By David Shepardson, Valerie Insinna and Tim Hepher

(Reuters) -Security checks on some Boeing (NYSE:) jets hit a snag over paperwork on Sunday, as U.S. authorities looked for a lacking panel that blew off a brand new Boeing 737 MAX 9 jet in midair on Friday.

The Federal Aviation Administration on Saturday ordered the short-term grounding of 171 Boeing jets put in with the identical panel after the eight-week-old Alaska Airways jet was pressured to make an emergency touchdown with a niche within the fuselage.

“They’ll stay grounded till the FAA is happy that they’re protected,” the company stated in a press release on Sunday.

On Saturday, the FAA initially stated the required inspections would take 4 to eight hours, main many within the trade to imagine the planes might in a short time return to service.

However standards for the checks have but to be agreed between the FAA and Boeing, that means airways have but to obtain detailed directions, individuals accustomed to the matter stated.

The FAA should approve Boeing’s inspection standards earlier than inspections might be accomplished and planes can resume flights.

Of the 171 planes coated by the order, 144 are working in the USA, in line with information from aviation analytics agency Cirium. Turkish Airways, Panama’s Copa Airways and Aeromexico stated they had been grounding affected jets.

Sometimes, every time planemakers order routine upkeep checks, they get paperwork authorized by regulators upfront.

However as a result of the response to the sudden Alaska incident was comparatively swift, Boeing has not but secured FAA approval to inform airways learn how to perform the regulator’s order.

The FAA has the ultimate phrase on how the order is carried out.

“Whereas these steps are being accomplished, United has parked all of its 79 737 Max 9s,” the airline stated in a press release.

“We’ve begun steps akin to eradicating the inside panel to entry the emergency door, and begun preliminary inspections whereas awaiting remaining directions,” it stated, including:

“Inspections might be accomplished after remaining procedures are obtained from the FAA”.

Boeing declined to touch upon whether or not it had submitted its inspection standards to the FAA, which had no additional remark.

‘TERRIFYING’

Alaska Airways on Sunday canceled 163 flights, or 21%, and stated journey disruptions from the grounding are anticipated to final by at the least midweek. United canceled 230 flights on Sunday, or 8% of scheduled departures.

The door plug tore off the left aspect of an Alaska Airways jet following takeoff from Portland, Oregon, en path to Ontario, California, forcing pilots to show again and land safely with all 171 passengers and 6 crew on board.

“I think about this was a reasonably terrifying occasion. We do not usually discuss psychological accidents, however I’m certain that occurred right here,” Nationwide Transportation Security Board (NTSB) Chair Jennifer Homendy advised reporters on Saturday, including that it was too early to say what triggered the occasion.

The panel, put in place on some planes in lieu of a further emergency exit, is prone to have landed someplace within the western suburbs of Portland, however has not but been discovered. Authorities have requested the general public for assist discovering the panel.

The accident has put Boeing again underneath scrutiny because it awaits certification of its smaller MAX 7 in addition to the bigger MAX 10, which is required to compete with a key Airbus mannequin.

In 2019, international authorities subjected all MAX planes to a wider grounding that lasted 20 months after crashes in Ethiopia and Indonesia linked to poorly designed cockpit software program killed a complete of 346 individuals.

Boeing has delivered 214 of the 737 MAX 9, or 15% of the greater than 1,300 MAX plane in service, most of which might nonetheless fly.

‘VERY FORTUNATE’

Friday’s Alaska accident is the second to focus consideration on the survivability of cabins coming inside days of a collision at Tokyo’s Haneda airport involving an Airbus A350 and a Japanese Coast Guard aircraft. No airline passengers had been killed in both accident, although 5 crew on the Coast Guard turboprop died.

Within the Alaska Airways emergency, NTSB Chair Homendy stated the 2 seats subsequent to the portion of fuselage that blew out had been unoccupied. There have been some minor accidents, she stated.

“We’re very, very lucky right here that this did not find yourself in one thing extra tragic,” Homendy stated. Elements of the seat subsequent to the fuselage, together with the pinnacle relaxation, had been lacking.

Portland police and fireplace departments didn’t reply to requests for touch upon the search.

The additional exit door is often put in by low-cost airways utilizing extra seats that require further evacuation routes. Nonetheless, these doorways are plugged on jets with fewer seats. To passengers, the world seems like a traditional window seat.

Airways with bizarre doorways as an alternative of the particular alternative panels can proceed to fly the 737 MAX 9 jets.

The fuselage for Boeing 737s is made by Kansas-based Spirit AeroSystems (NYSE:), which additionally manufactured and put in the plug that suffered the blowout.

However sources accustomed to the method stated Boeing additionally has a possible position, because it usually removes the semi-fitted door panel after receiving the fuselages by rail from Spirit. It makes use of the hole to feed in cabin gear and pace up manufacturing, earlier than finishing remaining set up.

Spirit referred inquiries to Boeing, which didn’t reply to a request for touch upon who carried out remaining set up.

Boeing and Spirit have suffered a succession of manufacturing snags.