BRDubois,
“I have not questioned the root cause, and see no call to. I question things in the CAB and ALPA reports only when they make no sense. All I'm working on is the impact and breakup sequence. I don't question that the CAB fulfilled their basic role of explaining the incident and helping to correct the system that led to it. I accept that an unsafetied fitting was the cause.”
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Now.
“Was the cause....” you are very kind. The CAB calls it a “probable cause”. You take it beyond even their own work, into “was the cause...”
I venture to say no one here on thread can post or describe the actual construction of the slack absorber that required a safety wire, presumably two, one for each of opposite threaded stainless connectors.
I can’t get an answer as to a proposed opinion that a safety wire, by definition, is not primary structure, but a fail safe item that only locks thread travel after a complete failure of the primary locking system.
If an Electra depended only on a safety wire to lock the cable threaded connector, I wouldn't go near it, certainly not to fly in it.....
Further, there appears to be no science regarding the recovered boost unit and its seizure. I have proposed that the boost unit, and/or its power arm could easily have jammed, or froze, due to chaotic control inputs due manual manipulation of the cockpit yokes.
Also sloppy is this: The “damaged by fire” statement is represented as conclusion, but although likely correct, how do we know damage did not occur prior to impact? We don’t and the possibility is not eliminated. The inference is that such prior damage is not possible.
Do we know if in manual mode, the ailerons have an independent and isolated cable loop that is not involved with the hydraulics? If not, in manual the ailerons are driven via the (unpowered) hydraulic system that makes up the boost loop?
Boost quadrant translates flight station inputs through the boost control arm, its cylinder, and valves? Part direct cable, then manually “pumped” through the boost, into the rods, arms, and bearings that comprise the final drive?
Any A/P folks out there? Anyone with a more explicit schematic of the flight control rigging?
Craig. Here, “...Concours77 just shot down my scenario of a forward pitchover at the final site, by noticing the post in the ditch. ...”
No, I didn’t. The aircraft almost certainly “pitch poled” over the ditch. I wrote that earlier, and still hold it as very likely. I also believe the tail section and fuselage remained attached, though loosely, and they pitch poled simultaneously, though not in any familiar orientation one with the other. There is no chance the tail was inverted whilst sliding, that is ludicrous.
The structures that kept tail to wing were undoubtedly the keel beams, as strong or stronger than the main and aft wing spars.
The wooden fence post in no way compromises the theory you Espouse. It shoots down only that the wings were full span, and the leading edge gouged the ditch out on impact. The ditch and the wreckage are in proximity due only to coincidence.
Last edited by Concours77; 31st Dec 2017 at 22:22.