Originally Posted by Checkboard
The more "well known" Air Florida flight 90, a 737 which crashed into the Potomac river was more an issue of incorrectly set engine thrust (due icing of the P2T2 engine sensors) than ice on the wing.
The accident you cite was
not due to incorrectly set engine thrust. I have little doubt that the PT2 probes were blocked; I also believe that this resulted in erroneous EPR readings in the cockpit. The flight crew set the takeoff EPR at the computed 2.04 setting and that, because of the PT2 error, only achieved approximately 75 percent of the available takeoff power. Undoubtedly, this increased the ground roll. But the point that goes unmentioned in this discussion is that the airplane was certificated to be able to accelerate to decision speed, or V1, (albeit with both engines operating), experience the complete failure of one engine, and be able to continue the takeoff safely. Again, I acknowledge that the takeoff roll would have been longer; however, once the computed V1 speed was reached, the accident airplane had 50 percent more power than was required for certification. I submit that regardless of how much time or distance was involved in getting the airplane to the V1 speed, once there, if it had one engine operating at full power, it should have flown as it was certificated to do. It had 2 engines operating at 75 percent power. Not only did this provide 50 percent more power than necessary, it was provided in a symmetrical manner. Yet the airplane failed to fly. Why would that be?
The point is that the accident was actually caused by something other than a low power setting. However, because this is a 30-year old accident, there may be little interest in learning more about it - so I'll refrain until I know that there might be some interest. If you
are interested in knowing what this additional information would be, I’d be glad to provide you with some facts that, while they were available at the time, were not given the attention they deserved. As a result, there was a large amount of misinformation being disseminated and the folks who took the vast majority of the “blame” were no longer around to offer their defense.
And ... just for accuracy in regulatory requirements ... with regard to operations in ice or snow, and the YouTube clip that lead off this thread ... the rules say the following...
No pilot may take off an airplane that has frost, ice, or snow adhering to any propeller, windshield, stabilizing or control surface; to a powerplant installation; or to an airspeed, altimeter, rate of climb, or flight attitude instrument system or wing, except that takeoffs may be made with frost under the wing in the area of the fuel tanks if authorized by the FAA.
One should note the operative wording in the requirement ...
adhering to ...