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-   -   So WestJet almost puts one of their 737 in the water while landing at St-Maarten... (https://www.pprune.org/rumours-news/592054-so-westjet-almost-puts-one-their-737-water-while-landing-st-maarten.html)

underfire 31st Mar 2017 00:52

Well, as I stated, we dont know how far they were out, but the one still images, shows the turbulence on the water from the ac going on for quite a while, as I stated, that is an unknown. The person taking the image also stated that she saw the aircraft flying very low, grabbed the camera and took the image, so it appears it was for a while, and the FR ADSB data concurs.

You, nor anyone else, has no idea of what transpired, and everyone is hypothesizing.

The EGPWS systems are different, and when WJ initially started with these, many procedures that had been in use, began setting off the alarms. The way the system forward looks, and understand the glidepath between the FAF and threshold, and the associated ROC. This has nothing to do with ILS. Many obstacles and terrain which were not previously an issue, became issues and had to be added to the database.
There were issues with procedures in Adelaide with QANTAS for the same reasons.

Do you really think that that distance from threshold, at about 50 feet from a surface, there would be no warnings, especially with a 60 second forward looking capability?

Do you really think the altitude calls were not annunciated by the system? minima that far out or 50 that far out?

EDIT: Just so you know, ATC systems in AUS use geometric, not baro altitude from the ADSB broadcasts.

Mostly Harmless 31st Mar 2017 00:54

I never knew there were so many armchairs in the world.

alph2z 31st Mar 2017 01:10


Originally Posted by Capn Bloggs (Post 9724730)
That's how your post read.

May I suggest that if you don't know, then either don't say or write a clear disclaimer that you are hypothesising. I would wager there are plenty of readers on here who don't know, and reading your missives will give them the wrong ideas, especially since what you wrote above about warnings is largely irrelevant to this incident.


Is this is based on detailed knowledge of the system or just a hypothesis? They didn't look "too far out" to me. I would doubt very much if the EGPWS would have been squawking at them.

You and many others I agree with; and I know Kalman filters and their derivation of. Mixed up english and topics.

Capn Bloggs 31st Mar 2017 10:07


Originally Posted by Underfire
Many obstacles and terrain which were not previously an issue, became issues and had to be added to the database.

You're talking nonsense. The E in EGPWS is purely GPS & database-based. If an obstacle is not in the database, the box won't squawk that you are going to hit it! It n to a forward-looking radar.

There is the "off-airport" mode, but as I said, based on what I have seen using the system for many years, I doubt that it would have given a warning.

aterpster 31st Mar 2017 12:43

Bloggs,


You're talking nonsense. The E in EGPWS is purely GPS & database-based. If an obstacle is not in the database...
What he is saying is correct. Obstacles have been added with better surveys and better data subsequent to the inception of EGPWS. And, there is a "peaks and obstacles" option for additional $$$$ that provides greater accuracy and fidelity of terrain near airports where RNP AR approaches are in use.

There is a possibility that the EVA 777 that came dangerously close to Mt. Wilson near KLAX the past December did not have the many antennas on Mt. Wilson in their EGPWS database. One of those towers is almost 1,000 feet, agl, atop the highest point on that mountain.

PJ2 31st Mar 2017 16:59


Originally Posted by I-FORD
More than necessary precious TC time have been spent on investigating a non-event just to satisfy the ever growing public hunger for sensationalistic news related to air transport.

You would not be offering such views if the outcome had been only slightly different as in the UPS CFIT accident at Birmingham and the Lion Air CFIT accident near Bali.

You can't argue both ways, as in, "only give it precious TC time if it was an accident". None of us has such predictive capabilities as to determine how close to an accident this and others like this was, and so must handle events like this one as serious in order to find out why it happened.

Even with the most sophisticated equipment which assists crew in building and maintaining a high degree of situational awareness, it remains a puzzle why this kind of event continues to occur. So I disagree with your somewhat polemical comments.

Jet Jockey A4 31st Mar 2017 18:37

@ I-FORD...

Don't forget the TSB opened an investigation into this incident.

AerocatS2A 31st Mar 2017 22:25


Originally Posted by aterpster (Post 9725300)
Bloggs,



What he is saying is correct. Obstacles have been added with better surveys and better data subsequent to the inception of EGPWS. And, there is a "peaks and obstacles" option for additional $$$$ that provides greater accuracy and fidelity of terrain near airports where RNP AR approaches are in use.

No, what he is saying is not correct. What he said was that with EGPWS some obstacles and terrain started giving warnings and then had to be entered into the database. If they weren't in the database then they can't have given warnings because the EGPWS wouldn't have known about them. Whatever Underfire's point is, he is not expressing it well. Maybe he meant that obstacles and terrain that were already in the database started giving warnings with EGPWS that weren't given with GPWS and that the system logic had to be adjusted to allow for them, but that's not what he said.

Jet Jockey A4 1st Apr 2017 12:53

From DaveReidUK's post 181..

"The Canadian TSB, on the other hand, opened an investigation on 17th March, categorising the event as a Class 3 - defined as:

"Individual occurrences that do not meet the criteria of Class 2 occurrences may be investigated when
1. there is significant public expectation that the TSB should independently make findings as to cause(s) and contributing factors; or
2. there is potential for better understanding the latent unsafe conditions contributing to a significant safety issue; or
3, a government representative so requests (pursuant to Section 14(2) of the CTAISB Act); or the Board must do so to meet its obligations or commitments."

As of today I don't know what the status of the TSB's investigation is on this event.

aterpster 1st Apr 2017 15:46


Originally Posted by AerocatS2A (Post 9725830)
No, what he is saying is not correct. What he said was that with EGPWS some obstacles and terrain started giving warnings and then had to be entered into the database. If they weren't in the database then they can't have given warnings because the EGPWS wouldn't have known about them. Whatever Underfire's point is, he is not expressing it well. Maybe he meant that obstacles and terrain that were already in the database started giving warnings with EGPWS that weren't given with GPWS and that the system logic had to be adjusted to allow for them, but that's not what he said.

Perhaps that's what he meant. I took it that way because perhaps I was reading too quickly.

DaveReidUK 1st Apr 2017 17:27


Originally Posted by I-FORD (Post 9726328)
I thougth that TSB investigated EVENTS, in this case the crew applied the right decision, went around and saved the day, so no event or Outcome, as the TEM teaches us.

You might want to have a read of ICAO Annex 13, in particular the definition of "serious incident" and the examples given of events that fall into that category.

RAT 5 2nd Apr 2017 10:37

I thougth that TSB investigated EVENTS, in this case the crew applied the right decision, went around and saved the day, so no event or Outcome, as the TEM teaches us. TC is the right agency to investigate the issue as they are paid to set the rules to PREVENT events or outcomes. If an attitude, behaviour, knowledge or else was applied in a situation and solved it that's exactly what it is requested by good airmanship no need for further investigation, the system reacted as expected so why keep digging? It looks just voyeurism to me.

I think that is over simplified. If a crew is dumped, unexpectedly and due to no fault of their own, in an undesirable situation and they escape from it, then job well done. If a crew, due to inappropriate actions, puts an a/c into an undesirable situation, and then, as they see a disaster unfolding, they decide to escape from it, then perhaps not quite so job well done. It would be necessary, from a learning point of view, to analyse the events completely and not just dismiss it as a non-event.

RealUlli 2nd Apr 2017 11:51

Microburst
 
(Disclaimer: SLF)

I've seen some mentions of a possible microburst. However, I haven't seen something I noticed in the video taken from the Sunset Bar:

There seems to be a squall there, the sunshades are whipped around quite a bit. Their direction also indicated quite a bit of tailwind for the plane.

Is that irrelevant or am I really the only one to spot it? It might also be the normal wind there (I seem to recall the METAR said 080@18 - is the beach at the approach of 09 or 27?)

I've recently been in the Windward Islands on a sailboat, the squalls described in another post are quite annoying. They come up, dump a ton of water on you, 5 minutes later they're gone again.

aterpster 2nd Apr 2017 21:27

The authoritative data are contained in the DFDR and hopefully has been read by the Canadian aviation authorities.

roybert 4th Jun 2018 18:07

For those interested the TSB has just released the report into this incident. http://www.bst-tsb.gc.ca/eng/rapport...2/a17f0052.pdf

Airbubba 4th Jun 2018 18:16

Thanks for posting that. :ok:

They went down to 40 feet off the water before the go around. :eek:

And, once again as in SFO, the Canadian CVR is missing:


Because the occurrence was originally assessed by WestJet as a non-reportable event, the cockpit voice recorder and the digital flight data recorder data were overwritten and were not available to the investigation.

FullWings 4th Jun 2018 21:56

Really good report, well worth a read. A lot of very relevant HF stuff in there as well.

An interesting detail is that they were cleared and flew the approach in vis well below minima but were unaware of that because they weren’t told by ATC. They also went visual before they could see the airport or runway (allowable), then misidentified another feature as the runway. Lowest point 39’AGL 0.3NM from the threshold.

Lots of things all lining up and nearly putting them in the water, classic “holes in the cheese” stuff. Plenty of learning points here...

aterpster 4th Jun 2018 23:11

I don't understand how the DFDR was overwritten. I thought they retained data for a relatively long period.

Jet Jockey A4 5th Jun 2018 00:29

Thank God there was a QAR on board that aircraft or else we would have never known the truth about how close that came to being a crash.

For Westjet to declare this a "non incident" and allow both the DFDR and CVR to be erased just proves you can not hold a company to police itself.

I would like to know why if the crew had no visual contact with the runway and had no visual height reference above the water, why they did not one of the pilots (PNF) monitor the Rad Alt and why it took a minimum of two EGWPS warnings before they decided to go around?

Finally now that the truth came out thanks to the QAR, what did Westjet do to the pilots and what steps have they taken for this not to happen again?

Airbubba 5th Jun 2018 01:14


Originally Posted by Jet Jockey A4 (Post 10165090)
Finally now that the truth came out thanks to the QAR, what did Westjet do to the pilots and what steps have they taken for this not to happen again?



Don't know about the pilots but this WestJet corrective action plan is mentioned in the report:



Following the occurrence, WestJet conducted a company investigation and developed a corrective action plan. The plan included

• a safety communication letter (Flight Safety Flash), sent to all pilots, explaining the incident and providing information regarding possible challenges and threats at the Princess Juliana International Airport (TNCM),

• revision of the route and aerodrome qualification document for TNCM,

• provision of a flight safety briefing on the incident to all crews at the annual ground school, and

• design of a new instrument approach at TNCM.

The revised route and aerodrome qualification document for TNCM contained the following additional information:

• **Extra diligence required in reduced visibility operations.** Build-up of land and buildings North of the runway can cause illusion of false runway, leading to lower approach angle. Cross check your visual track against our FMC [flight management computer] to ensure you are lined up with the actual runway.

• Due to difficulty in acquiring visual confirmation of runway in reduced visibility conditions, it is recommended to consider abandoning the approach if you do not identify the runway ¼ mile back from the MAP [missed approach point].


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