Boeing 'omitted key safeguards' on 737 Max that were installed on a military jet

Boeing’s expected fix for the 737 Max flight control system will make it more like that used in military tanker

A Boeing 737 Max 9 at Boeing Field in Seattle, Washington. The FAA suspended operations of the 737 Max on March 13 after the Ethiopian Airlines flight 302 crash. AFP
A Boeing 737 Max 9 at Boeing Field in Seattle, Washington. The FAA suspended operations of the 737 Max on March 13 after the Ethiopian Airlines flight 302 crash. AFP

Boeing engineers working on a flight-control system on the grounded 737 Max omitted safety guards that were previously included in an earlier version of that system used on a military tanker jet.

Engineers who created the Manoeuvring Characteristics Augmentation System (MCAS) more than a decade ago for a military refuelling plane had designed it to rely on inputs from multiple sensors and with limited power to move the tanker’s nose, the Wall Street Journal reported, citing sources.

This approach was taken as a deliberate protection against the system acting erroneously or causing a pilot to lose control. In contrast, the Max's version of MCAS, relied on input from just one of the plane’s two sensors that measure the angle of the plane’s nose.

A Boeing spokesman declined to explain to WSJ why the systems differ on two aeroplanes, but said “the systems are not directly comparable”.

Investigators have said erroneous data fed into the MCAS was a common link in a chain of events leading to the fatal crashes of a Lion Air 737 Max jet in Indonesia in October 2018 and an Ethiopian Airlines 737 Max aircraft in March 2019 which killed all 346 people aboard the two planes.

Boeing’s expected fix for the 737 Max will make its MCAS more like the one used in the tanker, the WSJ reported, citing people familiar with the matter.

The US plane maker has said the Max, with its revised MCAS, will be among the safest aeroplanes ever to fly.

The Max has been grounded for six months, putting a financial and operational strain on airlines, but the US aviation regulator has not set a time for approving its return to the skies.

Flydubai on Monday reported a loss in the first half of its financial year, joining a growing number of global airlines facing financial pressure from the Boeing 737 Max grounding, and warned of more pressure on its performance if the ban continues.

Updated: October 1, 2019 03:24 AM

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