Return to service: 90-hour solution to Boeing 737 MAX simulator fault?

Spicejet is the biggest customer in India for Boeing 737 MAX planes. It has 11 of these planes in its fleet and 144 pilots to fly them

It takes only two hours —roughly the time it takes for a plane to fly from Delhi to Mumbai — for a pair of pilots to complete their training on the 737 MAX simulator at Boeing’s centre in Noida, the only one of its kind in India. Going by this estimate, all the 90 Spicejet pilots who the civil aviation regulator barred from flying the 737 MAX can be retrained in 90 hours.

“Retraining a couple of pilots will take two hours,” a Spicejet spokesperson told Business Standard.

The budget carrier is the biggest customer in India for Boeing 737 MAX planes. It has 11 of these planes in its fleet and 144 pilots to fly them. On Wednesday, the Directorate General of Civil Aviation (DGCA) asked 90 of those pilots not to fly the planes until they had been retrained.

An airline official said the DGCA’s decision arose from issues of “return to service” requirements for the 737 MAX. India, along with a host of other nations, had grounded these planes in 2019 after the crash of an Ethiopian Airlines Boeing 737 MAX on March 10 near Addis Ababa. India lifted the ban in August 2021 after Boeing changed the aircraft’s software and other systems to enhance safety.

This “return to service” required pilots to be re-trained at Boeing’s Noida facility, which Canada-based CAE Inc operates. The DGCA found deficiencies in the systems that kick in when the aircraft faces aerodynamic stalling while mid-air. It reportedly found a dysfunctional “stick shaker” that violently vibrates the control wheel of the plane in the event of a stall. This hampered the pilots’ ability to gauge the plane’s pitch when the last-resort emergency warning in the cockpit came on. The vibration of the stick-shaker is the final indicator of a plane’s ability to stay aloft when all other audio emergency warning systems have either been activated or failed.

CAE Inc had not responded to Business Standard’s queries till the time of publishing this story. An airline official said that though there were problems with the stick-shaker in the simulator, “no changes would be required to be made in the simulator software and only the unserviceable parts needed to be replaced” before the 90 banned pilots could be re-trained.

The DGCA’s decision to make retraining of 737 MAX pilots as a condition for return to service is in sync with the US Federal Aviation Admin­istration (FAA), which, too, had asked pilots to be re-trained on 737 MAX simulators while clearing the plane’s return to service.

One of the things pilots were to be trained in was the change in the movement of the plane on autopilot after the activation of the stick-shaker. Both flight commanders as well as captains had to undergo the training.

The 737 MAX pilots have had to undergo several other training requirements, such as in how to control the aircraft going nose up on autopilot, dealing with automatic deactivation of the autopilot system, and in situations when the flight director might not work. The flight director system enables an aircraft to follow its trajectory at a certain altitude.

Boeing made significant changes in the 737 MAX’s Manoeuvring Characteristics Augmentation System (MCAS). According to Boeing, the MCAS is activated only when the plane is being flown manually and ‘unusual conditions’ occur at the same time and not in normal flying circumstances.

In addition to being well-versed with the new MCAS functions and operations, pilots need to undergo training on how to deal with wrong flight control computer commands that change the aircraft’s speed on erroneous readings of the airflow.

In case the 737 MAX computers fail to gauge the airflow correctly, the pilots are trained to adjust the speed of the plane manually. In addition to demonstrating their skills after training on a simulator, pilots also have to go through a trial on a real plane.