Inside the Defence Force's 757 planes: Breaking down the details

The defence force plane has hit the headlines again for breaking down while flying the prime minister around the world.

RNZ political reporter Anneke Smith and visual journalist Nate McKinnon take readers inside the aircraft for a close-up look at its interior, functions and an Air Force insider's perspective on getting a new plane.

What's it like inside?

First things first, the Royal New Zealand Air Force (RNZAF) Boeing 757 looks like a commercial aircraft on the inside. It's the Hercules (used for airports which have short runways) which has a cargo-style interior where passengers strap in along the side of the plane.

The 757 can carry up to 156 passengers, or 126 in a "VIP rig", mission commander Brendon Clark told RNZ on a flight from Papua New Guinea to Brisbane this week.

The seating is sectioned like a commercial aircraft too, with VIPs at the front followed by business class and then an economy equivalent.

The prime minister sits up front, followed by ministers, delegation members, media and defence force personnel.

Instead of commercial airline staff, passengers are looked after by uniformed personnel. They push trolleys up and down the aisle with snacks, drinks and meals and do the safety checks before landing and take-offs.

"Our people are outstanding. They're well trained and they love it, this is why they're here," Clark said.

What's the plane used for?

The Defence Force planes (there are two Boeing 757s) were mostly used for transporting cargo around the Pacific, Clark said.

"What a lot of people misunderstand about these aircraft is that this is not a VIP aircraft. About 12 to 15 percent of its flying hours are used for VIP transport, but we have the ability to take out the seats so this can be completely empty."

The planes were used during New Zealand's response to the recent landslide in Papua New Guinea and during civil unrest in the Solomon Islands.

"So when that's happening, we'll have lots of generators, tarpaulins, fuel, water, those sorts of things. The 757 is a bigger, heavier and faster aircraft than a C-130 [Hercules] so we can get those sorts of things to supported areas."

In saying all of that, VIP travel is an important part of the plane's purpose. The United States' vice president flies around in a Boeing 757. Clark describes it as "the perfect continental plane".

The New Zealand prime minister has to fly with the Defence Force if they want the red carpet treatment at airports around the world.

"If you want to be a first world country ... have a red carpet and engage correctly at the right level with our partner nations with a business delegation and a press delegation, this is the sort of thing you need to have," Clark said.

Should we get a new plane?

There is a cross-party consensus we should get a new plane - but whether we can afford one is another question.

Clark estimates it would cost north of $100 million to buy a new 757 with the desired freight hauling capability.

He was at pains to point out commercial airlines had faults too, but he said they were just not as noticeable as passengers could relocated to another aircraft.

Speaking after the most recent Defence Force breakdown in Papua New Guinea, Air New Zealand chief executive Greg Foran said airlines were complex operations.

"We have some advantage in that we've got a fleet of 100 planes so we can move things around. It's challenging when you don't have so many planes and I think the Air Force team are doing a pretty job actually, when you consider everything they've got to deal with."

Clark said any decision to buy a new plane was not for him.

"Aircraft are expensive to operate. That's a political decision. Defence doesn't buy votes in New Zealand so this needs to be a bipartisan decision."

Prime Minister Christopher Luxon has said he sees value in replacing the plane, and the coalition will look at this as part of its new defence strategy.