Shares of ST Engineering (S63.SI) plummeted 3.10% in Friday's trading session, as investors reacted to news of a UPS plane crash investigation that could potentially involve the company's maintenance services. The sharp decline comes as the National Transportation Safety Board (NTSB) announced it would probe the maintenance history of the ill-fated UPS cargo plane that crashed in Louisville, Kentucky, earlier this week.

According to reports, the MD-11 freighter involved in the crash had undergone repairs in San Antonio, Texas, weeks before the incident. Singapore-based ST Engineering, which provides airframe maintenance for UPS's MD-11 aircraft and operates a repair facility in San Antonio, has been mentioned in connection with the investigation. While the company has declined to comment on the specific case, it stated that it would cooperate fully with relevant authorities when contacted.

The NTSB's focus on the plane's maintenance history has raised concerns among investors about potential implications for ST Engineering, should any issues be discovered during the investigation. It's important to note that there is currently no evidence linking poor maintenance to the crash, which resulted in at least 13 fatalities, including three UPS pilots.