Updraught

[embayweather]

i was flying my aircraft today in the beach where I normally go. Not high, not far, just practising manoeuvres for my PfCO. But I noticed that it was getting very high, and indeed almost at the point of not being able to see it when it was on the farthest leg of the square I was flying.
I believe it had been caught up in an updraught, or thermal. There had been some Mamma clouds mixed in with a stratocumulus layer gradually encroaching, which I knew meant serious vertical motion, but I had thought they were far enough away not to worry. Clearly I was wrong. Nearly got caught out, in one of those tummy turning moments when you think the precious craft will vanish. Serious reduction in height by moving the left stick well down , and the right stick to take the craft further away from the edge of what I now know to be a cold front.
A gentle warning to all about how volatile the atmosphere can be. I should have known better too I have been an amateur and professional meteorologist for fifty years. Always check the weather properly before flying. Today I didn't and nearly lost .
More can be found in these clouds here
Mammatus cloud - Wikipedia

 

[John Locke]

That's an interesting theory. It's hard to believe an updraft that strong could take your craft up so much since the craft, with no stick input, will automatically maintain elevation. The craft is capable of up to about 10mph vertically (maybe it's 11mph, not sure). However, if the barometric pressure radically changed in the flight area, that may fool the barometer in the craft to think it needs to elevate. But I find it hard to believe the barometric pressure can change that much, to take your craft out of sight with no stick input. Good story though, and now I'm wondering how this happened. Was it windy where you were?

 

[Philltayl]

That's an interesting theory. It's hard to believe an updraft that strong could take your craft up so much since the craft, with no stick input, will automatically maintain elevation. The craft is capable of up to about 10mph vertically (maybe it's 11mph, not sure). However, if the barometric pressure radically changed in the flight area, that may fool the barometer in the craft to think it needs to elevate. But I find it hard to believe the barometric pressure can change that much, to take your craft out of sight with no stick input. Good story though, and now I'm wondering how this happened. Was it windy where you were?

Yes, it can and does happen, even with large aircraft, it can override the autopilot altitude hold and cause a rapid increase in altitude.

 

[John Locke]

Yes, it can and does happen, even with large aircraft, it can override the autopilot altitude hold and cause a rapid increase in altitude.

Where are you located to have these kind of weather anomalies? Did you feel any wind where you flew from? And how far away would you estimate the craft was when this happened?

 

[Philltayl]

Where are you located to have these kind of weather anomalies? Did you feel any wind where you flew from? And how far away would you estimate the craft was when this happened?

It can happen anywhere, more so in the tropics.......VS can exceed 1000ft/min.....

 

[Meta4]

I believe it had been caught up in an updraught, or thermal.
Serious reduction in height by moving the left stick well down

You can check the flight data to confirm what was happening and see some actual numbers.
Go to https://www.phantomhelp.com/LogViewer/Upload/
Follow the instructions to upload your flight record.
Come back and post a link to share.
In active weather like you describe, the air pressure might also have been changing fast enough to make for some inaccuracy in the indicated height too perhaps?
.

 

[Bakersfield Quad]

My Piper Cherokee 180c, was dragged upward over 14,000 before getting out of an up draft only 40 miles from home, a mountain wave that could not be seen.
In a hang glider, I have ridden thermals to nearly 14,000', air is very powerful.
BQ

 

[embayweather]

The flight records were lost when the app crashed sadly. It was blowing force 4/5 to the point I was going to abandon the flight because it was getting very gusty too. It is usually windy in the beach as there is a very long fetch for the wind. I live on the NE coast of Morecambe Bay in the UK . My own weather station about 500 yards away was recording gusts up to 19 kts which means that in the coast they were well into the 20's. Higher up, I was flying around 40m AGL, they would have been worse. I did not look at the upper air charts before I left but the approaching cloud should have rung more alarm bells than it did. If you have significant downdrafts to cause the cloud formation then there has to be associates updrafts. There were some smallish Cb clouds above the Lake District further away, with one or two having anvils. Nothing very large.
All in all warnings which I should have been more aware of. Clearly I need more sleep, well something at least .

 

[rstekeur]

I could see it happen in a winged aircraft. These quads are about as aerodynamic as a rock. What holds the altitude, the GPS or barometer?

 

[Philltayl]

I could see it happen in a winged aircraft. These quads are about as aerodynamic as a rock. What holds the altitude, the GPS or barometer?

Nature can be a cruel *****....

 

[embayweather]

Various things work together to hold the altitude when the flight is powered, but when an updraught occurs the force of that updraft, thermal or similar can overcome the force of the rotors and take the craft away upstairs. Hence the reason never to fly close to a Cb. I am not sure what the FAA rule is in that but over here it is measured in miles.
For all I know above the mammatus layer could have been an embedded Cb. That's why I was so foolish to fly without checking things first.