The National Transportation Safety Board has ruled that a stuck engine valve contributed to the forced landing of a tour helicopter on May 19, 2012.



No one was injured, although the helicopter, which landed in a sand pit, was substantially damaged.



According to a factual report scheduled to be approved by the board in May, an inspector who examined the badly damaged helicopter found a “build-up of oil carbon deposits” around one of the exhaust valves, the report said.



The inspector also noted that “air tour operations seem to be prone” to that type of build-up due to “quick multiple shutdowns.”



He added that the tour company, Timberview Helicopters, has since established a post-flight cool down procedure to prevent further problems.



The sightseeing flight had taken off from the Destin Airport and was about 200 feet off the ground when the pilot noticed that the engine needle had “spiked” and remained at the top of the gauge, the report said.



She turned the helicopter to go back to the airport but realized she was losing altitude too rapidly to make it back.



The helicopter made a hard landing, breaking off the tail boom.



The pilot and two passengers were able to get out of the helicopter before rescue crews arrived.



Representatives from Timberview said they were unable to talk because of a “family emergency.”