August 30, 2014: HAL has revealed that it plans to undertake comprehensive wind tunnel tests to study spin and recovery characteristics for compliance to FAR-23 (aerobatic category) standards on its HTT-40 basic trainer aircraft by the end of this year or early 2015. HAL has announced its requirement for a test agency to design and manufacture the required scale model/s to achieve all test objectives, which include rotary and static tests towards development of mathematical model for analyzing the spin and recovery characteristics of HTT-40. The scope of work includes model design, manufacture, testing, analysis of results and associated mathematical model generation for compliance. HAL has revealed that the HTT-40 weighs about 3000 kg. The winning vendor will also be required to provide a simulation (mathematical) model of the HTT-40 aircraft to aid HAL in understanding predicted aircraft spin response and recovery controls based on wind tunnel/ other data. Already fighting an up-hill battle on the basic trainer front, HAL wants to ensure there are no slippages in the programme. And given the problems it has had with the HJT-36 in terms of spin and stall characteristics, in addition to "very low" engine flying hours before overhaul.