Philippine Airlines Flight 116 (en route between Davao City and Manila) was hijacked by six terrorists. The aircraft was forced to land at Zamboanga. On May 23, security forces tried to storm the plane and a gun battle broke out, during which some grenades were set off by the hijackers, which damaged the aircraft beyond repair. Ten passengers and three hijackers were killed. The remaining 3 hijackers were caught and sentenced to death. On March 2, 1987, Philippine Airlines Flight 171 from Davao damaged its engine when its landing was aborted by a herd of cows which strayed on the runway. The plane had slowed down its engine when the pilot saw the cows on the runway. The plane flew past the cows and landed safely on its second approach. All the 94 passengers of the plane were safe. On May 3, 2006, Cebu Pacific Flight 393, a Douglas DC-9 from Davao, was on final approach on Runway 27 at 9:15 am. After touchdown, the left main gear of the aircraft burst. All 100 passengers were safe, but the aircraft was stuck on the runway. Because of this, the airport was closed for 23 hours. Air Philippines flights to Zamboanga were canceled, as well as all Philippine Airlines afternoon flights to and from Zamboanga and Cebu Pacific flights to Manila. A South East Asian Airlines flight from Jolo that was about to land in Zamboanga was ordered to go back due to the incident. The Cebu Pacific Zamboanga station advised their Manila hub about the problem, sending two new landing gears to Zamboanga. However, since the aircraft was stuck on the runway, the plane that was going to deliver the planes gear landed at Pagadian Airport and helicopters of the Philippine Air Force delivered the landing gears to the airport. The next day, the aircraft was removed from the runway and normal airport operations resumed. Due to the incident, Philippine Airlines and Air Philippines were forced to hold special flights. On December 28, 2006, a Philippine Air Force assault helicopter crashed during an emergency landing Thursday on the airport's runway. The pilots of the rocket-firing MG520 helicopter, which is used against al-Qaeda-linked militants and communist guerrillas, were on a routine maintenance flight when they decided to make an emergency landing for unclear reasons. The MG530 was damaged and its two pilots were slightly injured and shaken by the crash landing.