Boeing called it a "production issue'' and told 16 airlines, including Southwest, American and United, to temporarily ground certain Max aircraft from service.
The planes will be inspected to "allow for verification that a sufficient ground path exists for a component of the electrical power system.''
"The FAA will ensure the issue is addressed,'' the Federal Aviation Administration said in a statement. "Passengers should contact airlines about possible flight delays and cancellations.''
Southwest Airlines, the largest U.S. operator of the plane, has not experienced any "operational challenges'' related to the electrical issue, but has removed 30 of its 58 Max aircraft from service, according to spokeswoman Brandy King.
She said passengers due to fly on the grounded planes will be accommodated on other Boeing 737s in its fleet. Southwest only flies Boeing 737s.
"Southwest anticipates minimal disruption to our operation,'' King said in a statement.
American Airlines spokesman Curtis Blessing said the airline is grounding 17 recently delivered Boeing 737 Max aircraft. Its other 24 Max planes are not affected as they were delivered before the November ungrounding of the aircraft.
“As we shared when we returned the 737 MAX to commercial service, the safety of our customers and team members comes above all else. It’s with this unequivocal standard that we rigorously maintain and monitor all our aircraft — including the Boeing 737 MAX — to ensure every plane in the air is safe."
United has removed 16 of its 30 737 Max planes, according to a statement.
"We have been in touch with the FAA and Boeing and will continue to work closely with them to determine any additional steps that are needed to ensure these aircraft meet our rigorous safety standards and can return to service,'' the airline said. "We are working to swap out aircraft to minimize the impact to our customers.''
Alaska has removed all four of its 737-9 Max planes from service for inspections and work to be done, according to spokesman Ray Lane.
The Max was grounded in March 2019 following two fatal crashes that killed 346 people.
This article originally appeared on US Travel Today