The CFM International LEAP engines of the 737 MAX are placed higher and further forward in relation to the wing than on previous 737s, destabilizing the aircraft pitch at high angles of attack (AoA). Boeing designed a Maneuvering Characteristics Augmentation System (MCAS) to compensate. If the 737 MAX aircraft's nose pitches up higher than usual, potentially leading to a stall, the MCAS senses the excess lift and automatically lowers the aircraft's nose to avoid the stall.[1] If the AoA sensors malfunction, the MCAS may initiate an unplanned dive that the crew are not prepared to deal with.