Boeing expects its F/A-18 production line in St Louis, Missouri to keep humming for the foreseeable future, despite mixed signals from the US Navy about acquiring additional aircraft.

"I can easily envision the production line going beyond 2020," says Michael Gibbons, vice president and programme manager of Boeing's F/A-18E/F Super Hornet and E/A-18G Growler aircraft. "I could envision, easily, several more years of buys by the US Navy."

Super Hornet - US Navy

US Navy

The USN is currently "looking for their best options for procuring jets", he adds, while Lockheed Martin continues development of its F-35 Joint Strike Fighter, which may not reach initial operational capability with the service until 2019.

Gibbons made his comments on 9 December at NAS Patuxent River in Maryland, following a USN ceremony marking the 35th anniversary of the F/A-18, which first flew in 1978.

Production of the fighter is currently scheduled to end in 2016, when Boeing completes the last aircraft currently on order by the navy. Those aircraft are being procured in the current fiscal year 2014, which ends next September.

Super Hornets cost $51-$52 million each including warfare systems and General Electric F414 engines, while the electronic warfare-roled Growler costs about $9 million more, according to Gibbons.

He insists Boeing has no plans to shut the production line, which currently completes four aircraft per month, but which will slow to three monthly by 2016. Production could ultimately slip to two aircraft monthly and remain financially viable, according to Gibbons.

But signals from the navy have been mixed.

On 17 October, the service posted a pre-solicitation notice on the US website, announcing it intended to buy up to 36 additional aircraft in FY2015. The navy backpedaled a few weeks later, removing the notice.

On 9 December, US Navy Capt Frank Morley told Flightglobal he was responsible for posting the notice, calling it "a mistake".

"Administratively, it was an error [and was] my responsibility," Morley says, adding that the notice was an effort to ensure the navy maintains its aircraft "options."

"We pulled [the notice] back because it shouldn't have been out there," Morley says. "It was no indication of what the intent of the budget is for [fiscal year] 2015."

The navy notes it has decided to extend the service life of its F/A-18s to up to 9,900h, and fly the aircraft until at least 2030 or 2035. The aircraft's original design life was 6,000h.

In addition, the service is considering upgrading the fighters with conformal fuel tanks, which could boost fuel capacity by almost 1,600kg (3,500lb).

Gibbons expects the navy's intentions will become clear in January, when details of President Barack Obama's FY2015 budget proposal emerge.

Boeing will need to decide by March whether to begin investing in materials needed to build additional jets, Gibbons says. He also notes the programme could be buoyed by orders from other countries, like Australia, Brazil, Canada, Denmark, Kuwait and Malaysia.