FAA issued 737 MAX’s LEAP-1B engine corrosion issue: The FAA has released a new Airworthiness Directive for some CFM LEAP-1B engines used in the 737 MAX family of aircraft. The Directive addresses corrosion caused by long-term storage of planes, which can result in reduced thrust in certain cases. The remedy is simple enough, and it does not place a huge burden on the affected airlines.

When an aircraft is parked for an extended period of time without use, it is common for certain parts to begin to display signs of wear and tear. The global 737 MAX fleet was grounded for more than two years.

According to the FAA, there have been several reports of pressure sub-system (PSS) unit faults due to corrosion after storage for some CFM LEAP-1B engines. It explicitly states,

“In April 2021, the FAA received a report from CFM, the engine manufacturer, of numerous instances of PSS unit faults. The manufacturer reported these faults have been occurring since October 2020 and are a result of pressure transducer corrosion following extended storage periods. The manufacturer’s investigation found that certain PSS units, identified by serial number, have been exposed to conditions that make pressure transducers in these units susceptible to an increased rate of faults.”

The FAA has issued a new guideline requiring airlines to conduct repeated engine tests. The US authority stated that for Leap-1B engines that were restored to service but had less than 15 hours of electrical power applied to the PSS unit within the previous 90 days, the airline should monitor the engine maintenance messages related to the pressure transducer until the unit had 15 or more hours of electrical power.

Meanwhile, the FAA needed a one-time engine review for engines that had been returned to service and had already collected 15 or more hours of electrical power to the PSS units during the previous 90 days or completed 5 flight cycles.

The same law applies to air carriers that still have Leap-1B engine-powered aircraft in long-term storage. The FAA also cautioned that if any maintenance flaws were discovered during the tests, air carriers would have to replace the PSS units.

According to the FAA’s AD, it affected 158 engines registered in the United States. This fault has nothing to do with the electrical problem that was recorded in late April.

Electrical Issues Affecting More Boeing 737 MAX | Jetline Marvel