On 14 August 2012, a Boeing 737-800 crew continued a previously stable ILS Cat 1 approach below the prescribed MDA without having acquired the prescribed visual reference. The aircraft was then damaged by a high rate of descent at the initial touchdown in the undershoot in fog. The occurrence was not reported by either the crew or the attending licensed engineer who discovered consequent damage to the aircraft. Dense fog had prevented ATC visual awareness. The Investigation attributed the undershoot to violation of minima and to both pilots looking out for visual reference leaving the flight instruments unmonitored.