Air New Zealand plane struck by lightning en route to Rarotonga, returns to Auckland

An Air New Zealand plane en route to Rarotonga has been struck by lightning, forcing it to return to Auckland this morning. Photo / Supplied

An Air New Zealand plane en route to Rarotonga has been forced to return to Auckland shortly after takeoff after it was struck by lightning, the Herald understands.

Passengers, surely looking forward to enjoying the Cook Islands sun, endured about an hour of the plane circling over Tāwharanui before heading back to Auckland, a city beset with rain.

Flight NZ942 turned around off the coast of Tāwharanui Peninsula in north Auckland after circling around about seven times.

The plane took off about 6am and started circling about 30 minutes into the flight.

It landed back in Auckland about 8am.

The Herald has approached Air New Zealand for comment.

The aircraft was an Airbus A321-271NX.

What happens when lightning strikes a plane?

Planes are designed to withstand and fly safely when struck by lightning.

More lightning strikes occur while in clouds, during the climb and descent phases of flight, than any other flight phase.

The reason is that lightning activity is more prevalent between 5000 to 15,000 feet (1524m to 4572m).

Airplanes that fly short routes, in areas with high incidence of lightning activity, are likely to be struck more often than long-haul airplanes operating in more benign lightning environments.

A Boeing paper on lightning strike says a single bolt of lightning can contain as much as 1 million volts or 30,000 amps.

The amount and type of damage an airplane experiences when struck by lightning can vary greatly, depending on factors such as the energy level of the strike, the attachment and exit locations, and the duration of the strike.

The aluminium used on most commercial aircraft conducts electricity and allows the lightning to pass across the skin of the aircraft, with the current usually exiting the aircraft at the tail.

Static wicks (small wires that are screwed into the trailing edge of plane wings) discharge static electricity that an aircraft picks up as it moves through the air but also dissipate a lightning strike.

During the initial stages of a lightning strike on an airplane, a glow may be seen on the nose or wing tips caused by ionisation of the air surrounding the leading edges or sharp points on the airplane’s structure.

The Boeing paper says passengers and crew may see a flash and hear a loud noise when lightning strikes the airplane.

Second Air NZ turnaround this week

It wasn’t the first international Air New Zealand flight that had to return to Auckland this week - a damaged pilot’s windscreen forced a plane headed to Japan to turn around miles above the Pacific Ocean on Monday.

Passengers on flight ANZ99, from Auckland to Tokyo, learnt their plane would have to go back to New Zealand as it passed near Vanuatu.

Air New Zealand’s chief operational integrity and safety officer David Morgan said flight NZ99 returned to Auckland so the plane could be repaired.

Morgan said aircraft windows are made of multiple layers to withstand any damage - but the plane had to return to Auckland as part of the airline’s standard operating procedure.

A passenger on the plane told the Herald a pilot made an in-flight announcement saying there was an issue with the aircraft which could only be fixed in Auckland.

“Getting turned around to go back home three hours in an eleven-hour flight is not ideal,” the passenger said.