Crosswinds and CRFI for the "Big" guys

[Rookie]

So heading back into YWG this morning and we get the wonderful news that the weather is now:

SPECI CYWG 181507Z 18025G31KT 1/4SM R36/1800V3000FT/D SN +BLSN VV002

RMK SN8

and the CRFI for runway 13 is .22.

Well the NDB for 18 would be nice for the into wind, but isn't really a reality for getting in, so I tell my FO we will do a PMA with the ILS for 13 if he is up to it (he is pretty green).

He agrees, so off we go. Bumpy as all hell, but the newbie is doing a relatively good job keeping the swords crossed.

One of the large, twin engine +100 seat airliners for a company that shall go nameless (to prevent this thread from turning into us vs. them) checks in with arrival. They are told of the weather and runway conditions and inform the controller that they can't accept 13 and they will need 18.

We got the lights on 13 about 1 mile back, I took control, and made a decent low vis (it was 1/4 below 50ft), x-wind, icey runway landing, if I do say so myself. Thank goodness for differential reverse!

The unnamed company missed on 18 and diverted to their alternate shortly after.

So the question I have is what are the limits as far as RFI and x-winds go for the big jets? Is braking more of an issue or is the potential loss of directional control more of an issue? How flexible can you be with strong crosswinds and low RFIs. Trying not to sound like a cowboy, it wasn't that much of a big deal for us in our trusty Metro II. I would imagine the ability for us to use differential reverse/power to keep tracking the centre line is the reason for that.

[Tiho]

Hey Tex, y'all might wanna check out AIP section Air 1.6.

The "recommended" max crosswind component for the runway you landed on, at that time, was 2 KTS! 'Course that's a recommendation fer us city slickers.

Sorry, couldn't resist the sarcasm.

[Steam Driven]

I would say that it would depend on your experience with landing in low CRFI and crosswinds, not to mention your trust in the accuracy of the reported CRFI. At times they can be hours old and conditions will have either improved or deteriorated.

We have a recommendation in our manual of a given value unless "optimum" conditions are present. "Optimum Conditions" is also defined. We also have a chart for crosswinds Vs. braking action. Finally, there is the trusty old Crosswind Vs. CRFI chart that can be found in the AIP and our manuals.

As for your "Cowboy" comment, one man's "Cowboy" is another man's pansy... What is acceptable for one guy is not necessarily good for the next. Even driving the same machine... You have to know your limits and fly within the guidelines laid out by your company. I've landed in YQT and used differential thrust to maintain centreline. Was it comfortable. No. Would I do it again. Probably not, however, experience has taught me that it is available and effective, should I need it.

Cheers.

[Vsplat]

There are significant issues with the accuracy and timeliness of CRFI. Not the least of which is that the value itself represents an average of the runway test, so very low and very high readings in sections (say, the section where you intend to brake) are dampened.

The issue of CRFI itself has just been wrung out in a specific TC working group on contaminated runways. I hope we see some changes as a result.

That said, is it better than nothing? Absolutely. Is it better than what the manufacturer says their aircraft will do? That depends. Manufacturer data tends to be modelled and assumes a specific surface. CRFI is what the runway is. Two perspectives, best when taken together, the whole being greater than the sum, if you get my drift.

About drift (sorry, couldn't resist). CRFI crosswind is a measure of lateral friction. It doesn't matter if you are a Metro or a B747, if there isn't any friction, then the wind will move you just as currents on water move a ship.

As for reverse, Remember that for an aircraft that is not perfectly aligned with the centreline, the reverse trust vector is partly rearward and partly to the side. Sometimes you have to cancel reverse to regain control.

A word about differential reverse. Props can sometimes get away with this practice depending on how their beta range is controlled. A weapon of last resort.

Intentionally applying differential reverse thrust on a jet landing with two good engines is taking needless risk. The cycle times and thrust control are simply too coarse to offer any kind of predictable control. Even with an engine out, if it is so slippery that thrust reverse is needed to save your life, the odds of departing the runway laterally or perpendicular to the centreline are excellent.

But, that is just my opinion

Vs

[Steam Driven]

"Intentionally applying differential reverse thrust on a jet landing with two good engines is taking needless risk.  The cycle times and thrust control are simply too coarse to offer any kind of predictable control.  Even with an engine out, if it is so slippery that thrust reverse is needed to save your life, the odds of departing the runway laterally or perpendicular to the centreline are excellent."

I should clarify my comments from my previous post. The Aircraft I was flying was the 737-200. The 737-200 has very effective reverse thrust and modulation is excellent and responsive for that aircraft.

I now fly the 737-700 and find that it's reverse thrust is not as effective, nor as responsive as the -200. The difference being in the "Cascade" type reversers which do maintain a forward thrust vector Vs. the "Deflector" or "buckets" on the -200 which completely block and deflect the thrust.

It comes around to experience, and not blanket statements about "needless risk". All aircraft behave differently, and that is why you must use your experience while operating within your company's operating policy.

Cheers.

[Vsplat]

Steam driven, it sounds like we are saying the same thing - not sure why the "blanket statement" comment.

As you point out, the technique you tried in YQT you probably wouldn't do again. It sounds like you did it to regain the centreline. You didn't plan to land on a low friction runway and rely on differential reverse. Different things.

I'm familiar with the 37's T/R system, as well as that of several small bizjets, the 320 and 330. Buckets are quicker than a sleeve, but nothing close to a prop, and even props struggle with this technique.

No one is criticising your experience, neither am I saying don't use whatever you've got to salvage a bad situation. The issue is how CRFI affects aircraft, and lateral friction effects are similar more than they are different.

At least in my opinion

Vs

[planett]

That same approach described this morning would not bother me in a metro, but it sure would have been a problem if there was any standing water at all even with half the crosswind. The differences between aircraft are significant when all the variables are considered, and until you know your limits, the CRFI privides a good conservative buffer. The time delay for differential reverse in even a small turbofan provides a daunting challenge, enough to make me always want to be symmetrical in application. A Garrett is in its element there.

[B75/76]

The CRFI and resulting x-wind limits as given in the AIP are not a/c specific and apply to all types. It is a judgement call based on, as mentioned previously, experience, company policy, a/c type etc.

For me it will often come down to the CYA factor. I would rather end up at my alternate than trying to explain my rational for going against the 'numbers'.

[Guest ACSideStick]

Hi Rookie,

Re:"So the question I have is what are the limits as far as RFI and x-winds go for the big jets? Is braking more of an issue or is the potential loss of directional control more of an issue? How flexible can you be with strong crosswinds and low RFIs. Trying not to sound like a cowboy, it wasn't that much of a big deal for us in our trusty Metro II."

Over 100 years ago, Wells Fargo was interviewing for the position of Stage Coach Drivers. Most applicants through the door, knowing the rough terrain that they would be expected to operate in, pushed their qualifications to the edge. When asked about how they felt about crossing the narrow mountain passes with a heavy wagon, 6 horses, and a coach full of passengers on board, the response was something like this, "I am an exceptional driver, and take pride in my skills. I have the ability to drive that wagon right to the edge of the cliff. I am well known for my skills. The next driver, when told of the previous drivers skill said "That sounds like he's learning, but I have the ability to put the wheels up to 1/2 over the cliff when needed. My skills are legendary". The third driver came in, and when told of the others skills was asked what he could do. The reply, I think, answers your question about CRFI limits and the big airlines, especially when you make a statement like "or is the potential loss of directional control more of an issue?

His reply was this-"They certainly sound like skilled horsemen, and I don't really think I'm what your looking for, you see, I spent many years working on being able to keep my team as far away from the cliff as is possible."

Guess who got the job?

I have had several years to contemplate interview questions with a major airline, and have always wondered, what makes the ultimate difference between one pilot and the other. Is there a measurable point in someones career to know when they are they ready(hours? Type? Skill?) Is there one question that is the only one that needs asking?

Remember, that long before you flew Worley's pipes, Those unnamed big twinjet pilots flew them. There is little that might be "skillful" to you, that wasn't done long ago in PA31, Metros, King Airs, Merlings, Hawkers, etc of those same pilots who went around and to their alternate today. They have scared themselves, and felt that adrenaline rush that happens when you've been to the edge of control, but everything went OK. We all have felt those feelings when momentarily, when we weren't quite sure how this was going to go.

We have many friends who didn't fare as well, and whose careers, and sometimes lives, were over in an instant, because they pushed it a bit too far, and luck-not skills was their only card left.

What's the answer to your question?

If I were to ask in an interview "What makes us believe you are ready for this, it would be the answer. "I can fly my aircraft completly within it's limits to it's destination, and get right down to minimums. If I can't land, I have the ablility to proceed directly to my alternate, go to the hotel and have dinner, no matter the inconvienience this might cause others. I won't feel bad in any way, and I will sleep soundly knowing that in no way, for one moment was I not sure of the outcome."

"or is the potential loss of directional control more of an issue? How flexible can you be with strong crosswinds and low RFIs. Trying not to sound like a cowboy, it wasn't that much of a big deal for us in our trusty Metro II."

[Guest ACSideStick]

PS. How much "potential loss of control" is reasonable to you?

[Guest directlaw]

SPECI CYWG 181507Z 18025G31KT 1/4SM R36/1800V3000FT/D SN +BLSN VV002

RMK SN8

I wouldn't land an Airbus on 13 in those conditions as it is well beyond the CFRI crosswind limit. Those charts although not perfect are all we have to keep our buts out of the weeds. I respect those charts end of story.

People put their lives in our hands. They trust us not to take undo risk. Once you go beyond those limits you are in test pilot land with pax on board. Would you feel comfortable being operated on by a Doctor who didn't follow guidelines? Who figured he would use you as a test case with no choice on your part.?

[Seeker]

PS. How much "potential loss of control" is reasonable to you?

ACsidestick:

I gotta say you're coming across with a real strong holier-than-thou attitude. Everything we do entails risk. You say landing in those conditions entails too much risk, well, maybe in an Airbus it does. Since he landed safely in the Metro I'd say that pretty much proves he was capable of handling the conditions.

seeker

[AIP]

ACsidestick:

I gotta say you're coming across with a real strong holier-than-thou attitude. Everything we do entails risk. You say landing in those conditions entails too much risk, well, maybe in an Airbus it does. Since he landed safely in the Metro I'd say that pretty much proves he was capable of handling the conditions.

seeker

Or did he get lucky ? ?

I found no holier than thou in those statements.

Everyone and every machine has its limits, experience teaches us what those limits are.

We are all pretty good at the armchair quarterback routine, BUT and it is a big BUT, we were not there at the time and as we who fly and have BEEN there can attest, it is a very dynamic thing. Never is it the same twice.

If that is the decision made and it was safe course of action, so be it.

No debate from me.

[Rookie]

Not that this makes my decision correct, but we had several flights deal successfully with the same conditions I did.

I didn't do it because I felt company pressure to. I didn't feel pressure to get our pax (this case frieght) in on time. I didn't do it because I had no alternate or no fuel. YBR was clear and we had lots of gas.

I did it because I was comfortable with the conditions. And to be brutally honest, I would probably do it again. The taxi in was more difficult than the approach/landing.

(now where'd I put my spurs..........)

[Guest rattler]

Just keep in mind the old saw: "There are old pilots and there are bold pilots but there are damned few old and bold pilots"

[Guest ikfu]

Gotta side with 'sidestick'. Mo - momentum is a bitch, as people that move to a heavy will attest. You actually have to use the brakes to get them down with all that energy, unlike the truckosaur, or diesel neuf where it was considered bad planning if you had to pull out the brakes.

[GDR]

Just keep in mind the old saw: "There are old pilots and there are bold pilots but there are damned few old and bold pilots" 

Now that I'm old and retired I think that I can safely say that it sounds like a no sweat operation to me. Now back in the old days .................

[handyman]

Not that this makes my decision correct, but we had several flights deal successfully with the same conditions I did.

I didn't do it because I felt company pressure to. I didn't feel pressure to get our pax (this case frieght) in on time. I didn't do it because I had no alternate or no fuel. YBR was clear and we had lots of gas.

I did it because I was comfortable with the conditions. And to be brutally honest, I would probably do it again. The taxi in was more difficult than the approach/landing.

(now where'd I put my spurs..........)

Rookie,

I think we have all been there years ago flying a small or smaller aircraft in challenging conditions. I understand where you’re coming from and I used to think like you. You’re flying a Metro and you feel you’re one with the machine. You fly lots in any given month and your proficiency is high. You may have lots of skill and this helps to accomplish this task. There is pressure whether perceived or not from the company, passengers, other pilots in your company and even yourself to succeed. You accomplished the landing and feel it was safe. You are obviously a very skilled pilot...BUT...skill is one thing and judgment another.

If you were low on fuel, it's wonderful that you have the knowledge and skill to perform the maneuver. But, you took a risk...why? This is a major factor I believe in why the industry has more accidents in smaller commercial aircraft than larger ones.

The large airlines have strict policies and criteria for landing. They can't afford to have an accident with 100 or 400 people on board. They are not willing to take the risk just to avoid a diversion.

Also remember, you obviously have the skill and accomplished the landing. What if another company Metro was behind you with a less capable pilot? Imagine the pressure on him. Would you feel any guilt if he attempted the landing and crashed?

Just a little food for thought.

Fly safe.

[sjsa]

Interesting thread.

I landed in YWG the night before last in a (100+ little, compared to some) jet when R13 was .24 CFRI.

I cant remember the wind but in any case it worked out to .22 CFRI x-wind while R36 was a direct x-wind but .39 CFRI. Our min CFRI is .25 @ WestJet so we said R36 was an "operational requirement" and proceeded to an uneventful landing with a x-wind CFRI of about .28.

I guess if we were forced into R18 by winds it would have been a night at the Valhalla.

I think beyond the hard rules of your company a pit in the tummy may be a good guideline. I do admit that as I age my tolerance for those pits in the tummy decrease

[.70 mach]

Rookie

I was once told the old saying," you have two bags: one bag full of luck and one empty bag of experience, your goal in this industry is too fill the bag of experience before your bag of luck runs out".

"Perimeter 610, a Swearingen SA226-TC Metro II , C-GIQF was on a scheduled flight, under instrument flight rules from St. Theresa Point to Winnipeg, Manitoba, with 2 pilots and 13 passengers on board. The crew was anticipating a visual approach to Rwy 36 at the Winnipeg airport but, because of conflicting traffic, accepted vectors for the ILS 13 . At Approximately 1908 the aircraft landed to the right of the centreline, then drifted further right and departed the runway surface..................."

So Rookie, ask that person if the decision to accept the approach for 13 paid off for him. I know circumstances are different in both cases but the decision making seemed the same. Your handle as "Rookie" makes me believe you might be new to the left seat of the "San Antonio sewer pipe" and with that I think you also mentioned that this was a freighter run. If you need bigger challenges take up "cougar wrestling" down at the Palomino because you might find yourself one night when you do run out of luck, on a dark stormy medivac into Red Sucker.

This is not to talk demeaning to you but rather give advice because many of us have sat in that very seat that you are in and can now laugh about the good old days.

[Rookie]

I am very familiar with the runway excursion you refer to, and unfortunately it is a very poor comparison. The circumstances and events that occured on that flight were many. I won't divulge the info here, but it wasn't as simple as landing on a slippery runway in a crosswind. But the decision was made to save time and to avoid a TS sitting east of the airport. Unfortunately the storm moved over the airport as the landing was being made. Again, I won't go into more detail than that.

In making the decision, I wasn't looking for a challenge. I made the decision based on what conditions I believed I, my FO, and my airplane could handle. I also don't believe "luck", as you put it, played a role in making a successful approach/landing in those conditions.

My rookie handle has been with me for 5 years. I am a relatively new captain on the metro (300hrs) but have almost 3000 total on type and 1000 mutli-PIC. By no means am I a veteran, but I am relatively experienced. I have done many a dark stormy medevac into YRS and many other places in the north. I have faced much larger challenges than that landing I refer to and so far have had no reason to make the CADORs. (knock on wood)

[Guest Horus]

Interesting discussion.

Now sjsa's post; about 3 back. sjsa seems to suggest a sliding CRFI? Maybe I am reading the post wrong. My understanding is that the CRFI for a runway is the CRFI; regardless of whether the wind is right down the pipe or a 90 degree x-wind.

The chart , Recommended Crosswind Limits for CRFI, only allows you to take the wind component read from the degrees off centerline, sraight down to a recommended CRFI limit. Anyone else?