Regardless of the mistakes that were made, they took into account potential civilian casualties before attempting egress.
A heartfelt sentiment no doubt, but what may escape the gallery is that they didn't effect any control once dual hydraulic failure ensued. You see, the T-38 is hydraulic controls with no RAT. Even windmilling hydraulics are insufficient to effect control sufficient for attitude change of consequence. In this case, even that is moot since the connection to the drive was severed on both engines. In other words, the aircraft was effectively semi-ballistic with two good engines and no control surfaces.
They had no way to affect impact point control, beyond power inputs affecting pitching moments. Thence, the decision to delay ejection may seem altruistic to you, but was borne more out of suspension of disbelief (the deceased attempted to continue to fly even after the qualified IP had given up on it). To be clear, the IP demanded the ejection in spite of the deceased continued attempt at bartering with the aircraft for control, as they were about to go LV below the horizon. The deceased was simply not mentally prepared of getting out of that airplane that day, and he paid the ultimate price for it. Yes, the IP made procedural mistakes relating to the crew coordination items in the checklist. That was very much contributing to the deceased finding himself panicked or incapacitated, either way fatally unable to do the actions of arming the seat like he should have accomplished before takeoff. I'm not casting aspersions, just relating how they found themselves in the position they did.
The report doesn’t explain why the torsional loading on the left shaft was increased...what was the cause of that (since loss of that increased the loading on the right, which was already heavily loaded due to a generator short on the right and caused the right shaft to be finally overloaded which gearbox is said to have already been compromised due to wear).
The arming issues may have caused the death, but they did not cause the crash. Were it not for the failure of shaft on the left side, the (over)loading of which was either not explained or I missed, the accident chain would not have begun. Am I totally missing something? I did read it pretty quickly and may have.
No, you're not missing anything. You did it in 6.9 seconds flat. Cigar for you sir.
So let me fill some gaps in what you're looking at, as SGOTI who may or may not have flown the accident airplane a time... or a dozen.
First, people need to understand how the system works. These airframe mounted gearboxes are simple transmissions designed to take the high RPM input of the turbine and mate it with one generator and one hydraulic pump per gearbox, and obviously one gearbox per engine.
Torsional loads transients reach a peak as noted in the report. Remember, even though these torsion load mainly deal with the generator, the hydraulic pump relies on the same gearbox to turn. The aircraft *WAS (*important editorial on my part) designed to be able to handle the entire electrical load on one generator, and handle the entire hydraulic demands of the flight control surfaces on one hydraulic pump.
Here's the answer to your question, and that will never be in that report. This isn't 1955.... It's 2017. What changed? A lot.
In that time, we've made hundreds of changes to the electrical demands of the aircraft, on ever increasingly worn cabling and ever increasing losses that increase the overall demands on the system, which ultimately boils down to a
higher baseline torque load on both generators and therefore both gearboxes' drive shaft. That's my opinion, but what do I know.
What I do know is we haven't done **ck all to the voltage regulator, crossover relays, and most importantly...our craptastic airframe mounted gearboxes.
The gearboxes have also not gotten any younger, and as listed by the report, the gearbox on the right engine had 7 failures in the preceding year and a half. 7 failures. You know how that makes ME feel when I have to strap into the thing? You guys would cry bloody murder if your alternator belt snapped 7 times in 18 months. Imagine now if further,
your steering was dependent on that belt not snapping and not merely your alternator.
So, torsional loads. Understand that under the 2017 paradigm these shafts are running, as a baseline, at a much higher torque than they were intended for. Meaning, they're running closer to the shearing value as part of the normal course of business, something they would never accept in 1955. OK, so why does that matter if it's still
under the threshold you might ask. Well, that means that when the gearbox shifts (this happens in the 65-75% engine RPM band, moving the throttle in either direction by the way) the box shifts like a tranny, and the load spikes momentarily. So then, as these things are already running at a higher baseline, hello momentary overtorque city. In the case of this airplane, you're now relying on the sole remaining, already-documented multiple offender, POS gearbox
that they kept fielding. And amongst us friends we know that thing had zero, nada, zilch, kaput shot in hell of getting them home without failing almost immediately the second they shifted that right throttle through the shift range.
So to put it in blunt terms: If neither component has the BONA FIDE ability to handle the entire demand in the course of normal field conditions as defined today, it is not accurate to assert you actually have redundant components in earnest. This undercuts the notion of redundancy to the point where it demands an evaluation of the outright redesign of the component and a new performance threshold established.
...And this is the problem.
