Ed Dartford
Well-Known Member
My son the 737 driver was home for a visit tells me some info that has been circulating in the pilot community.
US pilots have had better success dealing with the runaway trim issue. Many US pilots, including my son, formerly flew CRJ planes. The CRJ has automatic protection against runaway trim, (unlike the 737) and pilot training covers this. Perhaps that's why they didn't crash.
In the 727 with runaway nose down trim creates aerodynamic forces on the elevator that make manual trim adjustment to correct the problem so heavy that both pilots must haul on the wheel. We don't know, but It is susp[ected that the 737 may have the same problem. Runaway nose down trim is probably less frequent in the 727 because it doesn't have rogue software causing it.
It is possible to relieve the aerodynamic force by pushing the yoke forward (counterintuitive) and that will allow trim adjustment.
US pilots have had better success dealing with the runaway trim issue. Many US pilots, including my son, formerly flew CRJ planes. The CRJ has automatic protection against runaway trim, (unlike the 737) and pilot training covers this. Perhaps that's why they didn't crash.
In the 727 with runaway nose down trim creates aerodynamic forces on the elevator that make manual trim adjustment to correct the problem so heavy that both pilots must haul on the wheel. We don't know, but It is susp[ected that the 737 may have the same problem. Runaway nose down trim is probably less frequent in the 727 because it doesn't have rogue software causing it.
It is possible to relieve the aerodynamic force by pushing the yoke forward (counterintuitive) and that will allow trim adjustment.
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