While many aircraft are physically capable of performing powerbacks, many companies impose restrictions on the practice, mainly due to the risk of FOD (foreign object damage) from debris propelled into the air. This problem is magnified even more with planes having wing-mounted engines, as their proximity to the ground can exacerbate debris ingestion if powerbacks are used. Small metal objects are particularly dangerous as they can be propelled into terminal windows, employees on the ground or even the aircraft itself.[2] Applying the brakes when backing up also has the potential to cause a tailstrike.[3]