In 1989 he came to international attention as the captain of United Airlines Flight 232, which crashed in Sioux City, Iowa, after suffering a total loss of controls.

Having recovered and returned to service as a pilot, Haynes retired from United Airlines in 1991, and subsequently became a public speaker for aviation safety.

[5] Haynes lost his draft deferment while taking a semester off from Texas A&M, while the United States was engaged in the Korean War, and decided to join the U.S. Marine Corps.

[1][7] For most of his career with United Airlines he served as a flight engineer or co-pilot, refusing offers of promotion, because they would have required relocating from Seattle.

Without hydraulic fluid Haynes and his flight crew could not move the airplane's flaps and rudder or almost any other control surfaces.

[8] With very limited ability to control the airplane, Haynes had difficulty aligning with a runway, reducing speed and landing nose-up.

Haynes believed five factors contributed to the degree of success in Sioux City; luck, communications, preparation, execution, and cooperation.

According to NPR, "Haynes is widely seen as a hero among aviation experts, akin to Chesley "Sully" Sullenberger and his 'miracle on the Hudson.