A comment[0] by ehnus[1] from last time this was submitted[2] said:
> My favorite section is emergency procedures which contains gems like this:
> "If both the A and B hydraulic systems fail as indicated by illumination of the A HYD and B HYD warning lights and confirmed by loss of A and B hydraulic pressure and deteriorating control effectiveness:
In a similar vein, page 3-135[0] describes what to do when e.g. under missile fire ("the pilot is authorized to use the tactical limits listed...to exit the hostile area by the most expeditious means... Subsequent reentry into situations which rely on use of these limits is NOT authorized.") on the same page as the procedure for defogging the cockpit.
Nuclear propulsion manuals for the U.S. navy have similar wordings.
>By order of the commanding officer [actually a highranking person on carriers, compared to little ships where COs can be realtively junior and low ranking], this reactor limit may be ignored during tactical situations.
Legend has it that every CO (3, i think i heard) to invoke "when tactical" exceptions have been fired in the following review. The only thing worse than crashing a billion dollar boat is damaging the publics trust in naval nuclear power : )
I'm remembering back 40 years here. I worked in the engine room of a nuclear powered cruiser. We had a switch called something like "battle bypass" that would bypass all the auto scram functions. The military calls a shutdown scram while the commercial industry calls it trip. We had a captain rank captain and I believe all nuclear powered vessels had one.
When’s the last time a large US navy vessel was in a situation where exceeding limits was justifiable due to tactical needs? I’d probably wager that WW2 was the last time.
To be fair, on the same page also there is the “taxi slowly if broken tank” failure mode, because it “can be ingested by an inlet”.
For those who don’t have the picture in mind, the first DC-3’s fuel valve was next to the air inlet. One day the operator didn’t watch the refill (They didn’t have autostop valves at the time), the fuel overflowed into the inlet, which certainly mixed it studiously with the air and pulverized the whole into the cabin. Man, aviation was wild at its beginnings.
I like to picture a little checkbox next to this, so that you can put a checkmark in that box as your hurtle through the air, then dig out the "parachute operating procedure" checklist and start it from the top.
Imagine letting the nose fully roll over and having to time the ejection at max inertia... or you are doing a Dr. Strangeglove meets True Lies. So delightful.
Depends on whether your parachute is integral to the seat or you’re wearing a pack. If the chute is in the seat, I would highly recommend staying harnessed to it.
If you enjoy such gems, check out the procedures for C130 transport aircraft. An old colleague used to be a load master on them (before going into tech), and said the action required for a situation where your load is jammed on exit and you can’t cut the chutes deployed to extract the load from the cargo hold is “prepare for crash landing”.
I just checked a modern copy I have lying around and couldn't find that particular phrasing. However there are lots of other gems such as "a malfunction of the extraction system that causes cargo to move can be extremely hazardous."
Here is a video of the crash from a dashcam. This is probably the most detailed view of the stages of a plane crash I've ever seen.
https://www.youtube.com/watch?v=dLAvN4IUzoI
"Intentional spins are prohibited. The following technique is suggested if an inadvertent spin occurs; however, ejection may be the best course of action because spin recovery has not been demonstrated and is considered extremely unlikely."
Reminds me of my favorite line in the US Antarctic Program Field manual:
18.1i Crossing Crevasses
...
If a snowmobile or sled starts to break through a snowbridge, experience and circumstances will dictate whether to brake and attempt to hold the fall, or continue driving forward in hopes of getting across before a catastrophic collapse of the snowbridge. In either case, a change of underwear is recommended.
Must be nice to have that luxury. The same emergency in the AH-1Z basically says "good luck." Granted, a hydraulic failure of two redundant and independent systems is astronomically unlikely (and the outcome will almost certainly be fatal).
“The crew contacted United maintenance personnel via radio, but were told that, as a total loss of hydraulics on the DC-10 was considered "virtually impossible", there were no established procedures for such an event.”
Fascinating/harrowing stuff: Despite these losses, the crew was able to attain and then maintain limited control by using the throttles to adjust thrust to the remaining wing-mounted engines. By using each engine independently, the crew made rough steering adjustments, and by using the engines together they were able to roughly adjust altitude.
With no control surfaces, and using the engine thrust they attempted a landing - of the 296 people on board, 111 died.
Cases like that one are the reason that passenger aircraft won't be fully automated any time soon. Autopilots are unable to cope with unexpected system failures.
Because it is a helicopter? Ejection seats have been done for those. Explosive bolts release the blades, and then everything proceeds as normal. Here is one such helicopter:
That proves my point even more if the Cobra is even older. I imagine it would be extremely expensive to add an ejection system to a helicopter that wasn’t initially designed for it.
Laughter is provoked by a discontinuation of what your brain expects.
If you saw a dog walking a man on all fours, you would most likely laugh, because of the unexpectedness.
In this case, the unexpected terseness causes laughter. You don't expect what follows to just be "Eject". In a technical context like a manual, you expect what follows to be a detailed list of steps and instructions. When this expectation is shattered, you laugh.
Speaking of humour, I can't tell what I find funnier: the fact that someone didn't see how these checklist items could possibly be construed as humorous, or your clinically precise explanation of the concept of humour itself, complete with a mechanistic explanation and example. Together, they're a beautiful example of the tone of HN.
Everyone says they're funny because they're unexpected, but simple direction and plain language is exactly what I'd expect from an aviation checklist, so I have no idea.
It's not just they're unexpected. They're both expected and unexpected. You also expect a manual to have details. It's the sudden ending that is both fitting and not fitting that creates the humour shock.
Right, you have no control over the lift surfaces in this scenario. This would be the equivalent of your steering wheel suddenly not turning the wheels.
the SR-71 , at that point in failure, would still have the opportunity to 'hit the brakes' like you would in your car.
Both vehicles can still veer wildly out of control even under deceleration, sometimes being exaggerated by the event -- so the plane manual recommends ejection rather than other remediating maneuvers because it's understood that further maneuvers may put the plane into such an attitude that ejection is impossible or futile.
So, that said, the SR-71 can still hit the brakes at the point by which their primary control surfaces fail; it's probably just a mighty bad idea to try to do so. There's a few instances in a car that might be a bad idea, too.
Imagine the steering wheel falls off in heavy moderate speed traffic -- in many cases it'd be safer to let the car drift across the road crowning and slow itself on roadside barriers than it would be to slam the brakes and take the full force of the traffic behind you colliding with your vehicle.
> My favorite section is emergency procedures which contains gems like this:
> "If both the A and B hydraulic systems fail as indicated by illumination of the A HYD and B HYD warning lights and confirmed by loss of A and B hydraulic pressure and deteriorating control effectiveness:
> 1. Eject"
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[0] https://news.ycombinator.com/item?id=1338777
[1] https://news.ycombinator.com/user?id=ehnus
[2] https://news.ycombinator.com/item?id=1338504