Ethiopian Airlines flight ET 302
Pieces of the wreckage of Ethiopian Airlines flight ET 302
Pilots' unions say that their members' trust in the safety culture at Boeing is at rock bottom following a string of revelations about the grounded 737 Max, presenting another big hurdle for the manufacturer as its seeks to return the jet to service.

The plane maker's crisis deepened late on Tuesday after it admitted that the 737 Max will stay parked until the middle of this year, driving the company's shares down almost 4 per cent. Restoring confidence among captains, on whom it is counting to repair the trust of the flying public, will be critical to Boeing's ambitions.

Trust is "unequivocally" at a nadir, said Jon Horne, president of the 40,000-strong European Cockpit Association, following the publication earlier this month of damaging internal messages in which employees mocked regulators and discouraged airlines from pursuing the most expensive pilot training options.

Pilots want to mend ties, said Dennis Tajer, spokesman for the Allied Pilots Association, which represents 15,000 American Airlines pilots. But trust has been rebuilt and shattered more than once. "It's like a Jenga game, [trust] gets higher and higher, and then it tumbles down," he said. "These emails are beyond our worst nightmares. It's as if it's a poorly written screenplay that no one would believe — but it happened."

Jon Weaks, president of the Southwest Airlines Pilots Association, which is suing Boeing, said the company starts at "zero trust" with the union's 10,000 members.

Southwest's union sued the manufacturer in October, saying Boeing had rushed to deliver the Max "into the hands of trusting pilots" despite its problems. The scepticism is a reversal for a company that once enjoyed such cockpit popularity that pilots would quip: "If it's not Boeing, I'm not going." It also undercuts the company's strategy for returning the Max to service.

The company has distributed marketing materials to airlines that suggest one option to handle passengers who balk at flying the Max in the future will be to have pilots reassure them.

The same materials include video of Jim Webb, Boeing's chief commercial pilot, and say the company can provide airlines with a customer-soothing toolkit that includes videos featuring pilots.

"It is tempting to use pilots as PR stunts with pilot testimonies for Boeing, but that's not our role," said Mr Horne. "It is the regulators that have the access to the information."

Two crashes of 737 Max jets in the space of five months killed 346 people in Indonesia and Ethiopia. The flight control system later implicated in the disasters had not been mentioned in the flight manual. The American Airlines pilots union met Boeing executives after the first crash and encouraged regulatory action that would probably have grounded the plane, but Boeing resisted. After the second disaster, then Boeing chief executive Dennis Muilenburg further upset pilots with remarks that seemed to blame pilots for the crashes.

A pilot at a large European airline who asked not to be identified said trust for Boeing was at "an all-time low". He said he wanted to see the company and regulators "come clean with all the new systems that are different to past models, and come up with a comprehensive training plan, not just a three-hour iPad course."

In a move that could help relations, Boeing earlier this month reversed its longtime position and recommended that 737 Max pilots train in a flight simulator. Mr Tajer said his union's safety expert had a phone call last week with representatives from Boeing to discuss the details of training. "We're very focused on working with flight crews and our airline customers to re-earn their trust," a Boeing spokesman said.

Boeing has "a long way to go" to restore trust with the pilots in the European Cockpit Association, Mr Horne said. "It has lost its credibility as a manufacturer and failed in its response to the problem. They still don't get what it is they did wrong, they have been in denial, and there's questions over the culture at the company . . . It gives us the worry that they aren't able to sort out their house."