2018-10-29
Lion Air
Flight JT610
Departure
Soekarno-Hatta International Airport, Jakarta, Indonesia
Destination
Depati Amir Airport, Pangkal Pinang, Indonesia
Causation Breakdown
Recurrence Likelihood Today
Very Low
The redesigned MCAS uses both AOA sensors with disagreement detection, has limited authority, and can only activate once per event. Mandatory simulator training covering MCAS is now required in all jurisdictions. The 737 MAX was re-certified after 20 months.
Summary
Lion Air 610 was the first of two fatal Boeing 737 MAX crashes caused by the MCAS system. A faulty angle-of-attack sensor triggered repeated nose-down trim inputs the crew could not control. All 189 aboard were killed. Combined with the Ethiopian 302 crash five months later, the accident led to the longest grounding of a commercial aircraft type in history and a comprehensive reckoning with the FAA's delegation of safety certification to Boeing.
Cause & Investigation
Determined cause
MCAS software failure triggered by faulty angle-of-attack sensor
A miscalibrated angle-of-attack sensor fed false stall data to the Maneuvering Characteristics Augmentation System (MCAS), which repeatedly commanded the nose downward. The crew did not identify the MCAS runaway trim situation and could not overpower the nose-down inputs. Boeing had deliberately omitted MCAS from pilot documentation and training materials. The 737 MAX crashed into the Java Sea 13 minutes after takeoff.
Investigation body
Komite Nasional Keselamatan Transportasi (KNKT), Indonesia.
Timeline & Safety Improvements
Flight JT610 disaster
Boeing 737 MAX 8 operating for Lion Air. 189 fatalities, 0 survivors.
Formal investigation opened
Conducted by: Komite Nasional Keselamatan Transportasi (KNKT), Indonesia.
Cause determined: MCAS software failure triggered by faulty angle-of-attack sensor
A miscalibrated angle-of-attack sensor fed false stall data to the Maneuvering Characteristics Augmentation System (MCAS), which repeatedly commanded the nose downward. The crew did not identify the MCAS runaway trim situation and could not overpower the nose-down inputs. Boeing had deliberately omitted MCAS from pilot documentation and training materials. The 737 MAX crashed into the Java Sea 13 minutes after takeoff.
Improvement implemented
All Boeing 737 MAX aircraft worldwide were grounded for 20 months.
Improvement implemented
Boeing paid $2.5 billion in penalties and victim compensation.
Improvement implemented
MCAS was redesigned to use dual AOA sensor inputs and limit its authority.
Improvement implemented
FAA oversight procedures for aircraft certification were overhauled following congressional investigation.
Improvement implemented
Pilot training for 737 MAX now includes a dedicated MCAS/runaway trim module in all jurisdictions.