SpaceX CEO Elon Musk criticized Boeing’s CEO David Calhoun, accusing him of lacking the expertise needed to lead an aircraft company. Musk argued that “the CEO of an aircraft company should know how to design aircraft, not spreadsheets.”

Business Insider noted that Calhoun’s background in accounting rather than engineering supports Musk’s claim. This comes as Boeing struggles to return its Starliner spacecraft from the International Space Station due to helium leaks affecting its thruster system. NASA announced last week that the return journey is indefinitely delayed.

Meanwhile, Musk’s SpaceX has launched ten successful Crew Dragon missions to the ISS under the same NASA contract. Boeing’s ongoing issues highlight the need for new leadership with engineering expertise.

Boeing CEO, David Calhoun

Under Calhoun’s leadership, Boeing has faced multiple crises, including two 737 Max 8 crashes that killed 346 people and an ejected door plug forcing an emergency landing. Several whistleblowers have accused Boeing of inadequate safety standards.

Calhoun plans to step down at the end of the year, with many agreeing with Musk that Boeing needs a leader with engineering skills. Emirates president Tim Clark told CNBC that Boeing needs a strong engineering lead and a governance model prioritizing safety and quality.

However, finding a new head capable of addressing Boeing’s numerous challenges is difficult. The company faces a barrage of lawsuits, and prosecutors recommend federal criminal charges following the 737 Max 8 crashes. Several candidates have turned down Boeing’s offer, reflecting the daunting task ahead.