The U.S. Air Force has returned nearly 700 F-15 fighter jets to service after a Nov. 2 crash grounded the fleet.
Although the pilot was not killed, the military ordered the fleet of planes, made by Boeing Co., grounded a day later on "airworthiness concerns."
After completing safety inspections on more than 500 of the F-15s, the Air Force said Wednesday the fleet could be returned to service.
Industry experts and the Air Force are working with a federal plane crash investigation board to determine what caused the plane to go down, said Air Force Combat Gen. John Corley in a Nov. 21 memo to F-15 pilots.
There is one squadron of F-15s at Langley Air Force Base in Hampton.
The plane, flown by the Missouri Air National Guard, went down during a training exercise near Salem City. Corley asked pilots to "remain vigilant" to mitigate any unknown risks as the fleet returns to service.
The Air Force seeks to replace aging F-15s, some more than 30 years old, with Lockheed Martin Corp.'s F-22 Raptor. The latest version of the F-15 is being used in operations in Iraq and Afghanistan. Non-combat but critical-mission flights were flown on Lockheed's F-16s while the F-15 fleet was grounded.
The F-15 was first manufactured by St. Louis-based McDonnell-Douglas, which was purchased by Chicago-based Boeing some 10 years ago. Boeing delivered its last military F-15 to the Air Force in late 2004 but still manufactures the aircraft for non-military customers, the company said.
Shares of Boeing added $2.13, or 2.4 percent, to close at $89.54 on Friday's holiday-shortened session.
The NTSB is not expected to release its findings for several months on the cause of the deadly crash during a training mission.
Today, more than 800 aircraft, 14 percent of the fleet, are grounded or operating under restricted flying conditions.
The accident rate for this workhorse fighter has risen over the past few years, and two pilots have died in the past year.
Air Force will spend $1.5 billion over 10 years to replace planes' wings.