On others, they may be attached to the rear of the fuselage. These compartments, which house the engines, are called nacelles. Look at the different types of nacelle/pylon attachments and see how engines are numbered on large aircraft. Engine number one is the engine on the left(port) wing, or If there are two or more, nearest to the wing tip.
• A twin-engine aircraft would have number one engine either on the left wing or on the left of the fuselage if the engines were attached this way. Engine number two would be on the other side. Most three engine aircraft will have engine number two in the tail and engines one and three either on the wings (DC-10) or on the fuselage (B727).