Stussi613

I think you're right.

I'm pretty sure I remember reading in Captain Doug's book that if a pilot is on rest duty in the cockpit the flying pilot must be on 100% O2 while he is in charge of the aircraft. I believe this is the same if only one pilot is in the flight deck, but maybe Santander can confirm.

Lost In Saigon

Yes, when an aircraft drops 30,000' and is is TOTALLY out of control going inverted, there will be stronger G-forces.

That is not what happened to Air Canada. Air Canada had a minor altitude excursion of -400' and +400. BIG difference here.

Santander

Correct, as the plane was not in equilibrium there would have been G forces felt. -0.5g to +2g is a lot, so it's not surprising those people without a seatbelt were sent crashing back to their seats after they went "airborne" (likely for a split second). It's safe to assume the pitch did not stay constant during those 5 seconds.

So um... pilots aren't allowed to take a break?

fin 645

The full paragraph from the report is as follows:

During the pitch excursion, the aircraft pitch changed from the cruise attitude of 2 degrees nose up, to 6 degrees nose down followed by a return to 2 degrees nose up. The vertical acceleration forces (g) went to −0.5 g to +2.0 g in 5 seconds. Computed airspeed increased 7 knots then decreased 14 knots before recovering to cruise speed with the aircraft's altitude decreasing to 34 600 feet increasing to 35 400 feet and finally recovering to 35 000 feet

It says elsewhere that the entire incident lasted 45 seconds.

I also found it interesting that the report notes that no J passengers were injured (all belted up) while it seems some of the Y passengers were lying across 3 seats (low load in Y), in which circumstance it is hard to use the seat belt (I know, I did it a couple of weeks ago).

Also in these incidents, passengers use words like "plunge" and plummet", when in fact in this case, the drop was 400 feet. The same happened in the QF 330 incident off WA last year - many injuries due to a sudden drop, similarly described, but in once again comparatively small. I guess that proves even more the need to be buckled up.

RCyyz

+/- 400 feet is clearly not a plunge nor a plummet, but I would think that -0.5g to +2.0 g feels like a plunge and a plummet!

tcook052

Then we can argue terms as 5 seconds to me isn't "momentary", which is a fleeting moment or split second.

Regardless the event lasted long enough to require 14 passengers and one FA to be seen for their injuries.

Lost In Saigon

No, it was split second event. It only took a split second for the passengers to hit the ceiling and fall back down. The event was basically over once they hit the floor again.

tcook052

Okay, yeah, the actual passenger movements was a split second while the incident was a little longer.

What has lasted much longer than the event is the coverage around the world in the online media with everyone from The Mirror to NYT, WSJ, Daily Mail and The Australian all running articles.

rehoult

While it may seem hard to believe to those not trained in it, G forces are not felt in a dropping plane for very long. No different from the fact that G forces in a car are only felt momentarily; once you're at speed (i.e. done accelerating), you don't feel it anymore.

Take a look at the AF447 transcript (https://en.wikipedia.org/wiki/Air_Fr..._data_recorder). These guys were dropping like a rock for nearly 4.5 minutes, and 2 minutes into it they were still debating if they were descending or ascending. You'll also note they call the Captain from the rest area and he comes down to the cockpit without difficulty, because once at terminal velocity they couldn't feel any G forces anymore.

To those concerned about leaving one pilot alone in case something happens to him/her: it takes under a minute to get into the cockpit in an emergency like that. Given that you're starting at 38,000ft, that leaves lots of time for recovery once inside the cockpit.

RCyyz

I just read the TSB report and I have to say, this one sounds like just plain old pilot error.

I acknowledge the difficultly / near impossibility of identifying an oncoming plane at night, but it's pretty clear that standard procedures designed to, in large part, avoid exactly this kind of situation were pretty much ignored.

It's a shame that people were injured when instead simply following established procedures might have avoided the incident.

RCyyz

Had to smile at this one. Basic physics! There's a difference between speed and acceleration. As rehoult posts, once acceleration hits 0 you don't feel it but that's because there's nothing to feel.

TheOnlyWayTo Fly

Hopefully someone here will produce all the salient facts rather than us having to rely on the media reports which showed the Pilots Association rep calmly mentioning that the avoidance system was not activated... I'm sure that there's much more to this story but so far I am perplexed at how little accountability and concern is being shown by the pilots assoc and AC regarding a situation that produced several injuries. Also, can anyone shed light on a) why a 6hr overnight flight would be particularly susceptible to pilot fatigue (when ur on the night shift in any job, you prepare and sleep that day dont you?) and b) the regs apparently allow a 40min nap in the cockpit but this pilot was allowed to sleep for 75mins which contributed to sleep enertia when he woke up? Not taking sides here whatsoever, just trying to rationalize things in my own mind.

mhodge

Read again what I wrote before pressing a reply button. Whatever they are allowed let them do it (take a break or use the restroom). But is the captain allowed to spent 40mins outside of his cabin chatting with a FA? I witnessed that first hand 2 months ago on a MEX-YYZ flight and they weren't discussing any issues related to the flight or so (no, I could not avoid listening to their conversation being seated in the 2nd row).

mhodge

Momentary may be the key word but, for example, the pilot in this case
http://en.wikipedia.org/wiki/Aeroflot_Flight_593
certainly did not get to the cabin on time. Obviously, in a free fall no forces are felt but that does not last long. As you try to level the plane out the time without a possible movement can last pretty long (I'm not talking about small disturbances due to the turbulence).

rehoult

Most of the Europe flights are 7+ hours, with this one in particular being 8 hours (ignoring prep time).

People who regularly work night shift effectively modify their lives (and their families' lives) to allow sleep during the day. Pilots have it particularly rough because unlike most other night-time jobs, they don't fly every night, so their bodies can't get adjusted to it. Instead they go from working overnight to Europe, to flying the day flight back (normally starting before 5am in North America), to flying a there-and-back to YVR two days later. The end result is that their bodies (and their families) can never get into a regular schedule that supports productive sleep habits. Hence, tired pilots.

There are laws that say you can't speed, so why does it happen?

The answer is simple: they are just rules, people can choose to ignore them. In this case the Captain knowing ignored not just the time limit, but also the SD briefing. You can bet he'll get an earful about it.