A Boeing 737 MAX operated by Ethiopian Airlines, flight number ET302 has crashed shortly after take off from Addis Ababa airport killing all 157 on board.
The initial reports sound ominous for Boeing. While it’s far too early to talk about the cause, it’s not too early to talk about the second time the same type of aircraft has crashed in similar circumstances.
The accident is similar to last year’s crash of a Lion Air jet that plunged into the Java Sea in October 2018, killing all 189 people on board. These two crashes involved the Boeing MAX 8 aircraft. The Seattle based manufacturer is working with investigators in the Lion Air matter.
Boeing was forced into a speedy production process when Airbus announced its new Airbus A320neo family of aircraft with improved fuel burn and operating efficiency. It took six year between 2011 and 2017 for Boeing to redesign, build and gain certification from the FAA for its new 737’s.
As usual the testing process was comprehensive. For example the Boeing MAX’s were put through 2,000 flight hours as well as three hours of ETOPS testing.
Three thousand simulated simulated flight cycles were conducted and at first there were a few problems with the engines. For one, they were delivered late by manufacturer CFM International. It was a joint venture between GE Aviation and Safran Aircraft Engines, a division of Safran of France.
The first delivery was a MAX 8 was to Malindo Air, a subsidiary of Lion Air in May 2017. Just over a year later, the Java crash occurred.
Norwegian Air also flies the MAX 8, and after a one year of service, 130 of these redesigned planes had been delivered to 28 airlines or customers and logged over 41 000 flights in 118 000 hours – flying over 6.5 million passengers.
After 2017’s spotless aviation record with no major aviation crashes, things changed on October 29, 2018 when Lion Air Flight 610 plunged into the sea 13 minutes after take off from Soekarno-Hatta International Airport in Jakarta, Indonesia.
This was the first crash involving a 737 MAX, and the aircraft was only delivered two months before the accident.
Afterwards, Boeing issued a safety bulletin advising airlines about how they should approach the automated systems which are now thought to have caused the Lion Air crash.
The FAA also issued an emergency airworthiness directive followed quickly by Boeing’s update for flight crew operations. The company said there could be a fault in the aircraft’s angle of attack system that could cause the aircraft to violently pitch nose down. What terrifies pilots is that this could even occur AFTER the automatic pilot was switched off and pilots were hand-flying the aircraft.
Sensors in the aircraft apparently caused false data to be fed to the aircraft’s computer system, leading to it taking over the flight controls from a pilot even after he or she switched off the automated systems. The data erroneously reported that the plane had entered a stall, when in fact it was flying faster than the stall speed and the wings were not stalled at all.
This is catastrophic for aviators when faced with a threat at low altitude. You just don’t have time to press all the buttons, and I really feel for the pilots in both aircraft it it is indeed proven that the automatic system caused these crashes. It now appears that the electric stabiliser trim is what could have been pushed forward – and flight crews are told to switch these off when they hand-fly the plane.
Switching to manual trim is always the best way to fly, but in today’s busy cockpit perhaps in both instances the captain and first officer were concentrating and may have not had time to switch off the electric trims.
There are more similarities. Ethiopian Airlines 737 MAX had only been delivered four months ago.
Desmond Latham 