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[Gabriel]

During those high-workload and at the same time eyes-out-of-the-window appealing approaches, when the PF called "flaps 30" and you were the PM. Did you just move the handle or checked and confirmed the actual position of the flaps as shown by the flaps position indicator? And when you did the landing checklist, did you just recite the checklist by memory or actually visually and manually confirmed the status of each system before responding the challenge?...

[Gabriel]

Very nice animation of the events, a lot of information was extracted from the little data that is available.

https://www.youtube.com/watch?v=Ppo73zeAvDo

[Gabriel]

Evan, all this discussion started with this.

3WE: When the A-330 crashed in New York back in 2001, after the tail broke off...
Gabe: A300. And the difference is not minor. This accident would likely not have happened in an A330.
Evan: What makes you say that?
Gabe: A300 small pedal force and displacement required to effect full rudder deflection vs rudder-ratio approach in the A330 which requires full pedal force and deflection to effect full rudder deflection, and the influence of that difference in PIO

Are you ok with that? Any objection? (other than you don't agree with the likelihood of this accident not happening in the A330, which I addressed in my previous comment)

Did I say, at any point, that the pilot used rudder correctly? No. Because I don't think he did.
The pilot was incorrectly trained and was known for using the pilot aggressively. The way he used rudder was undoubtedly a cause of this accident.
This accident...

[Gabriel]

Ok. I don't. Increased forces and displacement required for a given control input are a known deterrent top PIO. Not that it is impossible, but it becomes more obvious and, especially, more bodily physically challenging. Remember that work = force * distance. So 3 times the force * 3 times the distance requires about 10 times the amount of work. Now repeat that work 10 times. It may even become exhausting to the point that it is really hard to do, and to do fast, which was required for this to happen....

[Gabriel]

Ok, Evan. You win. This accident would have also happened had the rudder pedals required 10 inch of travel and 50 pounds to apply max deflection. The fact that a minimum rudder displacement with a additional minimum force of top what is required to barely start moving the rudder is enough to effect full rudder input has nothing to do either with this accident or with the propensity of PIO.

[Gabriel]

Right, but you are not going to reach max overswing using only partial rudder. That is why this accident was unlikely to happen in an A330 because with its rudder pedals design, it would have made a full rudder PIO, requiring much more pedal deflection and force, physically much more difficult to accomplish, and hence much less likely. PIO. I said PIO. I didn't say single rudder input.



What? So do you think that the pilot was intentionally applying full opposite rudder at the point of max overswing, because he didn't understand rudders? Do you understand PIO?
It doesn't need yaw-roll coupling. You have PIO just in pitch. You have PIO just in roll. And this PIO was mostly yaw with minimum roll. Like the PIO that happens in cars.

Define "as needed" in "Input rudder as needed"....

[Gabriel]

Statue of limitations? Too late to prosecute him?...

[Gabriel]

All these airplanes need a very powerful rudder to control the critical engine failure with max thrust in the other engine at Vmcg which necessarily needs to be lower (by a small margin) than the minimum possible V1 (imagine a very lightweight take-off from a very short runway). At the same time, at the structural maneuver speed Va they need to withstand a sudden maximum rudder deflection to the point of max overswing and a sodden rudder centering from there. Those two requirement are kind of incompatible so the solution is to make said rudder deflection variable, so you get the real max max during take-off but the max travel reduces as speed increases.

In the A300, the limiting is done in the pedals themselves maintaining the pedal-to-rudder displacement ratio (called just rudder ratio) constant, which means that at higher speed (but still below Va) you have much less rudder pedal travel available from neutral to the "local" max deflection. Less deflection to reach...

[Gabriel]

A300. And the difference is not minor. This accident would likely not have happened in an A330.


Well, the problem is that apparently (and yes this is a stretch) he did not use rudder because to control yaw, but he thought that wake turbulence could flip the plane so he had to use upset recovery procedures and he attempted to use rudder to control roll rather than yaw (at least initially). Which goes back to......

[Gabriel]

This video recording act should be punishable with 20 years behind bars. It totally ruined what would have been a beautiful piece of art had they just kept the camera fixed with neutral zoom (no tele, no wide)....

[Gabriel]

Vertical speed indicator: 1250 fpm
Airspeed indicator: 220 kts
Flaps position indicator: 0
Flaps lever position: 0
Landing checklist: Not performed.
GPWS: "Five hundred. Too low - flaps. Terrain terrain. Sink rate. Woop Woop pull up"
PM: "500 ft, stable"
PF: "Check, continue"

Balme it on the visual instrument pattern circling extremely tight and extremely low approach with both pilots focusing out of the window and performing extreme banks with extreme Gs and extreme stall-speed-increase factors....

[Gabriel]

That who knows, knows. That who doesn't, is the boss.

[Gabriel]

I agree, and that was my point all the time (well, a good part of the time anyway). It is not the visual approach per se, but they way they flew it.



There is a reason why Yeti is blacklisted from flying in Europe, and I believe it is not IOSA certified either....

[Gabriel]

Interesting. I am not as much wrong as I am old. 1.7NM was the protected area for category C. The radii were revised in 2013 and now it is 2.7 for category 3. I was not aware.
Good call by the FAA. Another change is that now the radius depends on the MDA. Good call because at higher density altitudes the TAS increases for the same IAS, and so does the turn radius for a given bank angle.



What? No. A circling approach is an instrument approach (IFR) which, like almost all instrument approaches (ILS, LOC, VOR, GPS-based ones...), at some point transitions to visual when you get the runway in sight. In all instrument approaches, including circle-to-land, weather can be VMC or IMC, but rules are IFR. A pilot that is not instrument rated cannot fly a circle-to-land approach, in the same way that they cannot fly an ILS approach.

A visual approach is, well, visual. VFR rules apply and weather conditions MUST be VMC. That doesn't mean that you cannot...

[Gabriel]

I will try to explain it, keep in mind that I am not instrument rated and I may not get everything right. I will make up an example. But let's start with some definitions (by me, so again, maybe not perfect).

In a precision approach, like ILS, you have a decision altitude (DA) [1] which is the altitude by which you must initiate a go around if you don't have the runway environment in sight [2]. If you imitate the go-around at the DA, you WILL bust the DA because the plane cannot transition from descending to climbing instantly, and that's ok, the DA takes that into account.

In a non-precision approach (with or without vertical guidance), there is a minimum descent altitude (MDA) and a missing approach point (MAP). The MDA is how much you can descend without the runway in sight. You don't need to hold a vertical profile in a non-precision approach. You can descend to the MDA as quickly as you want after you crossed the previous altitude...

[Gabriel]

Form an expert in flying ATRs. It is a youtube channel that I follow and I was expecting his video on this accident.
(Note, I am not posting this with any particular agenda or to support or rebute any point, it is just interesting)

https://www.youtube.com/watch?v=wIlO-TBDyaw

[Gabriel]

In a circling approach the published minimum altitude is not the MDA, because a circling approach doesn't have an MDA.
A circling approach (formally called circle-to-land approach) is an instrument approach procedure to be flown in IMC.
This accident happened in a totally VFR condition, it was a visual approach, remember? There is no MDA, no DH, no published minimum altitude.
Finally, circling approach published minimum latitudes can be as low as 400ft, and believe me, you don't want to be in an A350 doing a circling approach at the published minimum because it would mean it would fly an ILS to the opposite runway, gather visual contact with the runway at some 400ft and from there turning some 30 degrees right, the 30 degrees left to enter the downwind, then turn base, then turn final hopefully a couple of miles out (by the way, during all this time you would be slowing down, extending flaps, extending gear, slow down more, more flaps, arming speedbrakes, arming autobrakes,...