A STUDY carried out for the US Navy by Calspan will provide clues to the effect of using full-flight hexapod simulators rather than in-flight training on pilots' ability to recover from in-flight upsets.

The USN is taking great interest in upset recovery training for its new weaponised P-8A maritime aircraft, a derivative of the Boeing 737-800. Given the aircraft's mission profile - low and fast over the ocean - the service is investigating how best to equip its pilots to handle upset conditions in an aircraft that has not been tested beyond the normal envelope.

Thirty navy pilots are taking part in the study - 10 in a "control" group, 10 who will be taught upset recovery in hexapod-based full-flight simulators and 10 who will receive the same training in Calspan's variable-stability Bombardier Learjet 25. The twin-engined business jet has been modified with a digital flight-control system that can emulate a variety of aircraft platforms and failure modes with respect to handling. The aircraft is tuned to handle like a large transport aircraft similar to the P-8A for the effort.

Calspan's director of flight training James Priest says the first two groups have completed the study. The control group received no initial training before being evaluated in the Learjet 25, and unannounced manoeuvres included a pitch runaway, asymmetric spoiler failure, rudder hard-over and a nose-low upset condition. After the initial testing, the pilots received 1h of normal flight activities and were tested again on the upset manoeuvres. The in-flight training group received an initial evaluation in the Learjet with the same anomalies as the control group, followed by 4h of ground training, then 1h of in-flight training in the Learjet focusing on alternative control strategies and a final retest of the manoeuvres.

The full-flight simulator group of 10 pilots will receive an in-flight evaluation in the Learjet 25 starting the first week of December, followed by ground training and an upset training session in a Sim Industries P-8A full-flight simulator with extended aerodynamic parameters. The final task will be 1h of flight testing for each in the Learjet to differentiate performance between the three groups.

Priest suspects the results will mirror a similar study the company undertook for cargo carrier FedEx Express. Because of the lack of g-force feedback, pilots will tend to over-control the aircraft in the simulator. "The g-force acts as a big filter on your control inputs," says Priest. "In the aircraft, when you start getting gs, you immediately stop pulling." But the other side of the coin was not ideal either, because pilots in the FedEx study tended to under-react in their control inputs during in-flight anomalies.

Source: Flight International