india

Updated: Apr 22, 2019 05:29 IST

Last week, the Boeing CEO said they were making steady progress towards certification of the software update for the grounded 737 Max and were committed to making it one of the safest airplanes ever to fly. But fixing the software problem might turn out to be easier for the beleaguered manufacturer than restoring consumer trust in the safety of the aircraft.

The entire chain of events involving the 737 Max — beginning with the fatal crash of Lion Air in Indonesia on October 29 — have thrown up a number of vital questions for which air travelers need answers. First, how did Boeing fail to detect the serious flaw in the flight control system before releasing it into the market? Second, why did it not provide adequate safeguards against possible erroneous activation of the flight control system? Third, how did the manufacturer overlook the need for extensive training of pilots to fly the new aircraft? The manufacturer needs to come clean on all these issues.

From all accounts, it seems the problem lies in the new flight control system — the Maneuvering Characteristics Augmentation System (MCAS) — introduced in 737 Max to enhance its pitch stability. To put it simply, MCAS pushes down the nose of the aircraft automatically whenever it senses that the airplane is in danger of an aerodynamic stall. And this action is triggered by a sensor that measures the ‘Angle of Attack’ — a parameter that determines how close the aircraft is to a stall. Even though Max had two AOA sensors, MCAS relied only on one sensor and if this gave an erroneous reading, then obviously the nose down action would also be uncalled for.

The problem was best explained in the detailed Emergency Airworthiness Directive issued by the United States Federal Aviation Authority to all air operators on November 7, after the Lion Air crash. Saying that an erroneous sensor input received by the flight control system could cause repeated nose-down trim commands, the directive said if not controlled, this condition could make it difficult for the crew to control the airplane, lead to significant altitude loss and “possible impact with terrain”.

This is exactly what happened with Lion Air. An incorrect data transmitted by the sensor lead to MCAS repeatedly pushing the nose of the aircraft down, negating all efforts of the pilots to counter it, resulting in the plane plunging into the Java sea, killing all 189 onboard.

The Lion Air pilots were not the only ones who had difficulty with the brand new aircraft. Soon after the Lion Air crash, several American pilots gave expression (on the Aviation Safety Reporting System) to the serious problems encountered with the sudden descent of the aircraft, lack of crucial information in the flight manual and the absence of adequate training , leading to confusion and difficulties while flying the aircraft.

But obviously, the measures initiated by Boeing to counter the problem and avert another air crash were not adequate. On March 10, Ethiopian Airline crashed within minutes of take off in almost identical circumstances, once again raising questions about the safety of the aircraft. The preliminary report on the investigation into the crash, released on April 4, said the crew followed procedures from Boeing, but could not stop the plane from repeatedly nose-diving and ultimately crashing, killing all 157 on board.

The twin tragedies have focused attention on the need for greater scrutiny of aircraft safety by manufacturers and regulators. It has also focused attention on the importance of proper training of pilots flying new aircraft. According to International Air Transport Association, there were 62 aircraft accidents and 523 fatalities in 2018, the highest number of accidents and fatalities since 2014. A more concerted effort is needed from all stakeholders to bring down these numbers and render air travel safer