Southwest flight 150agl 4 mile final into TPA

[dmspilot]

Runway 10/28 is rarely used by transport jets. This may have been their first time attempting to land on 10.

And? At work, I've had to go to airports I've never been to and land on runways I've never landed on all the time. Nothing strange or tricky about the RNAV 10 at TPA.

 

[Flying Keys]

I don't think there are any airlines doing dive-and-drive, we treat every approach, including RNAV, Localizer, VOR, etc., like a precision approach and go missed when we reached the DH/MDA. Therefore the location of the MAP isn't really relevant.

Would that be true if the crew mistook the FAWP for the MAWP? This doesn’t look like a dive and drive, this looked like a consistent descent to a point in space at which there was no runway. As always, I’m not saying that’s what happened, but if it was, I could see how it’s possible.

 

[dmspilot]

Would that be true if the crew mistook the FAWP for the MAWP? This doesn’t look like a dive and drive, this looked like a consistent descent to a point in space at which there was no runway.

I don't know why they would, even accidentally, because it's just not the way we think about approaches at the airline. I think it's more likely they just ignored or deleted the FAWP. I had someone accidentally delete the FAWP on me once, a check airman no less.

 

[wayneda40]

It's flown in LNAV and VNAV. My avatar shows the display. It would require ignoring the vertical path indicator once the "runway" was in sight.

Runway 10/28 is rarely used by transport jets. This may have been their first time attempting to land on 10.

You're saying this airliner doesn't have WAAS or for some other reason can't fly (or at least follow) an LPV??

 

[Tools]

Many don’t. I fly where some do and some don’t… in the same fleet! Part 121.

 

[Let'sgoflying!]

It would require ignoring the vertical path indicator

This is my point exactly.
This incident again shows the hazard of not using the tools available to avoid a major mishap.
Using an IAP to backup all visuals should almost be standard practice now.
Not 14 days ago I posted about observing a C130 that lined up on 22 at Biggs and were given a "Go-Around!", when they were planning on 22 KELP.

The issue we are talking about was a recurring problem years ago, and I thought the message had gotten out but it appears not.

Runway 10/28 is rarely used by transport jets. This may have been their first time attempting to land on 10.

Larry, do you offer this as what they would say in their defense? It would be a weak one if so.
Or more likely as an explanation. If so, I get that - but we have ways to prevent this.

 

[Larry in TN]

And?

And what? That is a threat. They would not have been familiar with the sight picture for that runway even though were likely very familiar with TPA. That can lead to errors.

Would that be true if the crew mistook the FAWP for the MAWP? This doesn’t look like a dive and drive

As dmspilot said, that's not how we fly approaches. We follow the VNAV path down to visual conditions or a missed approach at the DA/DDA, whichever comes first.

The last time I flew a dive-and-drive approach was in 2011 in a DC8.

You're saying this airliner doesn't have WAAS or for some other reason can't fly (or at least follow) an LPV??

We don't do LPV. We do GLS, which is a form of LAAS, and RNP down to 0.10.

This incident again shows the hazard of not using the tools available to avoid a major mishap.

That's true, if the assumptions we are making about what happened are correct.

Another threat, which we haven't considered, with VNAV approaches is that the vertical path is calculated, instead of being a fixed ground-based glideslope. It is possible for the VNAV to be wrong or incorrect modes selected on the MCP. If that were the case, the error could have been in how the approach was setup or a problem with the FMS.

It is curious that they immediately diverted to FLL instead of coming back around and flying the approach again. Were they going somewhere with an ILS for some reason?

do you offer this as what they would say in their defense?

I haven't offered any defense. How could I? I don't know what actually happened anymore than anyone else. I'm mostly pointing out the differences in how a 737 is operated.

 

[Albany Tom]

Stupid question from a non-airline guy - Is it possible that they had visual to the water, but had no idea how high up they were on a visual approach, because the altimeters were set wrong? Asking because I couldn't figure out how someone with vision couldn't tell they were only 150' up...until I saw the mention of "over water".

Over water without any landmarks or altimeter, I don't know how to tell how high is high, which is one of several reasons why I don't like being over water without sight of land.

 

[Jdm]

It's flown in LNAV and VNAV. My avatar shows the display. It would require ignoring the vertical path indicator once the "runway" was in sight.

Yes, VNAV PTH if it’s anything like the 757/767. Guessing the FMA’s went unnoticed when the aircraft deviated from PTH, or they never had path in the first place, which is a normally a requirement by the FAF.
Another possibility is using an unauthorized vertical mode to achieve PTH due to an MCP error. Either way it’s a major procedural infraction and non compliance of limitations

 

[Jdm]

You're saying this airliner doesn't have WAAS or for some other reason can't fly (or at least follow) an LPV??

I’m currently flying new Boeing equipment without WAAS. Unable LPV. It’s certified for LNAV/VNAV instead.

 

[Jdm]

Stupid question from a non-airline guy - Is it possible that they had visual to the water, but had no idea how high up they were on a visual approach, because the altimeters were set wrong? Asking because I couldn't figure out how someone with vision couldn't tell they were only 150' up...until I saw the mention of "over water".

Over water without any landmarks or altimeter, I don't know how to tell how high is high, which is one of several reasons why I don't like being over water without sight of land.

In addition to traditional altimeters, they also have radio altimeters which display a digital readout of height above the ground starting around 2,500 AGL. They also have a landing altitude reference bar that indicates in the form of a vertical tape that changes colors to indicate 1,000 and 500. Also have alerts of altitude below the tape reading 100’, 50’, 40’, 30’, 20’ 10’.

 

[Larry in TN]

Is it possible that they had visual to the water, but had no idea how high up they were on a visual approach, because the altimeters were set wrong?

Lots of things are possible. At this point, I'm trying to think of what is most probable.

I would be surprised if there was a significant error in the altimeter setting. They were roughly 1,300' low. That's a big altimeter setting error, ~1.30".

Over water without any landmarks or altimeter, I don't know how to tell how high is high, which is one of several reasons why I don't like being over water without sight of land.

The correct way is to use your VNAV path, altimeter, and radar altimeter.

You also get visual clues from the runway itself which can lead to visual illusions. For example, landing at LAS or SJO (San Jose, Costa Rica) both give the visual illusion of being much too high due to the slope of the terrain. If you're looking at a causeway, thinking it is a runway, the narrow width would also throw off your perception of height.

At this point, the most probably explanation by my judgement, is that, unfamiliar with sight picture for this runway, they broke out seeing the causeway and descended visually toward it. Plenty of information available to identify and repair that error but the one thing we do know is that they got very low, very early.

Back to the radar altimeter... We brief a stabilized approach plan before each approach. Many brief that they'll be at a certain speed and configuration at one fix and fully configurate by another. I prefer to brief gear down at 2,000' AFL (and descending) and final flaps at 1,500' AFL. I like that better than fixes because fixes change names and distance from touchdown. 2,000' and 1,500' is always 2,000' and 1,500'. It also keeps the radar altitude awareness higher. I think if I was in a similar situation, and mistook the causeway for the runway, the reference to the RA would have alerted me to the mistake sooner.

 

[tobnpr]

Most of the tech/IFR stuff above is over my head currently...
That said, I just focus on the fact that they were miles from the runway- and 150 ft or so AGL.
I mean, WTF- really?

 

[dmspilot]

 

[danhagan]

Not 14 days ago I posted about observing a C130 that lined up on 22 at Biggs and were given a "Go-Around!", when they were planning on 22 KELP.

That happens with KELP and the military Biggs Army airfield at least once a week due to the close proximity. The more experienced controllers at our field always give a warning to all AC approaching RWY 22 or 4 as "cleared approach RWY xx, Biggs army airfield 3 miles north" ...

 

[hindsight2020]

Perhaps no night visuals for the coal rollers would help them get caught up on whatever deficiencies they got in their ranks, before they kill 150 bargain shoppers and everybody gets told to wear diapers.

ETA: oops, too late.

 

[wayneda40]

I’m currently flying new Boeing equipment without WAAS. Unable LPV. It’s certified for LNAV/VNAV instead.

Wow, just wow. You'd think WAAS would be a pretty simple high-payback upgrade.

 

[Larry in TN]

Wow, just wow. You'd think WAAS would be a pretty simple high-payback upgrade.

So is RNP 0.10 capability and GLS could be.

 

[RussR]

Wow, just wow. You'd think WAAS would be a pretty simple high-payback upgrade.

As I understand it, it's a cost/benefit analysis. If you're an airline (like most of them) that flies only to major airports with multiple runways all with ILS, you really don't gain much with WAAS and LPV. You don't get lower minimums (often just the same as Cat I), and WAAS doesn't allow you to go to Cat II or III minimums. You already have other forms of RNAV for the enroute stuff. Retrofitting your existing fleet of hundreds of airplanes would be prohibitively expensive. And if you buy new airplanes with WAAS, then you have fleet differences and additional training requirements as the new airplanes trickle in.

I assume many airlines have determined it's just not worth it.