The Federal Aviation Administration is investigating after a Southwest Airlines flight came within 400ft of the ocean following an aborted landing attempt. 

The Boeing 737 MAX 8 plunged at a maximum descent rate of about 4,400ft per minute off the coast of Hawaii before climbing back up to safety on 11 April.

The plane had been flying between cities from Honolulu to Lihue airport in Kauai, but bad weather conditions prompted pilots to bypass a landing attempt.

During the go-around - when a plane flies back up in the air after deciding not to land - the first officer "inadvertently pushed forward on the control column while following thrust lever movement commanded by the autothrottle", according to a memo sent to pilots and seen by the Reuters news agency.

The action sent the aircraft dangerously close to hitting the Pacific Ocean.

Safety data confirmed the crew received a "DON'T SINK oral warning" followed by a "PULL UP oral warning", the memo said, but the first officer later said the crew did not hear the warnings.

There were no reports of injuries.

It comes as a separate Southwest Airlines Boeing 737 MAX 8 suffered damage to its infrastructure after it experienced what is known as a "Dutch roll" during a flight from Phoenix to Oakland in California on 25 May.

A "Dutch roll" refers to a combination of the aircraft tail swaying from side to side (yawing) and the plane rocking in a way that causes the wings to go up and down.

Pilots regained control and landed safety, but damage to the unit that controls backup power to the rudder was described as "substantial". The incident is being investigated by the National Transportation Safety Board.

'Emotional event'

In a post-incident debrief concerning the Hawaii flight, the pilots reportedly said seeing the severity of the flight's movements through an animated recreation "was a significant, emotional event," the Southwest memo said.

The memo added that the crew participated in comprehensive corrective actions and the airline is reviewing data and trends related to its procedures, training, standards, and performance.

Southwest said in a statement on 14 June that "the event was addressed appropriately as we always strive for continuous improvement".

Elsewhere, a plane bound for Melbourne, Australia, landed in the New Zealand city of Invercargill after a fire shut down one of its engines.

The Virgin Australia Boeing 737-800 jet was met with fire engines when it landed, about 50 minutes after it took off. The airline said in an emailed statement that the incident may have involved "a possible bird strike".

Boeing 737-800s are the generation of 737s before the newer MAXs, which have been hit with a series of safety concerns including a incident in which a chunk of fuselage fell out and two crashes which grounded the fleet.