On 29 October 2018 a LionAir Boeing 737MAX registered PK-LQP crashed 11 minutes after take-off in the Indonesian sea. Today, exactly 30 days after the accident, the Indonesian Authorities “KNKT” declared the aircraft to be “not airworthy”. YourAviation analyzed the case to find out what were the causes of this accident & why a brand new plane can be declared “not airworthy” after only 2 months of flying.

PK-LQP few weeks before the crash / Picture by Daniel Dominguez, JetPhotos

The Aviation world was shocked on the October 29th, 2018 as multiple reports of a crashed Boeing 737MAX made the headlines of the biggest news chains in the world. A few hours later the tragic incident was confirmed by the Indonesian Authorities. The 2-month old, LionAir B737 MAX 8 crashed into the Java Sea moments after it took off.
Soon after that, the President of the low-cost company announced that the aircraft used for flight JT610 had a “technical issue” the flight prior to JT610. This shocking news was accompanied by the insistence that “the problem would have been fixed”. According to Mr. Edward Sirait, the pilot performed all required “Pre-Flight Checks”. The plane would have been “airworthy”. Although he was then able to reassure many passengers, today, after the “preliminary AAIR*” being published, we found out that this was clearly not the case.

According to the report, the following point is according to the “factual information during the investigation”, counting as “findings” by the Komite Nasional Keselamatan Transportasi (KNKT, in English National Transportation Safety Committee):

  • Both Pilots were holders of valid licenses and medical certificates to operate the Boeing 737.
  • One day before the crash, the aircraft operated a flight from Denpasar to Jakarta. Prior to this flight, the Angle of Attack sensor (AoA) had been replaced.
  • The recorders showed the stick shaker activated during the rotation and remained active throughout the flight.
  • An IAS Disagree warning appeared on the left Primary Flight Display 400 feet after rotation of the previous flight. The Pilot in Command (PIC) crosschecked both PFDs and determined that the left PFD had a problem.
  • The PIC noticed that as soon as the SIC stopped the trim input, the aircraft automatically trimmed the aircraft nose down. After three automatic trim occurrences, the PIC switched the Stab Trim to CUT OUT.
  • After running Non-Normal-Checklists consisting of multiple problems,  continued the flight, as none of the checklists advised him “to land at the nearest airport”.
  • After the arrival in Jakarta, the PIC informed the engineer about the experienced problems. They wrote the items on the “Aircraft Flight Maintenance Log”.
  • The engineers ran multiple tests to solve the problems on the night of the 28. to the 29th of October. They were “satisfied” by the results, and for them on the ground, the problems “were solved”.
  • On the next morning, during flight JT610, the crash flight, a record shows that a difference of 20% between the 2 AoA’s has been recorded. The Pilots asked ATC to confirm speed & altitude to verify on their instrument.
  • The pilots then reported “flight control problem”
  • After the flaps been retracted, the aircraft nose went down because of the automatic trim being active (same problem as the flight before).
  • The pilots changed to Flaps 5 and deactivated the automatic trim.
  • At 23:25:18 UTC, the flaps were retracted to 0 again. Several seconds later the automatic trim began again to let the aircraft nose sink. Recordings show that this continued until the end of the flight.
  • The Aircraft Flight Maintenance Log recorded that since the 26th of October 2018 and until the occurrence date, several problems regarding the airspeed, the altitude flag on the captain’s PFD appeared three times. The Speed Trim Fail light illumination and the Mach Trim Fail light illumination were indicated two times and the Indicated Airspeed and the Altitude Disagree were shown on the flight preceding the accidental flight.

What is important to mention is that “findings” are a statement of conditions, events or circumstances in the accident sequence. They are significant steps for the finding of the accident cause, but are not always causal! They are essentially used for the understanding of the occurrence.

The Flight before experienced “stick shaker activation” during take-off & rotation. This condition must be seen as “un-airworthy” & the flight shouldn’t be continued. The pilots should have diverted.

Interestingly, the load sheet on flight JT610 showed 5 flight-attendants. The voyage report sheet showed 6 flight-attendants. This indicates that the information contained in the weight-and-balance sheet (load sheet) is inaccurate.

The authorities have recommended a complete review of the Standard Operating Procedure (SOP) & the checklists, in order to have the captain making the decision to continue the flight or not. They had also suggested that the paperwork must be all flight documents should be filled in properly, as per industry standards.

According to the investigator Nurcahyo Utomoo & the KNKT, the aircraft should not have been flown in this conditions. This means that after all the incidents on the flights previous JT610, the aircraft was deemed “not airworthy”.

Investigator Nurcahyo showing the details of the flights with an aircraft model / Picture by Darren Whiteside, REUTERS.

Multiple operating procedures, manuals, checklists have been reviewed in order to avoid future accidents like JT610. The Asian region has been the market leader in terms of growth of aviation globally, and the Indonesian airlines play a big role in it. It is essential for the Indonesian aviation regulatory body to step in and improve the safety culture in the region as there were 40 fatal accidents recorded over the past 15 years. The safety record of Indonesian airlines has been steadily improving over time after the bans imposed on them by federal bodies of the US and the European Union on grounds of safety violations.

*Aircraft Accident Investigation Report


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