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A teachable moment


FastEddieB

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Roger Lee just posted this YouTube video to another thread, which I've bookmarked as a "Favorite".

 

 

We have hashed out appropriate landing speeds ad nauseum, so this is not meant to convince anybody of anything, but to point out to students what I think is an important lesson.

 

Every Sport Pilot and Private Pilot had to demonstrate a landing at approximately stall speed on his or her checkride. I was taught to use maximum flaps as consistent with conditions. That has held me in good stead for many decades, though I realize it makes some pilots uncomfortable, and may not be appropriate in all planes.

 

Which leads one to ponder, how did it come about that the pilot in the video came to land in the manner he did? It sure looks to me like minimal flaps were used, and to be generous the landing looked to be at least 10 kts fast.

 

How much energy is implied by an extra 10 kts? Step by step, assuming a full flap stall speed of 40 kts...

 

1) Divide the smaller number (40) into the larger number (50). The result is 1.25.

 

2) That means 50 is 1.25 times larger than 40, or 25%.

 

But kintic energy increases as the square of that increase, so...

 

3) Square 1.25, or just multiply it by itself. The result is 1.5625

 

4) Expressed as a percentage, the plane landing at 50 kts has just over 56% more energy to dissipate after touchdown. Has to go somewhere, and you can see how some of it got dissipated in the video.

 

As I said, I think assuming 50 kt touchdown speed in the above video is quite conservative. As an exercise, maybe compute the numbers as above for 55 or even 60 kts. Or at the other extreme, at just 45 kts. All assuming a full flap stall speed of 40 kts.

 

I am not going to go back and forth with the "fly it on" crowd - we're all adults and can land in any manner and at any speed we choose to. But as the thread title says, I just did not want a teachable moment to slip away.

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I believe I know the instructor that worked with this pilot, transitioning him to a CTSW.  He's an old school guy, used to work the Tower at South Lake Tahoe when they had one.  This transition was a struggle.

 

My guess is the transition targeted 30* flaps as normal landings with a closed throttle.  No doubt the first CT forum provided a lot of new school fly it on thinking.

 

His skills may have been lacking that day but he was a very nice man.

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I meant to cast no aspersions.

 

Pondering about how a pilot gets into that situation is in no way a reflection on that person as a person.

 

I think Roger would like it that we were talking about him.  

 

As Roger Lee pointed out this didn't have to happen.  A high/long approach was an automatic go-around here.  Paying attention and steering after touchdown was another.

 

Eddie, you right this is a real world FDCT example of how minimizing landing speed minimizes mishaps.

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The phrase "teachable moment" is a sociopolitical term co-opted from a 1952 book by Robert Havighurst, "...It is important to keep in mind that unless the time is right, learning will not occur. Hence, it is important to repeat important points whenever possible so that when a student's teachable moment occurs, s/he can benefit from the knowledge."

 

The video shows a landing by a CT on a dirt strip where the pilot veered off to the side and hit some debris or a rock  and flipped the plane over.

 

The cause of the crash was debris/rock....nothing else can be safely assumed or "taught' looking at this crash IMHO.

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Looked like he tried to taxi to the side of the runway before he was slowed down, thought better of it and tried to re-enter the runway to avoid other airplanes, and just lost directional control.  It seems more of a taxi accident than a landing accident to me.

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Looked like he tried to taxi to the side of the runway before he was slowed down, thought better of it and tried to re-enter the runway to avoid other airplanes, and just lost directional control.  It seems more of a taxi accident than a landing accident to me.

 

Look at the control surfaces

 

Why at 10-11 seconds am I seeing the rudder?  Either Roger pushed the left pedal or the uneven surface turned it for him and he didn't correct.

 

It has the appearance of an intentional left turn.

 

============================================

 

What would it have looked like if he would have used 30/40* flaps and contacted the runway near the beginning at 13kt slower speed? 

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BTW, I also find it odd than once the airplane comes to rest the reaction is "I got that on film, too!" as if that is the most important thing in the situation.  And everybody just stands around looking at the airplane, not a single person moved at all to check on and help the pilot...

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Left rudder deflection at 10-11 seconds.

That's where he exits the runway going too fast and too close to other airplanes. That looked intentional to me, otherwise he would have corrected it more quickly. He waits several seconds before going back the other way at 13-15 sec. That's when the weight shift on the gear bites him hard. I wish the camera man had not missed the moment of the actual LOC.

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At 11 all 3 gear are still on the runway.  He is both drifting off and at this point turning off instead of turning on.

 

What you don't see tells more than what you do see.  You don't see flaps, 40* were called for. you don't see the stabilator deflected.  The stab should have been full aft at contact and kept there.  You also don't see the nose wheel in the air, these flat landings are fast landings.  I wonder if the throttle was even closed.

 

I have to agree, normal landings with 30*, and a full aft stick and a closed throttle are going to avoid mishaps.  If you do it all the time you are actually good at it when you need the slowest possible speed.

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I tried, the video is crappy enough I can't see where they are for sure.  I don't think you can either.   ;)

 

IOW

 

From 5-11 seconds the CT was angling to the left, that's a long time.  At 11 seconds there was no runway left the CT had arrived at the runway's edge.  At 11 seconds the only reasonable position for the rudder would be deflected to the right to provide steering back to the runway both from the nose wheel and aerodynamically.  At 11 seconds the rudder becomes the one thing we should not see but since we do the CT departs the runway at second 12.

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I talked to the piloty the day after it happened. It was choppered out. All the above in my original post led up to his incident. All could have been avoided. This landing should have been rehearsed in his head with a possible fly-by. It was a 2500' runway. Too short, narrow and humped in the middle for mistakes and a fair landing skilled person. When he was heavy on the brakes he was still too fast and his weight was not fully on the ground so steering and rudder control was an absolute must. When he landed long, hot and couldn't stop he was already in panic mode and quit thinking what was causing his real problem. Other CT's did land there during that time, but all landed at the begining of the runway, 30-40 flaps, 10+ knots slower, stayed off the heavy uncontrollable braking and didn't forget to steer.

This pilot should not have even been there. His landing skills were fair at best.

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I talked to the piloty the day after it happened. It was choppered out. All the above in my original post led up to his incident. All could have been avoided. This landing should have been rehearsed in his head with a possible fly-by. It was a 2500' runway. Too short, narrow and humped in the middle for mistakes and a fair landing skilled person. When he was heavy on the brakes he was still too fast and his weight was not fully on the ground so steering and rudder control was an absolute must. When he landed long, hot and couldn't stop he was already in panic mode and quit thinking what was causing his real problem. Other CT's did land there during that time, but all landed at the begining of the runway, 30-40 flaps, 10+ knots slower, stayed off the heavy uncontrollable braking and didn't forget to steer.

This pilot should not have even been there. His landing skills were fair at best.

 

Got it, thanks Roger.

 

CT, I agree with everything you said, it's just not clear from the video if he left the runway intentionally or drifted off by accident.  In any event, very sad.  He was definitely carrying too much speed into the landing, look at how flat his touchdown is.

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The runway had a center crown that would want to pull left, but it was easily steerable. He grabbed brakes and quit steering. The runway was narrow so steering was foremost. Even with the mistakes leading to this panic put it over the edge. He locked into one thing. Brakes, and they weren't there with his speed on dirt.

My original video is a little clearer than the downloaded version.

 

This was at a fly-in in Idaho. They should have never gone to this strip. You always plan runways around the worst landing pilot not the best. It was too remote with no immediate help. The risk for an incident with any of the pilots was too high to be a good choice.

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It was a 2500' runway. Too short...

Stipulated it was too short for this pilot on this day.

 

But 2,500' is not short for a CT. In fact, it's several times longer than a CT should require under the most adverse conditions.

 

The CTLS POH shows a landing roll with 30° flaps of 750' at max gross and 9,000' DA! At SL, less than 500'. Even allowing for adjustments for the landing surface, 2,500' should not be considered "short" for a CT pilot.

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To compound the speculation, at one point there was a claim that the left brake locked.  I have to agree... too fast, too little flaps, & beyond skill level.  While a CT CAN land on something like that, it looks like the potential wear/tear on the gear (esp front) would not be worth it.

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To compound the speculation, at one point there was a claim that the left brake locked.

I've actually used that as part of my thought experiment:

 

Me: "How would you land if you knew a brake was going to lock up on touchdown?"

 

Student: "As slowly as possibly."

 

Me: "Well, how do you know a brake is not going to lock up on your next touchdown?"

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Stipulated it was too short for this pilot on this day.

 

But 2,500' is not short for a CT. In fact, it's several times longer than a CT should require under the most adverse conditions.

 

The CTLS POH shows a landing roll with 30° flaps of 750' at max gross and 9,000' DA! At SL, less than 500'. Even allowing for adjustments for the landing surface, 2,500' should not be considered "short" for a CT pilot.

My interpretation is not that the runway is too short, but that he landed too short /or long (anyways to close to the parking area) , depends on your piont of view. Personally , I use brakes , the least possible on grass and/or gravel strips. Most of my breaking is aerodynamic.

 

Cheers

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