Head to Toe - S7-E15
Factual error: Lt.Col. Sarah Coffey wears the USAF uniform, but an Army insignia on her left collar (the MI "splatted bug"). An Air Force officer wears identical insignia on right and left collars (a dark oak leaf, in this case).
Factual error: Lt. Singer is wearing the wrong epaulets (shoulder boards). She is wearing the epaulets with a star on it instead of the legal emblem.
Chosen answer: When landing on an aircraft carrier, a pilot "calls the ball" by confirming to the landing signal officer (LSO) that they have the carrier, and more specifically its landing guidance systems in sight. Carriers use a Fresnel lens system which is a light only visible at a certain angle, so if a pilot sees the "ball" they are at the correct altitude and glide slope for landing.
Sierra1 ★