Kip Powick

Different Take on the HFX Crash of the AC 320

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9 minutes ago, canadairguy said:

I'm sorry, seeker, but I don't think that it's the airports that are too cheap.  A modern aircraft arriving at Halifax that night would have flown an RNAV approach to LPV minimums, rather than a non-precision approach.  It was 2015, after all.  Are there still aircraft in the fleet incapable of flying RNAV approaches?

The first LPV APP for runway 05 (from my source) shows MINS of 760' (which is 311' above ground) and 1 mile VIS.  The second shows 690' (250 above ground) and 1 mile VIS.  Neither is anywhere close to standard ILS MINS or CAT II MINS.  I understand that RNAV APPS (and LPV APPS) are sometimes pretty close to ILS MINS but remember the precision approaches will always have much better lighting.  If I was doing an approach on a dark and stormy night where the conditions were 300' and 3/4 in heavy snow and blowing snow and had the option of an ILS or RNAV LPV I know which one I'd choose.

I think some people (maybe not you) get a false sense of the viability of RNAV LPV approaches because they do one on an ILS runway - they get the benefit of the ILS standard lighting.  They get down to 300', see the lights and land thinking, "these RNAV approaches are just as good as ILSs." All the while not realizing that the same approach, in the same conditions to a non-ILS runway might not have been successful because the lighting would have been completely insufficient.

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Your point about lighting is valid, seeker.  Having said that, the LPV minimums are 101 feet lower than the LOC MDA and you get vertical guidance all the way to the runway.  As more and more RNAV approaches are published - most of them with LPV minimums - I think it's getting less and less likely that airports will be installing ILS's in the future.

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Hmmm.  This discussion seems familiar somehow.

First comment - were the crew using their own devices in the flight deck.  There would have been zero benefit in so doing and I have never seen this practiced at AC on any type.  Even with the current generation of iPads (not available at the time of this accident), there is no vertical information of use during approach.

Second, there is an error in the video - the crew saw cues which gave the impression they were runway lights, but in hindsight are believed to be from a different source.

As for the PAPI and actual runway lights, the situational awareness disconnect from the controller advising lights would be at strength 5, but then failing to actually do so, is significant.  A large component of this event was due to expectation bias.  While removing any one of a number of factors would have changed the entire outcome, this one presented a critical threat.  The difference from strength 4 to 5 is not a small increment.

FWIW

Vs

 

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3 hours ago, canadairguy said:

Your point about lighting is valid, seeker.  Having said that, the LPV minimums are 101 feet lower than the LOC MDA and you get vertical guidance all the way to the runway.  As more and more RNAV approaches are published - most of them with LPV minimums - I think it's getting less and less likely that airports will be installing ILS's in the future.

Nothing replaces an ILS, for many of the reasons mentioned above.

There is one reason only as to why airports won't be installing ILS's in the future (your quote), and that is cost $$$.

The old adage comes to mind, "you think safety is expensive, try having an accident"

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4 hours ago, canadairguy said:

Your point about lighting is valid, seeker.  Having said that, the LPV minimums are 101 feet lower than the LOC MDA and you get vertical guidance all the way to the runway.  As more and more RNAV approaches are published - most of them with LPV minimums - I think it's getting less and less likely that airports will be installing ILS's in the future.

Yes, guidance all the way to the runway, which you can't legally use without seeing the lights......and you can't see the lights because they're not part of an ILS installation and are substandard.

Believe me, I have flown many, many RNAV APPs and I know they are pretty good, most of the time but they're not as good as an ILS.  We don't see airports putting in ILSs because of the cost to install and the cost to run.  The GPS/RNAV saves money in the terminal area, saves money for the airport but it's worse from a safety perspective than we had 20 years ago (40 years ago?)  There's a couple of airports I go to where the RNAV APP will line you up with the runway edge - done it on different days with different fins and every time I'm lined up with the edge - never had an ILS treat me that way!

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1 hour ago, seeker said:

There's a couple of airports I go to where the RNAV APP will line you up with the runway edge - done it on different days with different fins and every time I'm lined up with the edge - never had an ILS treat me that way!

Like I said......

”Minimums”...... Go Around

Stable approach criteria.

Edited by rudder
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