3. REQUIREMENTS3.1 Design and construction3.1.1 Item and interface definition3.1.1.1 Interface and installation3.1.1.2 Installation hardware3.1.1.3 Interface loads3.1.1.4 Mounts3.1.1.4.1 Main mounts3.1.1.4.2 Ground handling mounts 3.1.1.4.3 Engine stiffness3.1.1.5 Control lever and signals3.1.1.5.1 Power command lever and signal3.1.1.5.2 Load demand command and signal3.1.1.5.3 Output speed lever and signal3.1.1.5.4 Fuel shutoff lever and signal3.1.1.5.5 Lever torque3.1.1.6 Subsystem interfaces3.1.1.7 Bleed air interface3.1.1.7.1 Customer bleed air contamination3.1.1.8 Drains and fluid collection devices3.1.1.9 Power absorber interface3.1.1.10 Power takeoff (PTO) 3.1.1.11 Starting drivetrain