The Netherlands Defense Safety Inspection Agency (Inspectie Veiligheid Defensie) is investigating an incident during a January military exercise in which a Dutch Air Force F-16 was damaged by live fire from a 20-millimeter cannon—its own 20-millimeter cannon. At least one round fired from the aircrafts M61A1 Vulcan Gatling gun struck the aircraft as it fired at targets on the Dutch militarys Vliehors range on the island of Vlieland, according to a report from the Netherlands NOS news service.
Two F-16s were conducting firing exercises on January 21. It appears that the damaged aircraft actually caught up with the 20mm rounds it fired as it pulled out of its firing run. At least one of them struck the side of the F-16s fuselage, and parts of a round were ingested by the aircrafts engine. The F-16s pilot managed to land the aircraft safely at Leeuwarden Air Base.
The incident reflects why guns on a high-performance jet are perhaps a less than ideal weapon. The Vulcan is capable of firing over 6,000 shots per minute, but its magazine carries only 511 rounds—just enough for five seconds of fury. The rounds have a muzzle velocity of 3,450 feet per second (1050 meters per second). That is speed boosted initially by the aircraft itself, but atmospheric drag slows the shells down eventually. And if a pilot accelerates and maneuvers in the wrong way after firing the cannon, the aircraft could be unexpectedly reunited with its recently departed rounds.
As Popular Mechanics Kyle Mizokami reported in 2017, this is not the first time this sort of thing has happened. During flight testing in 1956, a Grumman F-11 Tiger flying from Grummans test facility in Riverhead, New York fired a burst from four 20mm cannons toward the Atlantic Read More – Source