Pakistan has extended the deadline for Turkish Aerospace Industries to deliver 30 T129 helicopter gunships on order, amid US reluctance to grant Turkey technology export licenses, Defense News reported.

With the American move now seriously jeopardizing the sale, the Turkish government has tasked Tusas Engine Industries, TAI’s sister company, with developing an indigenous engine for the T129.

“Pakistan has agreed to give us another year [to resolve the problem]. We hope we will be able to develop our indigenous engine soon to power the T129,” Ismail Demir, the head of Turkey’s top procurement agency, said on Jan. 6. “After one year, Pakistan may be satisfied with the level of progress in our engine program, or the US may grant us the export license.”

In 2018 TAI signed a $1.5 billion agreement to sell a batch of 30 T129 helos to Pakistan. However, the company needs to secure US export licenses for any export deal with a third country. TAI produces the five-ton attack helicopter, which is based on its predecessor, the A129 Mangusta.

The T129 is a twin-engine multirole attack helicopter produced under license from the Italian-British company AgustaWestland. It’s powered by two LHTEC T800-4A turboshaft engines. Each engine can produce 1,014 kilowatts of output power. The T800-4A is an export version of the CTS800 engine. LHTEC, the maker of the engine, is a joint venture between the American firm Honeywell and the British company Rolls-Royce.

A procurement source told Defense News on Jan. 10 that Pakistan is also lobbying the US to support the deal.

But US diplomatic sources in Ankara said it’s unlikely Washington will issue the license given the cold nature of US-Turkish defense procurement ties. The US last year suspended Turkey’s membership in the multinational Joint Strike Fighter program in response to Turkey’s acquisition of the Russian-made S-400 air defense system.

But industry sources warn that any successful engine development program would take at least five to 10 years. TAI recently delivered its 56th helicopter gunship to the Turkish military.