Charles Cuthbertson Learmonth DFC & Bar (2 May 1917 – 6 January 1944) was an officer in the Royal Australian Air Force (RAAF) during World War II.

At a height of 1,000 ft (300 m) and about 18 mi (29 km) north-west of Rottnest Island his Beaufort began to shake violently.

The Australian-built Beauforts were plagued by a mysterious problem that had destroyed over 90 aircraft and killed many crews, including many under training at RAAF East Sale.

Shortly afterwards, the trim tab flicked to the extreme up position, over-powering Learmonth and forcing the aircraft to descend rapidly.

[3][4][5] With the information obtained from Learmonth's radio commentary the problem plaguing the Australian-built Beauforts was traced to a component in the elevator trim tab actuating unit.