Semantron 23 Summer 2023

The Boeing 737 Max crisis

handbook on the differences between the Max and its predecessor, […] The training materials did not mention the new software that later became a focus of the Lion Air crash investigation. ’ 55

Crashed & grounded: Flight JT610 and ET302

Despite Boeing’s initial success in the substantial number of orders, the subsequent crashes which killed 346 lives in total brought the production of B737 MAX aircraft to a complete halt, and for the following 22 months, no B737 MAX aircraft were airborne. 56 On 29 th October 2018, at 0620 local time (23:20 UTC), flight JT610, operated by Lion Air, with registration PK-LQP, 57 took off from Jakarta Soekarno- Hatta International Airport, bound for Depati Amir Airport. 11 minutes and 15 seconds after take-off, 58 at 0632 local time, it crashed into the Java Sea with a descent rate of more than 10,000 feet/minute, 59 killing 189 personnel on board. The Boeing 737 MAX 8 aircraft was delivered to Lion Air 2 months before the crash, and had approximately 900 hours of flight time. Both the Captain and the First Officer (FO) had accumulated a total of 9,462 hours on B737 aircraft. 60 At 23:20:16 UTC, the Digital Flight Data Recorder (DFDR) recorded a difference of 21° between the left and right AoA sensor. However, the Flight/Director (F/D) on the Captain Primary Flight Display (PFD) showed -1° down, while the FO’s PFD show ed +13° up. At 23:20:33 UTC when the aircraft lifted off the runway, the captain’s control column stick shaker activated. This is a system that indicates that the aircraft is in a stall position, according to the computer readings. Approximately 7 seconds after take-off, the MASTER CAUTION warning illuminated, advising ‘ Indicated Airspeed Disagree ’ . There is a 9 knots difference in the Indicated Airspeed (IAS) for the Captain and the FO. At 21:21:12 UTC, the FO advised ‘ Altitude Disagree ’ , and the system indicated a 230 feet difference in altitude. At 21:22:33 UTC, the AND trim was activated for the first time for 10 seconds, and the horizontal stabilizer pitch trim decreased from 6.1 units to 3.8 units. 21 seconds later, AND trim activated for the second time for 8 seconds at a low speed. Even though the aircraft was flying at 300 knots as the plane was diving down, the Enhanced Ground Proximity Warning System (EGPWS) still announced AIRSPEED LOW , while there remained a 12 knots difference in the Captai n and FO’s readings. From 23:23:18 UTC to 23:31:53 UTC, MCAS was activated at least 28 times, a sum of 101 seconds in total, while the captain tried interrupting the system by inputting Aircraft Nose Up (ANU) commands. In the book Crashing the 737 MAX, it was described as ‘ pilots lose tug-o-war with MCAS ’ . 61 ‘ The pilots continued to pull the control yoke backwards to try and lift the plane, exerting up to 50kg of

55 Gelles, et al. 2019, After 2 Crashes of New Boeing Jet, Pilot Training Now a Focus . 56 Federal Aviation Administration 2020, FAA Updates on Boeing 737 MAX . 57 Komite Nasional Keselamatan Transportasi 2019, Aircraft Accident Investigation Report – PK-LQP : xviii. 58 Coughlin 2020, Crashing the 737 MAX, Revision 1 : 16. 59 Komite Nasional Keselamatan Transportasi 2019, Aircraft Accident Investigation Report – PK-LQP : 27. 60 Ibid., 28, 29, 30. 61 Coughlin 2020, Crashing the 737 MAX, Revision 1 : 18.


Made with FlippingBook - Online catalogs