The A-10 was intended to fly from forward air bases and semi-prepared runways with a high risk of foreign object damage to the engines. The unusual location of the General Electric TF34-GE-100 turbofan engines decreases ingestion risk and allows the engines to run while the aircraft is serviced and rearmed by ground crews, reducing turn-around time. The wings are also mounted closer to the ground, simplifying servicing and rearming operations. The heavy engines require strong supports: four bolts connect the engine pylons to the airframe. The engines' high 6:1 bypass ratio contributes to a relatively small infrared signature, and their position directs exhaust over the tailplanes further shielding it from detection by infrared homing surface-to-air missiles. The engines' exhaust nozzles are angled nine degrees below horizontal to cancel out the nose-down pitching moment that would otherwise be generated from being mounted above the aircraft's center of gravity and avoid the need to trim the control surfaces to prevent pitching.