Flew into a wave rotor today

B

Brian Z

Well-Known Member
I took some friends up today and had a fun time flying through a mountain wave rotor just west of BJC. It is the unexpected that gets you. The air was nice and stable for the flight. There was a little haze and all the close airports were reporting six knots or less. The ceiling was 18000 or so. A front is supposed to pass later today and I could see the lenticulars forming up in the high teens to the north so I knew the winds were coming, but I was not concernend becuase of the local conditions.

I was flying north at 7500 about six miles west of BJC all fat, dumb and happy showing my out of town friends the sites. It was nice and smooth then I feel a slight bump and an uncommanded 15* roll to the right. I thought it must be some bumps from the front range ridge about six miles to the west. All of a sudden I feel a good push from the bottom with another right uncommanded roll. As it is getting stronger I look at the VS tape and it is at +1250 FPM and increasing. The max climb I saw was 1700 FPM. At that point I did not know what I was in, but I knew I did not want to stay there. I reduced the MP to 12" to start slowing to Va. About the time I got every thing set up and stable(everything is relative) to ride it out there were a few good moderate bumps and more rolls to the right. Then I get into the downward side of the rotor. That was much the same as the upward side except that the VS was opposite. The most I saw was a -1400 on the VS tape. Then as quick as it started it ended with a slight bump and we were all smooth again.

All in all it lasted around 15-20 seconds. The highest altitude I saw was 8100 while the lowest was 7400 once I stopped the downward momentum after exiting the rotor. For some reason I do not remember looking at the airspeed. The only control inputs I did was reducing the throttle and holding a level attitude. At no point did I feel I lost control of the attitude of the aircraft. Now I know that rotors are not a mid to high altitude phenomenon. I was around 1800 AGL when this happened.

Brian
 
Brian Z said:
I took some friends up today and had a fun time flying through a mountain wave rotor just west of BJC. It is the unexpected that gets you. The air was nice and stable for the flight. There was a little haze and all the close airports were reporting six knots or less. The ceiling was 18000 or so. A front is supposed to pass later today and I could see the lenticulars forming up in the high teens to the north so I knew the winds were coming, but I was not concernend becuase of the local conditions.

I was flying north at 7500 about six miles west of BJC all fat, dumb and happy showing my out of town friends the sites. It was nice and smooth then I feel a slight bump and an uncommanded 15* roll to the right. I thought it must be some bumps from the front range ridge about six miles to the west. All of a sudden I feel a good push from the bottom with another right uncommanded roll. As it is getting stronger I look at the VS tape and it is at +1250 FPM and increasing. The max climb I saw was 1700 FPM. At that point I did not know what I was in, but I knew I did not want to stay there. I reduced the MP to 12" to start slowing to Va. About the time I got every thing set up and stable(everything is relative) to ride it out there were a few good moderate bumps and more rolls to the right. Then I get into the downward side of the rotor. That was much the same as the upward side except that the VS was opposite. The most I saw was a -1400 on the VS tape. Then as quick as it started it ended with a slight bump and we were all smooth again.

All in all it lasted around 15-20 seconds. The highest altitude I saw was 8100 while the lowest was 7400 once I stopped the downward momentum after exiting the rotor. For some reason I do not remember looking at the airspeed. The only control inputs I did was reducing the throttle and holding a level attitude. At no point did I feel I lost control of the attitude of the aircraft. Now I know that rotors are not a mid to high altitude phenomenon. I was around 1800 AGL when this happened.

Brian
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Awesome post. Thank your from a flatlander down south.

Cordially,

b.
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Good times! Thanks for the share, I have certainly had some of my scariest/weirdest flying moments in and out of BJC. The Front Range never lets down for weather strangeness :)
 
From down here in COS, we have had quite a few days this past week where the waves were very obvious, espically South towards NM. I read somewhere that the state altitude record for a glider was something like FL450, riding one of these. They look really cool, maybe it's inexperience, but they scare the heck out of me! Cool story! BJC is a great airport, got my PPL there last year.
 
The wave that sets up along the front range is pretty amazing huh.

I fly gliders out of Boulder (and power out of BJC) and spend as much time up in the wave as I can.

Surfing the wave in a glider is an incredible experience. On a good day the updrafts will have you climbing at 2000 fpm+ with a straight and level attitude. In the glider we "surf" the updrafts and then approaching 18k feet plow through the downdraft, lose altitude, then fly back into the next updraft deeper in the mountains...and repeat. If I convert the lift into speed, I can cruise back and forth all along the front range at 120+ kts. You can stay up all day if you want. Its the cheapest flight time you will ever get! I have actually had days where I struggled to keep the glider below FL180 and was flying along with the airbrakes out. Of course I have had plenty of days where the wave I was expecting was nonexistent and I was back on the ground in 30-45 mins.

There is actually an area of airspace near boulder that is designated as a glider "wave window". We can get permission from ATC to climb as high as we want when the window is active and we are cleared into it. Many pilots from my club have surfed the wave well above 30k feet. The state record is 44k feet.

The cool thing is that you can do this to a degree in a cessna too (or any plane more or less). You will not get the same climb rates and glide ratio of course, but one could easily climb above the normal service ceiling of a cessna in the strongest part of the wave. You can actually use the wave to get over passes the cessna could not get over normally. (not that I recommend it without training of course...)

There is some wave information on our clubs web page if you are interested (the site is a bit out dated but still has some good info):

http://soarboulder.org/new_site/ssb_page.htm
 
Mateo303 said:
The wave that sets up along the front range is pretty amazing huh.

I fly gliders out of Boulder (and power out of BJC) and spend as much time up in the wave as I can.

Surfing the wave in a glider is an incredible experience. On a good day the updrafts will have you climbing at 2000 fpm+ with a straight and level attitude. In the glider we "surf" the updrafts and then approaching 18k feet plow through the downdraft, lose altitude, then fly back into the next updraft deeper in the mountains...and repeat. If I convert the lift into speed, I can cruise back and forth all along the front range at 120+ kts. You can stay up all day if you want. Its the cheapest flight time you will ever get! I have actually had days where I struggled to keep the glider below FL180 and was flying along with the airbrakes out. Of course I have had plenty of days where the wave I was expecting was nonexistent and I was back on the ground in 30-45 mins.

There is actually an area of airspace near boulder that is designated as a glider "wave window". We can get permission from ATC to climb as high as we want when the window is active and we are cleared into it. Many pilots from my club have surfed the wave well above 30k feet. The state record is 44k feet.

The cool thing is that you can do this to a degree in a cessna too (or any plane more or less). You will not get the same climb rates and glide ratio of course, but one could easily climb above the normal service ceiling of a cessna in the strongest part of the wave. You can actually use the wave to get over passes the cessna could not get over normally. (not that I recommend it without training of course...)

There is some wave information on our clubs web page if you are interested (the site is a bit out dated but still has some good info):

http://soarboulder.org/new_site/ssb_page.htm
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:yeahthat:

Wave soaring is awesome once you establish a normal breathing rate after you tow through the rotor. :laff:
 
Mateo303 said:
The wave that sets up along the front range is pretty amazing huh.

I fly gliders out of Boulder (and power out of BJC) and spend as much time up in the wave as I can.

Surfing the wave in a glider is an incredible experience. On a good day the updrafts will have you climbing at 2000 fpm+ with a straight and level attitude. In the glider we "surf" the updrafts and then approaching 18k feet plow through the downdraft, lose altitude, then fly back into the next updraft deeper in the mountains...and repeat. If I convert the lift into speed, I can cruise back and forth all along the front range at 120+ kts. You can stay up all day if you want. Its the cheapest flight time you will ever get! I have actually had days where I struggled to keep the glider below FL180 and was flying along with the airbrakes out. Of course I have had plenty of days where the wave I was expecting was nonexistent and I was back on the ground in 30-45 mins.

There is actually an area of airspace near boulder that is designated as a glider "wave window". We can get permission from ATC to climb as high as we want when the window is active and we are cleared into it. Many pilots from my club have surfed the wave well above 30k feet. The state record is 44k feet.

The cool thing is that you can do this to a degree in a cessna too (or any plane more or less). You will not get the same climb rates and glide ratio of course, but one could easily climb above the normal service ceiling of a cessna in the strongest part of the wave. You can actually use the wave to get over passes the cessna could not get over normally. (not that I recommend it without training of course...)

There is some wave information on our clubs web page if you are interested (the site is a bit out dated but still has some good info):

http://soarboulder.org/new_site/ssb_page.htm
Click to expand...
Is that how the Japanese guy got his glider so danged high and collided with the FalconJet a few years ago?
 
texas_pilot said:
Is that how the Japanese guy got his glider so danged high and collided with the FalconJet a few years ago?
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I think so... I believe he was in wave in Nevada. Another popular place for wave soaring.

Thats actually my biggest concern when in a glider. Not all of our club ships have a transponder, gliders are hard to see, we push right up to the limits of VFR cloud clearances, and people just do not expect you to be up there, especially at high altitudes.

Several in our club have had close calls with large aircraft. Last summer a guy in our club almost ended up as a hood ornament for a C-130.

There is some talk that transponders may become mandatory which I personally think would be a good idea. I know I fly the ships with transponders whenever possible.

Just remember, any time you see rotors in the mountains there is a decent chance there is a glider hanging out on the updraft side. On days with big cumulus clouds with nice flat bottoms, there is a good chance there is a glider somewhere underneath. Lastly, keep in mind that many areas popular for soaring are class G which means there may be a glider literally right at cloud base or right next to the rotor since all they have to do is remain clear and that's it!
 
Wow great story. I bet your pax weren't thrilled though. :D

Mateo303 said:
I think so... I believe he was in wave in Nevada. Another popular place for wave soaring.

Thats actually my biggest concern when in a glider. Not all of our club ships have a transponder, gliders are hard to see, we push right up to the limits of VFR cloud clearances, and people just do not expect you to be up there, especially at high altitudes.

Several in our club have had close calls with large aircraft. Last summer a guy in our club almost ended up as a hood ornament for a C-130.

There is some talk that transponders may become mandatory which I personally think would be a good idea. I know I fly the ships with transponders whenever possible.

Just remember, any time you see rotors in the mountains there is a decent chance there is a glider hanging out on the updraft side. On days with big cumulus clouds with nice flat bottoms, there is a good chance there is a glider somewhere underneath. Lastly, keep in mind that many areas popular for soaring are class G which means there may be a glider literally right at cloud base or right next to the rotor since all they have to do is remain clear and that's it!
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No transponders for gliders? Aren't mode C transponders required above 10k or is there an exemption for gliders?
 
juxtapilot said:
No transponders for gliders? Aren't mode C transponders required above 10k or is there an exemption for gliders?
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We fly well inside the mode C veil at KZPH, no transponders. Above 6,000, that puts you right in the middle of the LZARD FOUR arrival.

There is also jump zone that has 72 bodies falling from 13,500 every 10 minutes. No xpdr's on them either. Amazing that an aircraft doesn't hit someone more often.

Anyway, gliders get an exemption IF they were originally certificated without an electrical system. 91.125 paragraph 3.
 
I've never really thought about a hitting a wave rotor on my trip through Cheyenne, WY.

Made a stop in Lamar, CO with a plane that I was to deliver to Thermopolis, WY. Listened to the AWOS along the route and it stated moderate turbulence. As I was flying north from Lamar the weather was great and chilly with no major turbulence.

Then as I flew threw this invisible wall the airplane began to sway left and right, and then BOOM! What airliners conceive as moderate turbulence was severe turbulence for me. The airplane was shaking so bad, I let go of the controls and let it fly itself. There were no control inputs that made life easier because of the turbulence. I swore that either the wings were going to fall off or the control linkages were going to break.

Then as I got over Cheyenne airport, I got a gust of wind that pushed me from 7,500' to over 10,000'. Above 10K, the air smoothed out completely and I was happy until I looked at my ground speed. The speed was around 45 knots, going nowhere fast.

Checked my fuel and thought I could have made it further but looked ahead and I couldn't see through the misty and foggy air. Not really sure what I was looking through or what was ahead.

So I decided to land and refuel in Cheyenne. At the moment I was over the airport above 10K. When the tower told me to turn downwind, almost in less than a minute I was 5 miles from the airport. The tower asked where was I, I told them a 5 mile final. Then I had to remember that going below 10K the weather was REALLY bumpy, so the landing was not perfect.

Saying all this, I guess that was a wave rotor that pushed me that high in the sky. Come to find out later that night, Wyoming had a winter wind advisory that week that sucked!
 
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