Pilots familiar with "flying" six-axis motion Level D full flight simulators (FFS) will know how they lurch unnaturally when lateral forces are applied via the rudder or during rapid applications of roll. A common reaction is pilot-induced oscillation, writes David Learmount.
Sabena Flight Academy's development division (SFA-D) claimed to have devised a motion system control modifier called Lm² that makes an FFS "fly" like the real aeroplane and invited Flight International to try it out.
"Flying" a Boeing 737-300 FFS at SFA's base at Brussels Zaventem, I asked for a crosswind and was given 30kt (55km/h) from the right. Conditions were good night visual, I did not use the flight director or autothrottle, and for this first attempt the Lm² was not active. I managed the take-off adequately, but on approach I deliberately displaced the aircraft well to the left of the extended centreline for Brussels runway 25L so that recovering against the crosswind by about 1nm (1.85km) on short final would provide plenty of lateral lurches as I lined up the crabbing aircraft for landing. I kicked off drift at about the right time and tried to keep the lurching machine on the runway. It was a seriously inelegant attempt.
SFA kindly froze the system and put me back on the approach to do the same thing, but this time with the Lm² operating. It was a transformation. The simulator handled like the aircraft would. Its reactions to control inputs were predictable and natural. Just to prove the resulting safe landing was not a fluke, SFA suggested I try starting the approach to 25L and then do a late switch to 25R, but this time with crosswind from the left. It was a delight to do, and the landing was quite good. Leaving the runway entailed a left turn through about 130e_SDgr, and the tiller allowed me to keep the nosewheel perfectly on the centreline all the way without any swinging or over-correction.
Simulator flying could actually become fun for the first time, and much less sweaty.