Second crash of a new Boeing 737 Max in less than six months is worrying

Ethiopian Airlines jet crashed six minutes after take off from Addis Ababa, killing 157

An Ethiopian Airlines Boeing 737 Max 8 (ET-AVM), the same type of aircraft which crashed iafter taking off from  Addis Ababa in Ethiopia. Photograph: EPA/STR

An Ethiopian Airlines Boeing 737 Max 8 (ET-AVM), the same type of aircraft which crashed iafter taking off from Addis Ababa in Ethiopia. Photograph: EPA/STR

 

The second crash of a new Boeing 737 Max in less than six months will worry the dozens of airlines, including Ryanair, which have ordered this latest generation of what is generally considered to be the world’s safest passenger jet.

Ethiopian Airline’s flight 302 crashed on Sunday morning, six minutes after take off from Addis Ababa, killing all 157 on board.

Among them was Irish man Michael Ryan from Lahinch, Co Clare, who was working with the United Nations World Food Programme as global deputy chief engineer with the aid agency’s engineering division.

World Food Programme deputy chief engineer, Michael Ryan from Co Clare who was killed when Ethiopian Airlines flight ET302 bound for Nairobi crashed minutes after take off from the capital Addis Ababa killing all 157 people on board
World Food Programme deputy chief engineer, Michael Ryan from Co Clare who was killed when Ethiopian Airlines flight ET302 bound for Nairobi crashed minutes after take off from the capital Addis Ababa killing all 157 people on board

Difficulties controlling the aircraft

Aviation observers have noted from readily available networked data that the Ethiopian Airlines jet appeared to be behaving somewhat erratically just minutes after take off.

According to flightradar.com, which tracks automatic broadcasts from aircraft all over the world, it was not climbing at a steady rate. This could indicate that the pilots were experiencing difficulties in controlling their aircraft.

This may not be dissimilar from the behaviour of the Lion Air 737 Max which crashed into the Java Sea in Indonesia on October 29th last, killing 189. The black-box analysis of that flight demonstrated that the pilots had great difficulty in maintaining controlled flight as their aircraft repeatedly went into a nose-down dive.

Early reports suggest that the Ethiopian pilots declared they were having difficulties and wished to return to Addis Ababa.

The Lion Air crash investigation team has yet to file its final report but initial indications suggest that a system built into the aircraft’s flight management software may have been a contributory factor.

Software changes

The new 737 Max uses new state-of-the-art CFM engines. They are bigger than normal and, to prevent them contacting the runway, they are projected slightly forward of the wings where they can be mounted higher than usual. This has the side effect of changing the aircraft’s aerodynamic qualities.

Boeing altered the 737 Max’s flight-management software to account for this factor and make its handling similar to older Boeing 737s so that pilots can readily move from older aircraft to this latest generation of the plane.

One aspect of the software change is to make the aircraft automatically go into a shallow dive when it approaches what is known as a stall speed. In other words, when the airflow over the wings is reduced and the aircraft is in danger of losing “lift”. Pilots are trained to place their aircraft in a shallow dive when it is at risk of stalling but in the case of the 737 Max, the aircraft does it for them.

However, many pilots have claimed they were not told of this new feature or the fact that it might come into play when instruments indicating airspeed and angle of attack become unreliable and falsely indicate that the aircraft might be in danger of stalling.

The Lion Air jet had been having instrument problems and, even though the aircraft was otherwise flying normally, it is generally assumed that the anti-stall mechanism was triggered causing the otherwise normal flight to go into a dive.

Many US pilots have claimed that they were not trained to deal with this automatic reaction. However, given the controversy this issue has recently developed in the pilot community, it would be surprising if a safety-conscious airline such as Ethiopian had not trained its pilots appropriately.

Gerry Byrne is an aviation journalist

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