FAA Warns 737s Sitting in Storage Are Corroding During the Pandemic

(Bloomberg) -- Boeing Co. 737 planes in storage because of the coronavirus pandemic are at risk of losing power in both engines when they fly again and must be inspected, the U.S. Federal Aviation Administration said.

The emergency order applies to about 2,000 older Next Generation and Classic versions of Boeing’s workhorse single-aisle jet in the U.S., not the grounded 737 Max. Alaska Air Group Inc. said an engine shutdown during a recent flight was probably one of four instances in which the FAA said a corroded valve caused a failure.

Regulators mandated the inspections after airlines began bringing back some of the thousands of jetliners that were parked earlier this year as the pandemic all but erased travel demand. While there are detailed steps airlines must take to maintain planes in storage, the order suggests that the corrosion issue wasn’t previously known. The directive applies to aircraft that have flown 10 or fewer flights since being taken out of storage, and any jets still parked.

The Alaska Air incident occurred July 15 on a flight from Seattle to Austin, Texas. The plane made an emergency landing and touched down safely. The company is carrying out required inspections on six 737s at one of its maintenance bases.

‘Check Valves’

“We actually started our inspections of the check valves” before the FAA’s airworthiness directive was released, the airline said. “As additional aircraft are removed from storage, this work will be completed before they’re returned to service.”

The matter isn’t related to the software issue linked to two crashes of the Max that killed 346 people and prompted a worldwide grounding in March 2019. For the older aircraft needing the valve inspections, Boeing said it was helping operators handle any issues. Any plane that hasn’t flown for at least seven days must be checked.

“With airplanes being stored or used infrequently due to lower demand during the Covid-19 pandemic, the valve can be more susceptible to corrosion,” the planemaker said. “Boeing is providing inspection and replacement information to fleet owners if they find an issue.”

CFM International Inc., a joint venture of General Electric Co. and France’s Safran SA that makes engines for 737 jets, said it was working with Boeing on the matter.

Engine Interface

“FAA’s action is related to a Boeing external bleed air valve that interfaces with the engine,” GE said.

GE fell 2.8% to $6.85 at 1:13 p.m. in New York. Boeing slipped less than 1% to $174.82.

Some 3,200 airliners -- roughly half of the U.S. fleet -- were parked as of mid-May after U.S. passenger traffic plunged to less than 10% of prior-year levels in April, according to Airlines for America, a trade group.

Carriers have since returned some of those jets to service as U.S. passenger volumes have inched up to about a quarter of last year’s levels. A third of all passenger jets in the U.S. remain idled in storage, according to the group.

Southwest Airlines Co., which flies only Boeing 737s, said it didn’t anticipate any disruptions because of the FAA order. The carrier had about 400 aircraft in storage in April, when travel demand was at its lowest. It now has just 100 stored or temporarily parked.

Assessing ‘Applicability’

“While Southwest has not experienced the conditions described in the directive, we are currently reviewing the AD for applicability to our fleet,” said Brian Parrish, a spokesman for Southwest.

Delta Air Lines Inc., United Airlines Holdings Inc. and American Airlines Group Inc. also said the requirements wouldn’t affect their flight operations.

Only 19 of American’s 304 NG planes had been parked, with four falling under the FAA’s guidelines for inspections, the company said. Those checks were completed with no findings, and two additional planes being taken out of storage will also be inspected.

Aviation regulators in the European Union and India similarly ordered 737s to be checked for the issue. While the FAA doesn’t have authority in other countries, such inspection orders are almost always adopted by other regulators.

©2020 Bloomberg L.P.