Post by ironhammer on Mar 10, 2019 8:43:55 GMT -5
News are reporting that Ethiopian Airlines Flight ET 302 from Addis Ababa to Nairobi (Kenya) with 157 passengers has crashed. The airline CEO reported that there are no survivors. The plane in question was a 737-800 MAX, the latest generation of the narrow body 737, a workhorse for many airlines around the world.
This raises a question of the MAX's safety. Lion Air Flight 610 that crashed in October 2018, again with no survivors, was also a 737-800 MAX. It could just be a tragic and horrible coincidence, but the same type of plane crashing within the span of only a few months does raise potential questions on safety of the plane. In both crashes the plane was close to brand new. In the Lion Air Crash, investigators found that several flights with the plane prior to the crash, the pilots reported problems with the AOA (Angle of Attack) sensor and airspeed indicator. The AOA sensor in particular raised a lot of questions, because the 737 MAX has a new system called MCAS (Maneurving Characteristics Augmentation System). When Boeing engineers designed the MAX, to improve fuel efficiency, they shifted the engine and nose gear ever so slightly forward compared to the older 737s. This resulted in the plane potentially pitching up in certain conditions. Fearing that pilots might not notice this and put the plane in a stall situation, Boeing engineers designed the MCAS, which would give an uncommanded instruction (pilot having no input) to the stablizer to move upwards and neutralize upward pitch of the nose. But for the MCAS to work correctly, it must have accurate and properly functioning AOA sensor.
Pilot unions in the US have criticized Boeing for not informing them of MCAS and giving them no training on what to do if it malfunctions. Their fear is that in the event of AOA sensor problems (giving incorrect pitch angles), the MCAS could inadvertently be applied automatically, resulting in serious flight control problems and even crashes. Now MCAS was only supposed to become active when autopilot is off and the plane is flown manually. And in the case of US airlines with large fleets of 737 MAX, they are supposed to have a HUD (Head-up Display) that would warn pilots of a malfunctioning AOA sensor. But this HUD is optionally and not an essential item. Many low-cost carriers (such as Lion Air) do not have this HUD.
Whether MCAS was really responsible for the Lion Air (and this Ethiopian Airlines) crash remains to be seen, we won't get the whole picture until the final report is released. However, the FAA has issued emergency directives on the 737 MAX, and Boeing have held meetings with US pilot unions to address their concerns over this system. All this raise a question, is the 737-800 MAX safe? Should FAA consider grounding it (that would result in huge disruptions, but if there is a big safety risk, that might need to be undertaken). What do you think?
This raises a question of the MAX's safety. Lion Air Flight 610 that crashed in October 2018, again with no survivors, was also a 737-800 MAX. It could just be a tragic and horrible coincidence, but the same type of plane crashing within the span of only a few months does raise potential questions on safety of the plane. In both crashes the plane was close to brand new. In the Lion Air Crash, investigators found that several flights with the plane prior to the crash, the pilots reported problems with the AOA (Angle of Attack) sensor and airspeed indicator. The AOA sensor in particular raised a lot of questions, because the 737 MAX has a new system called MCAS (Maneurving Characteristics Augmentation System). When Boeing engineers designed the MAX, to improve fuel efficiency, they shifted the engine and nose gear ever so slightly forward compared to the older 737s. This resulted in the plane potentially pitching up in certain conditions. Fearing that pilots might not notice this and put the plane in a stall situation, Boeing engineers designed the MCAS, which would give an uncommanded instruction (pilot having no input) to the stablizer to move upwards and neutralize upward pitch of the nose. But for the MCAS to work correctly, it must have accurate and properly functioning AOA sensor.
Pilot unions in the US have criticized Boeing for not informing them of MCAS and giving them no training on what to do if it malfunctions. Their fear is that in the event of AOA sensor problems (giving incorrect pitch angles), the MCAS could inadvertently be applied automatically, resulting in serious flight control problems and even crashes. Now MCAS was only supposed to become active when autopilot is off and the plane is flown manually. And in the case of US airlines with large fleets of 737 MAX, they are supposed to have a HUD (Head-up Display) that would warn pilots of a malfunctioning AOA sensor. But this HUD is optionally and not an essential item. Many low-cost carriers (such as Lion Air) do not have this HUD.
Whether MCAS was really responsible for the Lion Air (and this Ethiopian Airlines) crash remains to be seen, we won't get the whole picture until the final report is released. However, the FAA has issued emergency directives on the 737 MAX, and Boeing have held meetings with US pilot unions to address their concerns over this system. All this raise a question, is the 737-800 MAX safe? Should FAA consider grounding it (that would result in huge disruptions, but if there is a big safety risk, that might need to be undertaken). What do you think?