The Israeli Air Force’s chief of staff has recommended the purchase of an additional 17 F-35 Joint Strike Fighter aircraft, but that decision is pending authorisation from the Israeli government.

Wednesday marked the roll-out of the first Lockheed Martin F-35I Adir, a slightly modified F-35A which will be delivered to Israel’s Nevatim Air Base in December. The U.S. has approved the sale of up to 75 F-35s to Israel and the country has signed contracts for 33 F-35s, the last of which will arrive around 2021, Israeli air force chief of staff Brigadier Gen. Tal Kelman told reporters Tuesday.

Israel has not made a decision on whether it will purchase the additional 17 F-35A-model fighters or when they would be delivered, Kelman says.

“Once we have a decision, we’ll know the timeline,” he says.

While Israel is committed to its order of A variant fighters, its air force is also mulling over a future purchase of the short takeoff and vertical landing (STOVL) F-35B. Israel would start purchasing F-35Bs if the country’s order exceeded 50 aircraft, Kelman says.

The F-35B's STOVL capability could offer significant advantages during an attack on an air base, Kelman says. But he also noted the aircraft’s drawbacks, including its smaller payload and fuel capacity than the conventional F-35A.

Kelman also reasons that regional conflicts would push Israel to complete aircraft maintenance within the country.

“Israel is in the middle of the Middle East and we’re in a daily conflict,” he says. “That is why we don’t want aircraft to leave, we cannot afford having a fighter aircraft go for three months [for] maintenance somewhere.”

While Israel will be able to complete normal aircraft maintenance, heavy maintenance would require significant investment and infrastructure, F-35 programme executive Lt Gen Christopher Bogdan says Wednesday. The US and Israel are forging tailored maintenance solution for Israel, but it won’t happen overnight, Bogdan says.

“There’s some policy issues in the US that we have to work on, there’s some investment by the Israeli government,” he said. “The good news is, when you deliver a new plane like this, you’re not going to need heavy maintenance for quite a long time so there is time to work the policy, infrastructure, tooling and training side to get Israel where they want to be.”

Israel’s push to complete maintenance at home would likely set them apart from other F-35 operators, who could leverage economies of scale with programme's larger, global maintenance infrastructure.

“Israel would like to be able to tap into that economy of scale, but their geo-political situation is such that they may have to do things on their own,” Bogdan says.