Articles taken from Flight International Magazine.

USAF rules out new F-15s and F-16s to narrow 'fighter gap'

Delays and cost overruns for the Lockheed Martin F-35 have not changed the US Air Force's plans to deactivate about 250 fighters later this year, says its chief of staff, Gen Norton Schwartz.

Lockheed flies first sensor-equipped F-35, one year late

The Lockheed Martin F-35 programme on 7 April reached the first flight milestone more than one year behind schedule with an aircraft equipped with a full suite of advanced sensors.

The BF-4 flight test aircraft was airborne for 45min, reaching an altitude of 15,500ft (4,700m). Besides standard flight tests, test pilot David Nelson also "checked" the operation of the mission systems, Lockheed says. The previous schedule called for first flight of BF-4 in March 2009.

Lockheed rejects Pentagon's cost estimates for F-35

Lockheed Martin has reached a key F-35 Joint Strike Fighter first flight milestone - and struck back at Department of Defense budget estimates warning that the much-delayed programme is heading for per-aircraft procurement costs of nearly double original estimates.

A year late, short take-off vertical landing test aircraft BF-4 made its first, 45min flight on 7 April. The flight was also the first for the F-35's full suite of advanced sensors.

US lawmakers push for back-up plans after F-35 cost increases

As cost estimates for the Lockheed Martin F-35 continue rising, some US lawmakers are pushing military officials to increase spending on fourth-generation fighters as a back-up.

Senator Joseph Lieberman of Connecticut says he considers the F-35 a "really extraordinary aircraft", but is concerned about the military's projected tactical aircraft shortfalls.

GE, Rolls sweeten offer on F-35 alternate engine price

A transatlantic team has sweetened its price offer to the US Department of Defense seeking to keep alive a threatened alternate engine for the F-35 Joint Strike Fighter.

In September, the General Electric-Rolls Royce Fighter Engine Team offered to deliver 21 F136 engines in Fiscal 2013 at a fixed price, converting the contract from a cost-plus structure years ahead of schedule.

The team now is offering to keep slashing prices for engines delivered in FY2014 and FY2015. A total of $1 billion of cost savings could be achieved if Pratt & Whitney responds by slashing their costs, says Jean Lydon-Rogers, chairman of the Fighter Engine Team.

ATK gains new work on F-35 structures

Alliant Techsystems (ATK) will continue building skins and start supplying inlet ducts for the Lockheed Martin F-35 Joint Strike Fighter under two new contracts valued at $250 million.

Worth $240 million, the first deal involves providing composite skins for the F-35's upper and lower wing-box and engine nacelles. The agreement includes 390 aircraft ordered during low rate initial production lots four to eight.

Meanwhile, Lockheed's centre fuselage supplier, Northrop Grumman, has selected ATK to begin supplying composite inlet ducts for F-35s under a $10 million contract. Follow-on orders for full-rate production, beginning in 2016, could be worth $40 million more.