About six months after the US regulatory authorities allowed Boeing’s 737 Max to resume flights, the liner turned out to be under close scrutiny again. On May 12, it became known that the aircraft had faced a number of problems related to updated equipment.

In April 2021, flights of over 100 Boeing 737 Max 24 airplanes were halted following the discovery of a potential electrical problem. Technical difficulties resulted in disruption to aircraft supplies. According to representatives of Boeing and the Federal Aviation Administration (FAA), this problem is currently being addressed.

Many experts claim the 737 Max was allowed back into service prematurely. The aviation concern needs to completely remedy issues that could lead to fatal crashes, experts emphasize. According to Boeing and the FAA, the problem of defective engineering first became apparent during the tests of a 737 Max 8. It turned out that electrical power systems on the aircraft did not work correctly. The fault stemmed from poor electrical bonding, which affected the efficiency. Experts suppose that some of the aircraft's components such as the pilots' main instrument panel and a standby power control unit were improperly grounded.

FAA experts note that this could have a negative effect on the operation of Boeing 737 Max’s certain systems. The worst case suggests critical situations, preventing continued safe flight and landing. Experts are worried that over time, other 737 Max aircraft may have similar problems. As a result, the aviation regulator issued an Airworthiness Directive for Boeing. The document states that the company's airplanes with malfunctioning equipment should be modified prior to operation.