Air guide controller insertable into or forming an air opening for controlling air flowing in along an air flow direction, having a flap arrangement comprising a plurality of flaps insertable into the air opening and arranged in a louver-like manner in relation to one another, wherein each flap comprises a square or rectangular flap surface extending along a flap axis of rotation, being bounded by flap longitudinal sides extending parallel to the flap axis of rotation and flap end sides extending transversely to the flap axis of rotation, wherein the flaps of the flap arrangement can be inserted along the flap axis of rotation at a first flap end face and an opposite, second flap end face, each in a relatively movable manner, in particular rotatably, into a joining partner, wherein each flap of the flap arrangement is adjustable by means of an adjustment device between an open position releasing the air opening and a closed position at least partially closing the air opening for selectively releasing and closing the air opening for realizing a thermal management of a motor vehicle arrangement downstream of the air opening in the air flow direction, wherein each flap of the flap arrangement is designed as a drive end at a flap end face, for which purpose each flap comprises, at this flap end face, a lever arm which acts on the flap axis of rotation and can be rotatably connected to a coupling rod, CHARACTERIZED IN THAT THAT each flap of the flap assembly is designed as a locking end on one flap face, for which at least one spring (16; 18) is provided between a flap and the joining partner, which is seated with at least one resilient spring tongue (16b, 16c), under deflection by the flaps and against the spring force of the spring tongue, between at least one flap and the joining partner in such a way that, in the event of a flap fracture of at least one flap of the flap arrangement, this spring tongue causes the flap arrangement to be locked. having a flap arrangement comprising a plurality of flaps insertable into the air opening and arranged in a louver-like manner in relation to one another, wherein each flap comprises a square or rectangular flap surface extending along a flap axis of rotation, being bounded by flap longitudinal sides extending parallel to the flap axis of rotation and flap end sides extending transversely to the flap axis of rotation, wherein the flaps of the flap arrangement can be inserted along the flap axis of rotation at a first flap end face and an opposite, second flap end face, each in a relatively movable manner, in particular rotatably, into a joining partner, wherein each flap of the flap arrangement is adjustable by means of an adjustment device between an open position releasing the air opening and a closed position at least partially closing the air opening for selectively releasing and closing the air opening for realizing a thermal management of a motor vehicle arrangement downstream of the air opening in the air flow direction, wherein each flap of the flap arrangement is designed as a drive end at a flap end face, for which purpose each flap comprises, at this flap end face, a lever arm which acts on the flap axis of rotation and can be rotatably connected to a coupling rod, CHARACTERIZED IN THAT THAT each flap of the flap assembly is designed as a locking end on one flap face, for which at least one spring (16; 18) is provided between a flap and the joining partner, which is seated with at least one resilient spring tongue (16b, 16c), under deflection by the flaps and against the spring force of the spring tongue, between at least one flap and the joining partner in such a way that, in the event of a flap fracture of at least one flap of the flap arrangement, this spring tongue causes the flap arrangement to be locked.