The S-55QT (Quiet Technology) conversion was started by Orlando Helicopter in the mid 1980s and continued by Vertical Aviation Technology (VAT) in the 1990s, at the request of Papillon Grand Canyon Helicopters who needed quieter helicopters for their sight-seeing flights. It features a 5-blade rotor instead of the standard 3-blade one, revised engine intakes and exhausts, and noise-suppressing engine covers. It also has extra large windows to improve the passenger's view. The conversion was certified in December 1999. This example still carries its old Papillon colours.