Do you really trust that wet runway performance data

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Rockie
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Re: Do you really trust that wet runway performance data

#51 Post by Rockie » Mon Sep 10, 2018 6:24 pm

pelmet wrote:
Mon Sep 10, 2018 5:37 pm
No guarantees but I'll stick with Inspector Whatever.
Of course you do, and I believe I've already suggested that. Do what you like in your C150 Pelmet, but if you fly for a living you would be wise to follow your company requirements. Or don't...
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Re: Do you really trust that wet runway performance data

#52 Post by C.W.E. » Mon Sep 10, 2018 6:50 pm

pelmet:

I used to fly for a company in Yellowknife that operated a DC6 and we often landed on the ice with it that was wet ice with no
snow cover at all.

It was just routine flying for us and of course there were no runway reports for us to figure out if we could land and at what cross wind component we could land and what landing distance we needed, we just let it stop when it could.



Could you discuss that with Rockie to get his opinion on that?
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Re: Do you really trust that wet runway performance data

#53 Post by Rockie » Mon Sep 10, 2018 6:56 pm

C.W.E. wrote:
Mon Sep 10, 2018 6:50 pm
Could you discuss that with Rockie to get his opinion on that?
Are you not able to discuss that with me yourself Chuck? My opinion is that you are as experienced at doing what I do as I am landing on ice flows in the arctic. I'll keep in my lane, you keep in yours.
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Re: Do you really trust that wet runway performance data

#54 Post by pelmet » Mon Sep 10, 2018 7:04 pm

C.W.E. wrote:
Mon Sep 10, 2018 6:50 pm
pelmet:

I used to fly for a company in Yellowknife that operated a DC6 and we often landed on the ice with it that was wet ice with no
snow cover at all.

It was just routine flying for us and of course there were no runway reports for us to figure out if we could land and at what cross wind component we could land and what landing distance we needed, we just let it stop when it could.
I landed on many ice strips as well as an F/O. Have to admit, not much wet ice. On the small props, it could be anywhere as far as the north pole but with the big props, the ice was usually(but not always) scarified on frozen lakes which made the braking quite reasonable and a crosswind more comfortable. Old ocean ice is usually not so good as new ice as long as it is thick enough. Thickness obviously was critical. We didn't have TALPA in those days either if I remember right.

That's not to say that there were not other flights that had incidents like landing at the wrong and very short for type) ice strip or doing a 360.

Some here do rely on the numbers to be able to figure it all out.

We always had reverse on my flights but not all company aircraft did. Did you have reverse on the DC-6?
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Re: Do you really trust that wet runway performance data

#55 Post by C.W.E. » Mon Sep 10, 2018 7:36 pm

Here is a nice video of reverse in a DC6 Pelmet.

On wet ice there would be no dust. :mrgreen:


http://calclassic.proboards.com/thread/5526
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Re: Do you really trust that wet runway performance data

#56 Post by C.W.E. » Mon Sep 10, 2018 7:49 pm

Are you not able to discuss that with me yourself Chuck? My opinion is that you are as experienced at doing what I do as I am landing on ice flows in the arctic. I'll keep in my lane, you keep in yours.
Interesting comment Rockie.

Have you had any experience driving in both lanes ?
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Re: Do you really trust that wet runway performance data

#57 Post by pelmet » Mon Sep 10, 2018 7:55 pm

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.
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Re: Do you really trust that wet runway performance data

#58 Post by C.W.E. » Mon Sep 10, 2018 8:05 pm

(Have seen toilet paper rolls dipped in fuel

That was the most common landing aids we had and we called them flare pots when I was flying the DC3 for Austin Airways in the late sixties and early seventies, actually they worked very well.

There was no GPS in those days, only ADF approaches at the northern villages.

The Twin Otter was a real nice airplane and the availability of GPS was like a miracle gift from God. :mrgreen:
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Re: Do you really trust that wet runway performance data

#59 Post by Rockie » Mon Sep 10, 2018 8:11 pm

You guys need a room?
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Re: Do you really trust that wet runway performance data

#60 Post by pelmet » Mon Sep 10, 2018 8:21 pm

C.W.E. wrote:
Mon Sep 10, 2018 8:05 pm
The Twin Otter was a real nice airplane and the availability of GPS was like a miracle gift from God. :mrgreen:
There were even jet operations on ice but I never got to do that unfortunately. More than one airline in Canada has done that.

Wet ice......I know one crew who got a surprise. Watch out for wet ice. I suppose from a crosswind point of view, differential reverse could save the day, have seen it discussed in the landing briefing but who wants to be there. And there were no TALPA charts to look at for that.
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Re: Do you really trust that wet runway performance data

#61 Post by C.W.E. » Mon Sep 10, 2018 8:50 pm

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. :D

Remember I am talking about landing on frozen lakes that have lots of room to land on, not runways at airports.
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Re: Do you really trust that wet runway performance data

#62 Post by pelmet » Mon Sep 10, 2018 8:54 pm

C.W.E. wrote:
Mon Sep 10, 2018 8:50 pm
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. :D

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.
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Re: Do you really trust that wet runway performance data

#63 Post by rookiepilot » Tue Sep 11, 2018 3:26 am

pelmet wrote:
Mon Sep 10, 2018 7:55 pm
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.
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Re: Do you really trust that wet runway performance data

#64 Post by Eric Janson » Wed Sep 19, 2018 8:52 am

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.
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Re: Do you really trust that wet runway performance data

#65 Post by Rockie » Wed Sep 19, 2018 9:15 am

Eric Janson wrote:
Wed Sep 19, 2018 8:52 am
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.
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Re: Do you really trust that wet runway performance data

#66 Post by Eric Janson » Wed Sep 19, 2018 2:00 pm

Rockie wrote:
Wed Sep 19, 2018 9:15 am

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.
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Re: Do you really trust that wet runway performance data

#67 Post by pelmet » Wed Sep 19, 2018 9:01 pm

Rockie wrote:
Wed Sep 19, 2018 9:15 am
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.
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Re: Do you really trust that wet runway performance data

#68 Post by Rockie » Thu Sep 20, 2018 1:21 am

Let us know how it goes this winter Pelmet when you can’t land anywhere after adding 30 - 40% to all your TALPA calculations.
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Re: Do you really trust that wet runway performance data

#69 Post by Rockie » Thu Sep 20, 2018 1:21 am

Let us know how it goes this winter Pelmet when you can’t land anywhere after adding 30 - 40% to all your TALPA calculations.
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Re: Do you really trust that wet runway performance data

#70 Post by pelmet » Thu Sep 20, 2018 5:41 am

Rockie wrote:
Thu Sep 20, 2018 1:21 am
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.
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Re: Do you really trust that wet runway performance data

#71 Post by Rockie » Thu Sep 20, 2018 10:33 am

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.
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Re: Do you really trust that wet runway performance data

#72 Post by pelmet » Thu Sep 20, 2018 12:16 pm

Rockie wrote:
Thu Sep 20, 2018 10:33 am
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.
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Re: Do you really trust that wet runway performance data

#73 Post by Rockie » Thu Sep 20, 2018 8:28 pm

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.
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Re: Do you really trust that wet runway performance data

#74 Post by pelmet » Fri Sep 21, 2018 4:00 pm

Rockie wrote:
Thu Sep 20, 2018 8:28 pm
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
Eric Janson wrote:
Wed Sep 19, 2018 2:00 pm
Rockie wrote:
Wed Sep 19, 2018 9:15 am

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.
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Re: Do you really trust that wet runway performance data

#75 Post by Rockie » Sun Sep 23, 2018 10:01 pm

pelmet wrote:
Fri Sep 21, 2018 4:00 pm
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.
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