In my previous post, The Boeing Scenario Debunked, I demonstrated the NTSB theory of the TWA 841 upset. The NTSB theory, however, does not match the physical evidence (the damaged airplane, debris field, FDR data) or the testimony of the crew. In the video below I offer an alternative theory that matches all of the evidence.
The most compelling part of this video involves a yaw damper system test. There are two yaw dampers on the 727. The yaw dampers limit rudder travel by reducing the hydraulic pressure available to the rudders from 3,000 psi to 800 psi. When the yaw damper system moves the rudder, the rudder pedals in the cockpit do not move. So the pilot has no idea that the yaw damper is doing anything at all. If the yaw damper was acting up and sending discrepant signals to the rudder, the only indication would be yawing of the airplane. As it happens, Hoot described seeing the nose yawing right and pausing several times before there was a significant yaw to the right which resulted in the plane rolling over. The yaw test video captures a sequence of yaw damper controlled rudder movements that closely match Hoot’s testimony as well as the FDR heading trace.
There is plenty of evidence to suggest that the slat had nothing to do with the upset but was instead lost during the recovery. Additionally, there are a number of incidents on record involving yaw damper system malfunction. See the post So what really happened.
Thanks again to the folks at Hallmark College who made this video possible.
Hoot gave me the information that you are writing about his high-altitude upset many years ago. I would like to read it when you finish. I understand you are still flying for American Airlines; do you remember an American Airlines check airman, Chuck Sisto, and his famous incident in a DC-4 one night near El Paso? Poor Sisto. After he got his pilot license back, he ended up as my co-pilot in the Middle East flying Muslim pilgrims from throughout the Middle East to the holy cities of Mecca and Medina. We even had a revolution thrown in, the one started by the CIA in 1953. We were in Abadan, Iran, the morning it started. Exciting! I flew for various airlines due to frequent furloughs, including Japan Airlines, and before that, a Navy Patrol Plane Commander. Hoot and I have known each other for years.
This incident reminds me of the NWA 747 incident with a hardover lower rudder. The airplane landed safely in Anchorage.