After the Lion Air crash in 2018, Boeing and the FAA, still not revealing MCAS, referred pilots to a revised checklist procedure that must be performed in case of a malfunction. Boeing then received many requests for more information and revealed the existence of MCAS in another message, and that it could intervene without pilot input.[3][4] According to Boeing, MCAS was supposed to compensate for an excessive nose up angle by adjusting the horizontal stabilizer before the aircraft would potentially stall. Boeing denied that MCAS was an anti-stall system, and stressed that it was intended to improve the handling of the aircraft.