BCR
Master Poster
- Joined
- Dec 6, 2008
- Messages
- 2,278
It is not impossible for the FDR to stop recording over 6 seconds away from the Pentagon with 1.5 DME recorded in the FDR. The FDR stores DME at a resolution of 0.25 NM, and the practical accuracy of DME where 77 was flying is at best 0.23 NM or worse. These errors alone allow 1.5 DME to be stored yet 77 is over 1.7 NM from DCA when 1.5 DME is stored. But I am only an experienced pilot heavy jet; and as an engineer I know modeling the errors in the DME from thwho flew left seat heavy jets in my twenties, Balsamo may never make it to the left seat e FDR allows 77 to be over 6 seconds away from the Pentagon and 1.5 DME is stored in the FDR. But a masters in engineering is all I have, maybe your p4t experts can model the DME errors and explain why I am wrong. They can’t. Why?
Now see, that is exactly what Rob tried to sell me two years ago. When I pointed out to him that one data point does not make a case, he went all cuckoo on me. Over and over I have presented solid analysis that indicate that the final DME value of 1.5 exhibits special cause features when compared to the entire DME data set. In other words, I focused on the thousand or so DME values that exhibit normal cause, and he wants to focus on the lone special cause point. Throw out the radar data because the DME value is 1.5 although modeling indicates it should be should be greater at that point in the flight path. Did AAL77 go supersonic for a short interval there at the end-of-flight?
I do not have to explain the special cause behind the final 1.5 DME value. I will leave that for the aeronautical guys to explore. I care about populations of data and determining what is normal for that population. If one guy wants to stand out from the crowd, then so be it. By the way, those two final RADES points are included in the GE model. However, just as another poster pointed out when I intentionally left in a similar radar return from the DCA set, it is not hard to figure out that they are not AAL77.
