Ethiopian air crash
A man carries a piece of debris on his head at the crash site of a Nairobi-bound Ethiopian Airlines flight near Bishoftu. Boeing has been working on a software upgrade for its B737 MAX family aircraft to rectify some issues revealed during investigation of an Indonesian jet crash five months back.MICHAEL TEWELDE/AFP/Getty Images

Could a timely software upgrade have prevented the death of 157 people aboard the Ethiopian Airlines Boeing 737 MAX 8 plane that crashed on Sunday minutes after takeoff from Addis Ababa en route to Nairobi? Indications are that Boeing has been working on the software changes in collaboration with the US Federal Aviation Administration (FAA) taking into account results of an investigation into the crash of an Indonesian Lion Air MAX 8 plane killing all 189 people aboard on October 29 last year.

FAA said in a note on Monday that the software changes will be available to airlines from next month, according to media reports. The Ethiopian plane crashed six minutes after takeoff from Addis Ababa in circumstances similar to that of a Lion Air aircraft that met with the accident 13 minutes into the flight after being airborne over Jakarta.

Directorate General of Civil Aviation (DGCA), the Indian aviation regulator, has ordered additional safety checks for MAX family aircraft that two private airlines - SpiceJet and Jet Airways - use. The number of nations that have grounded the aircraft has been growing, though the US authorities have not issued any specific safety warning. Singapore grounded the aircraft following China's similar action. Chinese airlines fly the most number of MAX family aircraft. While the Ethiopian Airline was quick to ground its fleet of 737 MAX aircraft, Brazil's Gol Airlines and Mexico's Aeromexico also suspended 737 Max flights.

The changes to the said software came into focus after a preliminary report in November from Indonesia's air crash investigators described the desperate battle between the pilots of Lion Air JT610 and the anti-stall flight system, according to a report on the Quartz website. The pilots' efforts to direct the plane's nose up were apparently countered by the plane's computer.

Boeing, which has in the past declined to comment on reports about the software update involving its anti-stall flight system for Max 8 and 9 models, gave details of its work on Monday, following the FAA notification. In the aftermath of Lion Air Flight 610, Boeing had been developing a flight control software enhancement for the 737 MAX, designed to make the aircraft safer, according to reports. The changes included updates to the Maneuvering Characteristics Augmentation System (MCAS) flight control law, pilot displays, operation manuals and crew training. The enhanced flight control law apparently incorporates angle of attack (AoA) inputs, limits stabilizer trim commands in response to an erroneous AoA reading, and limits the scope of the stabilizer command in order to retain elevator authority, the reports said.

Lion Air
Debris from the ill-fated Lion Air flight JT 610 floats at sea in the waters north of Karawang, West Java province, on October 29, 2018. The crash of an Ethiopian Airline flight in similar circumstances has brought back spotlights on the Indonesian jet's crash probe.ADEK BERRY/AFP/Getty Images

Airlines under strain from the grounding of Boeing 737 MAX 8 fleet have been eagerly awaiting the proposed software upgrade.

Though the FAA has not issued any warning regarding the flight worthiness of the Max 8 aircraft, despite the use of a large number of such aircraft by US airlines, the regulator is closely monitoring the developments, reports say.

Following the Lion Air crash, the US aviation authorities issued emergency directives to carriers to update flight manuals with information on what to do when the aircraft's anti-stall system is triggered by erroneous data from what's called an "angle-of-attack" sensor, according to a report on the Quartz website. The flight system reacts to such data by pointing the plane's nose sharply downward, experts say. Boeing has directed airlines to a checklist in manuals for stabilizing the aircraft in case of such mid-flight emergencies.

The FAA's Monday notification said Boeing upgraded flight control system would "provide reduced reliance on procedures associated with required pilot memory items." Memory items are procedures of importance that pilots are required to recall and execute in a given situation without consulting written manuals. The new software will also include features controlling response to angle-of-attack signals, and a "maximum command limit" on the number of times it can engage, said the FAA, adding that it expects to issue an airworthiness directive mandating the software enhancement by next month.

FAA says there are 387 MAX 8 and 9 aircraft flying worldwide, including 74 registered in the US. Reports say that the 737 MAX family is vital to Boeing, accounting for 47 per cent of its commercial aircraft delivery in 2018, and over 90 per cent of its unfilled orders, as of January.