraft proceeds, the FAA said international air safety regulators were agreeing on design fixes, according to a Feb. 6 Reuters report. Boeing says it has fixed a software issue and estimates the plane will return to service in mid-2020.
SOURCE USA TODAY reporting; Boeing; Shem Malmquist/Florida Institute of Technology; flightradar24.com; flightaware.com; Associated Press; Reuters; USA TODAY research