 Around 2005–2010, Bell and Boeing teamed up again to perform a conceptual study of a larger Quad TiltRotor (QTR) for the US Army's Joint Heavy Lift (JHL) program.The QTR is a larger, four rotor version of the V-22 with two tandem wings sets of fixed wings and four tilting rotors.In January 2013, the FAA defined US tiltrotor noise rules to comply with ICAO rules.