Do you really trust that wet runway performance data

[C.W.E.]

The beauty of landing on wet ice is you can just hold the crab angle and touch down and slide straight along your landing path pointed into the wind without having to worry about control inputs.

Remember I am talking about landing on frozen lakes that have lots of room to land on, not runways at airports.

[pelmet]

The beauty of landing on wet ice is you can just hold the crab angle and touch down and slide straight along your landing path pointed into the wind without having to worry about control inputs.

Remember I am talking about landing on frozen lakes that have lots of room to land on, not runways at airports.

Actually, you will find some of the biggest Boeing aircraft have landing in a crab on wet/slippery runways as an acceptable technique in crosswind conditions. However, I heard about some guys trying it on a dry runway recently and wishing they had not. Caught out by the deviation from centerline detection that goes straight back to the company(maybe pax complaints as well). They can detect just about anything these days...but not PAPI and VASI deviation alone.

[rookiepilot]

Thanks,

We used to go into ice strips at night as well. Pitch black all around(except for a few camp lights) on cloudy or moonless night with no PAPI/VASI and marginal lighting powered off a generator(Have seen toilet paper rolls dipped in fuel once for departure as well). I remember one place had one half of the lights fairly bright but the other half quite dim which could really screw up your profile as the first half of the runway didn't come into view until quite close-in.

We did have GPS and I would plan on being configured with gear down and flaps fully extended at five miles and 1500'. Then a 700 fpm descent with a target altitude for each mile back from the runway. If I was PNF, I would act a bit like a PAR guy and say the desired altitude as we reached each mile back. "4 miles, 2300 feet, adjust your rate of descent". If we were at 2400 feet, the PF knew exactly what to do right away. Once within a couple of miles, things seemed to get much easier(except the one time we landed in what appeared to be 1/2 mile vis or less in shallow fog...no kidding).

Twin Otter ice work was all daytime flying for me. Usually it was on hard(and usually really hard) wind-packed snow on top of the ice. One could break a ski if not careful. Sunny skies giving good depth perception was key for an unfamiliar location. We filled black garbage bags with snow for runway markers at some locations. If I remember right, for a required depth of freshwater ice, one needs more saltwater ice depth.

Cool stories. Such a different world of flying.

[Eric Janson]

Here's an incident in New Zealand.

https://www.atsb.gov.au/media/5774950/a ... -final.pdf

A very good report with a detailed look at the regulations and the shortcomings of the same.

[Rockie]

A very good report with a detailed look at the regulations and the shortcomings of the same.

A few things worth mentioning.

1. This incident predates TALPA by almost a year.
2. The crew regarded a "damp" runway as "dry" for their calculations. TALPA considers a damp runway as "wet".
3. TALPA calculations are more conservative than equivalent conditions pre-TALPA (sort of what SAFO 15009 recommends), and they also add an additional 15% as required.
4. There was a tailwind not considered in the calculations.
5. The last 1/3 of the runway was below the friction threshold where maintenance action is required. This information was not available to the crew, and that is definitely something that needs to be fixed.

[Eric Janson]

5. The last 1/3 of the runway was below the friction threshold where maintenance action is required. This information was not available to the crew, and that is definitely something that needs to be fixed.

That one surprised me - I would expect the runway to be closed if this was the case. Luckily they didn't go off the end - the Airport Authorities would probably be legally liable.

We use the airbus Flysmart App for landing distance calculations - very easy to modify data and re-calculate. We can also easily add MEL items and failures.

Paper charts belong to the past imho.

[pelmet]

5. The last 1/3 of the runway was below the friction threshold where maintenance action is required. This information was not available to the crew, and that is definitely something that needs to be fixed.

A classic example of why you can't trust the wet runway performance. It is based on an assumption that the runway meets the friction requirements. But I'm sure all those Caribbean(or other) third world countries we fly to meet the spec all the time.

https://www.thehindu.com/news/cities/mu ... 247826.ece


Beware of what advice you take.....and follow the appropriate SAFO's which are still valid according to the FAA. Saying that it needs to be fixed ain't gonna help you tomorrow.

[Rockie]

Let us know how it goes this winter Pelmet when you can’t land anywhere after adding 30 - 40% to all your TALPA calculations.

[Rockie]

Let us know how it goes this winter Pelmet when you can’t land anywhere after adding 30 - 40% to all your TALPA calculations.

[pelmet]

Let us know how it goes this winter Pelmet when you can’t land anywhere after adding 30 - 40% to all your TALPA calculations.

It can be very hazardous for a pilot to misinterpret what they read. I suggest that you re-read what I wrote and what the SAFO says. Wet runways due to heavy rain are a year-round phenomena and more likely in the summer(including the rarity of performance limited landing situations). Typically such situations are short-lived leading prudent pilots to delay a landing by 30 minutes or less on these rare occasions.

Beware of misinterpretations and misunderstandings.

[Rockie]

Ok. Tell us what your captains say when you let them know you can’t land because you added some arbitrary number onto the TALPA calculations, or that you think you should hold for 30 minutes waiting for the runway to dry.

[pelmet]

Ok. Tell us what your captains say when you let them know you can’t land because you added some arbitrary number onto the TALPA calculations, or that you think you should hold for 30 minutes waiting for the runway to dry.

Once again read the still valid SAFO 15009 on the FAA website for info on the applicable conditions. Nowhere does it say anything about waiting for a dry runway. Waiting for heavy rain to stop might be an idea though which unfortunately has led to many overruns over the years.

Beware of misinterpretation and misunderstanding....and what advice to believe.

[Rockie]

Heavy rain makes a runway contaminated, not wet. Heavy rain is also usually associated with CB’s putting one further outside the simple “wet runway” scenario you’re talking about.

15009 is like saying “be careful out there”. Thanks Pelmet, but the FAA themselves have since developed very specific ways to do that which the Industry is required (there’s that word again) to use. We are required (that word again) to use the most limiting of either reported or observed conditions in making our calculations. It just doesn’t get any clearer than that Pelmet.

But as I’ve said many times before, you’re welcome to do whatever you can convince your captain to do.

[pelmet]

Heavy rain makes a runway contaminated, not wet. Heavy rain is also usually associated with CB’s putting one further outside the simple “wet runway” scenario you’re talking about.

15009 is like saying “be careful out there”. Thanks Pelmet, but the FAA themselves have since developed very specific ways to do that which the Industry is required (there’s that word again) to use. We are required (that word again) to use the most limiting of either reported or observed conditions in making our calculations. It just doesn’t get any clearer than that Pelmet.

Glad that you believe what the FAA tells you to do. Read the earlier posted email information their Air Transport Division wrote about ops in heavy rain. I just suggest following regulating authority recommendations.

Time will prove me right(as it always does in my discussions with you) as seen here in this recently updated and critically important thread... http://www.avcanada.ca/forums2/viewtopi ... 1#p1052111

5. The last 1/3 of the runway was below the friction threshold where maintenance action is required. This information was not available to the crew, and that is definitely something that needs to be fixed.

That one surprised me - I would expect the runway to be closed if this was the case. Luckily they didn't go off the end - the Airport Authorities would probably be legally liable.

As we can see, even a highly experienced pilot might expect a runway to be closed if it doesn't meet the spec but guess what......things don't always happen as expected. And that incident was in a first world country. What do you expect in the third world including places like Mexico and the Caribbean where many Canadian pilots fly on a regular basis.

Beware of blindly following the numbers and of what advice you take. If the performance margins are very tight, maybe try plan B.

Until then, thanks for another discussion.......unless I get a further update from my request from the FAA on when we can expect changes to appropriate SAFO's to be made.

[Rockie]

I just suggest following regulating authority recommendations.

The “be careful out there” one from 2015 anyway. It’s the far more detailed requirements from 2016, 2017 and 2018 that you ignore. I’m beginning to suspect you’re a flight sim guy who reads a lot and pretends.

[pelmet]

I just suggest following regulating authority recommendations.

I’m beginning to suspect you’re a flight sim guy who reads a lot and pretends.

Oh oh, that would mean a flight sim guy knows more about performance than you......as backed up by the FAA.

[Rockie]

Well then, what do you do in the real world today when the properly applied RCAM says you can land safely, but after adding 30-40% as per 2015’s SAFO 15009 you cannot? How exactly does performance expert Pelmet adhere to his own recommendation then?

Explain the steps you personally follow to determine if it’s safe to land on a wet runway Pelmet - in the real world - today. What does your Captain and Chief Pilot say when you decide it’s unsafe to land after you add an additional 30-40% to the approved method of landing distance calculations?

Do you wave 2015’s SAFO 15009 in the air spouting “but, but, but the FAA says...”?

Answer truthfully Pelmet.

[pelmet]

Well then, what do you do in the real world today when the properly applied RCAM says you can land safely, but after adding 30-40% as per 2015’s SAFO 15009 you cannot? How exactly does performance expert Pelmet adhere to his own recommendation then?

Explain the steps you personally follow to determine if it’s safe to land on a wet runway Pelmet - in the real world - today. What does your Captain and Chief Pilot say when you decide it’s unsafe to land after you add an additional 30-40% to the approved method of landing distance calculations?

Do you wave 2015’s SAFO 15009 in the air spouting “but, but, but the FAA says...”?

Answer truthfully Pelmet.

The reality is that the situation rarely occurs. How often are you landing on a runway with loads of margin....almost always. Sometimes you are close to your performance margin but the weather is usually good. I might get a wet runway perhaps 1 in 20 times. And even when the runway is wet, rarely do we encounter a situation where there is heavy rain(I suppose it varies by carrier and area of operation). And it is much rarer to happen to be landing on a short runway where one is close to performamce limits combined with heavy rain. I don't remember encountering such a situation myself but it obviously happens and likely will sometime.

But in the end, it really is just using a bit of common sense.

So let's look at a real world situation based on an accident. I know, I know....you will say that it was before TALPA but it is a perfect example of not using common sense.

Wet runways, moderate to heavy rain on approach, heavy landing weight, one runway is short, one runway is long. The short one has the ILS, the long one has non-precision approach. Landing performance is within limits for the short runway, but why would you use it. Sure, one can say that the aircraft landed longer than desired but who hasn't floated a bit on landing. Why accept tight margins if an alternative is available with better margins.

I am talking about the Cargojet 727 in YQM a few years ago. Use some logic. All they had to do is choose the longer runway. If the exact same approach had been performed on the longer runway, it would have worked out OK. But that would have involved doing a non-precision approach. I wonder if they would have requested the longer runway if both had an ILS.

http://www.bst-tsb.gc.ca/eng/rapports-r ... 0a0032.pdf

As for what the chief pilot would say if one decided not to land if the crew was not comfortable...I hope at your company, they would say nothing(let us know). As for me, I am just a flight simmer so I don't have to worry about the captain, chief pilot, or anyone else. .

[Rockie]

A non-answer. This situation happens whenever the runway is wet and not very long Pelmet. In those cases adding 30-40% (which you conveniently do not address) easily puts you into the unsafe / undoable range. What then? When the numbers say you can, but First Officer performance specialist Pelmet says you can’t, what do your Captain and Chief Pilot say?

Actual cases Pelmet.

What’s that? It’s never happened to you?

What a surprise.....

[pelmet]

Actual cases Pelmet.

Just gave you one. Short runway, moderate to heavy rain. Performance numbers said OK. Went off the runway at 50 knots while hydroplaning. Probably would have happened using TALPA numbers as well. But if I had been the F/O on that flight where I guarantee you the 30-40% addidive recommended by the FAA showed that it was not possible to land on 06, I would have suggested 10. Actually, I would have anyway. The 727 can be landed at max landing weight on a 6000 foot dry runway but if it is wet and significant rain is falling, why on earth would you not choose the 8000 foot one.

Pelmet...hoping to achieve First Officer status as soon as I get my 1500 hours of flight simming. But at least I know more about performance than Rockie.