section_path: Design/Engines
section_name: Engines
paragraph_text: Engines
  
  The Boeing 787 has two engine options: the General Electric GEnx -1B and the Rolls-Royce Trent 1000. As of early 2020, of the 1,484 total 787 orders, 905 (61%) had selected General Electric engines, 476 (32%) had chosen Rolls-Royce engines, and 103 (7%) remained undecided.
  
  Both engines use a standardized electrical interface, enabling airlines to install either model with minimal modifications. This interchangeability reduces the time and cost typically associated with switching engine types and is particularly attractive to lessors, as it allows airlines to maintain a common engine type across their fleet when an aircraft changes ownership. While earlier aircraft could accommodate engines from different manufacturers, swaps were rarely performed due to their complexity and expense. Boeing has stated that engine changes on the 787 were designed to take approximately 24 hours, although lessors have reported that in practice it can take as long as 15 days.
  
  The 787's engines use an all-electric, bleedless system, adapted from the Sonic Cruiser, that eliminates the need for traditional superheated air conduits used for de-icing, cabin pressurization, and other functions. As part of its " Quiet Technology Demonstrator 2" program, Boeing integrated several noise-reduction features into the aircraft. These include an air inlet lined with sound-absorbing materials and an exhaust duct with a chevron -toothed pattern to promote quieter mixing of exhaust with ambient air. Boeing says these technologies make the 787 significantly quieter both inside the cabin and in surrounding areas, with sound levels kept below 85 decibels at airport boundaries.
  
  In 2016, Rolls-Royce began flight testing the Trent 1000 TEN engine, an upgraded version of the Trent 1000 featuring a new compressor system derived from the Trent XWB and a new turbine design for extra thrust, up to 78,000 lbf (350 kN).