Air Canada Accident in YHZ

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FICU
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Re: Air Canada Accident in YHZ

Post by FICU »

Illya Kuryakin wrote:
FICU wrote: ... engine thrust roll back, windshear, other major mechanical issue. Can't rule those out. Planting the jet 1100 feet short of the runway and 2600 feet short of the normal touch down point could be something other than CFIT.
If that was an issue, somebody would have made a comment by now. Keep looking for excuses though.
Illya
No excuses but I'm not ready to condem the pilots so fast. The TSB knows and we will in a few years.
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Re: Air Canada Accident in YHZ

Post by sportingrifle »

My first wish is that we could all play a little nicer and respectfully on this forum.

Disclaimer...I work for "Big Red." I am not going to speculate on the cause as they always seem way more complex than at first thought. My gut feeling is that there will be lotsa brown smelly stuff sticking to multiple entities when this report comes out.

Having said that, I have to agree with Rockie on this one - and I don't usually agree with Rockie! All non precision instrument approaches become either go arounds, or subsequent visual approaches. If you have the ceiling and visibility that is charted, you should hopefully see the actual runway when it comes time to decide which option to exercise. But for some reason, we allow and encourage the legal transition from an instrument procedure to a visual one in weather we otherwise wouldn't even consider flying visually in. If you see the faint glow from two approach lights you can legally continue, the unwritten/unspoken assumption being that on the aircraft's current stable trajectory all will be revealed momentarily. Most of the time it works but mainly by luck. Especially when you consider that once you are over the nice bright approach lights, all you can (hopefully) see are the dim runway edge lights. And the required visual reference to ensure you are somewhere near the approach lights and the required visual reference to descend precisely over a black hole in windshear, can be two very different things in reality. If the instrument approach terminates X miles from the runway at Y feet AGL, then they should be the ceiling and visibility limits to fly the approach. That way, when you break out, you should be able to see the actual runway you are trying to hit. Just my $0.02,
Cheers Sportingrifle.
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Re: Air Canada Accident in YHZ

Post by co-joe »

FICU wrote:
complexintentions wrote:Perhaps the ban does occasionally contribute to an a/c not being able to land where maybe some rockstar who's used to the local environment could land, but that's not really the best criteria for designing an approach IMO.
An example of the nonsense of the approach ban in one circumstance ...

Going into YYT the rvr was below the ban limit and Air Canada diverted to YDF. We were right behind them on vectors and had extra gas so ATC put us on an extended downwind and after a few minutes we did the approach once rvr was at the limit.

The funny thing... the approach lights and runway threshold lights with some centerline lights were completely visible in the clear night sky. The fog bank was well beyond the threshold and covered the rest of the airport. We did the approach to landing in clear skies and with visual reference to the runway. Air Canada had the same visual reference but had to divert because the rvr was too low and they didn't have the extra gas.

Now back to you regularly scheduled program...
Isn't that basically the definition of a localised phenomenon? Or do rvr a and b and/or tower reported vis have to be disagreeing for that to apply?
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Re: Air Canada Accident in YHZ

Post by HiFlyChick »

Wow - you guys have given me a lot to think about (and some of it has to do with how people need to at least be more civil on this forum - rudeness does NOT give your opinion more weight!)

That being said - I get where Rockie is coming from, but it seems to relate more to a non-precision approach (i.e. step-down method) - perhaps there should be clarification that for approaches without glideslope the pilots must see the runway environment as opposed to the approach lights. IF AC had had WAAS capabilities, then the visual reference to approach lights could be backed up by the glideslope of the LPV. I think that sometimes folks get in trouble at DH when they have a reasonable view of the lights (i.e. the required visual reference) and totally abandon the glideslope info provided by whatever nav aid in favour of ducking down based on staring at the ground lights.

And then there's the whole visibility discussion - vis can vary quite widely from one area within the fog bank to another (especially around Halifax). A reported vis of 1/2 mile from the tower position can indeed be totally different out at the end of 05 (they're something like 1.5 miles or more apart - can't give a precise measurement - too lazy to go get the plate and do the math, but 05 is now 10,000+ ft long and the tower is adjacent to the approach end of 32). Attempting an approach in any visibility should be safe, because in the end the onus is on the pilot to not continue if it isn't. To say that we should try and legislate out any sort of judgement is a flawed argument because pilots will always need to be able to elect to overshoot based on judgement - you can't always define every situation, and even the term "stabilised approach" is not something that can be totally nailed down. Is the approach stabilised if at a certain point there is shear that momentarily drifts me a dot below the approach? So how long is that "moment" allowed to be before the approach is no longer considered stabilised? 2 secs? 10 sec? 30 sec? And does not airplane speed also play into this (i.e. the slower you are going the longer it takes for you to get off the GP and the longer you have to make corrections)

Also, with regards to vis, the time of day will also play a factor - under the old rules when I could do an approach at 1200 RVR (no fancy FD in my little aircraft), I've made it in after dark on an ILS due to the brightness of the lights. I've also missed with the RVR at 1600 on a foggy day with the sun shining onto the fog bank.

There are so many different factors that affect whether or not an approach will be successful that the rules can't be so tight as to prevent certain airplanes/equipment and crews from even trying just because there are others that won't be able to make it, or worse yet, will continue into an unsafe situation.

<Let the flaming begin!>

Oh wait - forgot to say - saw the discussion on something fishy with the approach - it may be possible that windshear played a part. If I recall, during that brief period when they landed the gusts increased to something like 54 kts....

<OK - so NOW you can continue the flaming :) >
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Re: Air Canada Accident in YHZ

Post by Mach7 »

At the chance of being very unpopular, I feel the real culprit in this accident is the SCDA, (or CDA) approach.

This "elephant in the room", in my opinion is not as 'safe' an approach as a step down, (unless one is connected to a VNAV or has some sort of vertical guidance other than "dialing" in an estimated vertical speed).

The SCDA begins with a number of mental gymnastics to calculate the FAF crossing and rate of descent based on groundspeed, (easy for 05 Halifax as it is depicted on the chart, but some approaches are not so straight forward). You then must consider the changing aircraft ground speed in windy conditions and perform a missed approach at either the Decision Altitude or the MAP point WHICHEVER comes first.

As Pilots, were are programmed to see something of the Airport environment when we reach the DA, and many times the missed approach point has only been considered prior to the approach, but is (somewhat) ignored once we here the "100 above" call followed by "decide".

On an ILS you have a good idea where you will be when you get to minimums.....On a CDA, if you have NOT been doing the mathematical crosscheck inside the FAF and adjusting your VS accordingly (3 X dist + elev for 3 degree path)....or have NOT been concious of the missed approach point (DME), then it is a gamble what you are going to see when you get to your DA, but chances are you are not going to be right bang on profile.

On a step down, you get to MDA early and motor along until you get to the missed approach point...no math, no worry.

You also get a good taste of what the visibility is doing once level and are VERY aware of what you are supposed to see before you start down to the runway. If you see lights at 4 miles from the missed approach point, chances are its not the runway. Conversely if you start to see some of the airport environment at 1 or 2 miles back, well...you get the idea.

The point I am trying to make here is that you are waiting for one value to initiate a go-around on a step down procedure, the distance or point depicted on the approach plate to initiate a missed approach. If you pick up the runway environment prior to, then you have some time to decide if you are able to land safely off this approach. I usually wait until I identify the PAPIs (if available) and then start down on the two whites and two reds (and yes...there are PAPIs on runway 05)

I agree it may not be as 'stable' as the SCDA with respect to power and pitch changes for landing, but ask yourself how many well executed step downs have led to hull loss in the past 10 years, then look at the statistics on SCDA's.

Most Pilots are forced to do these SCDA's because it is the company policy, and consequently step downs approaches are frowned upon. The argument may be that it is not good to have full flap and gear down level at the MDA, but to do the SCDA you already had that same configuration prior to the FAF and that seemed to work pretty good (?).
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Re: Air Canada Accident in YHZ

Post by HiFlyChick »

Excellent point, Mach7 - I personally didn't see the problem with the step down vs the confusion of the SCDA, but since I only fly light twins I can't comment on the "dangers and difficulties" that are supposed to be intrinsic to a step-down on a large aircraft.

It's really only recently that TC mandated putting a SCDA approach into SOPs and I remember thinking at the time that SCDA may or may not have had a place 6 or 8 years ago, but WAAS has all but eliminated the need now. I never dreamt that a company the size of AC and flying the equipment they're flying would possibly have less capable equipment than what I am flying with in a Navajo!

Could someone who flies the big stuff comment on the difficulty of doing a step-down approach? Is it really as high risk as TC makes it out to be?
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rudder
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Re: Air Canada Accident in YHZ

Post by rudder »

HiFlyChick wrote:
Could someone who flies the big stuff comment on the difficulty of doing a step-down approach? Is it really as high risk as TC makes it out to be?
It is because the MAP and the VDP (visual descent point) are different for an aircraft with an approach GS of 130-140 kts.

If you see the runway coincident with the MAP there is zero chance of a stabilized approach to landing. And big airplanes that are not stable on approach is a leading contributing factor to landing accidents.
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Re: Air Canada Accident in YHZ

Post by Mach7 »

It is because the MAP and the VDP (visual descent point) are different for an aircraft with an approach GS of 130-140 kts.

Really? not the depicted on the approach plates we are using.
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Re: Air Canada Accident in YHZ

Post by HiFlyChick »

rudder wrote:It is because the MAP and the VDP (visual descent point) are different for an aircraft with an approach GS of 130-140 kts.

If you see the runway coincident with the MAP there is zero chance of a stabilized approach to landing. And big airplanes that are not stable on approach is a leading contributing factor to landing accidents.
I guess I'm being obtuse today (why pick on today ;) ), but I'm not sure I get what you are saying... The MAP on most non-precision approaches tends to be almost at the runway threshold and essentially too late to make a successful landing for most aircraft (except on extremely long runways and slow aircraft). In general, if you're going to get a landing out of a non-precision approach, it will happen well before the MAP, and I believe that the SCDA chart is such that the standard approach angle has you reaching the MDA well before the MAP. The whole concept of SCDA is that you act as if you are on an artificial glideslope and overshoot based on having reached the MDA and not waiting for the MAP.

That being said, I recall flying an approach that way one time to a runway without LPV but with SCDA info on the chart an executing the overshoot as proscribed at the MDA. On the second try, having reviewed the runway length and knowing the performance of our (light twin) aircraft, we came around for a second approach (two experienced captains flying together and having agreed on the second attempt) and levelled off at the MDA (i.e. only really half a SCDA an half a step-down, which I guess if you want to be picky is not really SCDA at all) and made it in - we saw it well before the MAP, but past the point where the 3 deg angle intercepts the MDA. I remember thinking at the time, though that the slow approach speed of the aircraft was what allowed us to complete the approach, other aircraft I fly that are faster would not have been able to do the slightly steeper angle required at the point where we went visual.
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Re: Air Canada Accident in YHZ

Post by trey kule »

CRM...PDM...SMS......

But some people seem to think (or not think at all), that they need TC to regulate what is safe....

Maybe TC should be putting some new regulations out that state..." If you are to stupid to know, or to figure out this approach is not a good idea.....then we will ban it"

TC has for years pushed the ideology that if it is not allowed, it must be unsafe, and ergo , if it is allowed it must be safe.

Pilot decision making? No no...it is all about what TC will allow.

while we are at it, why not get TC to ban all unitentional gear up landings...that should end a whole bunch of accidents according to this line of thinking

Own your mistakes. Pilots are not victims when they make bad decisions
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Re: Air Canada Accident in YHZ

Post by Mach7 »

@trey kule

You are correct, one must be responsible for ones mistake(s), that being said, (and I have no inside knowledge of the AC accident), if these Pilots were mandated to do a CDA and where not given the correct training on how to execute such an approach, then the company (IMO) has to take some of the responsibility.

How many CDA's has this crew accomplished in the last year or two? I bet not many.

There are many times I would rather have done a step down approach, but SOPs and company policy do not allow me that latitude, nor do they provide me with any training to do these approaches.

something to consider.......?
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Re: Air Canada Accident in YHZ

Post by trey kule »

To argue the point...no company can mandate you to do something unsafe..and no company can insist on you doing something unsafe. If they try, and you allow it, you have no business being responsable for other peoples' lives.
As to better , safer ideas. Is that what SMS reporting is all about? Lots of pilots bitch and complain about company procedures. But do nothing else. I think the psycho babblers call that resignation. Very few ever sit down and methodically and clearly put it in writing and submit it to the company. Not as a complaint, but as a suggestion how to do something safer or better.

Not getting training for a type of approach procedure you are expected to do....did I mention putting it in writing? and if no action is taken, putting it in writing again that you will not do the procedure without proper training...

I have been in this business for a very long time. And all to often after an accident people say it was inevitable....but they did nothing to prevent it.
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Re: Air Canada Accident in YHZ

Post by HiFlyChick »

Mach7 - do you fly larger aircraft or are you in the same boat as I am, which is preferring step-down to SCDA (but not having to choose anyway since all of our company aircraft have LPV)?

Still looking for comments on difficulty in step-downs on something of significant weight.....
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Re: Air Canada Accident in YHZ

Post by 55+ »

It should be noted that the minimum visibility approved and published in the CAP and RCAP for non-precision IAPs is 1sm. This is mandated by design criteria TP-308 and you will not see any non-precision IAP in Canada published with a vis less that 1sm.
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Re: Air Canada Accident in YHZ

Post by Mach7 »

@55+

You are somewhat correct, however most companies have an 'op' spec to bring them down to 3/4 or 1/2 mile if they utilize an SCDA approach or utilize the HGS.

@HiFlychick

I don't fly an overly large aircraft, but one that weighs in at 75k for landing and has quite a fast approach speed. In the old days, we did step downs with the Bae146 on a regular basis, with no problems in stability or safety.
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Re: Air Canada Accident in YHZ

Post by Rockie »

Step down approaches are not generally flown by transport category aircraft because they are proven to expose the aircraft to more risk of CFIT, and they result in an unstabilized state on short final which these aircraft are intolerant of. I don't know of any transport category operator that does them and Air Canada only does SCDA non-precision approaches.

Using the BARO-VNAV capability (we are non-WAAS equipped) affords us computed and displayed vertical guidance to cross the threshold at 50 feet on LNAV, LNAV/VNAV, VOR and NDB approaches (the last two advisory only) which makes the very safe. LOC based approaches however cannot be flown using BARO-VNAV as it is unavailable when tracking a localizer beam. In those cases we cross the FAF level and just before dial in whatever flight path angle (FPA) is appropriate. FPA is wind corrected and automatically compensates for changing ground speed, so provided you start on the correct slope everything should work out OK. Unfortunately there is no indication in the cockpit of your vertical position relative to the correct slope, and anything that temporarily disrupts the path (configuration changes, not starting on the correct slope, using an incorrect angle etc) and you really don't know where you are until you reach MDA.

That's why using a visibility below published for those types of approaches is a bad idea.

As Mach7 pointed out, when executing an ILS or even a non-LOC NPA with vertical guidance you know you are heading to the correct touchdown spot so using a visibility below published isn't such a problem. But with a LOC approach you don't know that for sure, and since you're not doing a step down you don't have the advantage of seeing the sight picture develop as you near the runway, instead you have to make an instant assessment at MDA without the same assurances vis-a-vis vertical position as an ILS.
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Re: Air Canada Accident in YHZ

Post by 55+ »

Mach7 wrote:@55+

You are somewhat correct, however most companies have an 'op' spec to bring them down to 3/4 or 1/2 mile if they utilize an SCDA approach or utilize the HGS.

@HiFlychick

I don't fly an overly large aircraft, but one that weighs in at 75k for landing and has quite a fast approach speed. In the old days, we did step downs with the Bae146 on a regular basis, with no problems in stability or safety.
Actually I am very much correct Mach7. Yes, an op specification is towards a specific company that meets pre-determined criteria be it equipment and/or training, however that is internal to company operations AC may have a'specification" for operations regarding non precision vis approval below what is published, no doubt. It is for their(AC) use only and as you know. doesn't apply to other carriers who do not have such approval
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Re: Air Canada Accident in YHZ

Post by FICU »

I've done many step down NPAs in a 737 in the arctic with no issues as long as you are prepared and ahead of the jet. We now have pseudo glideslope capability but if there is a ragged ceiling at MDA with good visibility below I may elect to do the step down to get to MDA prior to the VDP and reasonably expect to get into VMC conditions rather than the SCDA which may keep us IMC at MDA with no other option than a go-around.

Every situation requires a descion but step down approaches in a larger jet are not unsafe.
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Re: Air Canada Accident in YHZ

Post by Old fella »

FICU wrote:I've done many step down NPAs in a 737 in the arctic with no issues as long as you are prepared and ahead of the jet. We now have pseudo glideslope capability but if there is a ragged ceiling at MDA with good visibility below I may elect to do the step down to get to MDA prior to the VDP and reasonably expect to get into VMC conditions rather than the SCDA which may keep us IMC at MDA with no other option than a go-around.

Every situation requires a descion but step down approaches in a larger jet are not unsafe.
Going way back 35+ yrs ago plenty of B737, DC-8, DC-9, B727, L1011, B747 and the like did these old standard non precision approaches NDB, LOC/BC here in the windy/foggy Maritimes and I can't remember either AC,EPA, Nordair etc. driving one of their aircraft short of the runway on any of these approaches.
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Re: Air Canada Accident in YHZ

Post by Rockie »

I used to do stepdowns in heavy aircraft too and I defended them for the same reasons you guys do, I preferred having a sight picture develop as well rather than hoping I was in a position to land when I had to make an instant decision at MDA. But I was flying non-GPS equipped aircraft into places with scarce DME coverage so map shift was also an issue and NPA's were definitely non-precision. Technology is slowly catching up though, and SCDA's are safer than step downs for reasons that cannot be credibly argued against.

The main issue today is LOC based NPA's because they are the only ones left that airlines with halfway modern equipment cannot fly with vertical glide path guidance. Using less than published visibility with those is stacking the deck against yourself as this event seems to indicate.
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