Sit in the many, many rows where both you and they can’t recline and the problem is solved.
Reclining (or not) is a net zero
It’s net zero collectively. It’s not net zero individually.
Individually it’s a net positive
;o)
From the above link, I followed an imbedded link to an article about the 2018 fatal crash of another Thunderbird F-16. That article reported that the pilot experienced 8.56Gs before losing consciousness. I can understand someone blacking out from over 8 Gs. My question is: Is that an unusually high load? Are Thunderbird and Blue Angel pilots routinely pulling over 8Gs?
Bonus question: I know the Blue Angels don’t wear G-suits. Do the Thunderbirds?
Huh. I did not know that, and I never noticed. From AI overview:
No, the Blue Angels do not wear G-suits because they would interfere with their ability to perform their precise maneuvers and fly in tight formation. Instead, the pilots use a combination of elite physical fitness, specialized training to handle high-G forces, and muscle control techniques like “Hook breathing” to manage the effects of G-forces.
Also from AI:
Unlike the “Blue Angels” during the airshows, the “Thunderbirds” pilots do employ “G”-suits.
The F-16 is famously capable of pulling 9G. Sustained for a decent timeframe if you start fast.
General Dynamics used to make a 9G commemorative lapel pin we got awarded as a right of psssage during F-16 school. I still have mine. 9Gs fucking suck as a peak experience. But it is a peak experience.
Whether Thunderbirds or Blue Angels, I doubt that the diamond formation ever plans on that much. More like 5G tops. The solos do some hairpin turns that might well hit 9 briefly.
Somebody doing a last-ditch ground avoidance maneuver would pull all the jet can do. Which will be 9 if they’re fast enough. So >~300 knots.
I can’t speak to G-suits on the demo teams either in my era or now. The suits of that era increase your ultimate tolerance by 2-3G. Their real value is in reducing the fatigue of sustained lesser G loads.
I can’t even imagine 9 G’s. My vision starts narrowing at 3.
Preliminary report is at:
https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/201981/pdf
Note:
A few seconds later, the controller instructed the pilot to continue the turn to a 120° heading, but by this time the airplane had already descended to about 3,100 ft. With no response from the pilot, the controller transmitted, “November zero hotel golf, climbing?” Heavy breathing and “grunting” sounds could then be heard, and by that time the airplane had descended to about 1,500 ft and reached an airspeed of about 270 kts. The last ADS-B target was recorded a few seconds later, about 200 ft west and 350 ft above the impact location.
This sounds like it could this be a medical emergency: heart attack, stroke, pulmonary embolism, or aortic dissection, etc.
Another explanation might be some sort of pitch control jam or trim runaway where the pilot is pulling on the yoke for all they’re worth trying to arrest the pitchover. But no such luck. Crunch!
270KIAS is in the same ballpark as Vne. I don’t have the exact value to hand, but it’s near there one way or the other. The only thing that prevented them from getting a lot faster than that was hitting the ground first.
I note from the report they were IMC during the turn. Which opens the possibility of a spatial disorientation or instrument malfunction and by the time they dove out the bottom of the clouds they were screwed.
Evidently much of the cargo wasn’t well secured. The single heaviest item was, but not the rest. Perhaps spatial D leads to a steep descent, leads to cargo shift forward leads to both the pilot & seat getting whacked and maybe jammed forward against the yoke, plus loss of pitch authority due to out of range CG. Now the pilot is pulling like mad and getting no results. Crunch!
Other than maybe finding a FOD jam in the empennage or whether there were major engine or prop malfunctions, I rather doubt NTSB or us are going to learn much more about this accident.
Having done a charity cargo run in a small twin I’ll suggest that there is no need to secure the load. The plane is going to be maxed out dimensionally like a Tetris game. CG is a different matter. The pilot would need to know the total weight and the rough weight of each piece to load it properly.
Since the plane got as far as it did I would suggest it was within flyable CG. That leaves a medical issue or a runaway trim or similar mechanical issue. Trying to pull the yoke back in an emergency may involve grabbing the mic button without even trying. That would account for the noises. If the mic was pressed deliberately during an emergency then I’d expect a May Day.
An accident cause which is somewhat unusual:
Plane crashed after 3D-printed part collapsed
Examination of the aircraft revealed that a plastic air induction elbow attached to the fuel
controller had collapsed (Figure 3), severely restricting the induction airflow to the engine,
causing the loss of power.The air induction elbow was a 3D-printed plastic component that had been installed during
the modification to the fuel system. A forward-facing air filter had been clamped to the
forward end of the elbow, but this had detached and was found loose in the lower engine
cowling.
You missed my point. I agree it was in a flyable CG when they took off and got to near where the problem started.
Then a possibility is that they started a dive for some reason, perhaps spatial disorientation. Then something shifted and now they were not in a flyable CG any more. Or the pilot was pinned forward with belly to yoke after something heavy ended up against the back of his seat. Or …
I’m not suggesting this did happen. I’m suggesting it could happen.
For sure if they’ve managed to cube out the space with cargo wedged in there tightly there’s not too much room for shifting. But a 20 or 30 degree descent can move stuff you might not have thought was moveable. Throw in some turbulence as they were passing that frontal roll and …
For darn sure something rather abrupt and totally unexpected dramatically altered the situation over the space of 30-ish seconds. The rest thereafter was just plummeting.
IIRC that was a big problem with AA191. Losing the engine was bad enough but, in theory, the plane could still climb out on the other engines.
But the final nail in the coffin was the flaps and slats retracted when the hydraulics were lost causing that wing to lose lift. Now they had no left engine and the right engine working hard pushing the plane to the left (yaw or roll or both but pushing left). When there was no lift on the left wing the plane rolled over and, so low to the ground, there was no chance to recover. And that is exactly what we saw happen.
Which leaves the question of why the default should be to retract the flaps/slats if hydraulic pressure is lost? Is it worse if the reverse is done (hydraulics lost and flaps/slats deploy)? Just can’t reasonably be designed to work that way? Something else?
A great question and out of my wheelhouse but there are smaller planes with automatic slats built into the leading edge. They’re spring loaded and extend when air speed is low and retract under air pressure.
IIRC, the Bf-109 had that.
I wasn’t trying to argue anything specific. Mostly trying to figure out the heavy breathing heard by the tower.
Different manufacturers took different approaches in different designs.
I would suggest you not think of it as a “default” behavior.
A better way to think of the slat design on a DC-10 is hydraulic pressure pushes them out into the extended position. And holds them out in the extended position. To retract them, hydraulic pressure is removed, and airloads plus perhaps springs pull them back in. This design leads to a low parts count, few moving parts, and light weight. All of which are generally virtues.
But also leads to them self-retracting in the event of certain hydraulic failures. I say “certain” because there’s a hydraulic fuse in the circuit which means if hydraulic pressure is lost system wide (by far the most common hydraulic failure scenario), the slats are held extended by trapped pressure in the lines downstream of the slat isolation fuse in each wing. But if a hydraulic line within the slat system is severed, then the trapped pressure escapes out the leak and the slats retract. There may be several separate fuses for different slat sections, or just one per wing.
I’m not expert on the DC-10 system, but that’s a thumbnail sketch of the DC9 / MD-80 leading edge slat system. Douglas and Boeing both don’t design subsystems from scratch with each new plane; they have a company standard way to approach these sorts of architecture decisions which evolves very slowly and only in response to changing tech or regulation or lessons learned from service. Those lessons might be maintenance hassles or they might be accidents or …
An alternative is to have each slat extend by hydraulic pressure then have some sort of mechanical latch to hold it there. Then on retraction, additional hydraulics have to unlatch all the latches and then push / pull the slats into the retract position. Where they again mechanically latch into place. Now you’re looking at 5x the parts count. And 5x the ways for things to go wrong. And the need to synchronize the latch movements with the application of extend / retract force. Lotta complexity and mechanical tolerances to deal with.
There’s always a tradeoff.
Is it just me or does anyone else get an OceanGate (private sub that imploded trying to tour the Titanic wreck) from this? I get they are completely different things. I guess it is the notion that a lot of serious engineering can be skipped cuz someone thinks they found a cheap way to do things.
It is a common complaint how expensive even the simplest parts for a plane can be due to regulations/testing but, while maybe that could be done better, there is a reason for it and we all benefit from it.