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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)

Herod 16th Mar 2017 08:01

All this talk about mis-set altimeters. Whatever happened to "Rad Alt live, altimeter check"? Particularly at a sea-level airport.

Aluminium shuffler 16th Mar 2017 12:10

In seven operators, I've never seen anyone use it as a crosscheck, Herod. Rad alt and baro alt seldom match, really just over the sea and Norfolk, so (probably) nobody has an SOP to do that.

FullWings 16th Mar 2017 12:21


In seven operators, I've never seen anyone use it as a crosscheck, Herod. Rad alt and baro alt seldom match, really just over the sea and Norfolk, so (probably) nobody has an SOP to do that.
We do, although unless you’re over the sea or flat ground there’s not enough information on the chart to tell much more than yes, there’s something underneath you.

Back to the incident, I too am perplexed as to how they ended up as low as they did if they were in constant visual contact with the runway & slope guidance. Must have been four reds for a while but corrective action only taken when within seconds of flare height over the ocean.

16024 16th Mar 2017 13:21

Rad alt alive crosscheck:
Our lot do it as well.

smith 16th Mar 2017 15:44

You saying this could be similar to the THY 737 at AMS where the rad alt was faulty and put it into retard flare. At least this time somebody noticed the drop in speed.

PJ2 16th Mar 2017 15:45

FullWings, re, "Must have been four reds . . .", I wondered too. I haven't yet finished reading the entire thread so perhaps the question is dealt with earlier in, but the Airport INFO chart shows nothing regarding visual vertical guidance installations.

Also, I saw nothing regarding night approaches on 10, (not permitted on 28, nor in IMC).

safetypee 16th Mar 2017 16:36

PJ / FW, " four reds ". " something beneath the aircraft ".
This assumes that PAPI was visible sometime after 'first contact'. Furthermore this poses the question, contact with which feature.
Conventional overland NPAs require visual contact with the runway environment, which can be interpreted as not requiring contact with the runway, and in extreme no approach lights.
Overwater NPAs such as this approach, then the immediate coastline may have been seen, but nothing more. This could be similar to a classic night 'black hole' illusion where the focus of attention is on a single dominant feature, resulting a low visual approach.
Also that when the PAPI should have been visible were the conditions suitable to immediately determine 'red' etc.
Thoughts?

RAT 5 16th Mar 2017 19:46

In seven operators, I've never seen anyone use it as a crosscheck, Herod. Rad alt and baro alt seldom match, really just over the sea and Norfolk, so (probably) nobody has an SOP to do that.

Oh dear; another item thing that used to be called airmanship and SA, but now requires an SOP so that pilots act like airman. Disappointing that standards have dipped so low.

Herod 16th Mar 2017 22:00

Rat5, are you suggesting that an altimeter check is a bad practice? Yes, I concede baro and rad alts will only agree over the sea, but even in other situations it does give a prompt to check that both baro-alts are set to the same figure, generally before you get dangerously close to terra firma. But in this case even more so, since they would agree within a few feet of one another.

Chuck Ellsworth 16th Mar 2017 23:28

SOP.

Paint by numbers so all artists are at the same level.

PJ2 17th Mar 2017 01:23

Hi safetypee;

Indeed: what was considered "contact" for this particular approach and what internal guidance and secondary (confirming) information was being used to verify on-slope/off-slope? The investigation will determine that. From what I know, WJ has a robust safety culture.

Retired now but our operation specified the meaning of "contact" for both VMC & IMC conditions and it was much like you describe - minor differences.

Along with the external vertical guidance, I think that good clues that can verify height vs. distance to go are also internal, from the ND, set to the lowest scale, and then using the usual 3:1 ratio, (a thousand feet out, 300ft height above the threshold or 300ft on the RA, and multiples of, etc., roughly), and descent rate vs. ground speed, (again for others looking for the "rules", a rough 3deg descent path can be determined thus: add a zero to the ground speed, divide by 2. eg. 140kts x 10 = 1400 / 2 = 700fpm).

Capn Bloggs 17th Mar 2017 01:41

Google Earth shows what looks like a PAPI installation at the start of the Aiming Point marking. There's also some type of installation (or foundations) at the 300m markers.

I would be very surprised if regular Hi Cap operations would be permitted with no visual or GS guidance available, especially there with an over-water approach. We (RPT) are simply not permitted (CASA rule) to operate without slope guidance of some type for more than 7 days.

Capn Bloggs 17th Mar 2017 01:51


Conventional overland NPAs require visual contact with the runway environment, which can be interpreted as not requiring contact with the runway, and in extreme no approach lights.
Dodgy Brothers Incorporated... :)

Drawing a long bow to interpret Macdonalds, then the beach, then the roundabout then the threshold as the runway "environment", if you know what I mean (going a bit overboard, I know). Our AIP says "“visual reference” means the runway threshold or approach lights or other markings identifiable with the landing runway clearly visible to the pilot".

PJ2 17th Mar 2017 02:07

Capn Bloggs - yes, your observations occurred to me also...it would be surprising not to have some vertical guidance - I just couldn't find that confirmed by the current Airport chart, that's all. I'm sure someone with experience into the field will come forward to answer the question.

Found a stock photo of the approach - PAPI installed. Symbol didn't seem to be on the chart, but that's what "Retired" means...

RAT 5 17th Mar 2017 09:03

Rat5, are you suggesting that an altimeter check is a bad practice?

Quite the opposite. In Line Training & Line Flying I used to demonstrate the X-check of RA 2500' & bro made sense knowing where you were. It was not a perfect match due terrain, but if you had SA you could make sense of it. My post was this: this addition to help SA should be airmanship and it's sad if it is only does by those who have an SOP to tell them to do it.
In many airlines the RA EGPWS blurts out an alert and the crew respond like parrots without thinking. That is the consequence of many SOP call outs I've experienced. They really were a Parrot Pantomime.

Skyjob 17th Mar 2017 10:24

Agreed RAT 5.

A simple crosscheck of radio altimeter simply makes crew aware they are now 2500' Above Ground Level and this should be resembled by the Altimeter taking into account Elevation underneath aircraft at time of activation.
Another tool to prevent Blunder Error in QNH settings...

Aluminium shuffler 17th Mar 2017 11:04

Such cross checks are fundamental airmanship, and I don't think anyone could legitimately criticise anyone for performing them. However, they are not in typical SOPs, and the point has been made in thread after thread about the demise of airmanship and the rise of SOP dogmatism. No-one in their right mind likes it, but that is the modern culture almost everywhere. With inexperienced trainers, only recently promoted to command months before getting a training ticket and only a few thousand hours in their book becoming the norm, it's not going to get better, either.

CONF iture 17th Mar 2017 21:15

PAPI on both sides for rwy 10 :



Also confirmed by the airport chart.

RAT 5 18th Mar 2017 08:45

Such cross checks are fundamental airmanship, however, they are not in typical SOPs, and the point has been made in thread after thread about the demise of airmanship and the rise of SOP dogmatism.

Opening paragraph of any SOP manual should read, "Airmanship at all times is an SOP."

but I take your point.

Herod 18th Mar 2017 13:54


Opening paragraph of any SOP manual should read, "Airmanship at all times is an SOP."
Rat5. I have to agree with you. I can't remember whether the altimeter check was SOP or whether it was just something I did. I've been retired over twelve years now, and things slip out of the mind.


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