Alterations and upgrades regularly occurred during overhauls. Triumph Engines also overhauls, repairs, manufactures and designs aftermarket aerospace components. A shortage of spare parts and qualified maintenance personnel resulted in improvised repairs and overhauls. Inspects, services, and overhauls aircraft fuel systems. Equipment overhauls and modifications are typically executed at this repair level. Activities include painting, maintenance, cabin checks, and overhauls of machinery. Electric Boat overhauls and undertakes repair work on fast attack class boats. A renovation show where Giosa overhauls real kitchens. It houses "Fliegerwerft 3", responsible for overhauls and maintenance of the C-130K Hercules and AB-212. Any major recruitment overhauls were likely to upset local power structures. Despite their recent overhauls, South West Trains withdrew the entire fleet in 2007. There were, however, no major overhauls of the core architecture. Several teams went through complete overhauls during the 1994 offseason. The class's design allows the boat to operate for about 15 years between major overhauls. Recommended engine TBO (Time Between Overhauls) is 5,000 hours.