Forensic Engineering: The Investigation of The Causes of Asymmetry Trailing Edge Flap During The Aircraft Boeing 737 Landing.

Forensic engineering is the application of engineering principles and methodology to answer questions of fact. These questions of fact are usually associated with accidents, crimes, catastrophic events, property degradation, and various types of failures. This research discusses a serious incident that occurred on a Boeing 737-300F aircraft operated by The XYZ airline which operates unscheduled domestic flights in Indonesia, with a flight route from Jakarta Soekarno International Airport (CGK) to Samsoedin Noor International Airport Banjarmasin (BDJ). When the plane was about to land, and the pilot operated the flaps from the 30o position to the 40o position, there was an asymmetry between the left and right flap trailing edges of more than 20o, which caused the plane to become unstable because it rolled to the left, and the pilot was unable to control the plane when landing, which causing a serious incident on the plane. This research aims to find the root cause of trailing edge flap asymmetry of more than 20o as an evaluation for companies in determining and implementing corrective and preventive actions so that this problem does not happen again in the future. This research will use forensic engineering investigation methods and carry out chemical composition testing (Optical Emission Spectroscopy); metallographic testing (micro and macro structure observations); FESEM testing and microchemical composition testing (EDS); and hardness testing. Then for each test result an analysis is carried out based on scientific knowledge. The results of the investigative analysis were to find the root cause of the trailing edge flap asymmetry problem of more than 20o. After getting the root cause of each method, the author then compares the results of one method with another method to draw conclusions to consider and determine corrective and preventive actions to be taken and implemented in the company or organization.