The T-45 high angle of attack evaluation : the testing of an advanced trainer aircraft

Thesis statement: The objective of this thesis is to document the testing of the T-45 for its viability as an Out of Control Flight (OCF) and Spin trainer in the High Angle of Attack (HAOA) regime for the US Navy Advanced Jet Training syllabus.

In October 1993, following the completion of the primary contractor's High Angle of Attack (HAOA) demonstration program, a Navy HAOA evaluation commenced. The purpose of the Navy HAOA testing was to evaluate the flying qualities and engine operability of the T-45A airplane, and determine its suitability for the undergraduate jet trainer mission in the HAOA flight regime. Areas investigated included departure resistance, vertical maneuvering and tailslides, operational maneuvering, Air Combat Maneuvering (ACM), and an evaluation of upright spins. Due to the possibility of entry into a potentially unrecoverable inverted spin mode, intentional inverted spins were prohibited and upright spin testing was restricted.

This thesis discusses the events and background that lead up to the Navy's HAOA flight testing, the tests and their results, and any appropriate recommendations that ensued with specific concern on airplane design changes and/or modifications.

In summary, the T-45A was not in compliance with the Test and Evaluation Master Plan (TEMP) due to: (1) technical characteristics associated with out-of-control flight (OCF) training, and (2) the T-45A was not capable of the upright rudder-induced or lateral stick-induced departures required by the TEMP, reference 1. The following major deficiencies were identified during the testing: the inability to perform all phases of the out- of-control flight training mission, and the airplane's susceptibility to inadvertent entry into unrecoverable inverted spins. However, the noted major deficiencies are not enough to stop the introduction of the airplane into the fleet but should be considered significant enough to be corrected as soon as possible.