Boeing has backed off from previous forecasts that the 40-year-old F-15 production line would shut down next year in the absence of new orders, adding that there are a "number of pending" orders for the type.

"It is premature and inappropriate for us to even speculate on when the production line might close," Boeing said in a statement responding to questions from Flightglobal.

On 21 October last year, the Obama administration notified the US Congress of a possible sale of 72 F-15Es to Riyadh, but the deal with Saudi Arabia has now been pending for almost a year.

The proposed deal included significant capability upgrades for the nation's existing F-15SAs.

The 2010 notification signalled that the administration intended to move forwards with the sale, despite objections from Israel.

The Israeli government had openly expressed concerns that the sale of upgraded F-15Es to Saudi Arabia could erode its qualitative military advantage in the Middle East.

But the contract for the new batch of F-15s was never signed by Saudi Arabia, and the status of any negotiations remains unclear.

In mid-2010, Boeing officials said they would need a new contract for the F-15 before the end of 2011, to avoid a break in the production line.

The company is scheduled to deliver the last of 21 F-15Ks to South Korea in March 2012 (one pictured below), and Singapore's order for 24 F-15SGs is scheduled to be completed next year.

 F-15K - Boeing

© Boeing

For now, the US airframer does not appear to be panicking about the possibility of a break in production.

In addition to the pending Saudi Arabian deal, the F-15SE Silent Eagle variant is competing for a follow-on contract in South Korea for 40 to 60 aircraft.

The competition includes the Eurofighter Typhoon, Lockheed Martin F-35 Joint Strike Fighter and Sukhoi's PAK-FA.

However, Seoul is not planning to award a contract until at least October 2012.

The F-15 has been in continuous production for nearly 40 years, and is one of five active fighter production lines in the USA.

Boeing's F/A-18E/F Super Hornet is scheduled to remain in production for the US Navy through to at least 2015.

Lockheed Martin is shutting down F-22 production in April next year, but its F-16 backlog is filled through 2014. F-35 production is planned to continue for nearly 25 years.

Source: Flight International