Flight Test Course


Just before the last year of my degree on Aeronautical Engineering I had the opportunity to follow a Flight Test Course, which was supplied by the University of Cranfield in their National Flying Laboratory Centre (a H.P Jetstream 100 specially modified for these purposes). 

Between the first conceptual designs and the building of the first units of the new product there are many steps to walk on the aircraft design. One of the last steps is the Flight Test.
An experimental prototype is built for this stage, which is used to test all the aspects related to the stability, safety, manoeuvers, lift, thrust, engine power and performance,...etc.
Before each flight a flight briefing was carried on, covering parameters displayed, what to read, when to read it, additional points to look for, probable flight duration,...etc. 

After the flight there was a post flight analysis, during which the students were expected to work in groups (but often worked individually!) to produce graphs, derivatives, etc. with assistance from staff members. 

The course structure was as shown below:
The atmosphere; measurement of speed, height, and temperature; pressure errors (PE) and their measurement, air data computers, simple range measurement. 
  • Flight 1: To measure PEs and fuel flows at different speeds.
  • Analysis 1: Production of PECs, calculation of pressure altitude, estimation of static temperature, calculation of equivalent and true airspeed, use of this data to produce simple range plot.
Lift (and incidence), drag and their effect on cruise performance, comparison of power and thrust producing engines. 
  • Flight 2: Measurement of thrust and incidence in level flight.
  • Analysis 2: Calculation of the lift/drag polar, estimation of best endurance and range speeds, comparison with results from Flight 1.
Longitudinal static and manoeuvre stability, Longitudinal modes of motion. 
  • Flight 3: Measurement of out of trim elevator angles and forces in straight and turning flight, demonstration and recording short period and phugoid.
  • Analysis 3: Calculation of stick fixed and stick free neutral and manoeuvre points, estimation of short period and phugoid natural frequency and damping.
Lateral stability and lateral modes of motion.
  • Flight 4: Measurement using steady heading side slips, demonstration and recording of roll subsidence mode, dutch roll, and spiral mode.
  • Analysis 4: Produce plots of conrol deflections against SS angle (calculate Yv, Nv, Lv), analyse recordings of lateral modes.
Iñaki Rodriguez Rebolledo
Curriculum Vitae, 2004