Reply #3: Tire/gear failure was 1st on my mind too .. [View All]

[DemoTex]

But NTSB vice-chairman Robert Sumwalt seems to have ruled those out.

US Air 5050 began the takeoff roll with fully deflected rudder trim. Without going into the sorry story of how it (the rudder trim) got that way, how it was missed during checklists, or why a brand-new first officer on his first-ever revenue flight was allowed to perform his first-ever takeoff with paying passengers on board on the proverbial dark and stormy night, suffice it to say that the captain (when he finally realized the f/o was drifting off the runway centerline and assumed control of the aircraft himself) was able to keep the 737-400 within the width of the runway. However, because he (the captain) did not "believe" in auto-brakes and because his decision to reject the takeoff was delayed, the jet ran off the end of runway 31.

A decision to reject a takeoff does not come easy. A rejected takeoff is fraught with peril. A high-speed reject (above V1) is done only as the lesser of other disastrous consequences (mainly, the perception that the aircraft cannot be safely flown). Perception is a highly subjective concept at 150 mph.

The arc does suggest that whatever the problem was, aircraft steering (rudder, nose-wheel steering, differential braking, etc) was minimally effective. If it was a flight control problem the DFDR (digital flight data recorder) will tell the tale .. and soon. Rudder trim alone would not have resulted in that much of an excursion from the runway centerline, unless there were other factors at work (including pilot incapacitation).

The USAir 5050 rudder-trim accident is a case study in error chain management. Or mismanagement as the case was that night in 1989.