TTDF Recruitment August 2020, Air Guard, Coast Guard and Regiment Vacancies. For the position of Officer Cadet. The mission of the Trinidad and Tobago Defence Force Reserves is to be a highly professional, well trained, combat-ready force that will respond effectively in support of the regular forces of the Republic of Trinidad and Tobago and the national community. As a member of the Reserves, you will play a key role in supporting this mission. The Reserves is an arm of the Trinidad and Tobago Defence Force, which falls under the authority of the Ministry of National Security.