Flight Testing

Airworthiness certification for G-NFLA Jetstream 31

Overview

Flight tests conducted on G-NFLA BAE Jetstream 31 at the National Flying Laboratory Center located with Cranfield University to evaluate aerodynamic properties and assessment of aircraft performance, control and stability to comply with sections CS 13 and CS 17 of the CAA for airworthiness certification.

Program Summary

A comprehensive set of flight tests included in-person testing of the airplane to calibrate instrumentation, followed by running test sorties to assess longitudinal, lateral and directional stability, along with gathering sufficient data on the Roll Mode and Phugoid. The aircraft was determined to be statically stable with little correction required for the Roll Mode.

A series of flight tests were performed in Fall 2012, as a part of ongoing efforts to corroborate previous years of test results to determine aerodynamic performance, engine performance and flight stability with the objective of improving airworthiness and safety.

Basic instrumentation calibration tests were conducted to accurately determine flight speed. On-board instrumentation using LabView provided lift and drag data during flight in a) clean configuration while cruising and b) with flaps during takeoff and landing. Engine thrust was directly measured to determine climb and cruise performance. Longitudinal stability was determined with phugoid and short-period oscillation. Lateral and directional stability was determined for roll mode, Dutch roll, and spiral mode.

Flight Test Engineer

National Flying Laboratory Center

Sep 2012 — Mar 2013

Test results were later used to determine effective control laws that could be tested in a simulator that was used for development, testing and training pilots. Results for tip vortex descent trajectories from numerical simulations provide details of dynamic stall that can be delayed with active flow control methods. This could result in higher operating rotor speeds, allowing greater available engine power for control and maneuverability. Ongoing efforts were made to mitigate airframe-engine drag arising from installation effects.