A flight assistance apparatus for providing assistance in flying an aircraft, including: a yoke operated by a pilot of the aircraft; and a flight instruction section that instructs, with an aid of the yoke, the pilot to fly the aircraft in such a manner as to avoid a critical flight range when the aircraft approaches the critical flight range. Accurate detection of peak signals for blade measurements can be obtained by the microwave sensor. Retrofitting the digital image acquisition thus does not require any intervention in safety-related parts of the panoramic X-ray machine.