According to reports, an A-10 Thunderbolt II accidentally fired a rocket near the city of Tucson, Arizona during a training flight on Thursday morning. Air Force officials announced on Friday that an investigation into the incident is already underway.

The venerable A-10 Thunderbolt II recently received a new lease on life in the form of a new Boeing service contract that should keep the aging close-air-support legend flying into the 2030s, but as outlets continued to pick the new re-winging contract apart, different reports regarding the legendary close-air-support aircraft began to surface on Thursday. According to the Air Force, the A-10 was flying a routine training mission around the Jackal Military Operations Area, located about 60 miles northeast of Tucson, when the pilot inadvertently fired an M-156 rocket just after 10:40 a.m. local time.

The rocket landed in an uninhabited area of desert, and according to official statements, did not cause any fire or injuries. However, according to an Air Force press release, the Jackal Training Area is not designated for munitions release, meaning no live-fire aircraft exercises are conducted in the area.

The M-156 is a white phosphorus rocket used primarily help mark targets and start fires. The nearly 9-pound warhead is comprised of 2 pounds of white phosphorus (WP) and 2 ounces of Composition B high explosive. Upon impact, the explosive ruptures the warhead housing and disperses a cloud of extremely hot white phosphorus to produce smoke. The A-10 Warthog in that deployed the weapon hailed from the 354th Fighter Squadron, which is part of Davis-Monthan Air Force Base’s 355th Fighter Wing. The pilot has not been identified.

Although often equipped with rockets or bombs, the A-10s real claim to fame is its legendary 30 mm General Electric GAU-8/A Avenger rotary canon. The massive gun weighs in at 619 pounds unloaded and is two feet wide and an astonishing 20 feet long. The platform fires 30mm rounds at the astonishing rate of 3,900 rounds per minute, fired from its rotating array of seven barrels. That means the GAU-8/A releases a whopping 65 rounds per second when unleashed onto a target.