First turbulence experience

[RFguy]

Bit of a story here....

Well today, at Cowra, YCWR I  did my morning exercises as prescribed by my instructor, EPs, one overhead. Got the hang the descent rate of that aircraft, now.  not much wind to speak of. practicing my coordination in figure-8s

Then.

Then after doing some other stuff, coffee, decided to just go for a leisurely fly @ 96K CAS (16lph), instead of 115K CAS (26 lph)  . Have a look around. loiter at 2000 AGL... 

Went down south, around a bit, very nice, then headed back north and a 35 kts headwind came up. Not to worry, no hurry. 

Back North  for 20 min to orbit Thruster88's house, like all pilots, go do orbits over your mates house until they come outside.

Hit the most horrendous turbulence over his house, Stu says it is the range nearby, I descend, not much difference, then I head east away from the mountains, no difference. worse !

 

This was the worst turbulence/ most uncomfortable feeling ever in a fixed wing aircraft - ever.  golly ! Aircraft getting bumped around every angle, pitch, yaw, roll.    I tighten my seatbelt- harness, slow down a bit (more)

I'm not worried or concerned the aircraft will break, and there is no trouble flying or keeping the aircraft in control

 

It's just damn uncomfortable. I feeling was, "I want to get on the ground out of this right now ". headed back to YCWR.

Got back into normal circuit, landed fine , I wasn't even worried about the landing difficulty, just did it ....it was a faster over the fence takeoff-flaps (stage 1) landing, wind about +30deg off the nose 15-20 kts. that's alright..  Golly what a relief.

 

But-

Imagine if I was do a job as a commercial pilot. Boss says  " go fly up to Moree and pick something up" and that's what you do. the flying is uncomfortable but not hazardous.

 

Fortunately I only had to deal with it for 25 minutes.

I'm curious though that I wasn't concerned,  but i was uncomfortable in a way I just cannot describe.

 

Have others had this experience ? My first.  

 

It was NOT like bumps and thermals and sinks, and like flying over the hot dirt in summer at 500 feet. That's different. 

 

Glen-

Edited July 31, 2021 by RFguy

[Thruster88]

I dislike turbulence especially in the RV. I will always fly high to avoid it if possible. On decent will be in the green arc and will slow down more if it is rough. 

The wind was fairly strong today, this is 6 hours later at 2500 but not much change. Can see the ranges about 10-15 nm north.

 

[turboplanner]

19 minutes ago, RFguy said:

Fortunately I only had to deal with it for 25 minutes.

I'm curious though that I wasn't concerned,  but i was uncomfortable in a way I just cannot describe.

 

Have others had this experience ? My first.  

 

It was NOT like bumps and thermals and sinks, and like flying over the hot dirt in summer at 500 feet. That's different. 

 

Glen-

Yes, and probably most of us, it's one of the downsides of travelling by light aircraft.

It's also a good example of getting some experience; puts a different view on the Students who do all their flying in the one package - PPL in 3 weeks, then off of a trip around Australia without ever having experienced a crosswind, heat sink, wind shear and your experience.

Sounds like you handled it methodically.

[TurbAero]

I can’t say that I’ve experienced this in a light aircraft yet due to my limited light aircraft experience, but as a former professional pilot, I have definitely experienced this on several occasions.  There are some you just don’t forget.

 

I was on the bunk of a Hercules between Kota Kinabalu and Penang at night that penetrated a line of thunderstorms. I thought the wings were going to get torn off.

 

In a Falcon bizjet from Luxor to Sharm el Sheikh, on descent in crystal clear skies through 13,000’ we ran into clear air turbulence for about 30 seconds that was quite frankly horrific.

 

Same again in a bizjet at Mach 0.8+ at 45,000’ over Turkey, we were in clear skies, smooth air and steady 120 knot winds about 6,000’ above the cloud tops where there were embedded CBs and we hit CAT for about 20 seconds.  It was extremely uncomfortable with positive and negative g jolting, but that set off stall warnings, stick shakers etc.  We couldn’t maintain an accurate altitude, losing about 1,000’ in the chaos of the event.  We simply had to try to maintain an attitude with the aircraft trying to roll left and right, and trying not to stall or overspeed the aircraft.  I felt very uncomfortable.

 

There are definitely times when I have been in truly severe turbulence where I was not only uncomfortable, but downright scared.  I was certainly wishing at those times that I was on the ground!

 

I agree with Turbs. It sounds like you handled it methodically.  It could have been a period of anxiety that you felt, making you feel uncomfortable.  This is a fairly natural reaction to sustained turbulence, but is a reaction that generally reduces with experience and exposure to the airborne environment.  I have certainly experienced this and I suspect that pretty well all pilots will have experienced the same at some point.  

[cscotthendry]

If it was windy (20kt+) and you were in proximity to hills, you may have experienced wake turbulence from the hills. It extends quite a ways above the height of the hills and quite a distance down wind too. As the winds get stronger, so does this type of turbulence. Be very wary of the lee side of mountains and hills in windy weather and expect turbulence there. Below the height of the hills, you can expect Rotor effects as well. Rotor can smash you into the ground and can exceed your aircraft's climb rate which can prevent you from climbing out of it.

I don't mean to frighten you, just to make you aware of where the turbulence is coming from so that you expect it if you fly in those areas in those conditions.

[RFguy]

Thanks everyone for writing their experiences.  And TurbAero- well that incident over Turkey sounds like you will never forget.

 

I can only guess there is a threshold wind speed ..... IE the production of turbulence is non linear with airspeed.

Just like other aerodynamics, IE the turbulence gets 'detached' from the area of the rough surfaces and continues. 

Some reading required to understand the precise mechanics and airspeed-severity curves and statistics.

 

I am familiar with mountain turbulence, living in Canberra and Denver .. it is a regular feature from the big mountains west of the city....and I am familiar  downwash from hills etc (spending alot of my life in a Jetranger creeping up hills in windy weather) 

 

I've flown in this region now over four seasons, with 15 kts aloft from same direction.,  but I never experienced this in the area. and th hills are not big, only 1000' max above the plains. but they are sharp and abrupt.

 

 

 

 

 

 

Edited July 31, 2021 by RFguy

[Ironpot]

The SIGMET overlay feature on the EFB is real handy and, in my experience, real accurate too.

 

Over the last few days there has been a SIGMET current for the Cowra area that was stationary  " Severe turbulence SFC to 7000" 

[Kyle Communications]

When I was trying to bet my 25hrs up on "The Girlfriend" after building her I could only go 25nm for those 25hrs. So I used to do Caboolture to Kilcoy to Caloundra in various different formats. One day it was about a 20kt south westerly and I was about 2500 ft on the leaward side of Mt Tibrogargun which is only about 1200 ft high I think..if that...I was about 5nm to the NE of the mountain and I got the shock of my life..the girlfriend was tossed around like a feather and went to 90deg several times..luckily I was under the max rough air speed of 74 kts...it frightened the crap out of me...that was rotors off the mountain and rising double bounces as it was a lot higher than the mountain so it may have been the second hop...all I know is now I am very aware of lea sides of anything on windy days...learnt my lesson hard and fast...same as my first real experience with DA...learnt that pretty quick as well...we dont have that where I normally fly but I was away for this one and the airport was a lot higher than I normally fly in but it was a stinking hot day ..thats what made the difference

 

[RFguy]

Wow Mark, that's quite a story.  Maybe my anxiety/ discomfort I felt was actual fear (from one side of my brain)  PLUS the hyper-rational side of my brain also saying "airplane wont break dont worry".

 

[Blueadventures]

On 31/07/2021 at 7:11 PM, Thruster88 said:

I dislike turbulence especially in the RV. I will always fly high to avoid it if possible. On decent will be in the green arc and will slow down more if it is rough. 

The wind was fairly strong today, this is 6 hours later at 2500 but not much change. Can see the ranges about 10-15 nm north.

 

Also, I hate NW winds with a passion, they are always shite.  Cheers.

[Old Koreelah]

On 01/08/2021 at 7:25 AM, RFguy said:

…hills are not big, only 1000' max above the plains. but they are sharp and abrupt.

As you say Glen, it’s not so much their height as the shape of the hills. I’ve met glider pilots who could ride waves up to 19,000’. Those waves were generated by the relatively low Snowy Mts and the ranges east of Warwick.

 

Yesterday I flew for an hour and was surprised by the turbulence generated by the low ridges around our flat Liverpool Plains. Sure diminishes the fun factor.

Pre-Covid when flying longer trips I liked to get up above 7,500’ into smooth air. Trouble is, getting down again thru the washing machine is damned uncomfortable, even scary at times.

 

That’s bad enough in a well-tested 24-reg aeroplane, but a home-built might require a bigger margin for error.

Luckily, we Rec. Flyers can stay home when its a bit rough.

[RFguy]

Indeed. Have been reading about what causes these eddys to detach from the surface and go off onto the plains of the western slopes, 20 nm away.

 

The fluid dynamics are the same as the small heatsinks and printed circuit components I work on at the milli-meter scale- except that the scale is bigger !

 

These are actually known as 'detached eddys', and there is a critical shear velocity to make this happen- where they let go of the local surface , I never knew this definition, I generally don't run airflow in electronics cooling to those sort of conditions....

 

I'll obsess for a week reading about geological  surfaces and production of these detached rolly pollys.

 

[Old Koreelah]

5 minutes ago, RFguy said:

Indeed. Have been reading about what causes these eddys to detach from the surface and go off onto the plains of the western slopes, 20 nm away...

Detached eddies? That’s all we need out here on the flat country!

 

As others have mentioned, the air can sneak up and smack you. At least during droughts we might get visual warning of a Willy-willy by the dust and crap they carry up.

[Steve L]

Catches you by surprise eh Mark. . . Have you ever experienced a breaking wave? Look them up. I was returning back to Gawler in the Bulldog, and from the south east we fly over a range (1900) before descending to Gawler. Wind was 40Kt and gusting, Because of lee winds I over flew the range at 4400 and increased speed a little, that’s well over double the height. . I had my hand on the control ready to reduce power for decent when in a split second I was completely inverted. I applied full power and corrected the plane, walk in the park for the Bulldog. . .  A breaking wave is a rare phenomenon which took an airliner down in Japan years ago. I have spoke to a few heavies and they assure me they are very rare, but still good to study.  I can’t recall it being in my GA training syllabus years ago. 

Edited August 2, 2021 by Steve L

[APenNameAndThatA]

13 hours ago, Kyle Communications said:

When I was trying to bet my 25hrs up on "The Girlfriend" after building her I could only go 25nm for those 25hrs. So I used to do Caboolture to Kilcoy to Caloundra in various different formats. One day it was about a 20kt south westerly and I was about 2500 ft on the leaward side of Mt Tibrogargun which is only about 1200 ft high I think..if that...I was about 5nm to the NE of the mountain and I got the shock of my life..the girlfriend was tossed around like a feather and went to 90deg several times..luckily I was under the max rough air speed of 74 kts...it frightened the crap out of me...that was rotors off the mountain and rising double bounces as it was a lot higher than the mountain so it may have been the second hop...all I know is now I am very aware of lea sides of anything on windy days...learnt my lesson hard and fast...same as my first real experience with DA...learnt that pretty quick as well...we dont have that where I normally fly but I was away for this one and the airport was a lot higher than I normally fly in but it was a stinking hot day ..thats what made the difference

 

What’s DA?

[Thruster88]

4 hours ago, APenNameAndThatA said:

What’s DA?

Density Altitude 

[Kyle Communications]

Steve

 

It certainly did...It made me very gunshy. I was a low time pilot then and it is indeliby imprinted into my brain. I am so aware of it now when winds are more than about 15kts.

 

We dont really have too much of a issue for DA where I fly but even a small altitude can make a difference in your aircrafts perfomance. I picked up a mate from a airfield west of here to go to a breakfast and it is about 2000ft AMSL so nothing you would usually worry about. But when we finally got back there to drop him off the temperature of the day had gone from about 20degC when I picked him up to about 40degC when I was landing back at his airfield....I had my aircraft drop from about 1mtr above the runway...it was an arrival...not a landing. The extra weight of the pax and the extra fuel I had on board I was probably at about 560kg. The aircraft performance was drasticaly degraded. It sort of shocked me a bit because we never usually see that as most places I fly are around sea level. So I can imagine the huge differences when these guys overseas are landing at 7 and 10 thousand feet. 

 

 

[facthunter]

Welcome to the world of 3 dimensional aircurrents.. Near the thermal equator where the intertropical convergence zone  exists takes cloud tops to over 60,000 feet and at the edge of jet streams where a 220 knot tailwind can exist.is another dangerous place. A bit more study of the earth's WEATHER will help as it's not going to get any better either. It was considered years ago that above about 18,000feet altitude put you over and above most of the troublesome stuff. but that's only the bit that''s affected by a few bit's of hot sand and the suns heat. The size of the plane doesn't make a lot of difference also when you get the big effects..Powerful updrafts or downdrafts will  affect either.. It will still take the plane with it.   AVOID crook conditions .Nev 

[Blueadventures]

22 hours ago, Kyle Communications said:

When I was trying to bet my 25hrs up on "The Girlfriend" after building her I could only go 25nm for those 25hrs. So I used to do Caboolture to Kilcoy to Caloundra in various different formats. One day it was about a 20kt south westerly and I was about 2500 ft on the leaward side of Mt Tibrogargun which is only about 1200 ft high I think..if that...I was about 5nm to the NE of the mountain and I got the shock of my life..the girlfriend was tossed around like a feather and went to 90deg several times..luckily I was under the max rough air speed of 74 kts...it frightened the crap out of me...that was rotors off the mountain and rising double bounces as it was a lot higher than the mountain so it may have been the second hop...all I know is now I am very aware of lea sides of anything on windy days...learnt my lesson hard and fast...same as my first real experience with DA...learnt that pretty quick as well...we dont have that where I normally fly but I was away for this one and the airport was a lot higher than I normally fly in but it was a stinking hot day ..thats what made the difference

 

Agree, North Westerlies up here are the lee side of numerous mountains, crap to fly in.

[RFguy]

I'm sure there are some fluid dynamics online model that use digital terrain models. (good ones- less so google earth as it is  pretty soft (low resolution on the edges) 

 

so you can get a visual picture of your region for a specific airflow

 

[Jabiru7252]

On 31/07/2021 at 6:20 PM, RFguy said:

Bit of a story here....

Well today, at Cowra, YCWR I  did my morning exercises as prescribed by my instructor, EPs, one overhead. Got the hang the descent rate of that aircraft, now.  not much wind to speak of. practicing my coordination in figure-8s

Then.

Then after doing some other stuff, coffee, decided to just go for a leisurely fly @ 96K CAS (16lph), instead of 115K CAS (26 lph)  . Have a look around. loiter at 2000 AGL... 

Went down south, around a bit, very nice, then headed back north and a 35 kts headwind came up. Not to worry, no hurry. 

Back North  for 20 min to orbit Thruster88's house, like all pilots, go do orbits over your mates house until they come outside.

Hit the most horrendous turbulence over his house, Stu says it is the range nearby, I descend, not much difference, then I head east away from the mountains, no difference. worse !

 

This was the worst turbulence/ most uncomfortable feeling ever in a fixed wing aircraft - ever.  golly ! Aircraft getting bumped around every angle, pitch, yaw, roll.    I tighten my seatbelt- harness, slow down a bit (more)

I'm not worried or concerned the aircraft will break, and there is no trouble flying or keeping the aircraft in control

 

It's just damn uncomfortable. I feeling was, "I want to get on the ground out of this right now ". headed back to YCWR.

Got back into normal circuit, landed fine , I wasn't even worried about the landing difficulty, just did it ....it was a faster over the fence takeoff-flaps (stage 1) landing, wind about +30deg off the nose 15-20 kts. that's alright..  Golly what a relief.

 

But-

Imagine if I was do a job as a commercial pilot. Boss says  " go fly up to Moree and pick something up" and that's what you do. the flying is uncomfortable but not hazardous.

 

Fortunately I only had to deal with it for 25 minutes.

I'm curious though that I wasn't concerned,  but i was uncomfortable in a way I just cannot describe.

 

Have others had this experience ? My first.  

 

It was NOT like bumps and thermals and sinks, and like flying over the hot dirt in summer at 500 feet. That's different. 

 

Glen-

I used to fly the TB10 Tobago in 35° temperatures and 30 knot winds, rough as guts but tolerable. I could never get used to strong turbulence in my Jabiru. I took off one day in gusty hot winds and 30°C. It was dreadful. Rolling 30° or more but really violently and the 'pot holes' were so bad I was sure the wings were going to come off. The water bottle on the passenger seat disappeared down the back of the plane somewhere and the video camera came off its mount. Landing was just as bad, I remember seeing the wing tip about one foot off the runway while floating along as Jabs do. I'll never fly in hot gusty conditions in my Jab again. Flying is meant to be enjoyed. Only glider pilots like that sort of 'thermal activity'.

[turboplanner]

18 hours ago, Jabiru7252 said:

I used to fly the TB10 Tobago in 35° temperatures and 30 knot winds, rough as guts but tolerable. I could never get used to strong turbulence in my Jabiru. I took off one day in gusty hot winds and 30°C. It was dreadful. Rolling 30° or more but really violently and the 'pot holes' were so bad I was sure the wings were going to come off. The water bottle on the passenger seat disappeared down the back of the plane somewhere and the video camera came off its mount. Landing was just as bad, I remember seeing the wing tip about one foot off the runway while floating along as Jabs do. I'll never fly in hot gusty conditions in my Jab again. Flying is meant to be enjoyed. Only glider pilots like that sort of 'thermal activity'.

The history of the J170 is interesting. The model before it was the J160 which I felt flew very well (Victoria south coast), much like a GA aircraft, but apparently there were complaints of slow climb speed in the northern, hotter parts of Australia, so a much more effective, and longer, wing was put on the existing fuselage, which worked for those northern customers very well. However, in the much colder more compressed air there was too much lift and the short fuselage/tail fin/rudder was no match for the increased yaw drag of gusty winds. For some reason my instructors insisted we come in with crossed controls, so in a stiff onshore wind you were often out of rudder authorit and a gust would spin you round, so some very novel corrective action was needed. Jabiru fixed it with a retro kit, but it wouldn't surprise me if what you experience originates in those very high efficiency wings.

[RFguy]

Right on Turbs. 100%. 
after the initial J170C ventral fin kit which solved the directional authority in landings, the D version went with a bigger tail  ,  different thrust offset, and moved the engine forward a little to improve load carrying CG.

 

Still, I think these are super and safe  and forgiving airframes. Up there with best in industry. Very happy with my J230. 

 

 

[MattP]

I’ve only had two experiences where I was genuinely scared or just plain wanted off this ride now. 
 

One was in a c172 many years ago starting my ppl and coming out of Essendon. I got caught in a decent wind shear just after takeoff combined with the usual mechanical garbage coming off the buildings taking off on 17. The thing dropped and rolled and by the time I figured out wtf just happened i was rolling left and sinking with full power on, it was terrifying especially with my massive few hours of experience at the time. Never been more thankful for an instructor next to me. Decided to just turn right back and go home. Took a while for me to get any form of confidence back.

 

Second was as a paxing over the pacific during the night, over the itcz and we hit turbulence the likes of which I’ve never experienced and then it was over. We didn’t divert so it can’t have been that bad but it sure felt it.

 

I am not a huge fan of turbulence but will be more confident in bumps in heavier ga than stuff with numbers on the side as the lighter wing loading makes them more prone to upsets in rough air. I do slow down though, which I’m amazed many people don’t, especially when you see the difference in many raa types between manoeuvring speed and the published cruise speeds.
 

I also scrub when it’s just not fun or if I have a non pilot passenger and it’s not going to be great as one of the luxuries we have as recreational pilots is saying nope. No point in subjecting others to a ride in a washing machine and contributing to the little aeroplane phobia many people have.

 

Doing things like flying in the morning or summer evenings / nights can be better than trying to slog into a 30kt northerly on a hot day!

[kiwiaviator]

I reckon you found some sort of rotor Glen. Back in the lower North island of NZ where I fly (when I'm allowed home) the mountain wave off the Tararua Ranges often forms multiple rotor 'fronts' out to 30 miles. The secondary 'fronts' often can't been seen and have seen me in unintended aerobatic attitudes at times. On the positive side, I have rode the wave at times which can be fun. Its why the gliding altitude world record was set in 1968 in that area by the recently deceased Doug Yarrell https://www.stuff.co.nz/sport/other-sports/102076811/glider-record-still-soars-50-years-later