National Flying Laboratory Course
Following the end of my 2nd year of university, I attended the National Laboratory Course with other aeronautical engineering students. This consisted in 3 days of demonstration flights taking place in a modified Jetstream 31 (G-NFLA) turbo-prop from Cranfield University.
“This course builds on the theoretical teaching given to aeronautical engineering students by demonstrating how the performance and handling qualities of a real aircraft can be measured, and the data reduced to a form which describes some characteristics of the aircraft.”
Briefings took place in the morning of the day of each flight. Different topics where covered in relation with the flight demonstration that would follow. These ranged from “Drag and Aircraft Performance” to “Lateral and Longitudinal Dynamic Stability. A small booklet containing reference information about the aircraft and each topic was handed out at the start of the course. The demonstration flights conveniently departed from the nearby Southampton airport (SOU/EGHI). The University organised a bus shuttle service to the Signature Flight hangar usually used for the handling of private jets. Students were split into smaller groups with a flight taking off every 45 minutes. Upon entering the aircraft, a video safety briefing was given on the screen fitted behind each seat. These were then switched to a front-mounted camera by one of the crew during taxi and take-off. The hot and sunny weather made the flight quite turbulent as the we experienced patches of high thermals. The pilot was cleared by ATC to an airspace south of the Isle of Wight. Once we reached the designated zone, the screens where switched to display the relevant live flight parameters (airspeed, pitch, roll etc). The pilot then executed the different manoeuvres to demonstrate aircraft static stability and dynamic response. This included running though the main dynamics modes such as Short Period Oscillation and Phugoid (longitudinal) and Dutch Roll and Spiral mode (lateral). For the last one, the pilot banked the Jetstream 31 enough to trigger the bank angle cockpit warning. At the back, the increasing g-force could clearly be felt which left some students rather pale. On the final flight, a stall demonstration was given. The pilot took the aircraft beyond its Vmin limit at which point the stick shaker activated, shortly followed by the stick pusher, which transformed the flight into an intense roller-coaster making the aircraft plunge sharply with loose objects suddenly floating in the cabin.
The whole experience was very enriching as I was given a quality in situ demonstration of the theoretical knowledge acquired in my university modules a few months beforehand. It allowed me to appreciate the impact of the main performance parameters that characterise an aircraft for different flight phases. Most interestingly, analysing how these are coupled with each other (e.g. stability and manoeuvrability) helped me evaluate the importance of certain necessary trade-offs in the design of an aircraft. This has inspired me to select a Design Search and Optimisation (DSO) module in my 4th year which covers the modern techniques used for estimating these key trade-offs.