Boeing’s new flagship, the 777X, is threatened with similar safety failings to the US aerospace giant’s ill-fated 737 Max, according to internal emails.

Damning messages released as part of a US Senate probe into two 737 Max fatal crashes highlight Boeing staff fears that the 777X – a modified version of an existing plane – may be vulnerable to technical problems.

In an email from June 2018, before the first Max crash, one Boeing worker wrote: “Best part is we are re-starting this whole thing with the 777X with the same supplier and have signed up to an even more aggressive schedule.”

Another member of staff warns about a relentless cost focus, saying: “We put ourselves in this position by picking the lowest-cost supplier and signing up to impossible schedules. Why did the lowest ranking and most unproven supplier receive the contract? Solely based on the bottom dollar. Not just the Max but also the 777X! Supplier management drives all these decisions.”

The Max is a upgraded version of a Sixties design, and the crashes have been linked to a system installed on it to make it handle like earlier aircraft. Boeing used this as a sales feature, saying that pilots of earlier 737s would be able to fly the Max without retraining.