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Vance
10-30-2008, 03:54 PM
We worked on the Predator yesterday installing the new, one piece crank seal. I let the goo dry over night.

It looked like a beautiful day to fly, clear, cool and no wind.

I hurried through my tasks and was down at the airport by 10:00 and in the air by 10:20.

Winds were at 040 degrees??? at 4kts. I was going to fly the pattern three times and come in for fuel and look for leaks.

I was going to fly to San Louis Obispo for lunck if everything checked out.

The airport was busy, landing and departing on 30. With my vertical card compass I could see that was an almost direct cross, slightly from the rear. I asked for a wind check as I taxied to 30 and it came back 030 degrees at 4kts which is a direct crosswind.

Take off went well and she leapt off the ground and climbed at 900 feet per minute with her nearly empty tanks and the cool air. I started backing off at 700 feet and went right past 800 feet still climbing at over 500 feet per minute at 2,000 rpm.

The turn to crosswind seemed a little odd and she had trouble knowing which way to point her nose. She started to descend at 1,800 rpm and I went right past 800 feet to 700 feet and caught her with 2,500 rpm.

I thought to myself, “This will be instructive.”

I rolled back the power abeam the numbers and turned base a little soon. I overshot the runway and had to come back for final. That landing was uneventful.

The wind sock at the approach end of the runway was flaccid. There were no rotor management challenges and she spooled right back up and leapt into the air again. I hit the big lift again at the end of the runway and she was even more vague about which way to point her nose. The windsock beneath me was a direct cross and out straight. I asked for a wind check and it was 12kts variable.

Each windsock I could see was headed in a different direction. The approach end of 30 was flaccid. My ground speed on down wind was 22 miles per hour at 50 miles per hour indicated airspeed. I turned cross wind and picked up a lot of ground speed. She stepped down about 10 feet twice on short final but the landing was uneventful.

She leapt off the ground again but this time I didn’t overshoot my target altitude. I lost about 50 feet turning crosswind and the turn was vague. On downwind we were at 18 mile per hour ground speed at 55 miles per hour indicated airspeed. My heading was wandering around and it took constant power changes to maintain my target altitude.

I called for a full stop landing and I was number two behind the Aero Commander on a right downwind abeam the tower for 30. I reported the Aero Commander in sight at my 9 O’clock high. I was cleared to land number two behind the Aero Commander. I know this pilot and he is proud of his prowess and confident in his aircraft. He came in high, stepped down around 20 feet twice and went around. The tower told him that winds were favoring runway 2.

I took two large steps down and decided to go around. The Aero Commander was making a teardrop??? Entrance to 2 when the tower said “142 Mike Golf, the winds are rapidly changing, they are now favoring 20. I watched the Aero Commander make a very untidy landing beneath me and the tower asked me my intentions. “Experimental 142 Mike Golf, I will make a left 360 and decide” I replied.

I found a big tail wind on heading 020 and had trouble maintaining my altitude. At 2,000 rpm I continued to climb. I asked to land on 20 and made a very vague base to final. I was cleared to land. As I stepped down over the hangers on short final I wondered how I would explain the rollover on the forum. As I crossed 12 showing 55 miles per hour indicated air speed and 500 feet per minute decent suddenly the indicated airspeed dropped to just above 20 miles per hour and I began a very rapid decent. I added power and pointed the nose at the ground and just as it was time to flare I saw 50 miles per hour indicated airspeed. My ground speed was 65 miles per hour and as we drew near earth, the ground seemed to accelerate. I was about to add more power to go around when I touched down. The tower told me to make a 180 degree turn and turn right at Alpha. I thanked them for their patience and asked for time to let my rotor spool down.

I visited Curtis in the tower and he said he had never seen the winds do that. He watched the wind socks change and that is why he gave me so many gratuitous wind checks. I asked him for the proper phraseology for I have no idea what I am going to do now and he felt that my left 360 plus “give me a minute to think about that,” was fine. He gave me a final wind check, 150 degrees at 18kts, gusts to 29kts.

The crank seal is no longer leaking and now we get to track down some of the less prolific leaks.

Thank you, Vance

fiveboy
10-30-2008, 05:03 PM
JEESH THAT SOUNDS HAIRY.I had to laugh about "how do I explain it on the forum"...Ive had that same fear!

helipaddy
10-30-2008, 05:55 PM
The wind sock was flaccid!
Brilliant choice of word, Vance!

Reminds me of a way a student of mine figured out Anabatic and Katabatic winds, he was looking puzzeled as to remember which wind went up the hill and which went down, and it was with an expression on his face as if he had discovered nuclear fusion, he announced to the class; "Up on Annie and down on Kathy!"

Mayfield
10-30-2008, 07:39 PM
The windsock beneath me was a direct cross and out straight. I asked for a wind check and it was 12kts variable.

Each windsock I could see was headed in a different direction. The approach end of 30 was flaccid. My ground speed on down wind was 22 miles per hour at 50 miles per hour indicated airspeed. I turned cross wind and picked up a lot of ground speed. She stepped down about 10 feet twice on short final but the landing was uneventful.

Vance,

You observed the above on your second pattern. Why did you fly the third pattern?

It appears you would not have been required to exhibit exceptional skill on the third landing if you had decided to full stop after the second.

I'm just trying to understand your thought process Vance. Did you feel compelled to fly the third pattern because your mission plan called for three patterns?

Best regards,

Jim

Vance
10-30-2008, 08:05 PM
Hello Jim,

I flew the second pattern better than the first.

I was trying to learn about what was happening.

The wind check from the tower did not indicate there was a problem.

I have often experienced wind shear on the approach end of 30.

Until the last lap the wind sock at the approach end was flaccid.

In my opinion it did not become unmanageable until the aborted landing.

Curtis, ATC, said he had not ever seen the wind come up that quickly or be that divergent.

I exhibited poor judgment.

Thank you, Vance

Mayfield
10-30-2008, 08:34 PM
Thanks Vance,

I'm pleased you landed safely.

Jim

JEFF TIPTON
10-31-2008, 04:55 AM
Vance you might want to download Advisory circular Pilot Windshear Guide "AC 00-54" available at this link

http://www.airweb.faa.gov/Regulatory_and_Guidance_Library/rgAdvisoryCircular.nsf/0/b3fb7dd636fb870b862569ba0068920b/$FILE/AC00-54.pdf

Also you might want to view the youtube video on Microburst's at this link

www.youtube.com/watch?v=TkavH9aZue8

Mike Schallmann
10-31-2008, 05:33 AM
On a related note I had a microburst hit my house this summer when I was gone, It took off a 90ft long by 4' wide section of roof off my house--my Son in Law and grandson -bless their hearts -- repaired the section and cleaned up the mess. When we got home several weeks later you couldnt even tell it was damaged. The only thing was that we are still missing a table and a couple of chairs--

Vance
10-31-2008, 05:59 AM
Thank you Jeff, that is some very interesting reading.

Each time I would say “there was none of that,” they would describe a situation with less warning.

Because I was flying the pattern I did not check further than the ATIS information for weather. I had checked AccuWeather.com before I left home and there was nothing that jumped out at me. Their hour by hour prediction looked benign. There were no unusual cloud formations and as I drove to the airport with the top and windows down there were no unusual winds. As I wrote that I realized that it was cool when I left home and the wind was warm at the airport just a few miles away.

I did notice my altimeter changing significantly on my third circuit, but not soon enough to do anything.

Jim is correct; I should have stopped after the second landing. My overconfidence got the better of me.

I have seen many of these things before at SMX and I have found flying the pattern in gradually increasing winds to be instructive. What made this event unusual was what appeared to be consistent weather with gradual increase in the wind followed by this very sudden increase in wind velocity and such extreme and localized changes in wind direction.

Curtis, in the tower had been watching my progress and he recognized my challenge on the third circuit. That is why he started gratuitous wind checks. As he put it “I felt like I could have walked faster than your down wind speed and your turns and decent looked uncharacteristically sloppy.”

I feel fortunate once again to have learned an important lesson without paying the price.

As I was coming in a student pilot and instructor were headed out in a Cessna 152. They only made one pattern.

In the next 15 minutes winds continued to increase but by the time I got home they were at 4 miles per hour and variable on my weather station. In the evening they picked up again and it began to rain.

Thank you, Vance

Vance
10-31-2008, 06:24 PM
I just finished reading every word of the advisory circular that Jeff posted.

I printed it out and read it very carefully.

I struggle to understand it.

Thank you Jeff.

Apparently the kind of wind I experienced at SMX is not that unusual.

The only warning sign I saw of it was dust near the hills.

There were no lenticular clouds and no thunderstorm activity.

There was no rain.

It was a warm wind near the ocean.

I found it very interesting.

It could have come out much worse.

Much of the techniques to manage wind shear were only remotely applicable.

I feel that understanding it better will make me a better pilot.

It seemed to be the approach of a weather front.

I need to mitigate my arrogance and curb my curiosity.

Jim was correct; I should have landed after the second circuit.

Thank you, Vance

Resasi
11-03-2008, 12:44 PM
It is instructive and useful to have you share your observations so carefully with us Vance. Thank you.

Vance
11-03-2008, 02:21 PM
Thank you Leigh,

I struggle to learn what it means to be a good pilot.

Given my background that tends to mean pushing my skillset.

I need to learn to make better aviation decisions.

I am grateful to receive the advice that helps me work through the learning process.

I am pleased that someone of your experience finds it instructive.

I expect to continue to struggle through the learning process.

I hope that people with more experience will continue to help and not tire of my conundrums or the plodding way I address them.

I would love to become a very good pilot.

Thank you, Vance

Resasi
11-03-2008, 03:28 PM
You are making all the right moves Vance. I am learning new things every single day and hope to continue to do so. This whole gyro scene I find incredibly interesting and the flying massively exhilarating.

j4flyer
11-03-2008, 06:38 PM
Hi Vance, congrats on the successful lesson. ( but don't push your luck, good guys are few)Your flight explains what I read in the weather data text for that day. The airports all around the area had winds in the 200-230 degree sector with 5-15Kts of wind. A few airports, yours included had winds coming from the North. I thought this unusual given the very short distance between these airports. I have to agree with the wind shear explaination. Winds going different directions at different altitudes or a change in wind speed at different altitudes can cause shear. These winds were likely caused by the approaching system coupled with terrain.

j4flyer
11-03-2008, 06:41 PM
I almost forgot, Bob Aspegren and I will be at AOPA in San Jose on Sat. If you attend, give me a call on my cell and lets have lunch-Bob Lewis

Vance
11-03-2008, 07:36 PM
Hello Bob,

It was a remarkable experience and I am not sure I would see it coming if it happened again. Most of the warning signs weren’t there. There was a big dust cloud along the mountains but I didn’t see it until I had touched down.

Slightly divergent wind socks and wind shear at the end of 30 are not that unusual.

I did not imagine that it would build so fast.

I look forward to seeing you and Bob at the AOPA convention.

I hope to be heading up Wednesday evening and staying through Saturday. I don’t have a room yet and I am not registered.

Thank you, Vance