Final answer:
The statement is true; if both AOA probe heaters fail in icing conditions, it could cause a sharp uncommanded nose-down attitude that may be uncontrollable by normal controls or overrides.
Step-by-step explanation:
The statement is True. If both Angle of Attack (AOA) probe heaters were to fail in icing conditions, it could lead to the probes becoming obstructed by ice. The AOA probes are critical sensors that measure the aircraft's angle of attack, which is the angle between the chord line of the wing and the oncoming air. The aircraft's flight control systems use this information to determine the aircraft's aerodynamic state and to warn of an impending stall. Should the probes become iced over, the system may receive incorrect data, potentially causing the onboard computers to interpret the situation as a high AOA and initiate a nose-down correction to avoid a stall.
This would result in a sharp uncommanded nose-down attitude that could be difficult or impossible to override with normal control inputs, including stick forces or paddle switch actuation. Modern aircraft have systems and redundancies to deal with such issues, including de-icing systems for the AOA probes and flight envelope protection that should prevent extreme maneuvers. However, the failure of critical sensors like the AOA probes can still present a significant safety risk.